Optical coupling of bare optoelectronic components and flexographically printed polymer waveguides in planar optronic systems

NASA Astrophysics Data System (ADS)

Wang, Yixiao; Wolfer, Tim; Lange, Alex; Overmeyer, Ludger

2016-05-01

Large scale, planar optronic systems allowing spatially distributed functionalities can be well used in diverse sensor networks, such as for monitoring the environment by measuring various physical quantities in medicine or aeronautics. In these systems, mechanically flexible and optically transparent polymeric foils, e.g. polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET), are employed as carrier materials. A benefit of using these materials is their low cost. The optical interconnections from light sources to light transmission structures in planar optronic systems occupy a pivotal position for the sensing functions. As light sources, we employ the optoelectronic components, such as edgeemitting laser diodes, in form of bare chips, since their extremely small structures facilitate a high integration compactness and ensure sufficient system flexibility. Flexographically printed polymer optical waveguides are deployed as light guiding structures for short-distance communication in planar optronic systems. Printing processes are utilized for this generation of waveguides to achieve a cost-efficient large scale and high-throughput production. In order to attain a high-functional optronic system for sensing applications, one of the most essential prerequisites is the high coupling efficiency between the light sources and the waveguides. Therefore, in this work, we focus on the multimode polymer waveguide with a parabolic cross-section and investigate its optical coupling with the bare laser diode. We establish the geometrical model of the alignment based on the previous works on the optodic bonding of bare laser diodes and the fabrication process of polymer waveguides with consideration of various parameters, such as the beam profile of the laser diode, the employed polymer properties of the waveguides as well as the carrier substrates etc. Accordingly, the optical coupling of the bare laser diodes and the polymer waveguides was simulated. Additionally, we demonstrate optical links by adopting the aforementioned processes used for defining the simulation. We verify the feasibility of the developed processes for planar optronic systems by using an active alignment and conduct discussions for further improvements of optical alignment.

Heterogeneous integration of thin film compound semiconductor lasers and SU8 waveguides on SiO2/Si

NASA Astrophysics Data System (ADS)

Palit, Sabarni; Kirch, Jeremy; Mawst, Luke; Kuech, Thomas; Jokerst, Nan Marie

2010-02-01

We present the heterogeneous integration of a 3.8 μm thick InGaAs/GaAs edge emitting laser that was metal-metal bonded to SiO2/Si and end-fire coupled into a 2.8 μm thick tapered SU8 polymer waveguide integrated on the same substrate. The system was driven in pulsed mode and the waveguide output was captured on an IR imaging array to characterize the mode. The waveguide output was also coupled into a multimode fiber, and into an optical head and spectrum analyzer, indicating lasing at ~997 nm and a threshold current density of 250 A/cm2.

Demonstration of an optical phased array using electro-optic polymer phase shifters

NASA Astrophysics Data System (ADS)

Hirano, Yoshikuni; Motoyama, Yasushi; Tanaka, Katsu; Machida, Kenji; Yamada, Toshiki; Otomo, Akira; Kikuchi, Hiroshi

2018-03-01

We have been investigating an optical phased array (OPA) using electro-optic (EO) polymers in phase shifters to achieve ultrafast optical beam steering. In this paper, we describe the basic structures of the OPA using EO polymer phase shifters and show the beam steering capability of the OPA. The designed OPA has a multimode interference (MMI) beam splitter and 8-channel polymer waveguides with EO polymer phase shifters. We compare 1 × 8 MMI and cascaded 1 × 2 MMI beam splitters numerically and experimentally, and then obtain uniform intensity outputs from the 1 × 8 beam splitter. We fabricate the EO polymer OPA with a 1 × 8 MMI beam splitter to prevent intensity dispersion due to radiation loss in bending waveguides. We also evaluate the optical beam steering capability of the fabricated OPA and found a 2.7° deflection of far-field patterns when applying a voltage difference of 25 V in adjacent phase shifters.

Multimode Directional Coupler

NASA Technical Reports Server (NTRS)

Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor)

2016-01-01

A multimode directional coupler is provided. In some embodiments, the multimode directional coupler is configured to receive a primary signal and a secondary signal at a first port of a primary waveguide. The primary signal is configured to propagate through the primary waveguide and be outputted at a second port of the primary waveguide. The multimode directional coupler also includes a secondary waveguide configured to couple the secondary signal from the primary waveguide with no coupling of the primary signal into the secondary waveguide. The secondary signal is configured to propagate through the secondary waveguide and be outputted from a port of the secondary waveguide.

Electro-optical line cards with multimode polymer waveguides for chip-to-chip interconnects

NASA Astrophysics Data System (ADS)

Zhu, Long Xiu; Immonen, Marika; Wu, Jinhua; Yan, Hui Juan; Shi, Ruizhi; Chen, Peifeng; Rapala-Virtanen, Tarja

2014-10-01

In this paper, we report developments of electro-optical PCBs (EO-PCB) with low-loss (<0.05dB/cm) polymer waveguides. Our results shows successful fabrication of complex waveguide structures part of hybrid EO-PCBs utilizing production scale process on standard board panels. Test patterns include 90° bends of varying radii (40mm - 2mm), waveguide crossing with varied crossing angles (90°-20°), cascaded bends with varying radii, splitters and tapered waveguides. Full ranges of geometric configurations are required to meet practical optical routing functions and layouts. Moreover, we report results obtained to realize structures to integrate optical connectors with waveguides. Experimental results are shown for MT in-plane and 90° out-of-plane optical connectors realized with coupling loss < 2dB and < 2.5 dB, respectively. These connectors are crucial to realize efficient light coupling from/to TX/RX chip-to-waveguide and within waveguide-to-fiber connections in practical optical PCBs. Furthermore, we show results for fabricating electrical interconnect structures e.g. tracing layers, vias, plated vias top/bottom and through optical layers. Process compatibility with accepted practices and production scale up for high volumes are key concerns to meet the yield target and cost efficiency. Results include waveguide characterization, transmission loss, misalignment tolerance, and effect of lamination. Critical link metrics are reported.

Development of a technology for fabricating low-cost parallel optical interconnects

NASA Astrophysics Data System (ADS)

Van Steenberge, Geert; Hendrickx, Nina; Geerinck, Peter; Bosman, Erwin; Van Put, Steven; Van Daele, Peter

2006-04-01

We present a fabrication technology for integrating polymer waveguides and 45° micromirror couplers into standard electrical printed circuit boards (PCBs). The most critical point that is being addressed is the low-cost manufacturing and the compatibility with current PCB production. The latter refers to the processes as well as material compatibility. In the fist part the waveguide fabrication technology is discussed, both photo lithography and laser ablation are proposed. It is shown that a frequency tripled Nd-YAG laser (355 nm) offers a lot of potential for defining single mode interconnections. Emphasis is on multimode waveguides, defined by KrF excimer laser (248 nm) ablation using acrylate polymers. The first conclusion out of loss spectrum measurements is a 'yellowing effect' of laser ablated waveguides, leading to an increased loss at shorter wavelengths. The second important conclusion is a potential low loss at a wavelength of 850 nm, 980 nm and 1310 nm. This is verified at 850 nm by cut-back measurements on 10-cm-long waveguides showing an average propagation loss of 0.13 dB/cm. Photo lithographically defined waveguides using inorganic-organic hybrid polymers show an attenuation loss of 0.15 dB/cm at 850 nm. The generation of debris and the presence of microstructures are two main concerns for KrF excimer laser ablation of hybrid polymers. In the second part a process for embedding metal coated 45° micromirrors in optical waveguiding layers is described. Mirrors are selectively metallized using a lift-off process. Filling up the angled via without the presence of air bubbles and providing a flat surface above the mirror is only possible by enhancing the cladding deposition process with ultrasound agitation. Initial loss measurements indicate an excess mirror loss of 1.5 dB.

Polymer waveguide based hybrid opto-electric integration technology

NASA Astrophysics Data System (ADS)

Mao, Jinbin; Deng, Lingling; Jiang, Xiyan; Ren, Rong; Zhai, Yumeng; Wang, Jin

2014-10-01

While monolithic integration especially based on InP appears to be quite an expensive solution for optical devices, hybrid integration solutions using cheaper material platforms are considered powerful competitors because of the high freedom of design, yield optimization and relative cost-efficiency. Among them, the polymer planar-lightwave circuit (PLC) technology is regarded attractive as polymer offers the potential of fairly simple and low-cost fabrication, and of low-cost packaging. In our work, polymer PLC was fabricated by using the standard reactive ion etching (RIE) technique, while other active and passive devices can be integrated on the polymer PLC platform. Exemplary polymer waveguide devices was a 13-channel arrayed waveguide grating (AWG) chip, where the central channel cross-talk was below -30dB and the polarization dependent frequency shift was mitigated by inserting a half wave plate. An optical 900 hybrid was also realized with one 2×4 multi-mode interferometer (MMI). The excess insertion losses are below 4dB for the C-band, while the transmission imbalance is below 1.2dB. When such an optical hybrid was integrated vertically with mesa-type photodiodes, the responsivity of the individual PD was around 0.06 A/W, while the 3 dB bandwidth reaches 24 ~ 27 GHz, which is sufficient for 100Gbit/s receivers. Another example of the hybrid integration was to couple the polymer waveguides to fiber by applying fiber grooves, whose typical loss value was 0.2 dB per-facet over a broad spectral range from 1200-1600 nm.

Organic-inorganic hybrid material SUNCONNECT® for photonic integrated circuit

NASA Astrophysics Data System (ADS)

Nawata, Hideyuki; Oshima, Juro; Kashino, Tsubasa

2018-02-01

In this paper, we report the feature and properties about organic-inorganic hybrid material, "SUNCONNECT®" for photonic integrated circuit. "SUNCONNECT®" materials have low propagation loss at 1310nm (0.29dB/cm) and 1550nm (0.45dB/cm) respectively. In addition, the material has high thermal resistance both high temperature annealing test at 300°C and also 260°C solder heat resistance test. For actual device application, high reliability is required. 85°C /85% test was examined by using multi-mode waveguide. As a result, it indicated that variation of insertion loss property was not changed significantly after high temperature / high humidity test. For the application to photonic integrated circuit, it was demonstrated to fabricate polymer optical waveguide by using three different methods. Single-micron core pattern can be fabricated on cladding layer by using UV lithography with proximity gap exposure. Also, single-mode waveguide can be also fabricated with over cladding. On the other hands, "Mosquito method" and imprint method can be applied to fabricate polymer optical waveguide. Remarkably, these two methods can fabricate gradedindex type optical waveguide without using photo mask. In order to evaluate the optical performance, NFP's observation, measurement of insertion loss and propagation loss by cut-back methods were carried out by using each waveguide sample.

Integrated optical components in thin films of polymers

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey; Abdeldayem, Hossin; Venkateswarlu, Putcha; Teague, Zedric

1995-01-01

The results will be reported on the study of integrated optical components based on nonlinear optical polymeric films. Polymers poly(methyl methacrylate) (PMMA) and polyimide (PI) doped with organic laser dyes 4-dicyanomethylene-2-methyl-6-p dimethylaminostyryl-4H pyran (DCM) and 1, 3, 5, 7, 8 - pentamethyl-2,6 -diethyl-pyrromethene -BF2-complex (Pyrommethene 567, PM-567) were selected as materials for light guiding films. Additionally, UV polymerized polydiacetylene (PDA) on glass substrate was used as a waveguide material. Optical waveguides were fabricated using spin coating of preoxidized silicon wafers (1.5 micrometer silicon oxide layer) with organic dye/polymer solution followed by soft baking. the modes in slab waveguides were studied using prism coupling techniques. Measured values of mode coupling angles in multimode waveguides were used to calculate film thickness and refractive index for different polarizations. Refractive index anisotropy was found in PDA waveguide. The optimal conditions of spin coating for single mode waveguide fabrication were estimated. Propagation losses were measured by collecting the light scattered from the trace of a propagating mode either by scanning photo detector or by CCD camera. Different types of light coupling techniques were used including end-dire coupling, prism and grating coupling. Mechanical printing technique was developed for coupling grating fabrication resulting in gratings with 4% diffraction efficiency. The gratings demonstrated good stability with diffraction efficiency relaxation rate 2.4 dB/hour at a temperature approximately 15-20 C below glass transition point. Dye doped waveguides were transversally pumped with frequency doubled Nd:YAG Q-switched laser producing intensive light emission with apparent 6 kW/sq cm pump threshold and spectrum narrowing near 617 nm peak in the case of DCM doped waveguide. PM-567 doped waveguide pumped with CW Ar(+) laser (514 nm wavelength) far below threshold (0.1 W/sq.cm pump power) demonstrated emission spectrum narrowing near 616 nm peak with 18% power conversion slope efficiency. In this case emission spectrum modification was caused by the enhanced light absorption along the direction of propagating waveguide modes. Changing length, thickness, and other morphlogical waveguide parameters one can modify emission spectrum in predictable direction. The results show that polymeric waveguides, especially based on high temperature polymers such as Pl, can be used to produce a varietiy of active and passive silicon compatible integrated optical components for aerospace applications.

Raman, mid-infrared, near-infrared and ultraviolet-visible spectroscopy of PDMS silicone rubber for characterization of polymer optical waveguide materials

NASA Astrophysics Data System (ADS)

Cai, Dengke; Neyer, Andreas; Kuckuk, Rüdiger; Heise, H. Michael

2010-07-01

Special siloxane polymers have been produced via an addition reaction from commercially available two-component addition materials by thermal curing. Polydimethylsiloxane (PDMS) based polymers have already been used in the optical communication field, where passive polymer multimode waveguides are required for short-distance datacom optical applications. For such purpose, materials with low intrinsic absorption losses within the spectral region of 600-900 nm wavelengths are essential. For vibrational absorption band assignments, especially in the visible and short-wave near-infrared region, the mid-infrared and Raman spectra were investigated for fundamental vibrations of the siloxane materials, shedding light onto the chemistry before and after material polymerization. Within the near-infrared and long-wave visible spectral range, vibrational C sbnd H stretching overtone and combination bands dominate the spectra, rendering an optical characterization of core and clad materials. Such knowledge also provides information for the synthesis and optical characterization, e.g., of deuterated derivatives with less intrinsic absorption losses from molecular vibrations compared to the siloxane materials studied.

Advanced Optical Fibers for High power Fiber lasers

DTIC Science & Technology

2015-08-24

crystal fiber cladding . Advanced Optical Fibers for High Power Fiber Lasers http://dx.doi.org/10.5772/58958 223 lengths above the second-order mode cut...brightness multimode diode lasers for a given pump waveguide dimen‐ sion. In conventional double- clad fibers, low-index polymer coatings are typically used to...was below 0.2. The fiber was passive and there was no laser demonstration in this first attempt. The first cladding - pumping demonstration in an

Optical clock distribution in supercomputers using polyimide-based waveguides

NASA Astrophysics Data System (ADS)

Bihari, Bipin; Gan, Jianhua; Wu, Linghui; Liu, Yujie; Tang, Suning; Chen, Ray T.

1999-04-01

Guided-wave optics is a promising way to deliver high-speed clock-signal in supercomputer with minimized clock-skew. Si- CMOS compatible polymer-based waveguides for optoelectronic interconnects and packaging have been fabricated and characterized. A 1-to-48 fanout optoelectronic interconnection layer (OIL) structure based on Ultradel 9120/9020 for the high-speed massive clock signal distribution for a Cray T-90 supercomputer board has been constructed. The OIL employs multimode polymeric channel waveguides in conjunction with surface-normal waveguide output coupler and 1-to-2 splitters. Surface-normal couplers can couple the optical clock signals into and out from the H-tree polyimide waveguides surface-normally, which facilitates the integration of photodetectors to convert optical-signal to electrical-signal. A 45-degree surface- normal couplers has been integrated at each output end. The measured output coupling efficiency is nearly 100 percent. The output profile from 45-degree surface-normal coupler were calculated using Fresnel approximation. the theoretical result is in good agreement with experimental result. A total insertion loss of 7.98 dB at 850 nm was measured experimentally.

Roughness measurements on coupling structures for optical interconnections integrated on a printed circuit board

NASA Astrophysics Data System (ADS)

Hendrickx, Nina; Van Erps, Jürgen; Suyal, Himanshu; Taghizadeh, Mohammad; Thienpont, Hugo; Van Daele, Peter

2006-04-01

In this paper, laser ablation (at UGent), deep proton writing (at VUB) and laser direct writing (at HWU) are presented as versatile technologies that can be used for the fabrication of coupling structures for optical interconnections integrated on a printed circuit board (PCB). The optical layer, a highly cross-linked acrylate based polymer, is applied on an FR4 substrate. Both laser ablation and laser direct writing are used for the definition of arrays of multimode optical waveguides, which guide the light in the plane of the optical layer. In order to couple light vertically in/out of the plane of the optical waveguides, coupling structures have to be integrated into the optical layer. Out-of-plane turning mirrors, that deflect the light beam over 90°, are used for this purpose. The surface roughness and angle of three mirror configurations are evaluated: a laser ablated one that is integrated into the optical waveguide, a laser direct written one that is also directly written onto the waveguide and a DPW insert that is plugged into a cavity into the waveguiding layer.

Analysis of a single ring resonator with 2×2 90-degree multimode waveguide turning couplers

NASA Astrophysics Data System (ADS)

Chiu, C. L.; Liao, Yen-Hsun

2016-02-01

A novel design of a single ring resonator with two low-loss 2×2 90-degree multimode waveguide turning mirror couplers based on a InP structure. The coupling factor of the 2×2 90-degree multimode waveguide turning mirror coupler is inversed for K=0.85 to K=0.15 when one folding is achieved. The 2×2 90-degree turning mirror coupler for K=0.15 is (3/4)Lπ in length. Its length is reduced 3 times than the conventional straight 2×2 multimode waveguide interference coupler (9/4)Lπ in length for K=0.15. The cavity length of the curve waveguide (90-degree arc length) in this ring resonator with two 2×2 90-degree multimode waveguide turning couplers is decreased 1/2 times than with two 2×2 MMI couplers (180-degree arc length). The free spectral range (FSR) is increased 2 times. The output spectral response gets a FSR of 82 GHz for the device and a contrast of 4 dB and FWHM of 0.24 nm for the drop port. The results of numerical analysis calculated by the transfer functions in a single ring resonator are agreement with the experimental results.

Enhancement and inhibition of light tunneling mediated by resonant mode conversion.

PubMed

Kartashov, Yaroslav V; Vysloukh, Victor A; Torner, Lluis

2014-02-15

We show that the rate at which light tunnels between neighboring multimode waveguides can be drastically increased or reduced by the presence of small longitudinal periodic modulations of the waveguide properties that stimulate resonant conversion between the eigenmodes of each waveguide. Such a conversion, available only in multimode guiding structures, leads to periodic power transfer into higher-order modes, whose tails may considerably overlap with neighboring waveguides. As a result, the effective coupling constant for neighboring waveguides may change by several orders of magnitude upon small variations in the longitudinal modulation parameters.

Optimization of an integrated wavelength monitor device

NASA Astrophysics Data System (ADS)

Wang, Pengfei; Brambilla, Gilberto; Semenova, Yuliya; Wu, Qiang; Farrell, Gerald

2011-05-01

In this paper an edge filter based on multimode interference in an integrated waveguide is optimized for a wavelength monitoring application. This can also be used as a demodulation element in a fibre Bragg grating sensing system. A global optimization algorithm is presented for the optimum design of the multimode interference device, including a range of parameters of the multimode waveguide, such as length, width and position of the input and output waveguides. The designed structure demonstrates the desired spectral response for wavelength measurements. Fabrication tolerance is also analysed numerically for this structure.

Single-mode glass waveguide technology for optical interchip communication on board level

NASA Astrophysics Data System (ADS)

Brusberg, Lars; Neitz, Marcel; Schröder, Henning

2012-01-01

The large bandwidth demand in long-distance telecom networks lead to single-mode fiber interconnects as result of low dispersion, low loss and dense wavelength multiplexing possibilities. In contrast, multi-mode interconnects are suitable for much shorter lengths up to 300 meters and are promising for optical links between racks and on board level. Active optical cables based on multi-mode fiber links are at the market and research in multi-mode waveguide integration on board level is still going on. Compared to multi-mode, a single-mode waveguide has much more integration potential because of core diameters of around 20% of a multi-mode waveguide by a much larger bandwidth. But light coupling in single-mode waveguides is much more challenging because of lower coupling tolerances. Together with the silicon photonics technology, a single-mode waveguide technology on board-level will be the straight forward development goal for chip-to-chip optical interconnects integration. Such a hybrid packaging platform providing 3D optical single-mode links bridges the gap between novel photonic integrated circuits and the glass fiber based long-distance telecom networks. Following we introduce our 3D photonic packaging approach based on thin glass substrates with planar integrated optical single-mode waveguides for fiber-to-chip and chip-to-chip interconnects. This novel packaging approach merges micro-system packaging and glass integrated optics. It consists of a thin glass substrate with planar integrated singlemode waveguide circuits, optical mirrors and lenses providing an integration platform for photonic IC assembly and optical fiber interconnect. Thin glass is commercially available in panel and wafer formats and characterizes excellent optical and high-frequency properties. That makes it perfect for microsystem packaging. The paper presents recent results in single-mode waveguide technology on wafer level and waveguide characterization. Furthermore the integration in a hybrid packaging process and design issues are discussed.

Global optimization of multimode interference structure for ratiometric wavelength measurement

NASA Astrophysics Data System (ADS)

Wang, Qian; Farrell, Gerald; Hatta, Agus Muhamad

2007-07-01

The multimode interference structure is conventionally used as a splitter/combiner. In this paper, it is optimised as an edge filter for ratiometric wavelength measurement, which can be used in demodulation of fiber Bragg grating sensing. The global optimization algorithm-adaptive simulated annealing is introduced in the design of multimode interference structure including the length and width of the multimode waveguide section, and positions of the input and output waveguides. The designed structure shows a suitable spectral response for wavelength measurement and a good fabrication tolerance.

Multimode waveguide speckle patterns for compressive sensing.

PubMed

Valley, George C; Sefler, George A; Justin Shaw, T

2016-06-01

Compressive sensing (CS) of sparse gigahertz-band RF signals using microwave photonics may achieve better performances with smaller size, weight, and power than electronic CS or conventional Nyquist rate sampling. The critical element in a CS system is the device that produces the CS measurement matrix (MM). We show that passive speckle patterns in multimode waveguides potentially provide excellent MMs for CS. We measure and calculate the MM for a multimode fiber and perform simulations using this MM in a CS system. We show that the speckle MM exhibits the sharp phase transition and coherence properties needed for CS and that these properties are similar to those of a sub-Gaussian MM with the same mean and standard deviation. We calculate the MM for a multimode planar waveguide and find dimensions of the planar guide that give a speckle MM with a performance similar to that of the multimode fiber. The CS simulations show that all measured and calculated speckle MMs exhibit a robust performance with equal amplitude signals that are sparse in time, in frequency, and in wavelets (Haar wavelet transform). The planar waveguide results indicate a path to a microwave photonic integrated circuit for measuring sparse gigahertz-band RF signals using CS.

Planar waveguide sensor of ammonia

NASA Astrophysics Data System (ADS)

Rogoziński, Roman; Tyszkiewicz, Cuma; Karasiński, Paweł; Izydorczyk, Weronika

2015-12-01

The paper presents the concept of forming ammonia sensor based on a planar waveguide structure. It is an amplitude sensor produced on the basis of the multimode waveguide. The technological base for this kind of structure is the ion exchange method and the sol-gel method. The planar multimode waveguide of channel type is produced in glass substrate (soda-lime glass of Menzel-Glaser company) by the selective Ag+↔Na+ ion exchange. On the surface of the glass substrate a porous (~40%) silica layer is produced by the sol-gel method. This layer is sensitized to the presence of ammonia in the surrounding atmosphere by impregnation with Bromocresol Purple (BCP) dye. Therefore it constitutes a sensor layer. Spectrophotometric tests carried out showed about 50% reduction of cross-transmission changes of such sensor layer for a wave λ=593 nm caused by the presence of 25% ammonia water vapor in its ambience. The radiation source used in this type of sensor structure is a light emitting diode LED. The gradient channel waveguide is designed for frontal connection (optical glue) with a standard multimode telecommunications waveguide 62.5/125μm.

Reconfigurable optical interconnection network for multimode optical fiber sensor arrays

NASA Technical Reports Server (NTRS)

Chen, R. T.; Robinson, D.; Lu, H.; Wang, M. R.; Jannson, T.; Baumbick, R.

1992-01-01

A single-source, single-detector architecture has been developed to implement a reconfigurable optical interconnection network multimode optical fiber sensor arrays. The network was realized by integrating LiNbO3 electrooptic (EO) gratings working at the Raman Na regime and a massive fan-out waveguide hologram (WH) working at the Bragg regime onto a multimode glass waveguide. The glass waveguide utilized the whole substrate as a guiding medium. A 1-to-59 massive waveguide fan-out was demonstrated using a WH operating at 514 nm. Measured diffraction efficiency of 59 percent was experimentally confirmed. Reconfigurability of the interconnection was carried out by generating an EO grating through an externally applied electric field. Unlike conventional single-mode integrated optical devices, the guided mode demonstrated has an azimuthal symmetry in mode profile which is the same as that of a fiber mode.

Low-loss bloch wave guiding in open structures and highly compact efficient waveguide-crossing arrays

DOEpatents

Popovic, Milos

2011-03-08

Low-loss waveguide structures may comprise a multimode waveguide supporting a periodic light intensity pattern, and attachments disposed at the waveguide adjacent low-intensity regions of the light intensity pattern.

A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.; Simons, Rainee N.

2014-01-01

This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

One-Step Optogenetics with Multifunctional Flexible Polymer Fibers

PubMed Central

Park, Seongjun; Guo, Yuanyuan; Jia, Xiaoting; Choe, Han Kyoung; Grena, Benjamin; Kang, Jeewoo; Park, Jiyeon; Lu, Chi; Canales, Andres; Chen, Ritchie; Yim, Yeong Shin; Choi, Gloria B.; Fink, Yoel; Anikeeva, Polina

2017-01-01

Optogenetic interrogation of neural pathways relies on delivery of light-sensitive opsins into tissue and subsequent optical illumination and electrical recording from the regions of interest. Despite the recent development of multifunctional neural probes, integration of these modalities within a single biocompatible platform remains a challenge. Here, we introduce a device composed of an optical waveguide, six electrodes, and two microfluidic channels produced via fiber drawing. Our probes facilitated injections of viral vectors carrying opsin genes, while providing collocated neural recording and optical stimulation. The miniature (< 200 μm) footprint and modest weight (<0.5 g) of these probes allowed for multiple implantations into the mouse brain, which enabled opto-electrophysiological investigation of projections from the basolateral amygdala to the medial prefrontal cortex and ventral hippocampus during behavioral experiments. Fabricated solely from polymers and polymer composites, these flexible probes minimized tissue response to achieve chronic multimodal interrogation of brain circuits with high fidelity. PMID:28218915

OPTOELECTRONICS, FIBER OPTICS, AND OTHER ASPECTS OF QUANTUM ELECTRONICS: Influence of the Rayleigh backscattering on the mode composition of radiation in multimode graded-index waveguides with a quadratic refractive-index profile

NASA Astrophysics Data System (ADS)

Esayan, G. L.; Krivoshlykov, S. G.

1989-08-01

A method of coherent states is used to describe the process of Rayleigh scattering in a multimode graded-index waveguide with a quadratic refractive-index profile. Explicit expressions are obtained for the coefficients representing excitation of Gaussian-Hermite backscattering modes in two cases of practical importance: excitation of a waveguide by an extended noncoherent light source and selective excitation of different modes at the entry to a waveguide. An analysis is also made of the coefficients of coupling between forward and backward modes. Explicit expressions for the coefficients representing capture of backscattered radiation by a waveguide are obtained for two special cases of excitation (extended light source and zeroth mode).

Dry-film polymer waveguide for silicon photonics chip packaging.

PubMed

Hsu, Hsiang-Han; Nakagawa, Shigeru

2014-09-22

Polymer waveguide made by dry film process is demonstrated for silicon photonics chip packaging. With 8 μm × 11.5 μm core waveguide, little penalty is observed up to 25 Gbps before or after the light propagate through a 10-km long single-mode fiber (SMF). Coupling loss to SMF is 0.24 dB and 1.31 dB at the polymer waveguide input and output ends, respectively. Alignment tolerance for 0.5 dB loss increase is +/- 1.0 μm along both vertical and horizontal directions for the coupling from the polymer waveguide to SMF. The dry-film polymer waveguide demonstrates promising performance for silicon photonics chip packaging used in next generation optical multi-chip module.

Quantum interference between transverse spatial waveguide modes.

PubMed

Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

2017-01-20

Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing.

WDM package enabling high-bandwidth optical intrasystem interconnects for high-performance computer systems

NASA Astrophysics Data System (ADS)

Schrage, J.; Soenmez, Y.; Happel, T.; Gubler, U.; Lukowicz, P.; Mrozynski, G.

2006-02-01

From long haul, metro access and intersystem links the trend goes to applying optical interconnection technology at increasingly shorter distances. Intrasystem interconnects such as data busses between microprocessors and memory blocks are still based on copper interconnects today. This causes a bottleneck in computer systems since the achievable bandwidth of electrical interconnects is limited through the underlying physical properties. Approaches to solve this problem by embedding optical multimode polymer waveguides into the board (electro-optical circuit board technology, EOCB) have been reported earlier. The principle feasibility of optical interconnection technology in chip-to-chip applications has been validated in a number of projects. For reasons of cost considerations waveguides with large cross sections are used in order to relax alignment requirements and to allow automatic placement and assembly without any active alignment of components necessary. On the other hand the bandwidth of these highly multimodal waveguides is restricted due to mode dispersion. The advance of WDM technology towards intrasystem applications will provide sufficiently high bandwidth which is required for future high-performance computer systems: Assuming that, for example, 8 wavelength-channels with 12Gbps (SDR1) each are given, then optical on-board interconnects with data rates a magnitude higher than the data rates of electrical interconnects for distances typically found at today's computer boards and backplanes can be realized. The data rate will be twice as much, if DDR2 technology is considered towards the optical signals as well. In this paper we discuss an approach for a hybrid integrated optoelectronic WDM package which might enable the application of WDM technology to EOCB.

Tuned alexandrite laser for dentistry

NASA Astrophysics Data System (ADS)

Sulc, Jan; Jelinkova, Helena; Dostalova, Tatjana; Miyagi, Mitsunobu

1999-12-01

A tunable solid state laser system has been developed emitting visible light in the region from 710 to 775 nm, which can be used for medical applications. The laser head of this system is composed of alexandrite crystal rod, two dielectric mirrors, and a tuning element. The maximum reached output energy in the free running multimode regime was 400 mJ with the pulse duration of 70 micrometers . The output laser radiation was guided via a multimode quartz fiber or via a special fluorocarbon polymer-coated silver hollow glass waveguide. At first, this radiation with laser fluency of 2.5 J/cm2 was used for the ablation of dental calculus. Next, the laser radiation propagation in the root canal and its effect on bacteria was proved. The dissipated energy measurement was made inside and outside the tooth. Hence, the alexandrite laser could be useful for medical applications in dentistry.

Multi-mode horn antenna simulation

NASA Technical Reports Server (NTRS)

Dod, L. R.; Wolf, J. D.

1980-01-01

Radiation patterns were computed for a circular multimode horn antenna using waveguide electric field radiation expressions. The circular multimode horn was considered as a possible reflector feed antenna for the Large Antenna Multifrequency Microwave Radiometer (LAMMR). This horn antenna uses a summation of the TE sub 11 deg and TM sub 11 deg modes to generate far field primary radiation patterns with equal E and H plane beamwidths and low sidelobes. A computer program for the radiation field expressions using the summation of waveguide radiation modes is described. The sensitivity of the multimode horn antenna radiation patterns to phase variations between the two modes is given. Sample radiation pattern calculations for a reflector feed horn for LAMMR are shown. The multimode horn antenna provides a low noise feed suitable for radiometric applications.

Photonic lantern with multimode fibers embedded

NASA Astrophysics Data System (ADS)

Yu, Hai-Jiao; Yan, Qi; Huang, Zong-Jun; Tian, He; Jiang, Yu; Liu, Yong-Jun; Zhang, Jian-Zhong; Sun, Wei-Min

2014-08-01

A photonic lantern is studied which is formed by seven multimode fibers inserted into a pure silica capillary tube. The core of the tapered end has a uniform refractive index because the polymer claddings are removed before the fibers are inserted. Consequently, the light distribution is also uniform. Two theories describing a slowly varying waveguide and multimode coupling are used to analyze the photonic lantern. The transmission loss decreases as the length of the tapered part increases. For a device with a taper length of 3.4 cm, the loss is about 1.06 dB on average for light propagating through the taper from an inserted fiber to the tapered end and 0.99 dB in the reverse direction. For a device with a taper length of 0.7 cm, the two loss values are 2.63 dB and 2.53 dB, respectively. The results show that it is possible to achieve a uniform light distribution with the tapered end and a low-loss transmission in the device if parameters related to the lantern are reasonably defined.

Waveguide Multimode Directional Coupler for Harvesting Harmonic Power from the Output of Traveling-Wave Tube Amplifiers

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.

2017-01-01

This paper presents the design, fabrication, and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from dissimilar frequency band waveguides, is capable of isolating power at the 2nd harmonic frequency from the fundamental power at the output port of traveling-wave tube amplifiers. Test results from proof-of-concept demonstrations are presented for Ku/Ka-band and Ka/E-band MDCs, which demonstrate sufficient power in the 2nd harmonic for a space borne beacon source for mm-wave atmospheric propagation studies.

Waveguide Multimode Directional Coupler for Harvesting Harmonic Power from the Output of Traveling-Wave Tube Amplifiers

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.

2017-01-01

The paper presents the design, fabrication, and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from dissimilar frequency band waveguides, is capable of isolating power at the 2nd harmonic frequency from the fundamental power at the output port of a high power traveling-wave tube amplifier. The major advantage of the MDC is significantly lower insertion loss compared to a diplexer. The presentation slides for the paper that was approved is attached. The tracking number for the paper that was approved is TN 37015.

Silicon-on-insulator multimode-interference waveguide-based arrayed optical tweezers (SMART) for two-dimensional microparticle trapping and manipulation.

PubMed

Lei, Ting; Poon, Andrew W

2013-01-28

We demonstrate two-dimensional optical trapping and manipulation of 1 μm and 2.2 μm polystyrene particles in an 18 μm-thick fluidic cell at a wavelength of 1565 nm using the recently proposed Silicon-on-insulator Multimode-interference (MMI) waveguide-based ARrayed optical Tweezers (SMART) technique. The key component is a 100 μm square-core silicon waveguide with mm length. By tuning the fiber-coupling position at the MMI waveguide input facet, we demonstrate various patterns of arrayed optical tweezers that enable optical trapping and manipulation of particles. We numerically simulate the physical mechanisms involved in the arrayed trap, including the optical force, the heat transfer and the thermal-induced microfluidic flow.

Thermo-optic devices on polymer platform

NASA Astrophysics Data System (ADS)

Zhang, Ziyang; Keil, Norbert

2016-03-01

Optical polymers possess in general relatively high thermo-optic coefficients and at the same time low thermal conductivity, both of which make them attractive material candidates for realizing highly efficient thermally tunable devices. Over the years, various thermo-optic components have been demonstrated on polymer platform, covering (1) tunable reflectors and filters as part of a laser cavity, (2) variable optical attenuators (VOAs) as light amplitude regulators in e.g. a coherent receiver, and (3) thermo-optic switches (TOSs) allowing multi-flow control in the photonic integrated circuits (PICs). This work attempts to review the recent progress on the above mentioned three component branches, including linearly and differentially tunable filters, VOAs based on 1×1 multimode interference structure (MMI) and Mach-Zehnder interferometer (MZI), and 1×2 TOS based on waveguide Y-branch, driven by a pair of sidelong placed heater electrodes. These thermo-optic components can well be integrated into larger PICs: the dual-polarization switchable tunable laser and the colorless optical 90° hybrid are presented in the end as examples.

Integrated-optic current sensors with a multimode interference waveguide device.

PubMed

Kim, Sung-Moon; Chu, Woo-Sung; Kim, Sang-Guk; Oh, Min-Cheol

2016-04-04

Optical current sensors based on polarization-rotated reflection interferometry are demonstrated using polymeric integrated optics and various functional optical waveguide devices. Interferometric sensors normally require bias feedback control for maintaining the operating point, which increases the cost. In order to resolve this constraint of feedback control, a multimode interference (MMI) waveguide device is integrated onto the current-sensor optical chip in this work. From the multiple outputs of the MMI, a 90° phase-shifted transfer function is obtained. Using passive quadrature demodulation, we demonstrate that the sensor could maintain the output signal regardless of the drift in the operating bias-point.

Simulation of the novel compact structure of an interferometric biosensor based on multimode interference waveguides

NASA Astrophysics Data System (ADS)

Xhoxhi, Moisi; Dudia, Alma; Ymeti, Aurel

2017-05-01

We propose the novel structure of an interferometric biosensor based on multimode interference (MMI) waveguides. We present the design of the biosensor using eigenmode expansion (EME) method in accordance with the requirements and standards of today's photonic technology. The MMI structures with a 90 nm Si3N4 core are used as power splitters with 5 outputs. The 5 high-resolution images at the end of the multimode region show high power balance. We analyze the coupling efficiency of the laser source with the structure, the excess loss and power imbalance for different compact MMI waveguides with widths ranging from 45 μm to 15 μm. For a laser source with a tolerance of +/-1mm in linearization we could achieve a coupling efficiency of 52%. MMI waveguides with tapered channels show excess loss values under 0.5 dB and power imbalance values under 0.08 dB. In addition, we show that for a 10 nm deviation of the source wavelength from its optimal value and for a 10 μm deviation of the MMI length from its optimal value, the performance of the MMI waveguides remains acceptable. Finally, we analyze the power budget of the whole biosensor structure and show that it is sufficient for the proper operation of this device.

High-speed electro-optic switch based on nonlinear polymer-clad waveguide incorporated with quasi-in-plane coplanar waveguide electrodes

NASA Astrophysics Data System (ADS)

Jiang, Ming-Hui; Wang, Xi-Bin; Xu, Qiang; Li, Ming; Niu, Dong-Hai; Sun, Xiao-Qiang; Wang, Fei; Li, Zhi-Yong; Zhang, Da-Ming

2018-01-01

Nonlinear optical (NLO) polymer is a promising material for active waveguide devices that can provide large bandwidth and high-speed response time. However, the performance of the active devices is not only related to the waveguide materials, but also related to the waveguide and electrode structures. In this paper, a high-speed Mach-Zehnder interferometer (MZI) type of electro-optic (EO) switch based on NLO polymer-clad waveguide was fabricated. The quasi-in-plane coplanar waveguide electrodes were also introduced to enhance the poling and modulating efficiency. The characteristic parameters of the waveguide and electrode were carefully designed and simulated. The switches were fabricated by the conventional micro-fabrication process. Under 1550-nm operating wavelength, a typical fabricated switch showed a low insertion loss of 10.2 dB, and the switching rise time and fall time were 55.58 and 57.98 ns, respectively. The proposed waveguide and electrode structures could be developed into other active EO devices and also used as the component in the polymer-based large-scale photonic integrated circuit.

Bi-directional triplexer with butterfly MMI coupler using SU-8 polymer waveguides

NASA Astrophysics Data System (ADS)

Mareš, David; Jeřábek, Vítězslav; Prajzler, Václav

2015-01-01

We report about a design of a bi-directional planar optical multiplex/demultiplex filter (triplexer) for the optical part of planar hybrid WDM bi-directional transceiver in fiber-to-the-home (FTTH) PON applications. The triplex lightwave circuit is based on the Epoxy Novolak Resin SU-8 waveguides on the silica-on-silicon substrate with Polymethylmethacrylate cladding layer. The triplexer is comprised of a linear butterfly concept of multimode interference (MMI) coupler separating downstream optical signals of 1490 nm and 1550 nm. For the upstream channel of 1310 nm, an additional directional coupler (DC) is used to add optical signal of 1310 nm propagating in opposite direction. The optical triplexer was designed and optimized using beam propagation method. The insertion losses, crosstalk attenuation, and extinction ratio for all three inputs/outputs were investigated. The intended triplexer was designed using the parameters of the separated DC and MMI filter to approximate the idealized direct connection of both devices.

Hard and flexible optical printed circuit board

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-02-01

We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

Intermode light diffusion in multimode optical waveguides with rough surfaces.

PubMed

Stepanov, S; Chaikina, E I; Leskova, T A; Méndez, E R

2005-06-01

A theoretical analysis of incoherent intermode light power diffusion in multimode dielectric waveguides with rough (corrugated) surfaces is presented. The correlation length a of the surface-profile variations is assumed to be sufficiently large (a less less than lambda/2pi) to permit light scattering into the outer space only from the modes close to the critical angles of propagation and yet sufficiently small (a less less than d, where d is the average width of the waveguide) to permit direct interaction between a given mode and a large number of neighboring ones. The cases of a one-dimensional (1D) slab waveguide and a two-dimensional cylindrical waveguide (optical fiber) are analyzed, and we find that in both cases the partial differential equations that govern the evolution of the angular light power profile propagating along the waveguide are 1D and of the diffusion type. However, whereas in the former case the effective conductivity coefficient proves to be linearly dependent on the transverse-mode wave number, in the latter one the linear dependence is for the effective diffusion coefficient. The theoretical predictions are in reasonable agreement with experimental results for the intermode power diffusion in multimode (700 x 700) optical fibers with etched surfaces. The characteristic length of dispersion of a narrow angular power profile evaluated from the correlation length and standard deviation of heights of the surface profile proved to be in good agreement with the experimentally observed changes in the output angular power profiles.

A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon-Gallium-Nitride Slot Waveguide Structures.

PubMed

Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

2016-06-25

In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)-gallium nitride (GaN) slot waveguide structure is presented-to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530-1565 nm) into four output ports with low insertion losses (0.07 dB).

Numerical model of the polymer electro-optic waveguide

NASA Astrophysics Data System (ADS)

Fan, Guofang; Li, Yuan; Han, Bing; Wang, Qi; Liu, Xinhou; Zhen, Zhen

2012-09-01

A numerical design model is presented for the polymer waveguide in an electro-optic modulator. The effective index method is used to analyze the height of the core waveguide and rib waveguide, an improved Marcatili method is presented to design the rib waveguide width in order to keep the strong single mode operation and have a good match with the standard fiber. Also, the thickness of the upper cladding layer is discussed through calculating the effective index of the multilayer planar waveguide structure has been obtained by setting the optical loss due to the metallic absorption to an acceptable value (<0.1 dB/cm). As a consequence, we take the EO polymer waveguide structure of UV15:CLD/APC:UFC170 as an example, an optimized design is reported.

Silica/Electro-optic Polymer Optical Modulator for MMW Receiving (Preprint)

DTIC Science & Technology

2014-05-01

radiation receiver with the use of a bowtie antenna . Waveguide design optimization is presented for a waveguide with an EO polymer core and silica/solgel...established. The bowtie antenna is simulated and shows a broadband response with a maximum at 5GHz and a 3dB-bandwidth of approximately 12GHz. A fiber...millimeter-wave (MMW) radiation receiver with the use of a bowtie antenna . Waveguide design optimization is presented for a waveguide with an EO polymer

Electro-optical backplane demonstrator with integrated multimode gradient-index thin glass waveguide panel

NASA Astrophysics Data System (ADS)

Schröder, Henning; Brusberg, Lars; Pitwon, Richard; Whalley, Simon; Wang, Kai; Miller, Allen; Herbst, Christian; Weber, Daniel; Lang, Klaus-Dieter

2015-03-01

Optical interconnects for data transmission at board level offer increased energy efficiency, system density, and bandwidth scalability compared to purely copper driven systems. We present recent results on manufacturing of electrooptical printed circuit board (PCB) with integrated planar glass waveguides. The graded index multi-mode waveguides are patterned inside commercially available thin-glass panels by performing a specific ion-exchange process. The glass waveguide panel is embedded within the layer stack-up of a PCB using proven industrial processes. This paper describes the design, manufacture, assembly and characterization of the first electro-optical backplane demonstrator based on integrated planar glass waveguides. The electro-optical backplane in question is created by laminating the glass waveguide panel into a conventional multi-layer electronic printed circuit board stack-up. High precision ferrule mounts are automatically assembled, which will enable MT compliant connectors to be plugged accurately to the embedded waveguide interfaces on the glass panel edges. The demonstration platform comprises a standardized sub-rack chassis and five pluggable test cards each housing optical engines and pluggable optical connectors. The test cards support a variety of different data interfaces and can support data rates of up to 32 Gb/s per channel.

Modeling multimode feed-horn coupled bolometers for millimeter-wave and terahertz astronomical instrumentation

NASA Astrophysics Data System (ADS)

Kalinauskaite, Eimante; Murphy, Anthony; McAuley, Ian; Trappe, Neil A.; Bracken, Colm P.; McCarthy, Darragh N.; Doherty, Stephen; Gradziel, Marcin L.; O'Sullivan, Creidhe; Maffei, Bruno; Lamarre, Jean-Michel A.; Ade, Peter A. R.; Savini, Giorgio

2016-07-01

Multimode horn antennas can be utilized as high efficiency feeds for bolometric detectors, providing increased throughput and sensitivity over single mode feeds, while also ensuring good control of beam pattern characteristics. Multimode horns were employed in the highest frequency channels of the European Space Agency Planck Telescope, and have been proposed for future terahertz instrumentation, such as SAFARI for SPICA. The radiation pattern of a multimode horn is affected by the details of the coupling of the higher order waveguide modes to the bolometer making the modeling more complicated than in the case of a single mode system. A typical cavity coupled bolometer system can be most efficiently simulated using mode matching, typically with smooth walled waveguide modes as the basis and computing an overall scattering matrix for the horn-waveguide-cavity system that includes the power absorption by the absorber. In this paper we present how to include a cavity coupled bolometer, modelled as a thin absorbing film with particular interest in investigating the cavity configuration for optimizing power absorption. As an example, the possible improvements from offsetting the axis of a cylindrically symmetric absorbing cavity from that of a circular waveguide feeding it (thus trapping more power in the cavity) are discussed. Another issue is the effect on the optical efficiency of the detectors of the presence of any gaps, through which power can escape. To model these effects required that existing in-house mode matching software, which calculates the scattering matrices for axially symmetric waveguide structures, be extended to be able to handle offset junctions and free space gaps. As part of this process the complete software code 'PySCATTER' was developed in Python. The approach can be applied to proposed terahertz systems, such as SPICASAFARI.

Mode converter based on an inverse taper for multimode silicon nanophotonic integrated circuits.

PubMed

Dai, Daoxin; Mao, Mao

2015-11-02

An inverse taper on silicon is proposed and designed to realize an efficient mode converter available for the connection between multimode silicon nanophotonic integrated circuits and few-mode fibers. The present mode converter has a silicon-on-insulator inverse taper buried in a 3 × 3μm(2) SiN strip waveguide to deal with not only for the fundamental mode but also for the higher-order modes. The designed inverse taper enables the conversion between the six modes (i.e., TE(11), TE(21), TE(31), TE(41), TM(11), TM(12)) in a 1.4 × 0.22μm(2) multimode SOI waveguide and the six modes (like the LP(01), LP(11a), LP(11b) modes in a few-mode fiber) in a 3 × 3μm(2) SiN strip waveguide. The conversion efficiency for any desired mode is higher than 95.6% while any undesired mode excitation ratio is lower than 0.5%. This is helpful to make multimode silicon nanophotonic integrated circuits (e.g., the on-chip mode (de)multiplexers developed well) available to work together with few-mode fibers in the future.

Fabrication of raised and inverted SU8 polymer waveguides

NASA Astrophysics Data System (ADS)

Holland, Anthony S.; Mitchell, Arnan; Balkunje, Vishal S.; Austin, Mike W.; Raghunathan, Mukund K.

2005-01-01

Polymer films with high optical transmission have been investigated for making optical devices for several years. SU8 photoresist and optical adhesives have been investigated for use as thin films for optical devices, not what they were originally designed for. Optical adhesives are typically a one component thermoset polymer and are convenient to use for making thin film optical devices such as waveguides. They are prepared in minutes as thin films unlike SU8, which has to be carefully thermally cured over several hours for optimum results. However SU8 can be accurately patterned to form the geometry of structures required for single mode optical waveguides. SU8 in combination with the lower refractive index optical adhesive films such as UV15 from Master Bond are used to form single and multi mode waveguides. SU8 is photopatternable but we have also used dry etching of the SU8 layer or the other polymer layers e.g. UV15 to form the ribs, ridges or trenches required to guide single modes of light. Optical waveguides were also fabricated using only optical adhesives of different refractive indices. The resolution obtainable is poorer than with SU8 and hence multi mode waveguides are obtained. Loss measurements have been obtained for waveguides of different geometries and material combinations. The process for making polymer waveguides is demonstrated for making large multi mode waveguides and microfluidic channels by scaling the process up in size.

A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon–Gallium-Nitride Slot Waveguide Structures

PubMed Central

Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

2016-01-01

In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)–gallium nitride (GaN) slot waveguide structure is presented—to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530–1565 nm) into four output ports with low insertion losses (0.07 dB). PMID:28773638

Multilayered photonic integration on SOI platform using waveguide-based bridge structure

NASA Astrophysics Data System (ADS)

Majumder, Saikat; Chakraborty, Rajib

2018-06-01

A waveguide based structure on silicon on insulator platform is proposed for vertical integration in photonic integrated circuits. The structure consists of two multimode interference couplers connected by a single mode (SM) section which can act as a bridge over any other underlying device. Two more SM sections acts as input and output of the first and second multimode couplers respectively. Potential application of this structure is in multilayered photonic links. It is shown that the efficiency of the structure can be improved by making some design modifications. The entire simulation is done using effective-index based matrix method. The feature size chosen are comparable to waveguides fabricated previously so as to fabricate the proposed structure easily.

Broadband and scalable optical coupling for silicon photonics using polymer waveguides

NASA Astrophysics Data System (ADS)

La Porta, Antonio; Weiss, Jonas; Dangel, Roger; Jubin, Daniel; Meier, Norbert; Horst, Folkert; Offrein, Bert Jan

2018-04-01

We present optical coupling schemes for silicon integrated photonics circuits that account for the challenges in large-scale data processing systems such as those used for emerging big data workloads. Our waveguide based approach allows to optimally exploit the on-chip optical feature size, and chip- and package real-estate. It further scales well to high numbers of channels and is compatible with state-of-the-art flip-chip die packaging. We demonstrate silicon waveguide to polymer waveguide coupling losses below 1.5 dB for both the O- and C-bands with a polarisation dependent loss of <1 dB. Over 100 optical silicon waveguide to polymer waveguide interfaces were assembled within a single alignment step, resulting in a physical I/O channel density of up to 13 waveguides per millimetre along the chip-edge, with an average coupling loss of below 3.4 dB measured at 1310 nm.

Polarization-dependent plasmonic splitter based on low-loss polymer optical materials

NASA Astrophysics Data System (ADS)

Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Liu, Yi-Ran; Zhao, Ning; Zhang, Tong

2018-01-01

A polarization-dependent optical beam splitter consisting of a straight long-range surface plasmon polariton (LRSPP) waveguide and an S-bend polymer waveguide was designed, fabricated and measured in this paper. At the splitting section, the two different waveguides are vertically coupled. The measurenment results show that the splitter operated in dual-channel mode at TM polarization, and single-channel mode at TE polarization. In addition, the polymer waveguide and LRSPP waveguide in the splitter exhibit low propagation loss of 0.51 dB/cm and 1.7 dB/cm, respectively. The hybrid beam splitter has wide potential applications in three dimensional (3D) multilayer photonic integrated circuits (PICs).

Operation of Ho:YAG ultrafast laser inscribed waveguide lasers.

PubMed

McDaniel, Sean; Thorburn, Fiona; Lancaster, Adam; Stites, Ronald; Cook, Gary; Kar, Ajoy

2017-04-20

We report fabrication and operation of multi-watt level waveguide lasers utilizing holmium-doped yttrium aluminum garnet (Ho:YAG). The waveguides were fabricated using ultrafast laser inscription, which relies on a chirped pulse ytterbium fiber laser to create depressed cladding structures inside the material. A variety of waveguides were created inside the Ho:YAG samples. We demonstrate output powers of ∼2  W from both a single-mode 50 μm waveguide laser and a multimode 80 μm waveguide laser. In addition, laser action from a co-doped Yb:Ho:YAG sample under in-band pumping conditions was demonstrated.

FIBER AND INTEGRATED OPTICS: Analysis of the characteristics of a radio signal at the output of a multimode interference-type fiber channel

NASA Astrophysics Data System (ADS)

Bratchikov, A. N.; Glukhov, I. P.

1992-02-01

An analysis is made of a theoretical model of an interference fiber channel for transmission of microwave signals. It is assumed that the channel consists of a multimode fiber waveguide with a step or graded refractive-index profile. A typical statistic of a longitudinal distribution of inhomogeneities is also assumed. Calculations are reported of the interference losses, the spectral profile of the output radio signal, the signal/noise ratio in the channel, and of the dependences of these parameters on: the type, diameter, and the length of the multimode fiber waveguide; the spectral width of the radiation source; the frequency offset between the interfering optical signals.

Board-to-board optical interconnection using novel optical plug and slot

NASA Astrophysics Data System (ADS)

Cho, In K.; Yoon, Keun Byoung; Ahn, Seong H.; Kim, Jin Tae; Lee, Woo Jin; Shin, Kyoung Up; Heo, Young Un; Park, Hyo Hoon

2004-10-01

A novel optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by optical plug and slot. We report an 8Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of ETRI's optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB. 3) Optical slot and plug for high-density(channel pitch : 500um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data on transmitter/ receiver system boards and for backplane interconnections. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The optical PCB is characteristic of low coupling loss, easy insertion/extraction of the boards and, especially, reliable optical coupling unaffected from external environment after board insertion.

Using a micro-molding process to fabricate polymeric wavelength filters

NASA Astrophysics Data System (ADS)

Chuang, Wei-Ching; Lee, An-Chen; Ho, Chi-Ting

2008-08-01

A procedure for fabricating a high aspect ratio periodic structure on a UV polymer at submicron order using holographic interferometry and molding processes is described. First, holographic interferometry using a He-Cd (325 nm) laser was used to create the master of the periodic line structure on an i-line sub-micron positive photoresist film. A 20 nm nickel thin film was then sputtered on the photoresist. The final line pattern on a UV polymer was obtained from casting against the master mold. Finally, a SU8 polymer was spun on the polymer grating to form a planar waveguide or a channel waveguide. The measurement results show that the waveguide length could be reduced for the waveguide having gratings with a high aspect ratio.

Athermal Silicon-on-insulator ring resonators by overlaying a polymer cladding on narrowed waveguides.

PubMed

Teng, Jie; Dumon, Pieter; Bogaerts, Wim; Zhang, Hongbo; Jian, Xigao; Han, Xiuyou; Zhao, Mingshan; Morthier, Geert; Baets, Roel

2009-08-17

Athermal silicon ring resonators are experimentally demonstrated by overlaying a polymer cladding on narrowed silicon wires. The ideal width to achieve athermal condition for the TE mode of 220 nm-height SOI waveguides is found to be around 350 nm. After overlaying a polymer layer, the wavelength temperature dependence of the silicon ring resonator is reduced to less than 5 pm/degrees C, almost eleven times less than that of normal silicon waveguides. The optical loss of a 350-nm bent waveguide (with a radius of 15 microm) is extracted from the ring transmission spectrum. The scattering loss is reduced to an acceptable level of about 50 dB/cm after overlaying a polymer cladding. (c) 2009 Optical Society of America

Optical waveguiding properties of colloidal quantum dots doped polymer microfibers.

PubMed

Yu, Jiahao; Wang, Xiongbin; Chen, Rui

2018-05-14

QDs-doped polymer microfibers are fabricated through direct drawing method. By adding the polymethylmethacrylate into polystyrene, the surface quality and flexibility of microfiber are improved. Under direct excitation by the focused laser, the polymer microfibers doped with different quantum dots emit different colors and act as an optical waveguide. The waveguide properties of the microfiber are studied in detail. It is found that refractive index of the substrate and diameter of microfiber are the most important factors that affect the optical loss of this waveguide. The microfiber does not produce significant polarization after being deposited on the substrate. Moreover, exciting the QDs-doped polymer microfiber through a blue LED is demonstrated. This structure may find widespread applications in integrated photonic devices.

Femtosecond laser micromachining of waveguides in silicone-based hydrogel polymers.

PubMed

Ding, Li; Blackwell, Richard I; Künzler, Jay F; Knox, Wayne H

2008-06-10

By tightly focusing 27 fs laser pulses from a Ti:sapphire oscillator with 1.3 nJ pulse energy at 93 MHz repetition rate, we are able to fabricate optical waveguides inside hydrogel polymers containing approximately 36% water by weight. A tapered lensed fiber is used to couple laser light at a wavelength of 632.8 nm into these waveguides within a water environment. Strong waveguiding is observed due to large refractive index changes. A large waveguide propagation loss is found, and we show that this is caused by surface roughness which can be reduced by optimizing the waveguides.

A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.; Simons, Rainee N.

2015-01-01

This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

Flexible transparent displays based on core/shell upconversion nanophosphor-incorporated polymer waveguides

PubMed Central

Park, Bong Je; Hong, A-Ra; Park, Suntak; Kyung, Ki-Uk; Lee, Kwangyeol; Seong Jang, Ho

2017-01-01

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443–900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser. PMID:28368021

Flexible transparent displays based on core/shell upconversion nanophosphor-incorporated polymer waveguides

NASA Astrophysics Data System (ADS)

Park, Bong Je; Hong, A.-Ra; Park, Suntak; Kyung, Ki-Uk; Lee, Kwangyeol; Seong Jang, Ho

2017-04-01

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443-900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser.

Reconfigurable Optical Elements Based on Single and Coupled Microdisk Resonators with Quantum DOT Active Media

DTIC Science & Technology

2012-06-29

of active-passive integrated polymer waveguides. The active waveguides consist of CdSe quantum dots dispersed in SU8 . Bottom panel shows CCD images...successfully demonstrated (i) incorporation of CdSe QDs into polymer and dielectric host and realization of devices such as active waveguides, microdisk...the significant outcomes of the program: • Successful incorporation of CdSe QDs into polymer and dielectric host and realization of devices such as

Radiation patterns of multimode feed-horn-coupled bolometers for FAR-IR space applications

NASA Astrophysics Data System (ADS)

Kalinauskaite, Eimante; Murphy, J. Anthony; McAuley, Ian; Trappe, Neal A.; McCarthy, Darragh N.; Bracken, Colm P.; Doherty, Stephen; Gradziel, Marcin L.; O'Sullivan, Créidhe; Wilson, Daniel; Peacocke, Tully; Maffei, Bruno; Lamarre, Jean-Michel; Ade, Peter A. R.; Savini, Giorgio

2017-02-01

A multimode horn differs from a single mode horn in that it has a larger sized waveguide feeding it. Multimode horns can therefore be utilized as high efficiency feeds for bolometric detectors, providing increased throughput and sensitivity over single mode feeds, while also ensuring good control of the beam pattern characteristics. Although a cavity mounted bolometer can be modelled as a perfect black body radiator (using reciprocity in order to calculate beam patterns), nevertheless, this is an approximation. In this paper we present how this approach can be improved to actually include the cavity coupled bolometer, now modelled as a thin absorbing film. Generally, this is a big challenge for finite element software, in that the structures are typically electrically large. However, the radiation pattern of multimode horns can be more efficiently simulated using mode matching, typically with smooth-walled waveguide modes as the basis and computing an overall scattering matrix for the horn-waveguide-cavity system. Another issue on the optical efficiency of the detectors is the presence of any free space gaps, through which power can escape. This is best dealt with treating the system as an absorber. Appropriate reflection and transmission matrices can be determined for the cavity using the natural eigenfields of the bolometer cavity system. We discuss how the approach can be applied to proposed terahertz systems, and also present results on how the approach was applied to improve beam pattern predictions on the sky for the multi-mode HFI 857GHz channel on Planck.

Polymer waveguide grating sensor integrated with a thin-film photodetector

PubMed Central

Song, Fuchuan; Xiao, Jing; Xie, Antonio Jou; Seo, Sang-Woo

2014-01-01

This paper presents a planar waveguide grating sensor integrated with a photodetector (PD) for on-chip optical sensing systems which are suitable for diagnostics in the field and in-situ measurements. III–V semiconductor-based thin-film PD is integrated with a polymer based waveguide grating device on a silicon platform. The fabricated optical sensor successfully discriminates optical spectral characteristics of the polymer waveguide grating from the on-chip PD. In addition, its potential use as a refractive index sensor is demonstrated. Based on a planar waveguide structure, the demonstrated sensor chip may incorporate multiple grating waveguide sensing regions with their own optical detection PDs. In addition, the demonstrated processing is based on a post-integration process which is compatible with silicon complementary metal-oxide semiconductor (CMOS) electronics. Potentially, this leads a compact, chip-scale optical sensing system which can monitor multiple physical parameters simultaneously without need for external signal processing. PMID:24466407

Photonic bandpass filter characteristics of multimode SOI waveguides integrated with submicron gratings.

PubMed

Sah, Parimal; Das, Bijoy Krishna

2018-03-20

It has been shown that a fundamental mode adiabatically launched into a multimode SOI waveguide with submicron grating offers well-defined flat-top bandpass filter characteristics in transmission. The transmitted spectral bandwidth is controlled by adjusting both waveguide and grating design parameters. The bandwidth is further narrowed down by cascading two gratings with detuned parameters. A semi-analytical model is used to analyze the filter characteristics (1500  nm≤λ≤1650  nm) of the device operating in transverse-electric polarization. The proposed devices were fabricated with an optimized set of design parameters in a SOI substrate with a device layer thickness of 250 nm. The pass bandwidth of waveguide devices integrated with single-stage gratings are measured to be ∼24  nm, whereas the device with two cascaded gratings with slightly detuned periods (ΔΛ=2  nm) exhibits a pass bandwidth down to ∼10  nm.

Polymer waveguides for electro-optical integration in data centers and high-performance computers.

PubMed

Dangel, Roger; Hofrichter, Jens; Horst, Folkert; Jubin, Daniel; La Porta, Antonio; Meier, Norbert; Soganci, Ibrahim Murat; Weiss, Jonas; Offrein, Bert Jan

2015-02-23

To satisfy the intra- and inter-system bandwidth requirements of future data centers and high-performance computers, low-cost low-power high-throughput optical interconnects will become a key enabling technology. To tightly integrate optics with the computing hardware, particularly in the context of CMOS-compatible silicon photonics, optical printed circuit boards using polymer waveguides are considered as a formidable platform. IBM Research has already demonstrated the essential silicon photonics and interconnection building blocks. A remaining challenge is electro-optical packaging, i.e., the connection of the silicon photonics chips with the system. In this paper, we present a new single-mode polymer waveguide technology and a scalable method for building the optical interface between silicon photonics chips and single-mode polymer waveguides.

Integrated polymer polarization rotator based on tilted laser ablation

NASA Astrophysics Data System (ADS)

Poulopoulos, Giannis; Kalavrouziotis, Dimitrios; Missinne, Jeroen; Bosman, Erwin; Van Steenberge, Geert; Apostolopoulos, Dimitrios; Avramopoulos, Hercules

2017-02-01

The ubiquitous need for compact, low-cost and mass production photonic devices, for next generation photonic enabled applications, necessitates the development of integrated components exhibiting functionalities that are, to date, carried out by free space elements or standard fiber equipment. The polarization rotator is a typical example of such tendency, as it is a crucial part of the PBS operation of future transceiver modules that leverage polarization multiplexing schemes for increasing the optical network capacity. Up to now, a variety of integrated polarization rotating concepts has been proposed and reported, relying, mainly, on special waveguide crossection configurations for achieving the rotation. Nevertheless, most of those concepts employ SiPh or III-V integration platforms, significantly increasing the fabrication complexity required for customizing the waveguide crossection, which in turn leads to either prohibitively increased cost or compromised quality and performance. In this manuscript we demonstrate the extensive design of a low-cost integrated polymer polarization rotator employing a right-trapezoidal waveguide interfaced to standard square polymer waveguides. First the crossection of the waveguide is defined by calculating and analyzing the components of the hybrid modes excited in the waveguide structure, using a Finite Difference mode solver. Mode overlaps between the fundamental polymer mode and each hybrid mode reveal the optimum lateral offset between the square polymer and the trapezoidal waveguide that ensures both minimum interface loss and maximized polarization rotation performance. The required trapezoidal waveguide length is obtained through EigenMode Expansion (EME) propagation simulations, while more than 95% maximum theoretical conversion efficiency is reported over the entire C-band, resulting to more than 13dB polarization extinction ratio. The polarization rotator design relies on the development of angled polymer waveguide sidewalls, employing the tilted laser ablation technology, currently available at CMST. Therefore, the aforementioned simulation steps adhere fully to the respective design rules, taking into account the anticipated fabrication variations

Chemical Sensors Based on Optical Ring Resonators

NASA Technical Reports Server (NTRS)

Homer, Margie; Manfreda, Allison; Mansour, Kamjou; Lin, Ying; Ksendzov, Alexander

2005-01-01

Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer polymer layer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in index of refraction of the polymer causes a measurable shift in the resonance peaks of the ring. In a prototype that has been used to demonstrate the feasibility of this sensor concept, the ring resonator is a dielectric optical waveguide laid out along a closed path resembling a racetrack (see Figure 1). The prototype was fabricated on a silicon substrate by use of standard techniques of thermal oxidation, chemical vapor deposition, photolithography, etching, and spin coating. The prototype resonator waveguide features an inner cladding of SiO2, a core of SixNy, and a chemical-sensing outer cladding of ethyl cellulose. In addition to the ring Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer polymer layer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in index of refraction of the polymer causes a measurable shift in the resonance peaks of the ring. In a prototype that has been used to demonstrate the feasibility of this sensor concept, the ring resonator is a dielectric optical waveguide laid out along a closed path resembling a racetrack (see Figure 1). The prototype was fabricated on a silicon substrate by use of standard techniques of thermal oxidation, chemical vapor deposition, photolithography, etching, and spin coating. The prototype resonator waveguide features an inner cladding of SiO2, a core of SixNy, and a chemical-sensing outer cladding of ethyl cellulose. In addition to the ring res

Design, Fabrication, and Packaging of Mach-Zehnder Interferometers for Biological Sensing Applications

NASA Astrophysics Data System (ADS)

Novak, Joseph

Optical biological sensors are widely used in the fields of medical testing, water treatment and safety, gene identification, and many others due to advances in nanofabrication technology. This work focuses on the design of fiber-coupled Mach-Zehnder Interferometer (MZI) based biosensors fabricated on silicon-on-insulator (SOI) wafer. Silicon waveguide sensors are designed with multimode and single-mode dimensions. Input coupling efficiency is investigated by design of various taper structures. Integration processing and packaging is performed for fiber attachment and enhancement of input coupling efficiency. Optical guided-wave sensors rely on single-mode operation to extract an induced phase-shift from the output signal. A silicon waveguide MZI sensor designed and fabricated for both multimode and single-mode dimensions. Sensitivity of the sensors is analyzed for waveguide dimensions and materials. An s-bend structure is designed for the multimode waveguide to eliminate higher-order mode power as an alternative to single-mode confinement. Single-mode confinement is experimentally demonstrated through near field imaging of waveguide output. Y-junctions are designed for 3dB power splitting to the MZI arms and for power recombination after sensing to utilize the interferometric function of the MZI. Ultra-short 10microm taper structures with curved geometries are designed to improve insertion loss from fiber-to-chip without significantly increasing device area and show potential for applications requiring misalignment tolerance. An novel v-groove process is developed for self-aligned integration of fiber grooves for attachment to sensor chips. Thermal oxidation at temperatures from 1050-1150°C during groove processing creates an SiO2 layer on the waveguide end facet to protect the waveguide facet during integration etch processing without additional e-beam lithography processing. Experimental results show improvement of insertion loss compared to dicing preparation and Focused Ion Beam methods using the thermal oxidation process.

Comparison of fabrication methods for microstructured deep UV multimode waveguides based on fused silica

NASA Astrophysics Data System (ADS)

Elmlinger, Philipp; Schreivogel, Martin; Schmid, Marc; Kaiser, Myriam; Priester, Roman; Sonström, Patrick; Kneissl, Michael

2016-04-01

The suitability of materials for deep ultraviolet (DUV) waveguides concerning transmittance, fabrication, and coupling properties is investigated and a fused silica core/ambient air cladding waveguide system is presented. This high refractive index contrast system has far better coupling efficiency especially for divergent light sources like LEDs and also a significantly smaller critical bending radius compared to conventional waveguide systems, as simulated by ray-tracing simulations. For the fabrication of 300-ffm-thick multimode waveguides a hydrouoric (HF) acid based wet etch process is compared to selective laser etching (SLE). In order to fabricate thick waveguides out of 300-ffm-thick silica wafers by HF etching, two masking materials, LPCVD silicon nitride and LPCVD poly silicon, are investigated. Due to thermal stress, the silicon nitride deposited wafers show cracks and even break. Using poly silicon as a masking material, no cracks are observed and deep etching in 50 wt% HF acid up to 180 min is performed. While the masked and unmasked silica surface is almost unchanged in terms of roughness, notching defects occur at the remaining polysilicon edge leading to jagged sidewalls. Using SLE, waveguides with high contour accuracy are fabricated and the DUV guiding properties are successfully demonstrated with propagation losses between 0.6 and 0:8 dB=mm. These values are currently limited by sidewall scattering losses.

Multimode Directional Coupler for Utilization of Harmonic Frequencies from TWTAs

NASA Technical Reports Server (NTRS)

Simmons, Rainee N.; Wintucky, Edwin G.

2013-01-01

A novel waveguide multimode directional coupler (MDC) intended for the measurement and potential utilization of the second and higher order harmonic frequencies from high-power traveling wave tube amplifiers (TWTAs) has been successfully designed, fabricated, and tested. The design is based on the characteristic multiple propagation modes of the electrical and magnetic field components of electromagnetic waves in a rectangular waveguide. The purpose was to create a rugged, easily constructed, more efficient waveguide- based MDC for extraction and exploitation of the second harmonic signal from the RF output of high-power TWTs used for space communications. The application would be a satellitebased beacon source needed for Qband and V/W-band atmospheric propagation studies. The MDC could function as a CW narrow-band source or as a wideband source for study of atmospheric group delay effects on highdata- rate links. The MDC is fabricated from two sections of waveguide - a primary one for the fundamental frequency and a secondary waveguide for the second harmonic - that are joined together such that the second harmonic higher order modes are selectively coupled via precision- machined slots for propagation in the secondary waveguide. In the TWTA output waveguide port, both the fundamental and the second harmonic signals are present. These signals propagate in the output waveguide as the dominant and higher order modes, respectively. By including an appropriate mode selective waveguide directional coupler, such as the MDC presented here at the output of the TWTA, the power at the second harmonic can be sampled and amplified to the power level needed for atmospheric propagation studies. The important conclusions from the preliminary test results for the multimode directional coupler are: (1) the second harmonic (Ka-band) can be measured and effectively separated from the fundamental (Ku-band) with no coupling of the latter, (2) power losses in the fundamental frequency are negligible, and (3) the power level of the extracted second harmonic is sufficient for further amplification to power levels needed for practical applications. It was also demonstrated that third order and potentially higher order harmonics are measurable with this device. The design is frequency agnostic, and with the appropriate choice of waveguides, is easily scaled to higher frequency TWTs. The MDC has the same function but with a number of important advantages over the conventional diplexer.

Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Feng; Spring, Andrew M.; Sato, Hiromu

2015-09-21

Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed and fabricated. The waveguide consists of a silicon core with a thickness of 30 nm and a width of 2 μm. The cladding is an EO polymer. Optical mode calculation reveals that 55% of the optical field around the silicon extends into the EO polymer in the TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. The measured half-wave voltage of the MZI with 7 μm spacing and 1.3 cm long electrodes is 4.6 V at 1550 nm. The evaluated EO coefficient is 70 pm/V, which is comparable to that ofmore » the bulk EO polymer film. Using ultra-thin silicon is beneficial in order to reduce the side-wall scattering loss, yielding a propagation loss of 4.0 dB/cm. We also investigated a mode converter which couples light from the hybrid EO waveguide into a strip silicon waveguide. The calculation indicates that the coupling loss between these two devices is small enough to exploit the potential fusion of a hybrid EO polymer modulator together with a silicon micro-photonics device.« less

FIBER AND INTEGRATED OPTICS: New type of heterogeneous nanophotonic silicon-on-insulator optical waveguides

NASA Astrophysics Data System (ADS)

Tsarev, Andrei V.

2007-08-01

A new type of optical waveguides in silicon-on-insulator nanostructures is proposed and studied. Their optical properties are simulated by the beam propagation method and discussed. A new design in the form of heterogeneous waveguide structures is based on the production of additionally heavily doped p+-regions on the sides of a multimode stripe waveguide (the silicon core cross section is ~200 nm × 16 μm). Such doping provides the 'single-mode' behaviour of the heterogeneous waveguide due to the decrease in the optical losses for the fundamental mode and increase in losses for higher-order modes. Single-mode heterogeneous waveguides can be used as base waveguides in photonic and integrated optical elements.

Rectangular-cladding silicon slot waveguide with improved nonlinear performance

NASA Astrophysics Data System (ADS)

Huang, Zengzhi; Huang, Qingzhong; Wang, Yi; Xia, Jinsong

2018-04-01

Silicon slot waveguides have great potential in hybrid silicon integration to realize nonlinear optical applications. We propose a rectangular-cladding hybrid silicon slot waveguide. Simulation result shows that, with a rectangular-cladding, the slot waveguide can be formed by narrower silicon strips, so the two-photon absorption (TPA) loss in silicon is decreased. When the cladding material is a nonlinear polymer, the calculated TPA figure of merit (FOMTPA) is 4.4, close to the value of bulk nonlinear polymer of 5.0. This value confirms the good nonlinear performance of rectangular-cladding silicon slot waveguides.

Acrylic and metal based Y-branch plastic optical fiber splitter with optical NOA63 polymer waveguide taper region

NASA Astrophysics Data System (ADS)

Ehsan, Abang Annuar; Shaari, Sahbudin; Rahman, Mohd Kamil Abd.

2011-01-01

We proposed a simple low-cost acrylic and metal-based Y-branch plastic optical fiber (POF) splitter which utilizes a low cost optical polymer glue NOA63 as the main waveguiding medium at the waveguide taper region. The device is composed of three sections: an input POF waveguide, a middle waveguide taper region and output POF waveguides. A desktop high speed CNC engraver is utilized to produce the mold inserts used for the optical devices. Short POF fibers are inserted into the engraved slots at the input and output ports. UV curable optical polymer glue NOA63 is injected into the waveguide taper region and cured. The assembling is completed when the top plate is positioned to enclose the device structure and connecting screws are secured. Both POF splitters have an average insertion loss of 7.8 dB, coupling ratio of 55: 45 and 57: 43 for the acrylic and metal-based splitters respectively. The devices have excess loss of 4.82 and 4.73 dB for the acrylic and metal-based splitters respectively.

Waveguide couplers with new power splitting ratios made possible by cascading of short multimode interference sections

NASA Astrophysics Data System (ADS)

Feng, David J. Y.; Lay, T. S.; Chang, T. Y.

2007-02-01

We show that it is possible to obtain 2 x 2 waveguide couplers with new power splitting ratios for cross coupling of 7%, 64%, 80% and 93% by cascading two short MMI sections. These couplers have simple geometry and low loss. They offer valuable new possibilities for designing waveguide power taps, high-Q ring resonators, ladder-structure optical filters, and loop-mirror partial reflectors.

Analysis of photonic spot profile converter and bridge structure on SOI platform for horizontal and vertical integration

NASA Astrophysics Data System (ADS)

Majumder, Saikat; Jha, Amit Kr.; Biswas, Aishik; Banerjee, Debasmita; Ganguly, Dipankar; Chakraborty, Rajib

2017-08-01

Horizontal spot size converter required for horizontal light coupling and vertical bridge structure required for vertical integration are designed on high index contrast SOI platform in order to form more compact integrated photonic circuits. Both the structures are based on the concept of multimode interference. The spot size converter can be realized by successive integration of multimode interference structures with reducing dimension on horizontal plane, whereas the optical bridge structure consists of a number of vertical multimode interference structure connected by single mode sections. The spot size converter can be modified to a spot profile converter when the final single mode waveguide is replaced by a slot waveguide. Analysis have shown that by using three multimode sections in a spot size converter, an Gaussian input having spot diameter of 2.51 μm can be converted to a spot diameter of 0.25 μm. If the output single mode section is replaced by a slot waveguide, this input profile can be converted to a flat top profile of width 50 nm. Similarly, vertical displacement of 8μm is possible by using a combination of two multimode sections and three single mode sections in the vertical bridge structure. The analyses of these two structures are carried out for both TE and TM modes at 1550 nm wavelength using the semi analytical matrix method which is simple and fast in computation time and memory. This work shows that the matrix method is equally applicable for analysis of horizontally as well as vertically integrated photonic circuit.

Planar polymer waveguides with a graded-index profile resulting from intermixing of methacrylates in closed microchannels

NASA Astrophysics Data System (ADS)

Missinne, Jeroen; Misseeuw, Lara; Liu, Xiang; Salter, Patrick S.; Van Steenberge, Geert; Adesanya, Kehinde; Van Vlierberghe, Sandra; Booth, Martin J.; Dubruel, Peter

2018-02-01

Graded-index waveguides are known to exhibit lower losses and considerably larger bandwidths compared to step-index waveguides. The present work reports on a new concept for realizing such waveguides on a planar substrate by capillary filling microchannels (cladding) with monomer solution (core). A graded-index profile is obtained by intermixing between the core and cladding material at the microchannel interface. To this end, various ratios of methyl methacrylate (MMA) and octafluoropentyl methacrylate (OFPMA) were evaluated as starting monomers and the results showed that the polymers P50:50 (50:50 MMA:OFPMA) and P0:100 (100% OFPMA) were suitable to be applied as waveguide core and cladding material respectively. Light guiding in the resulting P50:50/P0:100 waveguides was demonstrated and the refractive-index profile was quantified and compared with that of conventional step-index waveguides. The results for both cases were clearly different and a gradual refractive index transition between the core and cladding was found for the newly developed waveguides. Although the concept has been demonstrated in a research environment, it also has potential for upscaling by employing drop-on-demand dispensing of polymer waveguide material in pre-patterned microchannels, for example in a roll-to-roll environment.

Monolithic coupling of a SU8 waveguide to a silicon photodiode

NASA Astrophysics Data System (ADS)

Nathan, M.; Levy, O.; Goldfarb, I.; Ruzin, A.

2003-12-01

We present quantitative results of light coupling from SU8 waveguides into silicon p-n photodiodes in monolithically integrated structures. Multimode, 12 μm thick, and 20 μm wide SU8 waveguides were fabricated to overlap 40×180 μm2 photodiodes, with three different waveguide-photodiode overlap lengths. The attenuation due to leaky-mode coupling in the overlap area was then calculated from photocurrent measurements. The overlap attenuation ranged from a minimum of 2.2 dB per mm overlap length to a maximum of about 3 dB/mm, comparing favorably with reported nonpolymeric waveguide-Si photodiode attenuations.

Silicon cross-connect filters using microring resonator coupled multimode-interference-based waveguide crossings.

PubMed

Xu, Fang; Poon, Andrew W

2008-06-09

We report silicon cross-connect filters using microring resonator coupled multimode-interference (MMI) based waveguide crossings. Our experiments reveal that the MMI-based cross-connect filters impose lower crosstalk at the crossing than the conventional cross-connect filters using plain crossings, while offering a nearly symmetric resonance line shape in the drop-port transmission. As a proof-of-concept for cross-connection applications, we demonstrate on a silicon-on-insulator substrate (i) a 4-channel 1 x 4 linear-cascaded MMI-based cross-connect filter, and (ii) a 2-channel 2 x 2 array-cascaded MMI-based cross-connect filter.

Optical Sensors Based on Single on Arm Thin Film Waveguide Interferometer

NASA Technical Reports Server (NTRS)

Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

2000-01-01

Single-arm dual-mode optical waveguide interferometer utilizes interference between two modes of different order. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric structure containing a dye-doped polymer film onto a quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional) TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TE(sub 1) or TM(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye targeting a particular gaseous reagent. Change of the optical absorption spectrum of the dye caused by the gaseous pollutant results in change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As indicator dyes we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate that is sensitive to small concentrations of ammonia. The indicator dye demonstrated an irreversible increase in optical absorption near the peak at 350 nm being exposed to 5% ammonia in pure nitrogen at 600 Torr. The dye also showed reversible growth of the absorption peak near 600 nm after exposure to a vapor of standard medical ammonia spirit (65% alcohol). We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed a sensitivity to temperature change of the order of 2 C per 2pi phase shift. The sensitivity of the sensor to the presence of dTy ammonia is not less than 300 ppm per 2pi phase shift. The proposed sensor can be used as a robust stand-alone instrument for continuous environment pollution monitoring.

Vapor-Redissolution Technique for Reduction of POLYMER/Si Arrayed Waveguide Grating Loss

NASA Astrophysics Data System (ADS)

Zhang, Haiming; Zhang, Daming; Qin, Zhenkun; Ma, Chunsheng

An efficient vapor-redissolution technique is used to greatly reduce sidewall scattering loss in the polymer arrayed waveguide grating (AWG) fabricated on a silicon substrate. Smoother sidewalls are achieved and verified by scanning electron microscopy. Reduction of sidewall scattering loss is further measured for the loss measurement of both straight waveguides and AWG devices. The sidewall loss in straight polymer waveguide is decreased by 2.1 dB/cm, the insertion loss of our AWG device is reduced by about 5.5 dB for the central channel and 6.7 dB for the edge channels, the crosstalk is reduced by 2.5 dB, and 3-dB bandwidth is narrowed by 0.05 nm after the vapor-redissoluton treatment.

The hybrid photonic planar integrated receiver with a polymer optical waveguide

NASA Astrophysics Data System (ADS)

Busek, Karel; Jerábek, Vitezslav; Armas Arciniega, Julio; Prajzler, Václav

2008-11-01

This article describes design of the photonic receiver composed of the system polymer planar waveguides, InGaAs p-i-n photodiode and integrated HBT amplifier on a low loss composite substrate. The photonic receiver was the main part of the hybrid integrated microwave optoelectronic transceiver TRx (transciever TRx) for the optical networks PON (passive optical networks) with FTTH (fiber-to-the-home) topology. In this article are presented the research results of threedimensional field between output facet of a optical waveguide and p-i-n photodiode. In terms of our research, there was optimized the optical coupling among the facet waveguide and pi-n photodiode and the electrical coupling among p-i-n photodiode and input of HBT amplifier. The hybrid planar lightwave circuit (PLC) of the transceiver TRx will be composed from a two parts - polymer optical waveguide including VHGT filter section and a optoelectronic microwave section.

Tapered waveguides for guided wave optics.

PubMed

Campbell, J C

1979-03-15

Strip waveguides having half-paraboloid shaped tapers that permit efficient fiber to waveguide coupling have been fabricated by Ag ion exchange in soda-lime glass. A reduction in the input coupling loss has been accomplished by tailoring the diffusion to provide a gradual transition from a single-mode waveguide to a multimode waveguide having cross-sectional dimensions comparable to the core diameter of a single-mode fiber. Waveguides without tapers exhibit an attenuation of 1.0 dB/cm and an input coupling loss of 0.6 dB. The additional loss introduced by the tapered region is 0.5 dB. By way of contrast, an input coupling loss of 2.4 dB is obtained by coupling directly to a single-mode waveguide, indicating a net improvement of 1.3 dB for the tapered waveguides.

Polished polymide substrate

DOEpatents

Farah, John; Sudarshanam, Venkatapuram S.

2003-05-13

Polymer substrates, in particular polyimide substrates, and polymer laminates for optical applications are described. Polyimide substrates are polished on one or both sides depending on their thickness, and single-layer or multi-layer waveguide structures are deposited on the polished polyimide substrates. Optical waveguide devices are machined by laser ablation using a combination of IR and UV lasers. A waveguide-fiber coupler with a laser-machined groove for retaining the fiber is also disclosed.

Low-cost integrated-optic fiber couplers

NASA Astrophysics Data System (ADS)

Sheem, Sang K.; Zhang, Feng; Choi, Jong-Ho; Lee, Yong-Woo; Low, Sarah; Lu, Shih-Yau

1997-04-01

In an effort to lower the cost of fiber optic couplers, integrated optic channel waveguide circuits are made of a UV-curable polymer using a molding technique, and then a novel fiber-to-channel connecting approach is employed in which UV light radiating from an optical fiber core cures the polymer in the channel, thus accomplishing a 'touchdown' of the core-extension waveguide onto the walls of the channel waveguide.

Low-Loss Waveguides for Terahertz Frequencies

NASA Technical Reports Server (NTRS)

Siegel, Peter; Yeh, Cavour; Shimabukuro, Fred; Fraser, Scott

2008-01-01

Hollow-core, periodic bandgap (HCPBG) flexible waveguides have been proposed as a means of low-loss transmission of electromagnetic signals in the frequency range from about 300 GHz to 30 THz. This frequency range has been called the "terahertz gap" because it has been little utilized: Heretofore, there has been no way of low-loss guiding of terahertz beams other than by use of fixed-path optical beam guides with lenses and mirrors or multimode waveguides that cannot maintain mode purity around bends or modest discontinuities.

Nonlinear optical properties of organic materials V; Proceedings of the 5th Meeting, San Diego, CA, July 22-24, 1992

NASA Astrophysics Data System (ADS)

Williams, David J.

The present volume on nonlinear optical properties of organic materials discusses organic nonlinear optics, polymers for nonlinear optics, characterization of nonlinear properties, photorefractive and second-order materials, harmonic generation in organic materials, and devices and applications. Particular attention is given to organic semiconductor-doped polymer glasses as novel nonlinear media, heterocyclic nonlinear optical materials, loss measurements in electrooptic polymer waveguides, the phase-matched second-harmonic generation in planar waveguides, electrooptic measurements in poled polymers, transient effects in spatial light modulation by nonlinearity-absorbing molecules, the electrooptic effects in organic single crystals, surface acoustic wave propagation in an organic nonlinear optical crystal, nonlinear optics of astaxanthin thin films; and advanced high-temperature polymers for integrated optical waveguides. (No individual items are abstracted in this volume)

Polymer optical waveguide with multiple graded-index cores for on-board interconnects fabricated using soft-lithography.

PubMed

Ishigure, Takaaki; Nitta, Yosuke

2010-06-21

We successfully fabricate a polymer optical waveguide with multiple graded-index (GI) cores directly on a substrate utilizing the soft-lithography method. A UV-curable polymer (TPIR-202) supplied from Tokyo Ohka Kogyo Co., Ltd. is used, and the GI cores are formed during the curing process of the core region, which is similar to the preform process we previously reported. We experimentally confirm that near parabolic refractive index profiles are formed in the parallel cores (more than 50 channels) with 40 microm x 40 microm size at 250-microm pitch. Although the loss is still as high as 0.1 approximately 0.3 dB/cm at 850 nm, which is mainly due to scattering loss inherent to the polymer matrix, the scattering loss attributed to the waveguide's structural irregularity could be sufficiently reduced by a graded refractive index profile. For comparison, we fabricate step-index (SI)-core waveguides with the same materials by means of the same process. Then, we evaluate the inter-channel crosstalk in the SI- and GI-core waveguides under almost the same conditions. It is noteworthy that remarkable crosstalk reduction (5 dB and beyond) is confirmed in the GI-core waveguides, since the propagating modes in GI-cores are tightly confined near the core center and less optical power is found near the core cladding boundary. This significant improvement in the inter-channel crosstalk allows the GI-core waveguides to be utilized for extra high-density on-board optical interconnections.

Correlated tuning of the speckle pattern in an interferometer based on a multimode fiber-optic waveguide

NASA Astrophysics Data System (ADS)

Bykovskii, Iu. A.; Kul'Chin, Iu. N.; Obukh, V. F.; Smirnov, V. L.

1990-08-01

The correlated tuning of the speckle pattern in the radiation field of a single-fiber multimode interferometer is investigated experimentally and analytically in the presence of external action. It is found that correlated changes in the speckle pattern are observed in both the near and the far emission fields of the waveguide. An expression is obtained which provides a way to determine the maximum size of the speckle correlation region. The use of spatial filtering for isolating the effect of correlated speckle pattern tuning is suggested. It is shown that the use of a spatial filter makes it possible to increase the efficiency of fiber-optic transducers.

Low loss depressed cladding waveguide inscribed in YAG:Nd single crystal by femtosecond laser pulses.

PubMed

Okhrimchuk, Andrey; Mezentsev, Vladimir; Shestakov, Alexander; Bennion, Ian

2012-02-13

A depressed cladding waveguide with record low loss of 0.12 dB/cm is inscribed in YAG:Nd(0.3at.%) crystal by femtosecond laser pulses with an elliptical beam waist. The waveguide is formed by a set of parallel tracks which constitute the depressed cladding. It is a key element for compact and efficient CW waveguide laser operating at 1064 nm and pumped by a multimode laser diode. Special attention is paid to mechanical stress resulting from the inscription process. Numerical calculation of mode distribution and propagation loss with the elasto-optical effect taken into account leads to the conclusion that the depressed cladding is a dominating factor in waveguide mode formation, while the mechanical stress only slightly distorts waveguide modes.

Design of ultra-broadband terahertz polymer waveguide emitters for telecom wavelengths using coupled mode theory.

PubMed

Vallejo, Felipe A; Hayden, L Michael

2013-03-11

We use coupled mode theory, adequately incorporating optical losses, to model ultra-broadband terahertz (THz) waveguide emitters (0.1-20 THz) based on difference frequency generation of femtosecond infrared (IR) optical pulses. We apply the model to a generic, symmetric, five-layer, metal/cladding/core waveguide structure using transfer matrix theory. We provide a design strategy for an efficient ultra-broadband THz emitter and apply it to polymer waveguides with a nonlinear core composed of a poled guest-host electro-optic polymer composite and pumped by a pulsed fiber laser system operating at 1567 nm. The predicted bandwidths are greater than 15 THz and we find a high conversion efficiency of 1.2 × 10(-4) W(-1) by balancing both the modal phase-matching and effective mode attenuation.

Effects of design geometry on SU8 polymer waveguides

NASA Astrophysics Data System (ADS)

Holland, Anthony S.; Balkunje, Vishal S.; Mitchell, Arnan; Austin, Michael W.; Raghunathan, Mukund K.; Kostovski, Gorgi

2005-02-01

The spin-on photoresist SU8 from MicroChem has a relatively high refractive index (n=1.57 at 1550nm) compared with other polymers. It is stable and has high optical transmission at optical communication wavelengths. In this paper we study rib waveguides fabricated using SU8 as the core layer and thermoset polymers UV15 (n=1.50 at 1550nm) from Master Bond and NOA61 (n=1.54 at 1550nm) from Gentec as the cladding layers. The rib height is varied from 0.3 to 1.7μm high. This is part of the SU8 layer sandwiched between the cladding layers. The waveguides are tested to determine the effects of varying this geometry for single mode optical transmission. The lengths of the waveguides were 1.5 cm to 5 cm.

Polymer taper bridge for silicon waveguide to single mode waveguide coupling

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Middlebrook, Christopher T.

2016-03-01

Coupling of optical power from high-density silicon waveguides to silica optical fibers for signal routing can incur high losses and often requires complex end-face preparation/processing. Novel coupling device taper structures are proposed for low coupling loss between silicon photonic waveguides and single mode fibers are proposed and devices are fabricated and measured in terms of performance. Theoretical mode conversion models for waveguide tapers are derived for optimal device structure design and performance. Commercially viable vertical and multi-layer taper designs using polymer waveguide materials are proposed as innovative, cost-efficient, and mass-manufacturable optical coupling devices. The coupling efficiency for both designs is determined to evaluate optimal device dimensions and alignment tolerances with both silicon rib waveguides and silicon nanowire waveguides. Propagation loss as a function of waveguide roughness and metallic loss are determined and correlated to waveguide dimensions to obtain total insertion loss for the proposed taper designs. Multi-layer tapers on gold-sputtered substrates are fabricated through photolithography as proof-of-concept devices and evaluated for device loss optimization. Tapered waveguide coupling loss with Si WGs (2.74 dB) was experimentally measured with high correlation to theoretical results.

Polymer/silica hybrid waveguide temperature sensor based on asymmetric Mach-Zehnder interferometer

NASA Astrophysics Data System (ADS)

Niu, Donghai; Wang, Xibin; Sun, Shiqi; Jiang, Minghui; Xu, Qiang; Wang, Fei; Wu, Yuanda; Zhang, Daming

2018-04-01

A highly sensitive waveguide temperature sensor based on asymmetric Mach-Zehnder interferometer was designed and experimentally demonstrated. The interferometer is based on the polymer/silica hybrid waveguide structure, and Norland Optical Adhesive 73 (NOA 73) was employed as the waveguide core to enhance the temperature sensitivity. The influence of the different length differences between the two interferometer arms on the sensitivity of the sensor was systemically studied. It is shown that the maximum temperature sensitivity of -431 pm °C-1 can be obtained in the range of 25 °C-75 °C, while the length difference is 92 μm. Moreover, the temperature sensitivity contributions from different core materials were also investigated experimentally. It is shown that the waveguide material and microstructure of the device have significant influences on the sensitivity of the waveguide temperature sensor.

FIBER AND INTEGRATED OPTICS: Experimental investigation of energy transfer between modes in a graded-index fiber waveguide with periodic microbending of the axis

NASA Astrophysics Data System (ADS)

Garichev, V. P.; Krivoshlykov, S. G.; Jahn, I.-U.

1990-08-01

An experimental investigation was made of energy transfer between the lowest axially symmetric modes in a multimode graded-index fiber waveguide as a function of the amplitude of periodic bending of its axis. Selective excitation and detection of given modes in a waveguide was induced with the aid of synthesized holograms. The experimental curves were in satisfactory agreement with the results of a theoretical calculation and confirmed that the sensitivity of a mode to bending of the axis of a graded-index waveguide increased on increase in the mode number.

Facet-embedded thin-film III-V edge-emitting lasers integrated with SU-8 waveguides on silicon.

PubMed

Palit, Sabarni; Kirch, Jeremy; Huang, Mengyuan; Mawst, Luke; Jokerst, Nan Marie

2010-10-15

A thin-film InGaAs/GaAs edge-emitting single-quantum-well laser has been integrated with a tapered multimode SU-8 waveguide onto an Si substrate. The SU-8 waveguide is passively aligned to the laser using mask-based photolithography, mimicking electrical interconnection in Si complementary metal-oxide semiconductor, and overlaps one facet of the thin-film laser for coupling power from the laser to the waveguide. Injected threshold current densities of 260A/cm(2) are measured with the reduced reflectivity of the embedded laser facet while improving single mode coupling efficiency, which is theoretically simulated to be 77%.

Analysis of an optically controlled photonic switch.

PubMed

Attard, A E

1999-05-20

The principle that the coupling of light between two fiber waveguides can be controlled by the resonant interference of a third waveguide has been developed [Attard, Appl. Opt. 37, 2296-2302 (1998)]. Here significant details concerning the operation of a photonic switch are obtained, and a more complete analysis is presented. Multiple-resonant conditions are identified for slab and fiber control waveguides at large indices of refraction. Thus a selection of materials with an appropriate refractive index and a Kerr coefficient is rendered more easily. Furthermore it is shown that the light used to control the index of refraction in the control waveguide does not enter the output of the photonic switch but remains confined to the control waveguide, for either a slab or a multimode fiber control waveguide. Spatial fluctuations of the control light beam in the control waveguide do not affect the operation of the photonic switch. Tolerances have been determined for the spacing between the control waveguide and the photonic coupler and also for the index of refraction of the control waveguide.

Finite mode analysis through harmonic waveguides

PubMed

Alieva; Wolf

2000-08-01

The mode analysis of signals in a multimodal shallow harmonic waveguide whose eigenfrequencies are equally spaced and finite can be performed by an optoelectronic device, of which the optical part uses the guide to sample the wave field at a number of sensors along its axis and the electronic part computes their fast Fourier transform. We illustrate this process with the Kravchuk transform.

Extremely small polarization beam splitter based on a multimode interference coupler with a silicon hybrid plasmonic waveguide.

PubMed

Guan, Xiaowei; Wu, Hao; Shi, Yaocheng; Dai, Daoxin

2014-01-15

A novel polarization beam splitter (PBS) with an extremely small footprint is proposed based on a multimode interference (MMI) coupler with a silicon hybrid plasmonic waveguide. The MMI section, covered with a metal strip partially, is designed to achieve mirror imaging for TE polarization. On the other hand, for TM polarization, there is almost no MMI effect since the higher-order TM modes are hardly excited due to the hybrid plasmonic effect. With this design, the whole PBS including the 1.1 μm long MMI section as well as the output section has a footprint as small as ∼1.8 μm×2.5 μm. Besides, the fabrication process is simple since the waveguide dimension is relatively large (e.g., the input/output waveguides widths w ≥300 nm and the MMI width w(MMI)=800 nm). Numerical simulations show that the designed PBS has a broad band of ∼80 nm for an ER >10 dB as well as a large fabrication tolerance to allow a silicon core width variation of -30 nm<Δw<50 nm and a metal strip width variation of -200 nm<Δw(m)<0.

Manufacturing of polymer optical waveguides using self-assembly effect on pre-conditioned 3D-thermoformed flexible substrates

NASA Astrophysics Data System (ADS)

Hoffmann, Gerd-Albert; Wolfer, Tim; Zeitler, Jochen; Franke, Jörg; Suttmann, Oliver; Overmeyer, Ludger

2017-02-01

Optical data communication is increasingly interesting for many applications in industrial processes. Therefore mass production is required to meet the requested price and lot sizes. Polymer optical waveguides show great promises to comply with price requirements while providing sufficient optical quality for short range data transmission. A high efficient fabrication technology using polymer materials could be able to create the essential backbone for 3D-optical data transmission in the future. The approach for high efficient fabrication technology of micro optics described in this paper is based on a self-assembly effect of fluids on preconditioned 3D-thermoformed polymer foils. Adjusting the surface energy on certain areas on the flexible substrate by flexographic printing mechanism is presented in this paper. With this technique conditioning lines made of silicone containing UV-varnish are printed on top of the foils and create gaps with the exposed substrate material in between. Subsequent fabrication processes are selected whether the preconditioned foil is coated with acrylate containing waveguide material prior or after the thermoforming process. Due to the different surface energy this material tends to dewet from the conditioning lines. It acts like regional barriers and sets the width of the arising waveguides. With this fabrication technology it is possible to produce multiple waveguides with a single coating process. The relevant printing process parameters that affect the quality of the generated waveguides are discussed and results of the produced waveguides with width ranging from 10 to 300 μm are shown.

Scalable electro-photonic integration concept based on polymer waveguides

NASA Astrophysics Data System (ADS)

Bosman, E.; Van Steenberge, G.; Boersma, A.; Wiegersma, S.; Harmsma, P.; Karppinen, M.; Korhonen, T.; Offrein, B. J.; Dangel, R.; Daly, A.; Ortsiefer, M.; Justice, J.; Corbett, B.; Dorrestein, S.; Duis, J.

2016-03-01

A novel method for fabricating a single mode optical interconnection platform is presented. The method comprises the miniaturized assembly of optoelectronic single dies, the scalable fabrication of polymer single mode waveguides and the coupling to glass fiber arrays providing the I/O's. The low cost approach for the polymer waveguide fabrication is based on the nano-imprinting of a spin-coated waveguide core layer. The assembly of VCSELs and photodiodes is performed before waveguide layers are applied. By embedding these components in deep reactive ion etched pockets in the silicon substrate, the planarity of the substrate for subsequent layer processing is guaranteed and the thermal path of chip-to-substrate is minimized. Optical coupling of the embedded devices to the nano-imprinted waveguides is performed by laser ablating 45 degree trenches which act as optical mirror for 90 degree deviation of the light from VCSEL to waveguide. Laser ablation is also implemented for removing parts of the polymer stack in order to mount a custom fabricated connector containing glass fiber arrays. A demonstration device was built to show the proof of principle of the novel fabrication, packaging and optical coupling principles as described above, combined with a set of sub-demonstrators showing the functionality of the different techniques separately. The paper represents a significant part of the electro-photonic integration accomplishments in the European 7th Framework project "Firefly" and not only discusses the development of the different assembly processes described above, but the efforts on the complete integration of all process approaches into the single device demonstrator.

TM-pass polarizer based on multilayer graphene polymer waveguide

NASA Astrophysics Data System (ADS)

Cai, Ke-su; Li, Yue-e.; Wei, Wen-jing; Mu, Xi-jiao; Ma, A.-ning; Wang, Zhong; Song, Dan-ming

2018-05-01

A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed. The mode properties, the extinction ratio, the insertion loss and the bandwidth are also discussed. The results show that a TM-pass polarizer, which only guides the TM mode, can be achieved by multilayer graphene polymer waveguide. With length of 150 μm, the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 dB at optical wavelength of 1.55 μm. This device has an excellent performance, including large extinction ratio and low insertion loss within the spectral range from 1.45 μm to 1.6 μm.

Design and Fabrication of NxN Optical Couplers Based on Organic Polymer Opti al WaveGuides

DTIC Science & Technology

1994-08-01

lOxlO optical coupler utilizing photopolymerizable organic polymers. Background information on the theory of operation of the coupler culminating in a...Channel Waveguides Based on Photopolymerizable Di/Tri Acrylates," in Optoelecwonic Interconnects Ii, Ray T. Chen, John A. Neff, Editors, Proc. SPIE 2153, pp...demonstrated that acrylic polymers can be used to fabricate single-mode optical wavguides. The resins that we have formulated are photopolymerizable

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

PubMed Central

Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

2011-01-01

Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

Multistage Polymeric Lens Structures Integrated into Silica Waveguides

NASA Astrophysics Data System (ADS)

Tate, Atsushi; Suzuki, Takanori; Tsuda, Hiroyuki

2006-08-01

A waveguide lens, composed of multistage polymer-filled thin grooves in a silica planar lightwave circuit (PLC) is proposed and a low-loss structure has been designed. A waveguide lens in a silica slab waveguide has been fabricated using reactive ion etching (RIE) and formed by filling with polymer. Both an imagding optical system and a Fourier-transform optical system can be configured in a PLC using a waveguide lens. It renders the PLC functional and its design flexible. To obtain a shorter focal length with a low insertion loss, it is more effective to use a multistage lens structure. An imaging optical system and a Fourier-transform optical system with a focal length of less than 1000 μm were fabricated in silica waveguides using a multistage lens structure. The lens imaging waveguides incorporate a 16-24-stage lens, with insertion losses of 4-7 dB. A 4 × 4 optical coupler, using a Fourier-transform optical system, utilizes a 6-stage lens with losses of 2-4 dB.

Low-cost fabrication of optical waveguides, interconnects and sensing structures on all-polymer-based thin foils

NASA Astrophysics Data System (ADS)

Rezem, Maher; Kelb, Christian; Günther, Axel; Rahlves, Maik; Reithmeier, Eduard; Roth, Bernhard

2016-03-01

Micro-optical sensors based on optical waveguides are widely used to measure temperature, force and strain but also to detect biological and chemical substances such as explosives or toxins. While optical micro-sensors based on silicon technology require complex and expensive process technologies, a new generation of sensors based completely on polymers offer advantages especially in terms of low-cost and fast production techniques. We have developed a process to integrate micro-optical components such as embedded waveguides and optical interconnects into polymer foils with a thickness well below one millimeter. To enable high throughput production, we employ hot embossing technology, which is capable of reel-to-reel fabrication with a surface roughness in the optical range. For the waveguide fabrication, we used the thermoplastic polymethylmethacrylate (PMMA) as cladding and several optical adhesives as core materials. The waveguides are characterized with respect to refractive indices and propagation losses. We achieved propagation losses are as low as 0.3 dB/cm. Furthermore, we demonstrate coupling structures and their fabrication especially suited to integrate various light sources such as vertical-cavity surface-emitting lasers (VCSEL) and organic light emitting diodes (OLED) into thin polymer foils. Also, we present a concept of an all-polymer and waveguide based deformation sensor based on intensity modulation, which can be fabricated by utilizing our process. For future application, we aim at a low-cost and high-throughput reel-to-reel production process enabling the fabrication of large sensor arrays or disposable single-use sensing structures, which will open optical sensing to a large variety of application fields ranging from medical diagnosis to automotive sensing.

Design issues of a multimode interference-based 3-dB splitter.

PubMed

Themistos, Christos; Rahman, B M Azizur

2002-11-20

We have investigated important issues such as the power loss, the loss imbalance the fabrication tolerances, and the wavelength dependence for the design of a multimode interference-based 3-dB splitter on deeply etched InP waveguides under general, restricted, and symmetric interference mechanisms. For this investigation, we used the finite-element-based beam propagation approach. Results are presented.

Raman characterization of H:LiNbO3 waveguides

NASA Astrophysics Data System (ADS)

Savova, I.; Savatinova, I.; Kircheva, P.; Liarokapis, E.

2001-10-01

In this work we present polarized Raman measurements of z-cut multimode H:LiNbO3 waveguides in the κi- and βi-phase states. A spectrum with unexpected form and behaviour, originating from the layer at the very surface, was observed in samples with various degrees of Li-H substitution. Possible reasons for the presence of this strange spectrum are considered.

FIBER OPTICS: Method of calculation of the propagation constant for guided modes

NASA Astrophysics Data System (ADS)

Ardasheva, L. I.; Sadykov, Nail R.; Chernyakov, V. E.

1992-09-01

A new method of calculating the propagation constants and wave eigenfunctions of guided modes is proposed for axisymmetric translationally invariant fiber-optic waveguides with arbitrary refractive index profiles. The method is based on solving a parabolic scalar wave equation. A comparison is made between the numerical solution under steady-state conditions and the eigenfunctions of single-mode and multimode waveguides.

Multi-Mode Analysis of Dual Ridged Waveguide Systems for Material Characterization

DTIC Science & Technology

2015-09-17

characterization is the process of determining the dielectric, magnetic, and magnetoelectric properties of a material. For simple (i.e., linear ...field expressions in terms of elementary functions (sines, cosines, exponentials and Bessel functions) and corresponding propagation constants of the...with material parameters 0 and µ0. • The MUT is simple ( linear , isotropic, homogeneous), and the sample has a uniform thickness. • The waveguide

Fabrication of optical waveguides using laser direct writing method

NASA Astrophysics Data System (ADS)

Cho, Sung H.; Kim, Jung Min; Kim, Jae G.; Chang, Won S.; Lee, Eung S.

2004-09-01

Laser direct writing (LDW) process is developed using 3-rd harmonic Diode Pumped Solid State Laser (DPSSL) with the near UV wavelength of 355 nm. Photo-sensitive curable polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D patterns. We performed basic experiments for the various process conditions such as laser power, writing speed, laser focus, and optical polymer property to get the optimal conditions. This process could be applied to fabricate a single-mode waveguide without expensive mask projection method. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8.4μm width and 7.5μm height. Propagation loss of planar waveguide was 1.42 dB/cm at wavelength of 1,550 nm.

Ultrathin Au film on polymer surface for surface plasmon polariton waveguide application

NASA Astrophysics Data System (ADS)

Liu, Tong; Ji, Lanting; He, Guobing; Sun, Xiaoqiang; Wang, Fei; Zhang, Daming

2017-11-01

Formation of laterally continuous ultrathin gold films on polymer substrates is a technological challenge. In this work, the vacuum thermal evaporation method is adopted to form continuous Au films in the thickness range of 7-17 nm on polymers of Poly(methyl-methacrylate-glycidly-methacrylate) and SU-8 film surface without using the adhesion or metallic seeding layers. Absorption spectrum, scanning electron microscope and atomic force microscope images are used to characterize the Au film thickness, roughness and optical loss. The result shows that molecular-scale structure, surface energy and electronegativity have impacts on the Au film morphology on polymers. Wet chemical etching is used to fabricate 7-nm thick Au stripes embedded in polymer claddings. These long-range surface plasmon polariton waveguides demonstrate the favorable morphological configurations and cross-sectional states. Through the end-fire excitation method, propagation losses of 6-μm wide Au stripes are compared to theoretical values and analyzed from practical film status. The smooth, patternable gold films on polymer provide potential applications to plasmonic waveguides, biosensing, metamaterials and optical antennas.

Evaluation of hybrid polymers for high-precision manufacturing of 3D optical interconnects by two-photon absorption lithography

NASA Astrophysics Data System (ADS)

Schleunitz, A.; Klein, J. J.; Krupp, A.; Stender, B.; Houbertz, R.; Gruetzner, G.

2017-02-01

The fabrication of optical interconnects has been widely investigated for the generation of optical circuit boards. Twophoton absorption (TPA) lithography (or high-precision 3D printing) as an innovative production method for direct manufacture of individual 3D photonic structures gains more and more attention when optical polymers are employed. In this regard, we have evaluated novel ORMOCER-based hybrid polymers tailored for the manufacture of optical waveguides by means of high-precision 3D printing. In order to facilitate future industrial implementation, the processability was evaluated and the optical performance of embedded waveguides was assessed. The results illustrate that hybrid polymers are not only viable consumables for industrial manufacture of polymeric micro-optics using generic processes such as UV molding. They also are potential candidates to fabricate optical waveguide systems down to the chip level where TPA-based emerging manufacturing techniques are engaged. Hence, it is shown that hybrid polymers continue to meet the increasing expectations of dynamically growing markets of micro-optics and optical interconnects due to the flexibility of the employed polymer material concept.

Wide band cryogenic ultra-high vacuum microwave absorber

DOEpatents

Campisi, I.E.

1992-05-12

An absorber waveguide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the waveguide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the waveguide. 11 figs.

Design and characterization of Ge passive waveguide components on Ge-on-insulator wafer for mid-infrared photonics

NASA Astrophysics Data System (ADS)

Kang, Jian; Takagi, Shinichi; Takenaka, Mitsuru

2018-04-01

We present the design methodology for Ge passive components including single-mode waveguide, grating couplers, multimode interferometer (MMI) couplers, and micro-ring resonators on the Ge-on-insulator wafer at a 1.95 µm wavelength. Characterizations of the fabricated Ge passive devices reveal a good consistence between the experimental and simulation results. By using the Ge micro-ring device, we also reveal that the thermo-optic coefficient in the Ge strip waveguide is 5.74 × 10-4/°C, which is much greater than that in Si.

Low-to-high refractive index contrast transition (RICT) device for low loss polymer-based optical coupling

NASA Astrophysics Data System (ADS)

Calabretta, N.; Cooman, I. A.; Stabile, R.

2018-04-01

We propose for the first time a coupling device concept for passive low-loss optical coupling, which is compatible with the ‘generic’ indium phosphide (InP) multi-project-wafer manufacturing. A low-to-high vertical refractive index contrast transition InP waveguide is designed and tapered down to adiabatically couple light into a top polymer waveguide. The on-chip embedded polymer waveguide is engineered at the chip facets for offering refractive-index and spot-size-matching to silica fiber-arrays. Numerical analysis shows that coupling losses lower than 1.5 dB can be achieved for a TE-polarized light between the InP waveguide and the on-chip embedded polymer waveguide at 1550 nm wavelength. The performance is mainly limited by the difficulty to control single-mode operation. However, coupling losses lower than 1.9 dB can be achieved for a bandwidth as large as 200 nm. Moreover, the foreseen fabrication process steps are indicated, which are compatible with the ‘generic’ InP multi-project-wafer manufacturing. A fabrication error tolerance study is performed, indicating that fabrication errors occur only in 0.25 dB worst case excess losses, as long as high precision lithography is used. The obtained results are promising and may open the route to large port counts and cheap packaging of InP-based photonic integrated chips.

Controlling temperature dependence of silicon waveguide using slot structure.

PubMed

Lee, Jong-Moo; Kim, Duk-Jun; Kim, Gwan-Ha; Kwon, O-Kyun; Kim, Kap-Joong; Kim, Gyungock

2008-02-04

We show that the temperature dependence of a silicon waveguide can be controlled well by using a slot waveguide structure filled with a polymer material. Without a slot, the amount of temperature-dependent wavelength shift for TE mode of a silicon waveguide ring resonator is very slightly reduced from 77 pm/ degrees C to 66 pm/ degrees C by using a polymer (WIR30-490) upper cladding instead of air upper cladding. With a slot filled with the same polymer, however, the reduction of the temperature dependence is improved by a pronounced amount and can be controlled down to -2 pm/ degrees C by adjusting several variables of the slot structure, such as the width of the slot between the pair of silicon wires, the width of the silicon wire pair, and the height of the silicon slab in our experiment. This measurement proves that a reduction in temperature dependence can be improved about 8 times more by using the slot structure.

Interaction and dispersion of waveguide modes in an optical fiber with microirregularities of the core surface

NASA Astrophysics Data System (ADS)

Zadorin, A. S.; Kruglov, R. S.; Surkova, G. A.

2012-08-01

A self-consistent linear model is proposed for the transformation of the average intensity of the mode spectrum I( z) of the waveguide field in a multimode optical fiber with a stepped refractive index profile and the core having a rough surface. The model is based on the concept of the intermodal dispersion matrix of an elementary segment of the fiber, ∆, whose elements characterize the mutual transfer of energy between the waveguide modes, as well as their conversion to radiation modes on the specified interval. On this basis, the features of the transformation of the mode spectrum I( z) in a multimode optical fiber with a stepped refractive index profile are considered that is due to the effects of multiple dispersion of the signal by the stochastic irregularities of the duct. The effect of self-filtering of I( z) is described that results in the formation of a stable (normalized) distribution I*. The features of the normalization of the radiative damping of a group of modes I i ( z) in an optical fiber are considered.

Robustness of Light-Transport Processes to Bending Deformations in Graded-Index Multimode Waveguides

NASA Astrophysics Data System (ADS)

Boonzajer Flaes, Dirk E.; Stopka, Jan; Turtaev, Sergey; de Boer, Johannes F.; Tyc, Tomáš; Čižmár, Tomáš

2018-06-01

Light transport through a multimode optical waveguide undergoes changes when subjected to bending deformations. We show that optical waveguides with a perfectly parabolic refractive index profile are almost immune to bending, conserving the structure of propagation-invariant modes. Moreover, we show that changes to the transmission matrix of parabolic-index fibers due to bending can be expressed with only two free parameters, regardless of how complex a particular deformation is. We provide detailed analysis of experimentally measured transmission matrices of a commercially available graded-index fiber as well as a gradient-index rod lens featuring a very faithful parabolic refractive index profile. Although parabolic-index fibers with a sufficiently precise refractive index profile are not within our reach, we show that imaging performance with standard commercially available graded-index fibers is significantly less influenced by bending deformations than step-index types under the same conditions. Our work thus predicts that the availability of ultraprecise parabolic-index fibers will make endoscopic applications with flexible probes feasible and free from extremely elaborate computational challenges.

Design and fabrication of three-dimensional polymer mode multiplexer based on asymmetric waveguide couplers

NASA Astrophysics Data System (ADS)

He, Guobing; Gao, Yang; Xu, Yan; Ji, Lanting; Sun, Xiaoqiang; Wang, Xibin; Yi, Yunji; Chen, Changming; Wang, Fei; Zhang, Daming; Wu, Yuanda

2018-05-01

A polymer mode multiplexer based on asymmetric couplers is theoretically designed and experimentally demonstrated. The proposed X-junction coupler is formed by waveguides overlapped with different crossing angles in the vertical direction. A beam propagation method is adopted to optimize the dimensional parameters of the mode multiplexer to convert LP01 mode of two lower waveguides to LP11a and LP21a mode of the upper waveguide. The ultraviolet lithography and wet chemical etching are used in the fabrication process. A conversion ratio over 98% for both LP11a and LP21a mode in the wavelength range from 1530 to 1570 nm are experimentally demonstrated. This mode multiplexer has potential in broadband mode-division multiplexing transmission systems.

Organic Thin Films for Photonics Applications. Volume 14

DTIC Science & Technology

1997-01-01

progress of the polymer optical fiber (POF) and related photonics polymer for high-speed telecommunication is reviewed. The high-bandwidth perfluorinated ...silicon. In the waveguide spectrometry studies described above, ab- sorption was measured on slab waveguides where fabrication imperfections are... compound in scries I[//| and II|//| , we have determined in solution: - the ground-state dipole /{ using capacitive measurements - the static

Polymer planar waveguide Bragg gratings: fabrication, characterization, and sensing applications

NASA Astrophysics Data System (ADS)

Rosenberger, M.; Hessler, S.; Pauer, H.; Girschikofsky, M.; Roth, G. L.; Adelmann, B.; Woern, H.; Schmauss, B.; Hellmann, R.

2017-02-01

In this contribution, we give a comprehensive overview of the fabrication, characterization, and application of integrated planar waveguide Bragg gratings (PPBGs) in cyclo-olefin copolymers (COC). Starting with the measurement of the refractive index depth profile of integrated UV-written structures in COC by phase shifting Mach-Zehnder- Interferometry, we analyze the light propagation using numerical simulations. Furthermore, we show the rapid fabrication of humidity insensitive polymer waveguide Bragg gratings in cyclo-olefin copolymers and discuss the influence of the UV-dosage onto the spectral characteristics and the transmission behavior of the waveguide. Based on these measurements we exemplify that our Bragg gratings exhibit a reflectivity of over 99 % and are highly suitable for sensing applications. With regard to a negligible affinity to absorb water and in conjunction with high temperature stability these polymer devices are ideal for mechanical deformation sensing. Since planar structures are not limited to tensile but can also be applied for measuring compressive strain, we manufacture different functional devices and corroborate their applicability as optical sensors. Exemplarily, we highlight a temperature referenced PPBG sensor written into a femtosecond-laser cut tensile test geometry for tensile and compressive strain sensing. Furthermore, a flexible polymer planar shape sensor is presented.

GaN microring waveguide resonators bonded to silicon substrate by a two-step polymer process.

PubMed

Hashida, Ryohei; Sasaki, Takashi; Hane, Kazuhiro

2018-03-20

Using a polymer bonding technique, GaN microring waveguide resonators were fabricated on a Si substrate for future hybrid integration of GaN and Si photonic devices. The designed GaN microring consisted of a rib waveguide having a core of 510 nm in thickness, 1000 nm in width, and a clad of 240 nm in thickness. A GaN crystalline layer of 1000 nm in thickness was grown on a Si(111) substrate by metal organic chemical vapor deposition using a buffer layer of 300 nm in thickness for the compensation of lattice constant mismatch between GaN and Si crystals. The GaN/Si wafer was bonded to a Si(100) wafer by a two-step polymer process to prevent it from trapping air bubbles. The bonded GaN layer was thinned from the backside by a fast atom beam etching to remove the buffer layer and to generate the rib waveguides. The transmission characteristics of the GaN microring waveguide resonators were measured. The losses of the straight waveguides were measured to be 4.0±1.7  dB/mm around a wavelength of 1.55 μm. The microring radii ranged from 30 to 60 μm, where the measured free-spectral ranges varied from 2.58 to 5.30 nm. The quality factors of the microring waveguide resonators were from 1710 to 2820.

Comparison of self-written waveguide techniques and bulk index matching for low-loss polymer waveguide interconnects

NASA Astrophysics Data System (ADS)

Burrell, Derek; Middlebrook, Christopher

2016-03-01

Polymer waveguides (PWGs) are used within photonic interconnects as inexpensive and versatile substitutes for traditional optical fibers. The PWGs are typically aligned to silica-based optical fibers for coupling. An epoxide elastomer is then applied and cured at the interface for index matching and rigid attachment. Self-written waveguides (SWWs) are proposed as an alternative to further reduce connection insertion loss (IL) and alleviate marginal misalignment issues. Elastomer material is deposited after the initial alignment, and SWWs are formed by injecting ultraviolet (UV) light into the fiber or waveguide. The coupled UV light cures a channel between the two differing structures. A suitable cladding layer can be applied after development. Such factors as longitudinal gap distance, UV cure time, input power level, polymer material selection and choice of solvent affect the resulting SWWs. Experimental data are compared between purely index-matched samples and those with SWWs at the fiber-PWG interface. It is shown that < 1 dB IL per connection can be achieved by either method and results indicate lowest potential losses associated with a fine-tuned self-writing process. Successfully fabricated SWWs reduce overall processing time and enable an effectively continuous low-loss rigid interconnect.

Direct laser written polymer waveguides with out of plane couplers for optical chips

NASA Astrophysics Data System (ADS)

Landowski, Alexander; Zepp, Dominik; Wingerter, Sebastian; von Freymann, Georg; Widera, Artur

2017-10-01

Optical technologies call for waveguide networks featuring high integration densities, low losses, and simple operation. Here, we present polymer waveguides fabricated from a negative tone photoresist via two-photon-lithography in direct laser writing, and show a detailed parameter study of their performance. Specifically, we produce waveguides featuring bend radii down to 40 μ m, insertion losses of the order of 10 dB, and loss coefficients smaller than 0.81 dB mm-1, facilitating high integration densities in writing fields of 300 μ m×300 μ m. A novel three-dimensional coupler design allows for coupling control as well as direct observation of outputs in a single field of view through a microscope objective. Finally, we present beam-splitting devices to construct larger optical networks, and we show that the waveguide material is compatible with the integration of quantum emitters.

Highly stable and low loss electro-optic polymer waveguides for high speed microring modulators using photodefinition

NASA Astrophysics Data System (ADS)

Balakrishnan, M.; Diemeer, M. B. J.; Driessen, A.; Faccini, M.; Verboom, W.; Reinhoudt, D. N.; Leinse, A.

2006-02-01

Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature (T g) and photodefinable properties. The polymers tested are polysulfone (PS) and SU8. The electro-optic chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA), which was reported to have a high photochemical stability 1 has been employed in the current work. Tert-butyl-TCVDPA, having bulky side groups, was synthesized and a doubling of the electro-optic coefficient (r33) compared to the unmodified TCVDPA was shown. A microring resonator design was made based on the PS-TCVDPA system. SU8 (passive) and TCVDPA (active) channel waveguides were fabricated by the photodefinition technique and the passive waveguide losses were measured to be 5 dB/cm at 1550 nm.

Preparation of a new electro-optic polymer cross-linkable via copper-free thermal Huisgen cyclo-addition and fabrication of optical waveguides by Reactive Ion Etching.

PubMed

Cabanetos, Clément; Mahé, Hind; Blart, Errol; Pellegrin, Yann; Montembault, Véronique; Fontaine, Laurent; Adamietz, Frédéric; Rodriguez, Vincent; Bosc, Dominique; Odobel, Fabrice

2011-06-01

High-quality trails of ridge waveguides were successfully fabricated using a new cross-linkable polymer (PCC01) by UV photolithography followed by Reactive-Ion Etching (RIE) process. The cross-linking reaction of PCC01 is based on the copper-free Huisgen cyclo-addition between an azide and an acetylene group. The new cross-linkable polymer (PCC01) consists of a structural modification of the previously described materials (Scarpaci et al. Polym. Chem.2011, 2, 157), because the ethynyl group is functionalized by a methyl group instead of the TMS protecting group. This feature prevents the formation of silica (SiO(2)) generated by trimethylsilyl groups and which was stopping the engraving process before completion. Herein, we describe the synthesis, the NLO characterizations, and the fabrication of a high-quality ridge waveguide with PCC01. The new cross-linkable polymer PCC01 not only solves the problems encountered with our previously described polymers, but also presents an enhancement of the electro-optic stability, because d(33) coefficients up to 30 pm/V stable at 150 °C were recorded. © 2011 American Chemical Society

Three-dimensional patterning in polymer optical waveguides using focused ion beam milling

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Burrell, Derek; Middlebrook, Christopher

2016-07-01

Waveguide (WG) photonic-bridge taper modules are designed for symmetric planar coupling between silicon WGs and single-mode fibers (SMFs) to minimize photonic chip and packaging footprint requirements with improving broadband functionality. Micromachined fabrication and evaluation of polymer WG tapers utilizing high-resolution focused ion beam (FIB) milling is performed and presented. Polymer etch rates utilizing the FIB and optimal methods for milling polymer tapers are identified for three-dimensional patterning. Polymer WG tapers with low sidewall roughness are manufactured utilizing FIB milling and optically tested for fabrication loss. FIB platforms utilize a focused beam of ions (Ga+) to etch submicron patterns into substrates. Fabricating low-loss polymer WG taper prototypes with the FIB before moving on to mass-production techniques provides theoretical understanding of the polymer taper and its feasibility for connectorization devices between silicon WGs and SMFs.

TE modes of UV-laser generated waveguides in a planar polymer chip of parabolic refractive index profile

NASA Astrophysics Data System (ADS)

Shams El-Din, M. A.

2018-04-01

The UV-laser lithographic method is used for the preparation of Polymeric integrated-optical waveguides in a planar polymer chip. The waveguide samples are irradiated by an excimer laser of wavelength 248 nm with different doses and with the same fluencies. The refractive index depth profile for the waveguides, in the first zone is found to have a parabolic shape and Gaussian shape in the second one that can be determined by Mach-Zehnder interferometer. Both the mode field distribution and the effective mode indices for the first zone only are determined by making use of the theoretical mode and the experimental data. It is found that the model field distribution is strongly dependent on the refractive indices for each zone.

Femtosecond laser inscription of optical circuits in the cladding of optical fibers

NASA Astrophysics Data System (ADS)

Grenier, Jason R.

The aim of this dissertation was to address the question of whether the cladding of single-mode fibers (SMFs) could be modified to enable optical fibers to serve as a more integrated, highly functional platform for optical circuit devices that can efficiently interconnect with the pre-existing fiber core waveguide. The approach adopted in this dissertation was to employ femtosecond laser direct writing (FLDW), an inherently 3D fabrication technique that harnesses non-linear laser-material interactions to modify the fused silica fiber cladding. A fiber mounting and alignment technique was developed along with oil-immersion focusing to address the strong aberrations caused by the cylindrical fiber shape. The development of real-time device monitoring during the FLDW was instrumental to overcome the acute coupling sensitivity to laser alignment errors of +/-1 ?m positional uncertainty, and thereby opened a new practical direction for the precise fabrication of optical devices inside optical fibers. These powerful and flexible laser fabrication and characterization techniques were successfully employed to optimize optical waveguiding devices positioned within the core and cladding of optical fibers. X-, S-Bend, and directional couplers were developed to enable efficient coupling between the laser-formed cladding devices and the pre-existing core waveguide, enabling up to 62% power transfer over bandwidths up to 300 nm at telecommunication wavelengths. Precise alignment of femtosecond laser modification tracks were positioned inside or near the core waveguide of SMFs was further shown to enable a flexible reshaping of the optical properties to create multimode guiding sections arbitrarily along the fiber length. This core waveguide modification facilitated the precise formation of multimode interferometers along the core waveguide to precisely tailor the modal profiles, and control the spectral and polarization response. In-fiber multimode interference (MMI) splitters and couplers were fabricated with coupling ratios from 2% to 50% over a broad 350 nm bandwidth across the telecommunication band. Laser-induced birefringence was harnessed to generate polarization dependent MMI devices for strong polarization filtering (24 dB isolation), or polarization selective taps with up to 50% tapping efficiency over a 25 nm bandwidth. This dissertation is therefore the first demonstration of femtosecond laser direct writing as a flexible and monolithic means of embedding and integrating highly functional optical circuit devices within the cladding of optical fibers that can interconnect efficiently with the pre-existing fiber core waveguide. These developments represent a significant technological advancement for creating new 3D photonic integrated microsystems within the cladding of optical fibers and underpins a new technological platform of fiber cladding photonics.

Channel waveguides in glass via silver-sodium field-assisted ion exchange

NASA Technical Reports Server (NTRS)

Forrest, K.; Pagano, S. J.; Viehmann, W.

1986-01-01

Multimode channel waveguides have been formed in sodium aluminosilicate glass by field-assisted diffusion of Ag(+) ions from vacuum-evaporated Ag films. The two-dimensional refractive index profiles of the waveguides were controlled by varying the diffusion time, the diffusion temperature, and the electric field strength. Estimates of the diffusion rate through a strip aperture were obtained, assuming the electric field was strong 120-240 V/mm. The maximum change in refractive index in the sodium aluminosilicate glasses was estimated near 65 percent of the change in soda-lime silicate glass. The physical properties of the glasses are given in a table.

Long-wave infrared 1 × 2 MMI based on air-gap beneath silicon rib waveguides

NASA Astrophysics Data System (ADS)

Wei, Yuxin; Li, Guoyi; Hao, Yinlei; Li, Yubo; Yang, Jianyi; Wang, Minghua; Jiang, Xiaoqing

2011-08-01

The undercut long-wave infrared (LWIR) waveguide components with air-gap beneath are analyzed and fabricated on the Si-wafer with simple manufacturing process. A 1 × 2 multimode interference (MMI) splitter based on this structure is presented and measured under the 10.6μm wavelength experimental setup. The uniformity of the MMI fabricated is 0.76 dB. The relationship among the output power, slab thickness and air-gap width is also fully discussed. Furthermore, undercut straight waveguides based on SOI platform are fabricated for propagation loss evaluation. Ways to reduce the loss are discussed either.

Multi/demulti-plexer based on transverse mode conversion in photonic crystal waveguides.

PubMed

Zhou, Wen; Zhuang, Yuyang; Ji, Ke; Chen, He-ming

2015-09-21

A novel mode multiplexer and demultiplexer (MMUX/DEMMUX) based on 2-D photonic crystal (PC) at 1550 nm is proposed. The PC-based mode MMUX/DEMMUX including mode conversion function with a single-mode and multi-mode waveguides can be realized by quasi phase-matching TE(0) & TE(1) modes of two waveguides. 2DFinite-Difference-Time-Domain and beam propagation methods are used for simulation. The results show that PC-based mode MMUX/DEMMUX has the potential for high-capacity MDM optical communication systems with a low insertion loss (<0.36dB), low mode crosstalk (< -20.9 dB) and wide bandwidth (~100 nm).

Smooth and flat phase-locked Kerr frequency comb generation by higher order mode suppression

PubMed Central

Huang, S.-W.; Liu, H.; Yang, J.; Yu, M.; Kwong, D.-L.; Wong, C. W.

2016-01-01

High-Q microresonator is perceived as a promising platform for optical frequency comb generation, via dissipative soliton formation. In order to achieve a higher quality factor and obtain the necessary anomalous dispersion, multi-mode waveguides were previously implemented in Si3N4 microresonators. However, coupling between different transverse mode families in multi-mode waveguides results in periodic disruption of dispersion and quality factor, and consequently causes perturbation to dissipative soliton formation and amplitude modulation to the corresponding spectrum. Careful choice of pump wavelength to avoid the mode crossing region is thus critical in conventional Si3N4 microresonators. Here, we report a novel design of Si3N4 microresonator in which single-mode operation, high quality factor, and anomalous dispersion are attained simultaneously. The novel microresonator is consisted of uniform single-mode waveguides in the semi-circle region, to eliminate bending induced mode coupling, and adiabatically tapered waveguides in the straight region, to avoid excitation of higher order modes. The intrinsic quality factor of the microresonator reaches 1.36 × 106 while the group velocity dispersion remains to be anomalous at −50 fs2/mm. With this novel microresonator, we demonstrate that broadband phase-locked Kerr frequency combs with flat and smooth spectra can be generated by pumping at any resonances in the optical C-band. PMID:27181420

A novel C-shaped, gold nanoparticle coated, embedded polymer waveguide for localized surface plasmon resonance based detection.

PubMed

Prabhakar, Amit; Mukherji, Soumyo

2010-12-21

In this study, a novel embedded optical waveguide based sensor which utilizes localized surface plasmon resonance of gold nanoparticles coated on a C-shaped polymer waveguide is being reported. The sensor, as designed, can be used as an analysis chip for detection of minor variations in the refractive index of its microenvironment, which makes it suitable for wide scale use as an affinity biosensor. The C-shaped waveguide coupled with microfluidic channel was fabricated by single step patterning of SU8 on an oxidized silicon wafer. The absorbance due to the localized surface plasmon resonance (LSPR) of SU8 waveguide bound gold nano particle (GNP) was found to be linear with refractive index changes between 1.33 and 1.37. A GNP coated C-bent waveguide of 200 μ width with a bend radius of 1 mm gave rise to a sensitivity of ~5 ΔA/RIU at 530 nm as compared to the ~2.5 ΔA/RIU (refractive index units) of the same dimension bare C-bend SU8 waveguide. The resolution of the sensor probe was ~2 × 10(-4) RIU.

Fully optical backplane system using novel optical plug and slot

NASA Astrophysics Data System (ADS)

Cho, In-Kui; Ahn, Seung-Ho; Lee, Woo-Jin; Han, Sang-Pil; Kim, Jin-Tae; Choi, Chun-Ki; Shin, Kyung-Up; Yoon, Keun Byoung; Jeong, Myung-Yung; Park, Hyo Hoon

2005-10-01

A fully optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by an optical slot. We report a 10 Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of the optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB, 3) Optical slot and plug for high-density (channel pitch : 500 um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data between transmitter/receiver processing boards and backplane boards. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The transmitter/receiver processing boards are designed as plug types, and can be easily plugged-in and -out at an optical backplane board. The optical backplane boards are prepared by employing the lamination processes for conventional electrical PCBs. A practical optical backplane system was implemented with two processing boards and an optical backplane. As connection components between the transmitter/receiver processing boards and backplane board, optical slots made of a 90°-bending structure-embedded optical plug was used. A 10 Gb/s data link was successfully demonstrated. The bit error rate (BER) was determined and is 5.6×10 -9(@10Gb/s) and the BER of 8 Gb/s is < 10 -12.

Printing polymer optical waveguides on conditioned transparent flexible foils by using the aerosol jet technology

NASA Astrophysics Data System (ADS)

Reitberger, Thomas; Hoffmann, Gerd-Albert; Wolfer, Tim; Overmeyer, Ludger; Franke, Joerg

2016-09-01

The optical data transfer is considered as the future of signal transfer due to its various advantages compared to conventional copper-based technologies. The Aerosol Jet Printing (AJP) technology offers the opportunity to print materials with high viscosities, such as liquid transparent polymer adhesives (epoxy resins), on almost any possible substrate material and even in third dimension. This paper introduces a new flexible and comparatively cost-effective way of generating polymer optical waveguides through AJP. Furthermore, the conditioning of the substrate material and the printing process of planar waveguides are presented. In the first step, two lines with hydrophobic behavior are applied on foil material (PMMA, PVC, PI) by using a flexographic printing machine. These silicone based patterns containing functional polymer form barriers for the core material due to their low surface energy after curing. In the second step, the core material (liquid polymer, varnish) is printed between the barrier lines. Because of the hydrophobic behavior of the lines, the contact angle between the substrate surface and the liquid core material is increased which yields to higher aspect ratio. The distance between the barrier lines is at least 100 μm, which defines the width of the waveguide. The minimum height of the core shall be 50 μm. After UV-curing of the core polymer, the cladding material is printed on the top. This is also applied by using the AJP technology. Various tests were performed to achieve the optimal surface properties for adequate adhesion and machine process parameters.

Fabrication of poly(vinyl carbazole) waveguides by oxygen ion implantation

NASA Astrophysics Data System (ADS)

Ghailane, Fatima; Manivannan, Gurusamy; Knystautas, Émile J.; Lessard, Roger A.

1995-08-01

Polymer waveguides were fabricated by ion implantation involving poly(vinyl carbazole) films. This material was implanted by oxygen ions (O ++ ) of energies ranging from 50 to 250 keV. The ion doses varied from 1010 to 1015 ions / cm2. The conventional prism-film coupler method was used to determine the waveguiding nature of the implanted and unimplanted films. The increase of the surface refractive index in the implanted layer has been studied by measuring the effective refractive index (neff) for different optical modes. Electron spectroscopy chemical analysis measurements were also performed to assess the effect of ion implantation on the polymer matrix.

Assembly of optical fibers for the connection of polymer-based waveguide

NASA Astrophysics Data System (ADS)

Ansel, Yannick; Grau, Daniel; Holzki, Markus; Kraus, Silvio; Neumann, Frank; Reinhard, Carsten; Schmitz, Felix

2003-03-01

This paper describes the realization of polymer-based optical structures and the assembly and packaging strategy to connect optical fiber ribbons to the waveguides. For that a low cost fabrication process using the SU-8TM thick photo-resist is presented. This process consists in the deposition of two photo-structurized resist layers filled up with epoxy glue realising the core waveguide. For the assembly, a new modular vacuum gripper was realised and installed on an automatic pick and place assembly robot to mount precisely and efficiently the optical fibers in the optical structures. First results have shown acceptable optical propagation loss for the complete test structure.

Ink-jet printed fluorescent materials as light sources for planar optical waveguides on polymer foils

NASA Astrophysics Data System (ADS)

Bollgruen, Patrick; Gleissner, Uwe; Wolfer, Tim; Megnin, Christof; Mager, Dario; Overmeyer, Ludger; Korvink, Jan G.; Hanemann, Thomas

2016-10-01

Polymer-based optical sensor networks on foils (planar optronic systems) are a promising research field, but it can be challenging to supply them with light. We present a solvent-free, ink-jet printable material system with optically active substances to create planar light sources for these networks. The ink is based on a UV-curable monomer, the fluorescent agents are EuDBMPhen or 9,10-diphenylantracene, which fluoresce at 612 or 430 nm, respectively. We demonstrate the application as light source by printing a small area of fluorescent material on an optical waveguide fabricated by flexographic printing on PMMA foil, resulting in a simple polymer-optical device fabricated entirely by additive deposition techniques. When excited by a 405-nm laser of 10 mW, the emitted light couples into the waveguide and appears at the end of the waveguide. In comparison to conventional light sources, the intensity is weak but could be detected with a photodiode power sensor. In return, the concept has the advantage of being completely independent of any electrical elements or external cable connections.

24-ch microlens-integrated no-polish connector for optical interconnection with polymer waveguides

NASA Astrophysics Data System (ADS)

Shiraishi, Takashi; Yagisawa, Takatoshi; Ikeuchi, Tadashi; Daikuhara, Osamu; Tanaka, Kazuhiro

2013-02-01

We successfully developed a new 24-ch optical connector for polymer waveguides. The connector consists of a transparent thermoplastic resin that has two rectangular slits on one side for alignment of the waveguide films and integrated microlens arrays on the other side for coupling to the MT connector. Two 12-ch waveguide films were cut to a 3-mm width. The thickness of each waveguide film was controlled at 100 μm. The waveguide films were inserted into the slits until they touched the bottom face of the slit. Ultraviolet curing adhesive was used to achieve a short hardening process. The expanded beam in the transparent material is focused by the microlens arrays formed on the connector surface. This lens structure enables assembly without the need for a polishing process. We designed the lens for coupling between a step-index 40-μm rectangular waveguide and a graded-index 50-μm fiber. We achieved low-loss optical coupling by designing a method of providing asymmetric magnification between the horizontal and vertical directions in order to compensate for the asymmetric numerical aperture of the waveguide. The typical measured coupling losses from/to the waveguide to/from the fiber were 1.2 dB and 0.6 dB, respectively. The total coupling loss was as small as that of a physical contact connection.

Biologically inspired artificial compound eyes.

PubMed

Jeong, Ki-Hun; Kim, Jaeyoun; Lee, Luke P

2006-04-28

This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field of view similar to that of a natural compound eye. The spherical configuration of the microlenses is accomplished by reconfigurable microtemplating, that is, polymer replication using the deformed elastomer membrane with microlens patterns. The formation of polymer waveguides self-aligned with microlenses is also realized by a self-writing process in a photosensitive polymer resin. The angular acceptance is directly measured by three-dimensional optical sectioning with a confocal microscope, and the detailed optical characteristics are studied in comparison with a natural compound eye.

Microscopy with multimode fibers

NASA Astrophysics Data System (ADS)

Moser, Christophe; Papadopoulos, Ioannis; Farahi, Salma; Psaltis, Demetri

2013-04-01

Microscopes are usually thought of comprising imaging elements such as objectives and eye-piece lenses. A different type of microscope, used for endoscopy, consists of waveguiding elements such as fiber bundles, where each fiber in the bundle transports the light corresponding to one pixel in the image. Recently a new type of microscope has emerged that exploits the large number of propagating modes in a single multimode fiber. We have successfully produced fluorescence images of neural cells with sub-micrometer resolution via a 200 micrometer core multimode fiber. The method for achieving imaging consists of using digital phase conjugation to reproduce a focal spot at the tip of the multimode fiber. The image is formed by scanning the focal spot digitally and collecting the fluorescence point by point.

Multilayer polymer dielectric films for hollow glass waveguides

NASA Astrophysics Data System (ADS)

Kendall, Wesley; Harrington, James A.

2018-02-01

Hollow glass waveguides (HGWs) have been extensively investigated for the transmission of broadband, high-power radiation, particularly in the mid-infrared. One area of particular interest is the deposition of dielectric thin films within the hollow core of the HGW in order to reduce the losses at desired wavelengths. By implementing a thin film multilayer structure with high index mismatch between adjacent films, it is possible to dramatically improve the losses of the waveguides due to the thin film interference effect. Existing multilayer film research has utilized heavy metal halides, which although provide considerable index contrast, are toxic and unsuitable for clinical applications in which they are often used. Polymer dielectric thin films provide desirable optical properties for HGWs but are hindered by solvent compatibility in the deposition procedure. This work demonstrates implementation of a polymer multilayer dielectric thin film stack within a HGW, using ChemoursTM Teflon AF (n = 1.29) as the low-index material and polystyrene (n = 1.59) as the high-index material. These two polymers were deposited using liquid phase techniques within a HGW; the absorption spectra of waveguide as each layer was deposited on was analyzed in the mid-IR with an FTIR, and straight and bending losses were measured on a CO2 laser. Appreciable losses were realized with the addition of the second polymer film and the interference bands red-shifted with the second layer, suggesting the successful creation of the multilayer structure.

Characterization of long-range plasmonic waveguides at visible to near-infrared regime

NASA Astrophysics Data System (ADS)

Huang, Sheng-Ting; Lai, Chien-Chih; Sheu, Fang-Wen; Tsai, Wan-Shao

2017-12-01

Long-range surface plasmon polariton waveguides composed with thin gold stripes embedded in SU-8 polymer cladding with various stripe widths were fabricated. Material properties of the polymer cladding layer, gold thin film, and the device structures were discussed. Optical properties based on modal propagation were characterized at visible to near-infrared wavelengths. The measured propagation losses of waveguide widths from 3 to 9 μm at 633, 785, and 1550 nm are 7.5-18.8, 6.8-12.5, and 1.9-3.9 dB/mm, respectively. Guiding mode properties such as overlap integrals between the simulated and the measured fields and the polarization extinction ratios of the waveguides with different stripe widths were investigated at the telecommunication wavelength. Good accordance between the measurement and simulation results was presented.

Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides

PubMed Central

Chandrahalim, Hengky; Rand, Stephen C.; Fan, Xudong

2016-01-01

We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator – waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3′-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena. PMID:27600872

Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides.

PubMed

Chandrahalim, Hengky; Rand, Stephen C; Fan, Xudong

2016-09-07

We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator - waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3'-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena.

Brillouin scattering in planar waveguides. II. Experiments

NASA Astrophysics Data System (ADS)

Chiasera, A.; Montagna, M.; Moser, E.; Rossi, F.; Tosello, C.; Ferrari, M.; Zampedri, L.; Caponi, S.; Gonçalves, R. R.; Chaussedent, S.; Monteil, A.; Fioretto, D.; Battaglin, G.; Gonella, F.; Mazzoldi, P.; Righini, G. C.

2003-10-01

Silica-titania planar waveguides of different thicknesses and compositions have been produced by radio-frequency sputtering and dip coating on silica substrates. Waveguides were also produced by silver exchange on a soda-lime silicate glass substrate. Brillouin scattering of the samples has been studied by coupling the exciting laser beam with a prism to different transverse-electric (TE) modes of the waveguides, and collecting the scattered light from the front surface. In multimode waveguides, the spectra depend on the m mode of excitation. For waveguides with a step index profile, two main peaks due to longitudinal phonons are present, apart from the case of the TE0 excitation, where a single peak is observed. The energy separation between the two peaks increases with the mode index. In graded-index waveguides, m-1 peaks of comparable intensities are observed. The spectra are reproduced very well by a model which considers the space distribution of the exciting field in the mode, a simple space dependence of the elasto-optic coefficients, through the value of the refraction index, and neglects the refraction of phonons. A single-fit parameter, i.e., the longitudinal sound velocity, is used to calculate as many spectra as is the number of modes in the waveguide.

Optical modelling of far-infrared astronomical instrumentation exploiting multimode horn antennas

NASA Astrophysics Data System (ADS)

O'Sullivan, Créidhe; Murphy, J. Anthony; Mc Auley, Ian; Wilson, Daniel; Gradziel, Marcin L.; Trappe, Neil; Cahill, Fiachra; Peacocke, T.; Savini, G.; Ganga, K.

2014-07-01

In this paper we describe the optical modelling of astronomical telescopes that exploit bolometric detectors fed by multimoded horn antennas. In cases where the horn shape is profiled rather than being a simple cone, we determine the beam at the horn aperture using an electromagnetic mode-matching technique. Bolometers, usually placed in an integrating cavity, can excite many hybrid modes in a corrugated horn; we usually assume they excite all modes equally. If the waveguide section feeding the horn is oversized these modes can propagate independently, thereby increasing the throughput of the system. We use an SVD analysis on the matrix that describes the scattering between waveguide (TE/TM) modes to recover the independent orthogonal fields (hybrid modes) and then propagate these to the sky independently where they are added in quadrature. Beam patterns at many frequencies across the band are then added with a weighting appropriate to the source spectrum. Here we describe simulations carried out on the highest-frequency (857-GHz) channel of the Planck HFI instrument. We concentrate in particular on the use of multimode feedhorns and consider the effects of possible manufacturing tolerances on the beam on the sky. We also investigate the feasibility of modelling far-out sidelobes across a wide band for electrically large structures and bolometers fed by multi-mode feedhorns. Our optical simulations are carried out using the industry-standard GRASP software package.

High-performance polymer waveguide devices via low-cost direct photolithography process

NASA Astrophysics Data System (ADS)

Wang, Jianguo; Shustack, Paul J.; Garner, Sean M.

2002-09-01

All-optical networks provide unique opportunities for polymer waveguide devices because of their excellent mechanical, thermo-optic, and electro-optic properties. Polymer materials and components have been viewed as a viable solution for metropolitan and local area networks where high volume and low cost components are needed. In this paper, we present our recent progress on the design and development of photoresist-like highly fluorinated maleimide copolymers including waveguide fabrication and optical testing. We have developed and synthesized a series of thermally stable, (Tg>150 oC, Td>300 oC) highly fluorinated (>50%) maleimide copolymers by radical co-polymerization of halogenated maleimides with various halogenated co-monomers. A theoretical correlation between optical loss and different co-polymer structures has been quantitatively established from C-H overtone analysis. We studied this correlation through design and manipulation of the copolymer structure by changing the primary properties such as molecular weight, copolymer composition, copolymer sequence distribution, and variations of the side chain including photochemically functional side units. Detailed analysis has been obtained using various characterization methods such as (H, C13, F19) NMR, UV-NIR, FTIR, GPC and so forth. The co-polymers exhibit excellent solubility in ketone solvents and high quality thin films can be prepared by spin coating. The polymer films were found to have a refractive index range of 1.42-1.67 and optical loss in the range of 0.2 to 0.4 dB/cm at 1550nm depending on the composition as extrapolated from UV-NIR spectra. When glycidyl methacrylate is incorporated into the polymer backbone, the material behaves like a negative photoresist with the addition of cationic photoinitiator. The final crosslinked waveguides show excellent optical and thermal properties. The photolithographic processing of the highly fluorinated copolymer material was examined in detail using in-situ FTIR. The influence of various polymer

Inscription of type I and depressed cladding waveguides in lithium niobate using a femtosecond laser.

PubMed

Bhardwaj, S; Mittholiya, K; Bhatnagar, A; Bernard, R; Dharmadhikari, J A; Mathur, D; Dharmadhikari, A K

2017-07-10

We describe two types of waveguides (type I and depressed cladding) inscribed in lithium niobate using a variable repetition rate (200 kHz-25 MHz), 270 fs duration fiber laser. The type I modification-based waveguides have propagation losses in the range from 1.2 to 10 dB/cm at 1550 nm, depending on experimental parameters. These waveguides are not permanent; they deteriorate over time. Such deterioration of waveguides can be slowed down from 30 days to 100 days by pre-annealing the samples and by writing at a 720 kHz laser repetition rate. The propagation losses measured at 1550 nm show significant improvement for pre-annealed samples. The depressed cladding-inscribed waveguides are permanent, but the propagation loss depends on the number of damage tracks. A track separation of ∼1  μm between adjacent damage tracks yields the lowest propagation loss of 0.5 dB/cm at 1550 nm for a 40 μm diameter waveguide. We observe multimode guidance for sizes in the range of 20-80 μm in these waveguide structures at 1550 nm. Their crystalline nature is found to remain intact, as inferred from second-harmonic generation within the waveguide region.

Femtosecond laser-written double line waveguides in germanate and tellurite glasses

NASA Astrophysics Data System (ADS)

S. da Silva, Diego; Wetter, Niklaus U.; de Rossi, Wagner; Samad, Ricardo E.; Kassab, Luciana R. P.

2018-02-01

The authors report the fabrication and characterization of passive waveguides in GeO2-PbO and TeO2-ZnO glasses written with a femtosecond laser delivering pulses with 3μJ, 30μJ and 80fs at 4kHz repetition rate. Permanent refractive index change at the focus of the laser beam was obtained and waveguides were formed by two closely spaced laser written lines, where the light guiding occurs between them. The refractive index change at 632 nm is around 10-4 . The value of the propagation losses was around 2.0 dB/cm. The output mode profiles indicate multimodal guiding behavior. Raman measurements show structural modification of the glassy network. The results show that these materials are potential candidates for passive waveguides applications as low-loss optical components.

Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating

PubMed Central

Zheng, Yulong; Bremer, Kort

2018-01-01

In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing. PMID:29734734

Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating.

PubMed

Zheng, Yulong; Bremer, Kort; Roth, Bernhard

2018-05-05

In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing.

Gamma radiation effects on silicon photonic waveguides.

PubMed

Grillanda, Stefano; Singh, Vivek; Raghunathan, Vivek; Morichetti, Francesco; Melloni, Andrea; Kimerling, Lionel; Agarwal, Anuradha M

2016-07-01

To support the use of integrated photonics in harsh environments, such as outer space, the hardness threshold to high-energy radiation must be established. Here, we investigate the effects of gamma (γ) rays, with energy in the MeV-range, on silicon photonic waveguides. By irradiation of high-quality factor amorphous silicon core resonators, we measure the impact of γ rays on the materials incorporated in our waveguide system, namely amorphous silicon, silicon dioxide, and polymer. While we show the robustness of amorphous silicon and silicon dioxide up to an absorbed dose of 15 Mrad, more than 100× higher than previous reports on crystalline silicon, polymer materials exhibit changes with doses as low as 1 Mrad.

Characterization of passive polymer optical waveguides

NASA Astrophysics Data System (ADS)

Joehnck, Matthias; Kalveram, Stefan; Lehmacher, Stefan; Pompe, Guido; Rudolph, Stefan; Neyer, Andreas; Hofstraat, Johannes W.

1999-05-01

The characterization of monomode passive polymer optical devices fabricated according to the POPCORN technology by methods originated from electron, ion and optical spectroscopy is summarized. Impacts of observed waveguide perturbations on the optical characteristics of the waveguide are evaluated. In the POPCORN approach optical components for telecommunication applications are fabricated by photo-curing of liquid halogenated (meth)acrylates which have been applied on moulded thermoplastic substrates. For tuning of waveguide material refractive indices with respect to the substrate refractive index frequently comonomer mixtures are used. The polymerization characteristics, especially the polymerization kinetics of individual monomers, determine the formation of copolymers. Therefore the unsaturation as function of UV-illumination time in the formation of halogenated homo- and copolymers has been examined. From different suitable copolymer system, after characterization of their glass transition temperatures, their curing behavior and their refractive indices as function of the monomer ratios, monomode waveguides applying PMMA substrates have been fabricated. To examine the materials composition also in the 6 X 6 micrometers 2 waveguides they have been visualized by transmission electron microscopy. With this method e.g. segregation phenomena could be observed in the waveguide cross section characterization as well. The optical losses in monomode waveguides caused by segregation and other materials induce defects like micro bubbles formed as a result of shrinkage have been quantized by return loss measurements. Defects causing scattering could be observed by convocal laser scanning microscopy and by conventional light microscopy.

Planar waveguide microlenses for nonblocking photonic switches and optical interconnects

NASA Astrophysics Data System (ADS)

Glebov, Alexei L.; Huang, Lidu; Lee, Michael; Aoki, Shigenori; Yokouchi, Kishio

2004-09-01

Different types of planar waveguide microlenses are fabricated with PLC technologies from a variety of optical materials such as silica, photo-definable epoxy resins, and a number of other optical polymers. Hybrid microlenses are also fabricated in which the base of the lens, with a double concave gap, is formed from silica and the gap is filled with an optical polymer. The optimized lens structures provide the maximum coupling efficiencies between the input and output channels at distances up to 100 mm with a minimum channel pitch of 0.5-0.7 mm. Experimental and theoretical studies provide results on collimation and focusing properties of single and double microlenses made of silica, polymer, and silica/polymer. The evaluation of the temperature and wavelength effects on the collimation characteristics of the lenses demonstrate that the single lenses are more stable and, thus, more suitable for operations under varying conditions. Examples of the planar waveguide microlens applications are presented. In one application the microlens arrays are integrated in fast electrooptic photonic switching modules. In the other application the microlenses are embedded in the backplanes with nonblocking optical interconnects.

Rare-earth doped polymer waveguides and light emitting diodes

NASA Astrophysics Data System (ADS)

Slooff, L. H.

2000-11-01

Polymer-based optical waveguide amplifiers offer a low-cost alternative for inorganic waveguide amplifiers. Due to the fact that their refractive index is almost similar to that of standard optical fibers, they can be easily coupled with existing fibers at low coupling losses. Doping the polymer with rare-earth ions that can yield optical gain is not straightforward, as the rare-earth salts are poorly soluble in the polymer matrix. This thesis studies two different approaches to dope a polymer waveguide with rare-earth ions. The first one is based on organic cage-like complexes that encapsulate the rare-earth ion and are designed to provide enough coordination sites to bind the rare-earth ion and to shield it from the surrounding matrix. Chapter 2 describes the optical properties of Er-doped organic polydentate cage complexes. The complexes show clear photoluminescence at 1.54 mm with a bandwidth of 70 nm, the highest reported for an erbium-doped material so far. The luminescence lifetime is very short (~1 ms) due to coupling to vibrational overtones of O-H and C-H bonds. Due to this short luminescence lifetime, high pump powers (~1 W) are needed for optical gain in a waveguide amplifier based on these complexes. The pump power can be reduced if the Er is excited via the aromatic part of the complex, which has a higher absorption cross section. In Chapter 3 a lissamine-functionalised neodymium complex is studied in which the highly absorbing lissamine acts as a sensitiser. The lissamine is first excited into the singlet state from which intersystem crossing to the triplet state can take place. From there it can transfer its energy to the Nd ion by a Dexter transfer mechanism. Room-temperature photoluminescence at 890, 1060, and 1340 nm from Nd is observed, together with luminescence from the lissamine sensitiser at 600 nm. Photodegradation of the lissamine sensitiser is observed, which is studied in more detail in Chapter 4. The observed change in time of the spectral shape of the lissamine luminescence can be explained by assuming that two types of complexes exist. One type in which energy transfer to the Nd3+ ion can take place, and one that is not coupled to Nd. The highly absorbing sensitiser makes the standard butt-end coupling of the pump light into a waveguide amplifier impractical. The pump power can be used more efficiently by using a novel coupled waveguide system as described in Chapter 5. This employs gradual evanescent field coupling between parallel pump and signal waveguides. An alternative approach to make a rare-earth doped polymer waveguide is by combining the excellent properties of SiO2 as a host for the rare-earth with the easy processing of polymers. The optical properties of Er-doped silica films made by an acid-catalysed sol-gel synthesis are reported in Chapter 6. The Er exhibits long luminescence lifetimes of 10-12 ms, which indicates that OH from the wet chemical synthesis is successfully removed during the vacuum anneal treatment. Using a base-catalysed sol-gel synthesis, silica colloidal spheres with diameters of 175 and 340 nm were grown. Chapter 7 describes the luminescence properties of the 340 nm spheres, implanted with Er up to concentrations of 1.0 at.%. The Er shows a very long luminescence lifetime of 17 ms, and the radiative lifetime is estimated to be 20-22 ms, indicating a high quantum efficiency. This long luminescence lifetime is partly due to the low local optical density of states (DOS) in the free standing silica colloids. Optical gain calculations are made for the colloid/polymer waveguide that predicts a net gain of 8.7 dB at a pump power of 30 mW, for a 15 cm long waveguide. Such a length can be rolled up on an area of 16 mm2. In Chapter 8, calculations of the DOS are described for thin films as well as the spherical colloids. By comparing the calculation with experimentally probed decay rates, radiative and non-radiative components in the decay of Er are determined. Besides optical pumping of planar waveguide amplifiers it would be interesting if electrical pumping could be achieved. As a first step in this direction Chapter 9 reports 890 nm electroluminescence from lissamine-functionalised Nd complexes in a polymer light emitting diode. It is shown that the lissamine sensitiser plays a crucial role in mediating the energy transfer from the conjugated polymer to the Nd3+ ion, via singlet-singlet and triplet-triplet energy transfer. Finally, Chapter 10 gives an overview of important device considerations for the fabrication of optically and electrically pumped polymer-based planar optical amplifiers based on the novel materials concepts described in this thesis.

Integrated Miniature Arrays of Optical Biomolecule Detectors

NASA Technical Reports Server (NTRS)

Iltchenko, Vladimir; Maleki, Lute; Lin, Ying; Le, Thanh

2009-01-01

Integrated miniature planar arrays of optical sensors for detecting specific biochemicals in extremely small quantities have been proposed. An array of this type would have an area of about 1 cm2. Each element of the array would include an optical microresonator that would have a high value of the resonance quality factor (Q . 107). The surface of each microresonator would be derivatized to make it bind molecules of a species of interest, and such binding would introduce a measurable change in the optical properties of the microresonator. Because each microresonator could be derivatized for detection of a specific biochemical different from those of the other microresonators, it would be possible to detect multiple specific biochemicals by simultaneous or sequential interrogation of all the elements in the array. Moreover, the derivatization would make it unnecessary to prepare samples by chemical tagging. Such interrogation would be effected by means of a grid of row and column polymer-based optical waveguides that would be integral parts of a chip on which the array would be fabricated. The row and column polymer-based optical waveguides would intersect at the elements of the array (see figure). At each intersection, the row and column waveguides would be optically coupled to one of the microresonators. The polymer-based waveguides would be connected via optical fibers to external light sources and photodetectors. One set of waveguides and fibers (e.g., the row waveguides and fibers) would couple light from the sources to the resonators; the other set of waveguides and fibers (e.g., the column waveguides and fibers) would couple light from the microresonators to the photodetectors. Each microresonator could be addressed individually by row and column for measurement of its optical transmission. Optionally, the chip could be fabricated so that each microresonator would lie inside a microwell, into which a microscopic liquid sample could be dispensed.

Surface trimming of silicon photonics devices using controlled reactive ion etching chemistry

NASA Astrophysics Data System (ADS)

Chandran, S.; Das, B. K.

2015-06-01

Surface trimming of rib waveguides fabricated in 5-μm SOI substrate has been carried out successfully without any significant increase of propagation losses. A reactive ion etching chemistry has been optimized for trimming and an empirical model has been developed to obtain the resulting waveguide geometries. This technique has been used to demonstrate smaller footprint devices like multimode interference based power splitters and ring resonators after defining them photolithographically with relatively large cross-section rib waveguides. We have been also successful to fabricate 2D tapered spot-size converter useful for monolithic integration of waveguides with varying heights and widths. The taper length is again precisely controlled by photolithographic definition. Minimum insertion loss of such a spot-size converter integrated between waveguides with 3-μm height difference has been recorded to be ∼2 dB. It has been also shown that the overall fiber-to-chip coupling loss can be reduced by >3 dB by using such spot-size converters at the input/output side of the waveguides.

Application of laser speckle to randomized numerical linear algebra

NASA Astrophysics Data System (ADS)

Valley, George C.; Shaw, Thomas J.; Stapleton, Andrew D.; Scofield, Adam C.; Sefler, George A.; Johannson, Leif

2018-02-01

We propose and simulate integrated optical devices for accelerating numerical linear algebra (NLA) calculations. Data is modulated on chirped optical pulses and these propagate through a multimode waveguide where speckle provides the random projections needed for NLA dimensionality reduction.

Low-loss single mode light waveguides in polymer

NASA Astrophysics Data System (ADS)

Sieber, Heinrich; Boehm, Hans-Jürgen; Hollenbach, Uwe; Mohr, Jürgen; Ostrzinski, Ute; Pfeiffer, Karl; Szczurowski, Marcin; Urbanczyk, Waclaw

2012-06-01

We report on the development of a UV-lithography manufacturing process for low loss single mode light waveguides in a novel polymer and the characterization of the fabricated components in a broad wavelength range from 808 nm to 1550 nm. The main focus of this work lies in providing a quick and cost efficient production technique for single mode waveguides and low loss integrated optical circuits. To achieve this goal we chose a novel photo-structurable polymer host-guest-system consisting of SU8 and a low refractive dopant monomer. Near and far-field measurements at different wavelengths show that the mode propagating within a well designed integrated waveguide structure and the mode of a standard fiber can exhibit a mode overlap value of approximately 1 and suffer only very low coupling losses. We demonstrate excess loss of 0.14 dB/cm for 808 nm, 0.33 dB/cm for 1310 nm and 2.86 dB/cm for 1550 nm. Typical insertion loss values of straight waveguides with a length of 36 mm are 0.9 dB for 808 nm, 1.5 dB for 1310 nm and 10.4 dB for 1550 nm. Polarization dependent loss was found to be less than 0.2 dB on sets of test structures of 36 mm length. We measured material attenuation in the novel polymer material before cross-linking of approximately 0.04 dB/cm for 808 nm and around 0.20 dB/cm for 1310 nm respectively. The presented production technique is suitable to provide low loss and low cost integrated optical circuits for sensor and communication applications in a broad wavelength range.

Chemical, biochemical, and environmental fiber sensors IV; Proceedings of the Meeting, Boston, MA, Sept. 8, 9, 1992

NASA Astrophysics Data System (ADS)

Lieberman, Robert A.

Various paper on chemical, biochemical, and environmental fiber sensors are presented. Some of the individual topics addressed include: evanescent-wave fiber optic (FO) biosensor, refractive-index sensors based on coupling to high-index multimode overlays, advanced technique in FO sensors, design of luminescence-based temperature sensors, NIR fluorescence in FO applications, FO sensor based on microencapsulated reagents, emitters and detectors for optical gas and chemical sensing, tunable fiber laser source for methane detection at 1.68 micron, FO fluorometer based on a dual-wavelength laser excitation source, thin polymer films as active components of FO chemical sensors, submicron optical sources for single macromolecule detection, nanometer optical fiber pH sensor. Also discussed are: microfabrication of optical sensor array, luminescent FO sensor for the measurement of pH, time-domain fluorescence methods as applied to pH sensing, characterization of a sol-gel-entrapped artificial receptor, FO technology for nuclear waste cleanup, spectroscopic gas sensing with IR hollow waveguides, dissolved-oxygen quenching of in situ fluorescence measurements.

All-optical Integrated Switches Based on Azo-benzene Liquid Crystals on Silicon

DTIC Science & Technology

2011-11-01

Glass D263 SU8 Polymer Polymer NLC n̂ n̂ Refractive index @1.55 µm Materials n// = 1.689 n⊥= 1.502 n = 1.575 n = 1.516 E7 Glass D263 SU8 ...In the other case we have a nonlinear LCW based on glass substrates. It consists in a rectangular hollow realized in SU8 photoresist two glass...and discussion 5. All optical polymeric waveguide: methods, assumptions and procedure 6. All optical polymeric waveguide: results and discussion 7

Silicon photonic IC embedded optical-PCB for high-speed interconnect application

NASA Astrophysics Data System (ADS)

Kallega, Rakshitha; Nambiar, Siddharth; Kumar, Abhai; Ranganath, Praveen; Selvaraja, Shankar Kumar

2018-02-01

Optical-Printed Circuit Board (PCB) is an emerging optical interconnect technology to bridge the gap between the board edge and the processing module. The technology so far has been used as a broadband transmitter using polymer waveguides in the PCB. In this paper, we report a Silicon Nitride based photonic IC embedded in the PCB along with the polymers as waveguides in the PCB. The motivation for such integration is to bring routing capability and to reduce the power loss due to broadcasting mode.

Controlling morphology and chain aggregation in semiconducting conjugated polymers: the role of solvent on optical gain in MEH-PPV.

PubMed

Lampert, Zach E; Reynolds, C Lewis; Papanikolas, John M; Aboelfotoh, M Osama

2012-10-25

We report the results of a detailed investigation that addresses the influence of polymer morphology and chain aggregation, as controlled by the chemical nature of the solvent, on the optical gain properties of the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV). Using the variable stripe length technique in the picosecond regime, we have extensively studied the optical gain performance of asymmetric planar waveguides formed with thin MEH-PPV films spin-cast from concentrated chlorobenzene (CB) and tetrahydrofuran (THF) solutions onto thermally oxidized silicon substrates. CB and THF solvents were chosen based on their known ability to promote and effectively limit aggregate formation, respectively. Very large net gain coefficients are demonstrated, reaching values of 330 and 365 cm(-1), respectively, when optically pumping the waveguides with a maximum energy density of 85 μJ/cm(2). Our results clearly demonstrate that polymer morphology, and hence, the chain conformation dependence of the degree of aggregation in the films as controlled by the solvent, has minimal impact on the net gain. Moreover, the waveguides exhibit low loss coefficients of 10-20 cm(-1) at the ASE wavelength. These results question the importance of polymer morphology and aggregate formation in polymer-based optical devices operating at high excitation densities in the stimulated emission regime as would be characteristic of lasers and optical amplifiers.

Multistage polymeric lens structure in silica-waveguides for photonic functional circuits

NASA Astrophysics Data System (ADS)

Tate, Atsushi; Suzuki, Takanori; Tsuda, Hiroyuki

2005-04-01

A waveguide lens composed of multistage polymer-filled thin grooves in a silica planar lightwave circuit (PLC) is proposed and the low-loss structure is designed. Both an imaging optical system and a Fourier-Transform optical system can be configured in a PLC by use of a waveguide lens. It makes a PLC functional and its design flexible. Moreover, a focal length of a lens is tunable with large thermo-optic effect of the polymer. A concatenated lens is formed to attain a desirable focal length with low-loss. The thickness of each lens and the spacing are about 10-50 microns. The simulation showed that the radiation loss of the light propagate through 20-stage grooves filled with a polymer was only 0.868 dB when the refractive index of the polymer was 1.57, the groove width was 30 microns, and the spacing between adjacent grooves was 15 microns. For example, the single lens structure that the center thickness is 30 microns, the diameter is 300 microns, and the refractive index of the polymer was 1.57, have a focal length of 4600 microns. The focal length of 450 microns can be obtained with 20-stage concatenated lens structure. The larger numerical aperture can be realized with a polymer of higher refractive index. We have applied the concatenated lens structure to various photonic circuits including optical couplers, a variable optical attenuator.

Thermal-structural modeling of polymer Bragg grating waveguides illuminated by a light emitting diode.

PubMed

Joon Kim, Kyoung; Bar-Cohen, Avram; Han, Bongtae

2012-02-20

This study reports both analytical and numerical thermal-structural models of polymer Bragg grating (PBG) waveguides illuminated by a light emitting diode (LED). A polymethyl methacrylate (PMMA) Bragg grating (BG) waveguide is chosen as an analysis vehicle to explore parametric effects of incident optical powers and substrate materials on the thermal-structural behavior of the BG. Analytical models are verified by comparing analytically predicted average excess temperatures, and thermally induced axial strains and stresses with numerical predictions. A parametric study demonstrates that the PMMA substrate induces more adverse effects, such as higher excess temperatures, complex axial temperature profiles, and greater and more complicated thermally induced strains in the BG compared with the Si substrate. © 2012 Optical Society of America

Optical gain at 650 nm from a polymer waveguide with dye-doped cladding

NASA Astrophysics Data System (ADS)

Reilly, M. A.; Coleman, B.; Pun, E. Y. B.; Penty, R. V.; White, I. H.; Ramon, M.; Xia, R.; Bradley, D. D. C.

2005-12-01

Signal amplification at the polymer optical fiber low-loss window of 650 nm is reported in an SU8 rib waveguide coated with Rhodamine-640 doped poly(methyl methacrylate). A signal beam is end-fired into the facet of a 7×100μm waveguide and amplified by top pumping of the 2-μm-thick cladding region with a pulsed pump source focused into a 9-mm-long stripe. A gain of 14dB and a minimum signal-to-noise ratio of around 2 dB are achieved in a 15-mm-long device with a low threshold pump intensity of 0.25μJ/mm2, which is an order of magnitude lower than previously reported.

Three-mode all-optical (de)multiplexing on a SOI chip

NASA Astrophysics Data System (ADS)

Le, Yan-Si; Wang, Zhi; Li, Zhi-Yong; Li, Ying; Li, Qiang; Cui, Can; Wu, Chong-Qing

2018-01-01

An on-chip three-mode division multiplexing circuit using a simple ADC-based TE0 & TE1 & TE2 (de)multiplexer is demonstrated to improve the link capacity of on-chip optical interconnects. The proposed (de)multiplexer does not contain any tapered waveguide which is different from the previous mode (de)multiplexer based on ADCs. Here, we choose multimode waveguide width first and then confirm corresponding width of the other two waveguides. Thus the bus waveguide without any tapers can not only reduce complexity of (de)multiplexer but also reduce difficulty of the fabrication. Our simulation results show that the hybrid multiplexer has relatively low loss and low crosstalk about -40 dB, -26.99 dB and -28.72 dB for each mode around 1550 nm with a width-variation w =± 25 nm. These properties make the proposed mode-(de)multiplexer suitable for application in high-capacity data transmission.

Azo biphenyl polyurethane: Preparation, characterization and application for optical waveguide switch

NASA Astrophysics Data System (ADS)

Jiang, Yan; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong

2018-01-01

Azo waveguide polymers are of particular interest in the design of materials for applications in optical switch. The aim of this contribution was the synthesis and thermo-optic waveguide switch properties of azo biphenyl polyurethanes. A series of monomers and azo biphenyl polyurethanes (Azo BPU1 and Azo BPU2) were synthesized and characterized by FT-IR, UV-Vis spectroscopy and 1H NMR. The physical and mechanical properties of thin polymer films were measured. The refractive index and thermo-optic coefficient (dn/dT) of polymer films were investigated for TE (transversal electric) polarizations by ATR technique. The transmission loss of film was measured using the Charge Coupled Device digital imaging devices. The results showed the Azo BPU2 containing chiral azobenzene chromophore had higher dn/dT and lower transmission loss. Subsequently, a 1 × 2 Y-branch and 2 × 2 Mach-Zehnder optical switches based on the prepared polymers were designed and simulated. The results showed that the power consumption of all switches was less than 1.0 mW. Compared with 1 × 2 Y-branch optical switch, the 2 × 2 Mach-Zehnder optical switches based on the same polymer have the faster response time, which were about only 1.2 and 2.0 ms, respectively.

Distributed-feedback Terahertz Quantum-cascade Lasers with Laterally Corrugated Metal Waveguides

NASA Technical Reports Server (NTRS)

Williams, Benjamin S.; Kumar, Sushil; Hu, Qing; Reno, John L.

2005-01-01

We report the demonstration of distributed-feedback terahertz quantum-cascade lasers based on a first-order grating fabricated via a lateral corrugation in a double-sided metal ridge waveguide. The phase of the facet reflection was precisely set by lithographically defined facets by dry etching. Single-mode emission was observed at low to moderate injection currents, although multimode emission was observed far beyond threshold owing to spatial hole burning. Finite-element simulations were used to calculate the modal and threshold characteristics for these devices, with results in good agreement with experiments.

Investigation of evanescent coupling between tapered fiber and a multimode slab waveguide.

PubMed

Dong, Shaofei; Ding, Hui; Liu, Yiying; Qi, Xiaofeng

2012-04-01

A tapered fiber-slab waveguide coupler (TFSC) is proposed in this paper. Both the numerical analysis based on the beam propagation method and experiments are used for investigating the dependencies of TFSC transmission features on their geometric parameters. From the simulations and experimental results, the rules for fabricating a TFSC with low transmission loss and sharp resonant spectra by optimizing the configuration parameters are presented. The conclusions derived from our work may provide helpful references for optimally designing and fabricating TFSC-based devices, such as sensors, wavelength filters, and intensity modulators.

Optical Study of 2D Photonic Crystals in an InP/GaInAsP Slab Waveguide Structure

DTIC Science & Technology

2002-01-01

the values n,,,,. = 3.35 and n, ,, = 3.17 are assumed for the refraction index of GaInAsP and InP, respectively. The resulting structure is a multimode...contributes to increase out-of- plane scattering. On the other hand, when entering the PC, the hole pattern is felt as a low refractive index contrast...in an InP/GaInAsP step- index waveguide. Transmission (T) measurements through simple PC slabs and through one-dimensional (1D) Fabry-P6rot (FP

Large-core single-mode rib SU8 waveguide using solvent-assisted microcontact molding.

PubMed

Huang, Cheng-Sheng; Wang, Wei-Chih

2008-09-01

This paper describes a novel fabrication technique for constructing a polymer-based large-core single-mode rib waveguide. A negative tone SU8 photoresist with a high optical transmission over a large wavelength range and stable mechanical properties was used as a waveguide material. A waveguide was constructed by using a polydimethylsiloxane stamp combined with a solvent-assisted microcontact molding technique. The effects on the final pattern's geometry of four different process conditions were investigated. Optical simulations were performed using beam propagation method software. Single-mode beam propagation was observed at the output of the simulated waveguide as well as the actual waveguide through the microscope image.

Percolated microstructures for multi-modal transport enhancement in porous active materials

DOEpatents

McKay, Ian Salmon; Yang, Sungwoo; Wang, Evelyn N.; Kim, Hyunho

2018-03-13

A method of forming a composite material for use in multi-modal transport includes providing three-dimensional graphene having hollow channels, enabling a polymer to wick into the hollow channels of the three-dimensional graphene, curing the polymer to form a cured three-dimensional graphene, adding an active material to the cured three-dimensional graphene to form a composite material, and removing the polymer from within the hollow channels. A composite material formed according to the method is also provided.

Analysis and design of arrayed waveguide gratings with MMI couplers.

PubMed

Munoz, P; Pastor, D; Capmany, J

2001-09-24

We present an extension of the AWG model and design procedure described in [1] to incorporate multimode interference, MMI, couplers. For the first time to our knowledge, a closed formula for the passing bands bandwidth and crosstalk estimation plots are derived.

Relaxed tolerance adiabatic silicon coupler for high I/O port-density optical interconnects (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fard, Erfan; Norwood, Robert A.; Peyghambarian, Nasser N.; Koch, Thomas L.

2017-02-01

Widespread deployment of silicon photonics will benefit strongly from improved high-port-density interconnect solutions between chips, interposers, and other waveguide fabrics. We present an adiabatic silicon waveguide to polymer waveguide coupler design incorporating strong vertical asymmetries offering high efficiency, small footprint, and improved tolerance to lateral misalignment. The design incorporates a standard 450nm-wide silicon waveguide tapered down to 50nm over a distance of 200μm with a 1.6μm-thick polymer waveguide having a 4μm-wide core atop the taper. The coupler exhibits <0.1dB loss for both TE and TM modes based on 3-dimensional finite element modeling. Moreover, the modeled device exhibits less than 0.1dB excess loss with lateral misalignment of +/-2μm between polymer and silicon waveguide for TE mode, and 0.2dB excess loss with +/-1.6μm offset for the TM mode, and 1dB excess loss for both TE and TM modes with +/-2.7μm misalignment. This taper design should enable reduction in manufacturing costs due to a reduced on-chip footprint and the potential for lower-precision, higher-throughput assembly tools. The authors would like to acknowledge the support of AIM Photonics. This material is based on research sponsored by Air Force Research Laboratory under agreement number FA8650-15-2-5220. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the U.S. Government.

Polymer thermal optical switch for a flexible photonic circuit.

PubMed

Sun, Yue; Cao, Yue; Wang, Qi; Yi, Yunji; Sun, Xiaoqiang; Wu, Yuanda; Wang, Fei; Zhang, Daming

2018-01-01

Flexible and wearable optoelectronic devices are the new trend for an active lifestyle. These devices are polymer-based for flexibility. We demonstrated flexible polymer waveguide optical switches for a flexible photonic integrated circuit. The optical switches are composed of a single-mode inverted waveguide with dimensions of 5 μm waveguide width, 3 μm ridge height, and 3 μm slab height. A Mach-Zehnder structure was used in the device, with the Y-branch horizontal length of 0.1 cm, the distance between two heating branches of 30 μm, and the heating branch length of 1 cm. The optical field of the device was simulated by beam propagation to optimize the electrode position. The switching properties of the flexible optical switch with different working conditions, such as contact to the polymer, silicon, and skin, were simulated. The device was prepared based on the photo curved polymer and lithography method. The end faces of the flexible film device were processed using an excimer laser with optimized parameters of 28  mJ/cm 2 and 15 Hz. The response rise time and fall time on the PMMA substrate were measured as 1.98 ms and 2.71 ms, respectively. The power consumption was 16 mW and the extinction ratio was 11 dB. The response rise and fall times on the Si substrate were measured as 1.08 ms and 1.62 ms, respectively. The power consumption was 17 mW and the extinction ratio was 11 dB. The demonstrated properties indicate that this flexible optical waveguide structure can be used in the light control area of a wearable device.

Low Loss Nanostructured Polymers for Chip-scale Waveguide Amplifiers.

PubMed

Chen, George F R; Zhao, Xinyu; Sun, Yang; He, Chaobin; Tan, Mei Chee; Tan, Dawn T H

2017-06-13

On-chip waveguide amplifiers offer higher gain in small device sizes and better integration with photonic devices than the commonly available fiber amplifiers. However, on-chip amplifiers have yet to make its way into the mainstream due to the limited availability of materials with ideal light guiding and amplification properties. A low-loss nanostructured on-chip channel polymeric waveguide amplifier was designed, characterized, fabricated and its gain experimentally measured at telecommunication wavelength. The active polymeric waveguide core comprises of NaYF 4 :Yb,Er,Ce core-shell nanocrystals dispersed within a SU8 polymer, where the nanoparticle interfacial characteristics were tailored using hydrolyzed polyhedral oligomeric silsesquioxane-graft-poly(methyl methacrylate) to improve particle dispersion. Both the enhanced IR emission intensity from our nanocrystals using a tri-dopant scheme and the reduced scattering losses from our excellent particle dispersion at a high solid loading of 6.0 vol% contributed to the outstanding optical performance of our polymeric waveguide. We achieved one of the highest reported gain of 6.6 dB/cm using a relatively low coupled pump power of 80 mW. These polymeric waveguide amplifiers offer greater promise for integrated optical circuits due to their processability and integration advantages which will play a key role in the emerging areas of flexible communication and optoelectronic devices.

Bi-orthogonality relations for fluid-filled elastic cylindrical shells: Theory, generalisations and application to construct tailored Green's matrices

NASA Astrophysics Data System (ADS)

Ledet, Lasse S.; Sorokin, Sergey V.

2018-03-01

The paper addresses the classical problem of time-harmonic forced vibrations of a fluid-filled cylindrical shell considered as a multi-modal waveguide carrying infinitely many waves. The forced vibration problem is solved using tailored Green's matrices formulated in terms of eigenfunction expansions. The formulation of Green's matrix is based on special (bi-)orthogonality relations between the eigenfunctions, which are derived here for the fluid-filled shell. Further, the relations are generalised to any multi-modal symmetric waveguide. Using the orthogonality relations the transcendental equation system is converted into algebraic modal equations that can be solved analytically. Upon formulation of Green's matrices the solution space is studied in terms of completeness and convergence (uniformity and rate). Special features and findings exposed only through this modal decomposition method are elaborated and the physical interpretation of the bi-orthogonality relation is discussed in relation to the total energy flow which leads to derivation of simplified equations for the energy flow components.

Compact electro-optical module with polymer waveguides on a flexible substrate for high-density board-level communication

NASA Astrophysics Data System (ADS)

Weiss, J. R. M.; Lamprecht, T.; Meier, N.; Dangel, R.; Horst, F.; Jubin, D.; Beyeler, R.; Offrein, B. J.

2010-02-01

We report on the co-packaging of electrical CMOS transceiver and VCSEL chip arrays on a flexible electrical substrate with optical polymer waveguides. The electro-optical components are attached to the substrate edge and butt-coupled to the waveguides. Electrically conductive silver-ink connects them to the substrate at an angle of 90°. The final assembly contacts the surface of a package laminate with an integrated compressible connector. The module can be folded to save space, requires only a small footprint on the package laminate and provides short electrical high-speed signal paths. With our approach, the electro-optical package becomes a compact electro-optical module with integrated polymer waveguides terminated with either optical connectors (e.g., at the card edge) or with an identical assembly for a second processor on the board. Consequently, no costly subassemblies and connectors are needed, and a very high integration density and scalability to virtually arbitrary channel counts and towards very high data rates (20+ Gbps) become possible. Future cost targets of much less than US$1 per Gbps will be reached by employing standard PCB materials and technologies that are well established in the industry. Moreover, our technology platform has both electrical and optical connectivity and functionality.

Microminiature optical waveguide structure and method for fabrication

DOEpatents

Strand, O.T.; Deri, R.J.; Pocha, M.D.

1998-12-08

A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat. 32 figs.

Microminiature optical waveguide structure and method for fabrication

DOEpatents

Strand, Oliver T.; Deri, Robert J.; Pocha, Michael D.

1998-01-01

A method for manufacturing low-cost, nearly circular cross section waveguides comprises starting with a substrate material that a molten waveguide material can not wet or coat. A thin layer is deposited of an opposite material that the molten waveguide material will wet and is patterned to describe the desired surface-contact path pedestals for a waveguide. A waveguide material, e.g., polymer or doped silica, is deposited. A resist material is deposited and unwanted excess is removed to form pattern masks. The waveguide material is etched away to form waveguide precursors and the masks are removed. Heat is applied to reflow the waveguide precursors into near-circular cross-section waveguides that sit atop the pedestals. The waveguide material naturally forms nearly circular cross sections due to the surface tension effects. After cooling, the waveguides will maintain the round shape. If the width and length are the same, then spherical ball lenses are formed. Alternatively, the pedestals can be patterned to taper along their lengths on the surface of the substrate. This will cause the waveguides to assume a conical taper after reflowing by heat.

The methodology of preparing the end faces of cylindrical waveguide of polydimethylsiloxane

NASA Astrophysics Data System (ADS)

Novak, M.; Nedoma, J.; Jargus, J.; Bednarek, L.; Cvejn, D.; Vasinek, V.

2017-10-01

Polydimethylsiloxane (PDMS) can be used for its optical properties and its composition offers the possibility of use in the dangerous environments. Therefore authors of this article focused on more detailed working with this material. The article describes the methodology of preparing the end faces of the cylindrical waveguide of polymer polydimethylsiloxane (PDMS) to minimize losses during joining. The first method of preparing the end faces of the cylindrical waveguide of polydimethylsiloxane is based on the polishing surface of the sandpaper of different sizes of grains (3 species). The second method using so-called heat smoothing and the third method using aligning end faces by a new layer of polydimethylsiloxane. The outcome of the study is to evaluate the quality of the end faces of the cylindrical waveguide of polymer polydimethylsiloxane based on evaluating the attenuation. For this experiment, it was created a total of 140 samples. The attenuation was determined from both sides of the created samples for three different wavelengths of the visible spectrum.

Production and characterization of femtosecond laser-written double line waveguides in heavy metal oxide glasses

NASA Astrophysics Data System (ADS)

da Silva, Diego Silvério; Wetter, Niklaus Ursus; de Rossi, Wagner; Kassab, Luciana Reyes Pires; Samad, Ricardo Elgul

2018-01-01

We report the fabrication and characterization of double line waveguides directly written in tellurite and germanate glasses using a femtosecond laser delivering 30 μJ, 80 fs pulses at 4 kHz repetition rate. The double line waveguides produced presented internal losses inferior to 2.0 dB/cm. The output mode profile and the M2 measurements indicate multimodal guiding behavior. A better beam quality for the GeO2 - PbO waveguide was observed when compared with TeO2 - ZnO glass. Raman spectroscopy of the waveguides showed structural modification of the glassy network and indicates that a negative refractive index modification occurs at the focus of the laser beam, therefore allowing for light guiding in between two closely spaced laser written lines. The refractive index change at 632 nm is around 10-4, and the structural changes in the laser focal region of the writing, evaluated by Raman spectroscopy, corroborated our findings that these materials are potential candidates for optical waveguides and passive components. To the best of our knowledge, the two double line configuration demonstrated in the present work was not reported before for germanate or tellurite glasses.

Integrated polymer micro-ring resonators for optical sensing applications

NASA Astrophysics Data System (ADS)

Girault, Pauline; Lorrain, Nathalie; Poffo, Luiz; Guendouz, Mohammed; Lemaitre, Jonathan; Carré, Christiane; Gadonna, Michel; Bosc, Dominique; Vignaud, Guillaume

2015-03-01

Micro-resonators (MR) have become a key element for integrated optical sensors due to their integration capability and their easy fabrication with low cost polymer materials. Nowadays, there is a growing need on MRs as highly sensitive and selective functions especially in the areas of food and health. The context of this work is to implement and study integrated micro-ring resonators devoted to sensing applications. They are fabricated by processing SU8 polymer as core layer and PMATRIFE polymer as lower cladding layer. The refractive index of the polymers and of the waveguide structure as a function of the wavelength is presented. Using these results, a theoretical study of the coupling between ring and straight waveguides has been undertaken in order to define the MR design. Sub-micronic gaps of 0.5 μm to 1 μm between the ring and the straight waveguides have been successfully achieved with UV (i-lines) photolithography. Different superstrates such as air, water, and aqueous solutions with glucose at different concentrations have been studied. First results show a good normalized transmission contrast of 0.98, a resonator quality factor around 1.5 × 104 corresponding to a coupling ratio of 14.7%, and ring propagation losses around 5 dB/cm. Preliminary sensing experiments have been performed for different concentrations of glucose; a sensitivity of 115 ± 8 nm/RIU at 1550 nm has been obtained with this couple of polymers.

Fabrication of 8×8 MMI optical coupler in BK7 by ion-exchange

NASA Astrophysics Data System (ADS)

Li, Xia; Li, Xi-Hua; Zhou, Qiang; Jiang, Xiao-Qing; Yang, Jian-Yi; Wang, Ming-Hua

2005-01-01

The planar waveguide optical couplers are of prime importance in optical communication and optical signal processing system. Comparing with the optical fiber coupler (OFC) which fabricated by fused biconical taper technology, the planar waveguide couplers are more compact size, lower loss, better uniformity, easier manufacture and integration. Multimode interference (MMI) couplers have many advantages, such as compact size, wavelength and polarization insensitivity, fabrication tolerances and low loss, etc., which concentrate more and more attention. Conventional MMI devices are based on the uniform index waveguides. When the number of input/output waveguides becomes larger, the intrinsic propagation constant error, which will cause bad uniformity of output power, can"t be neglected. In fact, most waveguide devices are graded-index. With the enhanced compatibility of MMI coupler, the performance can be improved at the same time. Prior study shows that graded-index MMI couplers reach the best performance under certain index contrast. Among many available materials, glass is chosen to be the substrate of the coupler, because of its good features, such as low loss, ease fabrication, cheap cost, and so on. In this paper, an 8×8 MMI optical coupler is designed based on the principle of graded-index MMI. The coupler is composed of a waveguide, which is designed to support a large number of modes, and several access (usually single-mode) waveguides, which are used to launch light into and recover light from that multimode waveguide. The total length of the device is less than 3.5 centimeter, including S-bends which lead the multiple images to the output of the device with the spacing D=250μm to make the device fiber compatible. In this paper, we describe an experimental realization of the 8×8 graded-index MMI optical coupler and the measurement of its performance with the testing laser of the wavelength of 1.55μm. The device is fabricated by ion-exchange on BK7 glass substrate. During the ion-exchange process, a melting mixture of AgNO3 : (KNO3 : NaNO3) (molar ratio, 0.001:1) is used at 350~380°C for different times (range from 8 to 18 hours) to fabricate the coupler. The experimental results show that the performance of the optical coupler is quite promising. For instance, while launching light from No.5 waveguide, the uniformity of the device is approximately 0.72dB. Optimization of design and fabrication is going on to improve the total performance of the optical coupler.

Strong guided mode resonant local field enhanced visible harmonic generation in an azo-polymer resonant waveguide grating.

PubMed

Lin, Jian Hung; Tseng, Chun-Yen; Lee, Ching-Ting; Young, Jeff F; Kan, Hung-Chih; Hsu, Chia Chen

2014-02-10

Guided mode resonance (GMR) enhanced second- and third-harmonic generation (SHG and THG) is demonstrated in an azo-polymer resonant waveguide grating (RWG), comprised of a poled azo-polymer layer on top of a textured SU8 substrate with a thin intervening layer of TiO2. Strong SHG and THG outputs are observed by matching either in-coming fundamental- or out-going harmonic-wavelength to the GMR wavelengths of the azo-polymer RWG. Without the azo-polymer coating, pure TiO2 RWGs, do not generate any detectable SHG using a fundamental beam peak intensity of 2 MW/cm(2). Without the textured TiO2 layer, a planar poled azo-polymer layer results in 3650 times less SHG than the full nonlinear RWG structure under identical excitation conditions. Rigorous coupled-wave analysis calculations confirm that this enhancement of the nonlinear conversion is due to strong local electric fields that are generated at the interfaces of the TiO2 and azo-polymer layers when the RWG is excited at resonant wavelengths associated with both SHG and THG conversion processes.

The role of group index engineering in series-connected photonic crystal microcavities for high density sensor microarrays

PubMed Central

Zou, Yi; Chakravarty, Swapnajit; Zhu, Liang; Chen, Ray T.

2014-01-01

We experimentally demonstrate an efficient and robust method for series connection of photonic crystal microcavities that are coupled to photonic crystal waveguides in the slow light transmission regime. We demonstrate that group index taper engineering provides excellent optical impedance matching between the input and output strip waveguides and the photonic crystal waveguide, a nearly flat transmission over the entire guided mode spectrum and clear multi-resonance peaks corresponding to individual microcavities that are connected in series. Series connected photonic crystal microcavities are further multiplexed in parallel using cascaded multimode interference power splitters to generate a high density silicon nanophotonic microarray comprising 64 photonic crystal microcavity sensors, all of which are interrogated simultaneously at the same instant of time. PMID:25316921

Vertically-tapered optical waveguide and optical spot transformer formed therefrom

DOEpatents

Bakke, Thor; Sullivan, Charles T.

2004-07-27

An optical waveguide is disclosed in which a section of the waveguide core is vertically tapered during formation by spin coating by controlling the width of an underlying mesa structure. The optical waveguide can be formed from spin-coatable materials such as polymers, sol-gels and spin-on glasses. The vertically-tapered waveguide section can be used to provide a vertical expansion of an optical mode of light within the optical waveguide. A laterally-tapered section can be added adjacent to the vertically-tapered section to provide for a lateral expansion of the optical mode, thereby forming an optical spot-size transformer for efficient coupling of light between the optical waveguide and a single-mode optical fiber. Such a spot-size transformer can also be added to a III-V semiconductor device by post processing.

Direct write fabrication of waveguides and interconnects for optical printed wiring boards

NASA Astrophysics Data System (ADS)

Dingeldein, Joseph C.

Current copper based circuit technology is becoming a limiting factor in high speed data transfer applications as processors are improving at a faster rate than are developments to increase on board data transfer. One solution is to utilize optical waveguide technology to overcome these bandwidth and loss restrictions. The use of this technology virtually eliminates the heat and cross-talk loss seen in copper circuitry, while also operating at a higher bandwidth. Transitioning current fabrication techniques from small scale laboratory environments to large scale manufacturing presents significant challenges. Optical-to-electrical connections and out-of-plane coupling are significant hurdles in the advancement of optical interconnects. The main goals of this research are the development of direct write material deposition and patterning tools for the fabrication of waveguide systems on large substrates, and the development of out-of-plane coupler components compatible with standard fiber optic cabling. Combining these elements with standard printed circuit boards allows for the fabrication of fully functional optical-electrical-printed-wiring-boards (OEPWBs). A direct dispense tool was designed, assembled, and characterized for the repeatable dispensing of blanket waveguide layers over a range of thicknesses (25-225 μm), eliminating waste material and affording the ability to utilize large substrates. This tool was used to directly dispense multimode waveguide cores which required no UV definition or development. These cores had circular cross sections and were comparable in optical performance to lithographically fabricated square waveguides. Laser direct writing is a non-contact process that allows for the dynamic UV patterning of waveguide material on large substrates, eliminating the need for high resolution masks. A laser direct write tool was designed, assembled, and characterized for direct write patterning waveguides that were comparable in quality to those produced using standard lithographic practices (0.047 dB/cm loss for laser written waveguides compared to 0.043 dB/cm for lithographic waveguides). Straight waveguides, and waveguide turns were patterned at multimode and single mode sizes, and the process was characterized and documented. Support structures such as angled reflectors and vertical posts were produced, showing the versatility of the laser direct write tool. Commercially available components were implanted into the optical layer for out-of-plane routing of the optical signals. These devices featured spherical lenses on the input and output sides of a total internal reflection (TIR) mirror, as well as alignment pins compatible with standard MT design. Fully functional OEPWBs were fabricated featuring input and output out-of-plane optical signal routing with total optical losses not exceeding 10 dB. These prototypes survived thermal cycling (-40°C to 85°C) and humidity exposure (95±4% humidity), showing minimal degradation in optical performance. Operational failure occurred after environmental aging life testing at 110°C for 216 hours.

Analysis of hybrid dielectric-plasmonic slot waveguide structures with 3D Fourier Modal Methods

NASA Astrophysics Data System (ADS)

Ctyroky, J.; Kwiecien, P.; Richter, I.

2013-03-01

Recently, plasmonic waveguides have been intensively studied as promising basic building blocks for the construction of extremely compact photonic devices with subwavelength characteristic dimensions. A number of different types of plasmonic waveguide structures have been recently proposed, theoretically analyzed, and their properties experimentally verified. The fundamental trade-off in the design of plasmonic waveguides for potential application in information technologies lies in the contradiction between their mode field confinement and propagation loss: the higher confinement, the higher loss, and vice versa. Various definitions of figures of merit of plasmonic waveguides have been also introduced for the characterization of their properties with a single quantity. In this contribution, we theoretically analyze one specific type of a plasmonic waveguide - the hybrid dielectric-loaded plasmonic waveguide, or - as we call it in this paper - the hybrid dielectric-plasmonic slot waveguide, which exhibits very strong field confinement combined with acceptable losses allowing their application in some integrated plasmonic devices. In contrast to the structures analyzed previously, our structure makes use of a single low-index dielectric only. We first define the effective area of this waveguide type, and using waveguide parameters close to the optimum we analyze several waveguide devices as directional couplers, multimode interference couplers (MMI), and the Mach-Zehnder interferometer based on the MMI couplers. For the full-vector 3D analysis of these structures, we use modelling tools developed in-house on the basis of the Fourier Modal Method (FMM). Our results thus serve to a dual purpose: they confirm that (i) these structures represent promising building blocks of plasmonic devices, and (ii) our FMM codes are capable of efficient 3D vector modelling of plasmonic waveguide devices.

Polymer photonic crystal slab waveguides

NASA Astrophysics Data System (ADS)

Liguda, C.; Böttger, G.; Kuligk, A.; Blum, R.; Eich, M.; Roth, H.; Kunert, J.; Morgenroth, W.; Elsner, H.; Meyer, H. G.

2001-04-01

We present details of the fabrication, calculations, and transmission measurements for finite two-dimensional (2D) polymer photonic crystal (PC) slab waveguides, which were fabricated from a benzocyclobutene polymer on a low refractive index substrate from Teflon. A square air hole lattice (500 nm lattice constant, 300 nm hole diameter) was realized by electron beam lithography and reactive ion etching. Polarization and wavelength dependent transmission results show TE-like and TM-like stop gaps at 1.3 μm excitation wavelengths and are in good agreement with the calculated data obtained by 2D and three-dimensional finite difference time domain methods. Transmission was suppressed by 15 dB in the center of the TE-like stop gap for a PC length of ten lattice constants.

From SHG to mid-infrared SPDC generation in strained silicon waveguides

NASA Astrophysics Data System (ADS)

Castellan, Claudio; Trenti, Alessandro; Mancinelli, Mattia; Marchesini, Alessandro; Ghulinyan, Mher; Pucker, Georg; Pavesi, Lorenzo

2017-08-01

The centrosymmetric crystalline structure of Silicon inhibits second order nonlinear optical processes in this material. We report here that, by breaking the silicon symmetry with a stressing silicon nitride over-layer, Second Harmonic Generation (SHG) is obtained in suitably designed waveguides where multi-modal phase-matching is achieved. The modeling of the generated signal provides an effective strain-induced second order nonlinear coefficient of χ(2) = (0.30 +/- 0.02) pm/V. Our work opens also interesting perspectives on the reverse process, the Spontaneous Parametric Down Conversion (SPDC), through which it is possible to generate mid-infrared entangled photon pairs.

Photonic crystal slab waveguides in moderate index contrast media: Generalized transverse Bragg waveguides

NASA Astrophysics Data System (ADS)

Burckel, David Bruce

One of the anticipated advantages of photonic crystal waveguides is the ability to tune waveguide dispersion and propagation characteristics to achieve desired properties. The majority of research into photonic crystal waveguides centers around high index contrast photonic crystal waveguides with complete in-plane bandgaps in the photonic crystal cladding. This work focuses on linear photonic crystal waveguides in moderate index materials, with insufficient index contrast to guarantee a complete in-plane bandgap. Using a technique called Interferometric Lithography (IL) as well as standard semiconductor processing steps, a process flow for creating large area (˜cm 2), linear photonic crystal waveguides in a spin-deposited photocurable polymer is outlined. The study of such low index contrast photonic crystal waveguides offers a unique opportunity to explore the mechanisms governing waveguide confinement and photonic crystal behavior in general. Results from two optical characterization experiments are provided. In the first set of experiments, rhodamine 590 organic laser dye was incorporated into the polymer prior to fabrication of the photonic crystal slab. Emission spectra from waveguide core modes exhibit no obvious spectral selectivity owing to variation in the periodicity or geometry of the photonic crystal. In addition, grating coupled waveguides were fabricated, and a single frequency diode laser was coupled into the waveguide in order to study the transverse mode structure. To this author's knowledge, the optical mode profile images are the first taken of photonic crystal slab waveguides, exhibiting both simple low order mode structure as well as complex high order mode structure inconsistent with effective index theory. However, no obvious correlation between the mode structure and photonic crystal period or geometry was evident. Furthermore, in both the laser dye-doped and grating coupled waveguides, low loss waveguiding was observed regardless of wavelength to period ratio. These optical results indicated a need for a deeper understanding of the confinement/guiding mechanisms in such waveguide structures. A simplification of the full 2-D problem to a more tractable "tilted 1-D" geometry led to the proposal of a new waveguide geometry, Generalized Transverse Bragg Waveguides (GTBW), as well as a new propagation mode characterized by spatial variation in both the transverse direction as well as the direction of propagation. GTBW demonstrate many of the same dispersion tunability traits exhibited in complete bandgap photonic crystal waveguides, under more modest fabrication demands, and moreover provide much insight into photonic crystal waveguide modes of all types. Generalized Transverse Bragg Waveguides are presented in terms of the standard physical properties associated with waveguides, including the dispersion relation, expressions for the spatial field profile, and the concepts of phase and group velocity. In addition, the proposal of at least one obvious application, semiconductor optical amplifiers, is offered.

Electrical Transfer Function and Poling Mechanisms for Nonlinear Optical Polymer Modulators

NASA Technical Reports Server (NTRS)

Watson, Michael Dale

2004-01-01

Electro-Optic Polymers hold great promise in increased electro-optic coefficients as compared to their inorganic corollaries. Many researchers have focused on quantum chemistry to describe how the dipoles respond to temperature and electric fields. Much work has also been done for single layer films to confirm these results. For optical applications, waveguide structures are utilized to guide the optical waves in 3 layer stacks. Electrode poling is the only practical poling method for these structures. This research takes an electrical engineering approach to develop poling models and electrical and optical transfer functions of the waveguide structure. The key aspect of the poling model is the large boundary charge density deposited during the poling process. The boundary charge density also has a large effect on the electrical transfer function which is used to explain the transient response of the system. These models are experimentally verified. Exploratory experiment design is used to study poling parameters including time, temperature, and voltage. These studies verify the poling conditions for CLDX/APC and CLDZ/APEC guest host electro optic polymer films in waveguide stacks predicted by the theoretical developments.

Graphene-doped polymer nanofibers for low-threshold nonlinear optical waveguiding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Chao; Yu, Shao-Liang; Wang, Hong -Qing

Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes. Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters; they show excellent uniformity and surface smoothness for optical waveguiding. Owing to their tightly confined waveguiding behavior, light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced. Using approximately 1350-nm-wavelength femto-second pulses, we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse -1 (peak power ~1.3 W). Additionally, using 1064-nm-wavelength nanosecond pulses as switching light, we show all-opticalmore » modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of ~3.2 W.« less

Graphene-doped polymer nanofibers for low-threshold nonlinear optical waveguiding

DOE PAGES

Meng, Chao; Yu, Shao-Liang; Wang, Hong -Qing; ...

2015-11-06

Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes. Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters; they show excellent uniformity and surface smoothness for optical waveguiding. Owing to their tightly confined waveguiding behavior, light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced. Using approximately 1350-nm-wavelength femto-second pulses, we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse -1 (peak power ~1.3 W). Additionally, using 1064-nm-wavelength nanosecond pulses as switching light, we show all-opticalmore » modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of ~3.2 W.« less

Recent progress in InP/polymer-based devices for telecom and data center applications

NASA Astrophysics Data System (ADS)

Kleinert, Moritz; Zhang, Ziyang; de Felipe, David; Zawadzki, Crispin; Maese Novo, Alejandro; Brinker, Walter; Möhrle, Martin; Keil, Norbert

2015-02-01

Recent progress on polymer-based photonic devices and hybrid photonic integration technology using InP-based active components is presented. High performance thermo-optic components, including compact polymer variable optical attenuators and switches are powerful tools to regulate and control the light flow in the optical backbone. Polymer arrayed waveguide gratings integrated with InP laser and detector arrays function as low-cost optical line terminals (OLTs) in the WDM-PON network. External cavity tunable lasers combined with C/L band thinfilm filter, on-chip U-groove and 45° mirrors construct a compact, bi-directional and color-less optical network unit (ONU). A tunable laser integrated with VOAs, TFEs and two 90° hybrids builds the optical front-end of a colorless, dual-polarization coherent receiver. Multicore polymer waveguides and multi-step 45°mirrors are demonstrated as bridging devices between the spatialdivision- multiplexing transmission technology using multi-core fibers and the conventional PLCbased photonic platforms, appealing to the fast development of dense 3D photonic integration.

Micromolding of polymer waveguides

NASA Astrophysics Data System (ADS)

Hanemann, Thomas; Ulrich, Hermann; Ruprecht, Robert; Hausselt, Juergen H.

1999-10-01

In microsystem technology the fabrication of either passive or active micro optical components made from polymers becomes more and more evident with respect to the intense expanding application possibilities e.g. in telecommunication. Actually, the LIGA process developed at the FZK, Germany allows the direct fabrication of microcomponents with lateral dimensions in the micrometer range, structural details in the submicrometer range, high aspect ratios of up to several hundreds and a final average surface roughness of less than 50 nm in small up to large scales. The molding of polymer components for microoptical applications, especially in the singlemode range, is determined by the achievable maximum accuracy of the molding technique itself and of the acceptable tolerances for low damping and coupling losses. Following the LIGA and related technique e.g. mechanical microengineering we want to present in this work the fabrication of polymer singlemode waveguides using a combination of micromolding and light- curing steps.

Toward a biophotonic MEMS cell sensor

NASA Astrophysics Data System (ADS)

Powers, Michael A.; Koev, Stephan T.; Schleunitz, Arne; Yi, Hyunmin; Hodzic, Vildana; Bentley, William E.; Payne, Gregory F.; Rubloff, Gary W.; Ghodssi, Reza

2005-06-01

We present a new platform for the optical analysis of biomolecules based upon the polysaccharide chitosan. The versatile, stable, and compatible nature of chitosan makes it an ideal material for integrating biological materials in microfabricated systems. Chitosan"s pH-responsive solubility allows electrochemical deposition, while its chemical reactivity enables facile coupling of proteins, oligonucleotides, and other biomolecules by covalent bonds. This work demonstrates the spatially selective assembly of a fluorescent molecule on chitosan and its applicability to microscale optical transducers. We define multimode waveguides and fluidic channels on a Pyrex wafer using a single layer of SU-8. Our implementation of sidewall patterning of transparent electrodes (indium tin oxide) on SU-8 structures is demonstrated and can be highly beneficial to fluorescent signal transduction. In this optical configuration, normally incident excitation light illuminates a chitosan surface on the vertical face of a collector waveguide intersected by a microfluidic channel. We demonstrate the collection of the optical signal in the integrated waveguide and analyze the signal by coupling the waveguide to a grating spectrometer.

A coupled modal-finite element method for the wave propagation modeling in irregular open waveguides.

PubMed

Pelat, Adrien; Felix, Simon; Pagneux, Vincent

2011-03-01

In modeling the wave propagation within a street canyon, particular attention must be paid to the description of both the multiple reflections of the wave on the building facades and the radiation in the free space above the street. The street canyon being considered as an open waveguide with a discontinuously varying cross-section, a coupled modal-finite element formulation is proposed to solve the three-dimensional wave equation within. The originally open configuration-the street canyon open in the sky above-is artificially turned into a close waveguiding structure by using perfectly matched layers that truncate the infinite sky without introducing numerical reflection. Then the eigenmodes of the resulting waveguide are determined by a finite element method computation in the cross-section. The eigensolutions can finally be used in a multimodal formulation of the wave propagation along the canyon, given its geometry and the end conditions at its extremities: initial field condition at the entrance and radiation condition at the output. © 2011 Acoustical Society of America

What the ultimate polymeric electro-optic materials will be: guest-host, crosslinked, or side-chain?

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Zhang, Hua; Oh, Min-Cheol; Dalton, Larry R.; Steier, William H.

2003-07-01

Material processing and device fabrication of many different electro-optic (EO) polymers developed at USC are reviewed. Detailed discussion is given to guest-host CLD/APCs, crosslinking perfluorocyclobutane (PFCB) polymer CX1, and thermally stable side-chain polymers CX2 and CX3. Excellent EO performance (1.4V at 1.31 μm, 2.1 V at 1.55 μm) was achieved in CLD/APC Mach-Zehnder modulators (2-cm, push-pull). CLD/APCs also possess low optical losses (1.2 dB/cm in slab waveguides and in thick core channel waveguides). However, the guest-host materials only have limited thermal stability (110-132 °C in short term, <60 °C in long term) and require special techniques in device fabrication. The crosslinking polymer CX1 was able to provide long-term stability at 85 oC when fully cured. It also has a low optical loss (comparable to CLD/APCs) before curing and decent EO coefficient when poled at 180 °C. However, after the films were poled at the crosslinking temperatures (200 °C or above), the transmissions of the waveguides and EO activity became very poor due to poling-induced chromophore degradation. By judicial molecular design of both chromophore and monomer structures to suppress thermal motion of polymer segments, we were able to realize the same or even better thermal stability in side-chain polymers CX2 and CX3. Since no curing is needed, devices can be poled at their optimal poling temperatures, and all good properties can be obtained simultaneously. Despite the excellent solubility in chlorinated solvents, these side-chain polymers are resistant to some other organic solvents or solutions such as acetone, photoresist and various UV-curable liquids.

High-speed electro-optic polymers: mm-Wave applications and silica planar lightwave circuit integration

NASA Astrophysics Data System (ADS)

Chang, Daniel H.

The development of high speed polymer electro-optic modulators has seen steady and significant progress in recent years, enabling novel applications in RF-Photonics. Two of these are described in this Thesis: an Opto-Electronic Oscillator (OEO), which is a hybrid RF and optical oscillator capable of high spectral purity, and Photonic Time-Stretch, which is a signal processing technique for waveform spectral shifting with application to photonically-assisted A/D conversion. In both cases, the operating frequencies achieved have been the highest demonstrated to date. Application of this promising material to more complicated devices, however, is stymied by insertion loss performance. Current loss figures, while acceptable for single modulators, are too high for large arrays of modulators or intrinsically long devices such as AWGs or photonic-RF phase shifters. This is especially frustrating in light of a key virtue which polymers possess as a photonic material: its photolithographic process-ability makes patterning complex devices possible. Indeed, the current ascendancy of silica-based waveguide devices can be attributed largely to the same reason. In this Thesis, we also demonstrate the first hybrid device composed of silica planar lightwave circuits (PLCs) and polymer planar waveguides. Our approach utilizes grayscale lithography to enable vertical coupling between polymer and silica layers, minimizing entanglement of their respective fabrication processes. We have achieved coupling excess loss figures on the order of 1dB. We believe this is the natural next step in the development of electro-optic polymer devices. The two technologies are highly complementary. Silica PLCs, with excellent propagation loss and fiber coupling, are ideally suited for long passive waveguiding. By endowing them with the high-speed phase shifting capability offered by polymers, active wideband photonic devices of increasing complexity and array size can be contemplated.

Narrowband 1.5-{mu}m Bragg filter based on a polymer waveguide with a laser-written refractive-index grating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokolov, Viktor I; Panchenko, Vladislav Ya; Seminogov, V N

We report the fabrication of narrowband frequency-selective filters for the 1.5-{mu}m telecom window, which include a single-mode polymer waveguide with a submicron Bragg grating inscribed by a helium-cadmium laser. The filters have a reflectance R > 98 % and a nearly rectangular reflection band with a bandwidth {Delta}{lambda}{approx}0.4nm. They can be used as components of optical multiplexers/demultiplexers for combining and separating signals in high-speed dense wavelength-division multiplexed optical fibre communication systems. (laser components)

Optically reconfigurable patterning for control of the propagation characteristics of a planar waveguide

NASA Astrophysics Data System (ADS)

Wang, Y.; Klittnick, A.; Clark, N. A.; Keller, P.

2008-10-01

We demonstrate an easily fabricated all-optical and freely reconfigurable method of controlling the propagating characteristics of the optic path within a planar waveguide with low insertion losses by employing the optical patterning of the refractive index of an erasable and rewriteable photosensitive liquid crystal polymer cladding layer.

UV waveguides light fabricated in fluoropolymer CYTOP by femtosecond laser direct writing.

PubMed

Hanada, Yasutaka; Sugioka, Koji; Midorikawa, Katsumi

2010-01-18

We have fabricated optical waveguides inside the UV-transparent polymer, CYTOP, by femtosecond laser direct writing for propagating UV light in biochip applications. Femtosecond laser irradiation is estimated to increase the refractive index of CYTOP by 1.7 x 10(-3) due to partial bond breaking in CYTOP. The waveguide in CYTOP has propagation losses of 0.49, 0.77, and 0.91 dB/cm at wavelengths of 632.8, 355, and 266 nm, respectively.

Love-Wave Biosensors Using Cross-Linked Polymer Waveguides on LiTaO{sub 3} Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

BENDER,FLORIAN; CERNOSEK,RICHARD W.; JOSSE,F.

The design and performance of Love-wave sensors using cross-linked poly-(methyl methacrylate) waveguides of thickness of 0.3--3.2 {micro}m on LiTaO{sub 3} substrates are described. It is found that this layer-substrate combination provides sufficient waveguidance, and electrical isolation of the IDTs from the liquid environment to achieve low acoustic loss and distortion. In bio-sensing experiments, mass sensitivity up to 1,420 Hz/(ng/mm{sup 2}) is demonstrated.

Mode-independent attenuation in evanescent-field sensors

NASA Astrophysics Data System (ADS)

Gnewuch, Harald; Renner, Hagen

1995-03-01

Generally, the total power attenuation in multimode evanescent-field sensor waveguides is nonproportional to the bulk absorbance because the modal attenuation constants differ. Hence a direct measurement is difficult and is additionally aggravated because the waveguide absorbance is highly sensitive to the specific launching conditions at the waveguide input. A general asymptotic formula for the modal power attenuation in strongly asymmetric inhomogeneous planar waveguides with arbitrarily distributed weak absorption in the low-index superstrate is derived. Explicit expressions for typical refractive-index profiles are given. Except when very close to the cutoff, the predicted asymptotic attenuation behavior agrees well with exact calculations. The ratio of TM versus TE absorption has been derived to be (2 - n0 2/nf2 ) for arbitrary profiles. Waveguides with a linear refractive-index profile show mode-independent attenuation coefficients within each polarization. Further, the asymptotic sensitivity is independent of the wavelength, so that it should be possible to directly measure the spectral variation of the bulk absorption. The mode independence of the attenuation has been verified experimentally for a second-order polynomial profile, which is close to a linear refractive-index distribution. In contrast, the attenuation in the step-profile waveguide has been found to depend strongly on the mode number, as predicted by theory. A strong spread of the modal attenuation coefficients is also predicted for the parabolic-profile waveguide sensor.

Semiconductor laser using multimode interference principle

NASA Astrophysics Data System (ADS)

Gong, Zisu; Yin, Rui; Ji, Wei; Wu, Chonghao

2018-01-01

Multimode interference (MMI) structure is introduced in semiconductor laser used in optical communication system to realize higher power and better temperature tolerance. Using beam propagation method (BPM), Multimode interference laser diode (MMI-LD) is designed and fabricated in InGaAsP/InP based material. As a comparison, conventional semiconductor laser using straight single-mode waveguide is also fabricated in the same wafer. With a low injection current (about 230 mA), the output power of the implemented MMI-LD is up to 2.296 mW which is about four times higher than the output power of the conventional semiconductor laser. The implemented MMI-LD exhibits stable output operating at the wavelength of 1.52 μm and better temperature tolerance when the temperature varies from 283.15 K to 293.15 K.

Wavelength selection by dielectric-loaded plasmonic components

NASA Astrophysics Data System (ADS)

Holmgaard, Tobias; Chen, Zhuo; Bozhevolnyi, Sergey I.; Markey, Laurent; Dereux, Alain; Krasavin, Alexey V.; Zayats, Anatoly V.

2009-02-01

Fabrication, characterization, and modeling of waveguide-ring resonators and in-line Bragg gratings for wavelength selection in the telecommunication range are reported utilizing dielectric-loaded surface plasmon-polariton waveguides. The devices were fabricated by depositing subwavelength-sized polymer ridges on a smooth gold film using industrially compatible large-scale UV photolithography. We demonstrate efficient and compact wavelength-selective filters, including waveguide-ring resonators with an insertion loss of ˜2 dB and a footprint of only 150 μm2 featuring narrow bandwidth (˜20 nm) and high contrast (˜13 dB) features in the transmission spectrum. The performance of the components is found in good agreement with the results obtained by full vectorial three-dimensional finite element simulations.

Microfabricated ommatidia using a laser induced self-writing process for high resolution artificial compound eye optical systems.

PubMed

Jung, Hyukjin; Jeong, Ki-Hun

2009-08-17

A microfabricated compound eye, comparable to a natural compound eye shows a spherical arrangement of integrated optical units called artificial ommatidia. Each consists of a self-aligned microlens and waveguide. The increase of waveguide length is imperative to obtain high resolution images through an artificial compound eye for wide field-of - view imaging as well as fast motion detection. This work presents an effective method for increasing the waveguide length of artificial ommatidium using a laser induced self-writing process in a photosensitive polymer resin. The numerical and experimental results show the uniform formation of waveguides and the increment of waveguide length over 850 microm. (c) 2009 Optical Society of America

Low-loss multimode interference couplers for terahertz waves

NASA Astrophysics Data System (ADS)

Themistos, Christos; Kalli, Kyriacos; Komodromos, Michael; Markides, Christos; Quadir, Anita; Rahman, B. M. Azizur; Grattan, Kenneth T. V.

2012-04-01

The terahertz (THz) frequency region of the electromagnetic spectrum is located between the traditional microwave spectrum and the optical frequencies, and offers a significant scientific and technological potential in many fields, such as in sensing, in imaging and in spectroscopy. Waveguiding in this intermediate spectral region is a major challenge. Amongst the various THz waveguides suggested, metal-clad plasmonic waveguides and specifically hollow core structures, coated with insulating material are the most promising low-loss waveguides used in both active and passive devices. Optical power splitters are important components in the design of optoelectronic systems and optical communication networks such as Mach-Zehnder Interferometric switches, polarization splitter and polarization scramblers. Several designs for the implementation of the 3dB power splitters have been proposed in the past, such as the directional coupler-based approach, the Y-junction-based devices and the MMI-based approach. In the present paper a novel MMI-based 3dB THz wave splitter is implemented using Gold/polystyrene (PS) coated hollow glass rectangular waveguides. The H-field FEM based full-vector formulation is used here to calculate the complex propagation characteristics of the waveguide structure and the finite element beam propagation method (FE-BPM) and finite difference time domain (FDTD) approach to demonstrate the performance of the proposed 3dB splitter.

Application de la technologie des materiaux sol-gel et polymere a l'optique integree

NASA Astrophysics Data System (ADS)

Saddiki, Zakaria

2002-01-01

With the advancement of optical telecommunication systems, "integrated optics" and "optical interconnect" technology are becoming more and more important. The major components of these two technologies are photonic integrated circuits (PICs), optoelectronic integrated circuits (OEICs), and optoelectronic multichip modules ( OE-MCMs). Optical signals are transmitted through optical waveguides that interconnect such components. The principle of optical transmission in waveguides is the same as that in optical fibres. To implement these technologies, both passive and active optical devices are needed. A wide variety of optical materials has been studied, e.g., glasses, lithium niobate, III-V semiconductors, sol-gel and polymers. In particular, passive optical components have been fabricated using glass optical waveguides by ion-exchange, or by flame hydrolysis deposition and reactive ion etching (FHD and RIE ). When using FHD and RIE, a very high temperatures (up to 1300°C) are needed to consolidate silica. This work reports on the fabrication and characterization of a new photo-patternable hybrid organic-inorganic glass sol-gel and polymer materials for the realisation of integrated optic and opto-electronic devices. They exhibit low losses in the NIR range, especially at the most important wavelengths windows for optical communications (1320 nm and 1550 nm). The sol-gel and polymer process is based on photo polymerization and thermo polymerization effects to create the wave-guide. The single-layer film is at low temperature and deep UV-light is employed to make the wave-guide by means of the well-known photolithography process. Like any photo-imaging process, the UV energy should exceed the threshold energy of chemical bonds in the photoactive component of hybrid glass material to form the expected integrated optic pattern with excellent line width control and vertical sidewalls. To achieve optical wave-guide, a refractive index difference Delta n occurred between the isolated (guiding layer) and the surrounding region (buffer and cladding). Accordingly, the refractive index emerges as a fundamental device performance material parameter and it is investigated using slab wave-guide. (Abstract shortened by UMI.)

Fiber-coupled dielectric-loaded plasmonic waveguides.

PubMed

Gosciniak, Jacek; Volkov, Valentyn S; Bozhevolnyi, Sergey I; Markey, Laurent; Massenot, Sébastien; Dereux, Alain

2010-03-01

Fiber in- and out-coupling of radiation guided by dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) is realized using intermediate tapered dielectric waveguides. The waveguide structures fabricated by large-scale UV-lithography consist of 1-microm-thick polymer ridges tapered from 10-microm-wide ridges deposited directly on a magnesium fluoride substrate to 1-microm-wide ridges placed on a 50-nm-thick and 100-microm-wide gold stripe. Using fiber-to-fiber transmission measurements at telecom wavelengths, the performance of straight and bent DLSPPWs is characterized demonstrating the overall insertion loss below 24 dB, half of which is attributed to the DLSPPW loss of propagation over the 100-microm-long distance.

Complex approach to the investigation of short fiber-optic comunication lines

NASA Astrophysics Data System (ADS)

Sukhoivanov, I. A.; Kontar', A. A.; Kublik, A. V.; Makarevich, V. S.

The paper proposes a method of complex measurements based on the consideration of the parameters of all the elements used in a specific multimode fiber-optic communication line. It is shown that the error in measuring losses in waveguides up to 20 m long can reach a value of 60 percent.

Numerical analysis of a 3D optical sensor based on single mode fiber to multimode interference graphene design

NASA Astrophysics Data System (ADS)

Mutter, Kussay N.; Jafri, Zubir M.; Tan, Kok Chooi

2016-04-01

In this paper, the simulation and design of a waveguide for water turbidity sensing are presented. The structure of the proposed sensor uses a 2x2 array of multimode interference (MMI) coupler based on micro graphene waveguide for high sensitivity. The beam propagation method (BPM) are used to efficiently design the sensor structure. The structure is consist of an array of two by two elements of sensors. Each element has three sections of single mode for field input tapered to MMI as the main core sensor without cladding which is graphene based material, and then a single mode fiber as an output. In this configuration MMI responses to any change in the environment. We validate and present the results by implementing the design on a set of sucrose solution and showing how these samples lead to a sensitivity change in the sensor based on the MMI structures. Overall results, the 3D design has a feasible and effective sensing by drawing topographical distribution of suspended particles in the water.

Design of a broadband reciprocal optical diode in multimode silicon waveguide by partial depth etching

NASA Astrophysics Data System (ADS)

Zhu, Danfeng; Zhang, Jinqiannan; Ye, Han; Yu, Zhongyuan; Liu, Yumin

2018-07-01

We propose a design of reciprocal optical diode based on asymmetric spatial mode conversion in multimode silicon waveguide on the silicon-on-insulator platform. The design possesses large bandwidth, high contrast ratio and high fabrication tolerance. The forward even-to-odd mode conversion and backward blockade of even mode are achieved by partial depth etching in the functional region. Simulated by three-dimension finite-difference time-domain method, the forward transmission efficiency is about -2.05 dB while the backward transmission efficiency is only -22.68 dB, reaching a highest contrast ratio of 0.983 at the wavelength of 1550 nm. The operational bandwidth is up to 200 nm (from 1450 nm to 1650 nm) with contrast ratio higher than 0.911. The numerical analysis also demonstrates that the proposed optical diode possesses high tolerance for geometry parameter errors which may be introduced in fabrication. The design based on partial depth etching is compatible with CMOS process and is expected to contribute to the silicon-based all-optical circuits.

Design of a wideband tunable AWG using electro-optic polymers and push-pull electrode configuration for ultrafast photonic switching applications

NASA Astrophysics Data System (ADS)

Asquini, Rita; d'Alessandro, Antonio; Salusti, Andrea; Gizzi, Claudio

2003-08-01

A tunable waveguide grating router (WGR) design is reported, where a subpicosecond phase shift is obtained by means of the electro-optically induced refractive index change in the arms of an arrayed-waveguide grating (AWG) made of highly nonlinear poled polymer CLD-75/APC. The polymer consists of a guest-host system, formed by a ring-locked phenyltetraene bridged cromophore dispersed in an amorphous polycarbonate, with coefficient r33=55pm/V and propagation losses of 1.7dB/cm. We propose a multilayer structure on Si substrate, where segments of each waveguide of the AWG are sandwiched between a ground gold electrode and electrodes whose length varies over the AWG. Numerical simulations of a device with electrode length difference of 250μm show a tuning range of 11nm centered at 1550nm by varying the applied voltage from -90V to +90V. From the optimized AWG, a WGR operating with 16 channels spaced by 100GHz has been designed. The WGR is made of single-mode rib waveguides and buffers whose thicknesses are respectively 1.8μm and 1.7μm. A broader tunability range is obtained using the push-pull technique, which induces a refractive index change of opposite sign in two halves of the AWG. A crosstalk of -40dB with tuning range of 22nm over the C-band was figured out.

Evaluation of polymer based third order nonlinear integrated optics devices

NASA Astrophysics Data System (ADS)

Driessen, A.; Hoekstra, H. J. W. M.; Blom, F. C.; Horst, F.; Krijnen, G. J. M.; van Schoot, J. B. P.; Lambeck, P. V.; Popma, Th. J. A.; Diemeer, M. B.

1998-01-01

Nonlinear polymers are promising materials for high speed active integrated optics devices. In this paper we evaluate the perspectives polymer based nonlinear optical devices can offer. Special attention is directed to the materials aspects. In our experimental work we applied mainly Akzo Nobel DANS side-chain polymer that exhibits large second and third order coefficients. This material has been characterized by third harmonic generation, z-scan and pump-probe measurements. In addition, various waveguiding structures have been used to measure the nonlinear absorption (two photon absorption) on a ps time-scale. Finally an integrated optics Mach Zehnder interferometer has been realized and evaluated. It is shown that the DANS side-chain polymer has many of the desired properties: the material is easily processable in high-quality optical waveguiding structures, has low linear absorption and its nonlinearity has a pure electronic origin. More materials research has to be done to arrive at materials with higher nonlinear coefficients to allow switching at moderate light intensity ( < 1 W peak power) and also with lower nonlinear absorption coefficients.

Integration of a photonic crystal polarization beam splitter and waveguide bend.

PubMed

Zheng, Wanhua; Xing, Mingxin; Ren, Gang; Johnson, Steven G; Zhou, Wenjun; Chen, Wei; Chen, Lianghui

2009-05-11

In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 degrees waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20 dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future.

Interferometric imaging using Si3N4 photonic integrated circuits for a SPIDER imager.

PubMed

Su, Tiehui; Liu, Guangyao; Badham, Katherine E; Thurman, Samuel T; Kendrick, Richard L; Duncan, Alan; Wuchenich, Danielle; Ogden, Chad; Chriqui, Guy; Feng, Shaoqi; Chun, Jaeyi; Lai, Weicheng; Yoo, S J B

2018-05-14

This paper reports design, fabrication, and experimental demonstration of a silicon nitride photonic integrated circuit (PIC). The PIC is capable of conducting one-dimensional interferometric imaging with twelve baselines near λ = 1100-1600 nm. The PIC consists of twelve waveguide pairs, each leading to a multi-mode interferometer (MMI) that forms broadband interference fringes or each corresponding pair of the waveguides. Then an 18 channel arrayed waveguide grating (AWG) separates the combined signal into 18 signals of different wavelengths. A total of 103 sets of fringes are collected by the detector array at the output of the PIC. We keep the optical path difference (OPD) of each interferometer baseline to within 1 µm to maximize the visibility of the interference measurement. We also constructed a testbed to utilize the PIC for two-dimension complex visibility measurement with various targets. The experiment shows reconstructed images in good agreement with theoretical predictions.

Slot silicon-gallium nitride waveguide in MMI structures based 1x8 wavelength demultiplexer

NASA Astrophysics Data System (ADS)

Ben Zaken, Bar Baruch; Zanzury, Tal; Malka, Dror

2017-06-01

We propose a novel 8-channel wavelength multimode interference (MMI) demultiplexer in slot waveguide structures that operated at 1530 nm, 1535 nm, 1540 nm, 1545 nm, 1550 nm, 1555 nm, 1560 nm and 1565 nm wavelengths. Gallium nitride (GaN) surrounded by silicon (Si) was founded as suitable materials for the slot-waveguide structures. The proposed device was designed by seven 1x2 MMI couplers, fourteen S-band and one input taper. Numerical investigations were carried out on the geometrical parameters by using a full vectorial-beam propagation method (FVBPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530- 1565 nm) with low crosstalk ((-19.97)-(-13.77) dB) and bandwidth (1.8-3.6 nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

Analyzing the power coupled between partially coherent waveguide fields in different states of coherence.

PubMed

Withington, Stafford; Yassin, Ghassan

2002-07-01

A procedure is described for calculating the power coupled between partially coherent waveguide fields that are in different states of coherence. The method becomes important when it is necessary to calculate the power transferred from a distributed source S to a distributed load L through a length of multimode metallic, or dielectric, waveguide. It is shown that if the correlations between the transverse components of the electric and magnetic fields of S and L are described by coherence matrices M and M', respectively, then the normalized average power coupled between them is (eta) = Tr[MM']/Tr[M]Tr[M'], where Tr denotes the trace. When the modal impedances are equal, this expression for the coupled power reduces to an equation derived in a previous paper [J. Opt. Soc. Am. A 18, 3061 (2001)], by use of thermodynamic arguments, for the power coupled between partially coherent free-space beams.

1 × 4 MMI visible light wavelength demultiplexer based on a GaN slot-waveguide structure

NASA Astrophysics Data System (ADS)

Shoresh, Tamir; Katanov, Nadav; Malka, Dror

2018-07-01

High transmission losses are the key problem that limits the performance of visible light communication systems, which work on wavelength division multiplexing (WDM) technology. To overcome this problem, we propose a novel design for a 1 × 4 optical demultiplexer based on the multimode interference in a slot-waveguide structure that operates at 547 nm, 559 nm, 566 nm, and 584 nm. Gallium nitride and silicon oxide were found to be excellent materials for the slot-waveguide structure. Simulation results showed that the proposed device can transmit four channels that work in the visible light range with a low transmission loss of 0.983-1.423 dB, crosstalk of 13.8-18.3 dB, and bandwidth of 1.8-3.2 nm. Thus, this device can be very useful in visible light networking systems, which work on the WDM technology.

Ultrafast laser inscription of 3D components for spatial multiplexing

NASA Astrophysics Data System (ADS)

Thomson, Robert R.

2016-02-01

The thirst for bandwidth in telecommunications networks is becoming ever larger due to bandwidth hungry applications such as video-on-demand. To further increase the bandwidth capacity, engineers are now seeking to imprint information on the last remaining degree of freedom of the lightwave carrier - space. This has given rise to the field of Space Division Multiplexing (SDM). In essence, the concept of SDM simple; we aim to use the different spatial modes of an optical fibre as multiplexed data transmission channels. These modes could either be in the form of separate singlemodes in a multicore optical fibre, individual spatial modes of a multimode fibre, or indeed the individual spatial modes of a multimode multicore optical fibre. Regardless of the particular "flavour" of SDM in question, it is clear that significant interfacing issues exist between the optical fibres used in SDM and the conventional single-mode planar lightwave circuits that are essential to process the light (e.g. arrayed waveguide gratings and splitters), and efficient interconnect technologies will be required. One fabrication technology that has emerged as a possible route to solve these interconnection issues is ultrafast laser inscription (ULI), which relies on the use of focused ultrashort laser pulses to directly inscribe three-dimensional waveguide structures inside a bulk dielectric. In this paper, I describe some of the work that has been conducted around the world to apply the unique waveguide fabrication capabilities of ULI to the development of 3D photonic components for applications in SDM.

Optical temperature sensing on flexible polymer foils

NASA Astrophysics Data System (ADS)

Sherman, Stanislav; Xiao, Yanfen; Hofmann, Meike; Schmidt, Thomas; Gleissner, Uwe; Zappe, Hans

2016-04-01

In contrast to established semiconductor waveguide-based or glass fiber-based integrated optical sensors, polymerbased optical systems offer tunable material properties, such as refractive index or viscosity, and thus provide additional degrees of freedom for sensor design and fabrication. Of particular interest in sensing applications are fully-integrated optical waveguide-based temperature sensors. These typically rely on Bragg gratings which induce a periodic refractive index variation in the waveguide so that a resonant wavelength of the structure is reflected.1,2 With broad-band excitation, a dip in the spectral output of the waveguide is thus generated at a precisely-defined wavelength. This resonant wavelength depends on the refractive index of the waveguide and the grating period, yet both of these quantities are temperature dependent by means of the thermo-optic effect (change in refractive index with temperature) and thermal expansion (change of the grating period with temperature). We show the design and fabrication of polymer waveguide-integrated temperature sensors based on Bragggratings, fabricated by replication technology on flexible PMMA foil substrates. The 175 μm thick foil serves as lower cladding for a polymeric waveguide fabricated from a custom-made UV-crosslinkable co-monomer composition. The fabrication of the grating structure includes a second replication step into a separate PMMA-foil. The dimensions of the Bragg-gratings are determined by simulations to set the bias point into the near infrared wavelength range, which allows Si-based detectors to be used. We present design considerations and performance data for the developed structures. The resulting sensor's signal is linear to temperature changes and shows a sensitivity of -306 nm/K, allowing high resolution temperature measurements.

Fabrication of flexible grating sensing waveguide based on nano-imprint lithography and micro-replication process

NASA Astrophysics Data System (ADS)

Liu, Yueming; Tian, Weijian; Zhang, Shaojun

2009-05-01

Soft and flexible grating sensing waveguides is urgently demanded in application of micro-bending sensing and surface distortion sensing in medical catheter and smart skin sensing unit etc. Based on Nano-imprint Lithography and micro-replication process, polymer grating waveguides with core size 4μm×20μm and pitch 0.75μm are fabricated successfully in this paper. This novel grating waveguides is soft and flexible enough for related application and with the bio-medical safe feature when used in human body catheter. Fabricated processes are presented including the fabrication of micro mould and UV-replication process, and relative skills are discussed also in this paper.

Laser direct writing of complex radially varying single-mode polymer waveguide structures

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Peng, Jie; Middlebrook, Christopher T.

2015-07-01

Increasing board-to-board and chip-to-chip computational data rates beyond 12.5 Gbs will require the use of single-mode polymer waveguides (WGs) that have high bandwidths and are able to be wavelength division multiplexed. Laser direct writing (LDW) of polymer WGs provides a scalable and reconfigurable maskless procedure compared to common photolithography fabrication. LDW of straights and radial curves are readily achieved using predefined drive commands of the two-axis direct drive linear stage system. Using the laser direct write process for advanced WG structures requires stage-drive programming techniques that account for specified polymer material exposure durations. Creating advanced structures such as WG S-bends into single-mode polymer WG builds provides designers with the ability to affect pitch control, optical coupling, and reduce footprint requirements. Fabrication of single-mode polymer WG segmented radial arcs is achieved through a smooth radial arc user-programmed defined mathematical algorithm. Cosine and raised-sine S-bends are realized through a segmentation method where the optimal incremental step length and bend dimensions are controlled to achieve minimal structure loss. Laser direct written S-bends are compared with previously published photolithographic S-bend results using theoretical bend loss models. Fabrication results show that LDW is a viable method in the fabrication of advanced polymer WG structures.

Waveguide-loaded silica fibers for coupling to high-index micro-resonators

NASA Astrophysics Data System (ADS)

Latawiec, P.; Burek, M. J.; Venkataraman, V.; Lončar, M.

2016-01-01

Tapered silica fibers are often used to rapidly probe the optical properties of micro-resonators. However, their low refractive index precludes phase-matching when coupling to high-index micro-resonators, reducing efficiency. Here, we demonstrate efficient optical coupling from tapered fibers to high-index micro-resonators by loading the fibers with an ancillary adiabatic waveguide-coupler fabricated via angled-etching. We demonstrate greatly enhanced coupling to a silicon multimode micro-resonator when compared to coupling via the bare fiber only. Signatures of resonator optical bistability are observed at high powers. This scheme can be applied to resonators of any size and material, increasing the functional scope of fiber coupling.

Two-mode division multiplexing in a silicon-on-insulator ring resonator.

PubMed

Dorin, Bryce A; Ye, Winnie N

2014-02-24

Mode-division multiplexing (MDM) is an emerging multiple-input multiple-output method, utilizing multimode waveguides to increase channel numbers. In the past, silicon-on-insulator (SOI) devices have been primarily focused on single-mode waveguides. We present the design and fabrication of a two-mode SOI ring resonator for MDM systems. By optimizing the device parameters, we have ensured that each mode is treated equally within the ring. Using adiabatic Bezier curves in the ring bends, our ring demonstrated a signal-to-crosstalk ratio above 18 dB for both modes at the through and drop ports. We conclude that the ring resonator has the potential for filtering and switching for MDM systems on SOI.

Integration, photostability and spontaneous emission rate enhancement of colloidal PbS nanocrystals for Si-based photonics at telecom wavelengths.

PubMed

Humer, Markus; Guider, Romain; Jantsch, Wolfgang; Fromherz, Thomas

2013-08-12

We experimentally investigate PbS nanocrystal (NC) photoluminescence (PL) coupled to all-integrated Si-based ring resonators and waveguides at telecom wavelengths. Dissolving the NCs into Novolak polymer significantly improves their stability in ambient atmosphere. Polymer-NC blends of various NC concentrations can be applied to and removed from the same device. For NC concentrations up to 4vol%, the spontaneous emission rate into ring-resonator modes is enhanced by a factor of ~13 with respect to that into a straight waveguide. The PL intensity shows a linear dependence on the excitation intensity up to 1.64kW/cm(2) and stable quality factors of ~2500.

Refractive index sensor based on a polymer fiber directional coupler for low index sensing.

PubMed

Lee, Kwang Jo; Liu, Xiaoqi; Vuillemin, Nelly; Lwin, Richard; Leon-Saval, Sergio G; Argyros, Alexander; Kuhlmey, Boris T

2014-07-14

We propose, numerically analyze and experimentally demonstrate a novel refractive index sensor specialized for low index sensing. The device is based on a directional coupler architecture implemented in a single microstructured polymer optical fiber incorporating two waveguides within it: a single-mode core and a satellite waveguide consisting of a hollow high-index ring. This hollow channel is filled with fluid and the refractive index of the fluid is detected through changes to the wavelength at which resonant coupling occurs between the two waveguides. The sensor design was optimized for both higher sensitivity and lower detection limit, with simulations and experiments demonstrating a sensitivity exceeding 1.4 × 10(3) nm per refractive index unit. Simulations indicate a detection limit of ~2 × 10(-6) refractive index units is achievable. We also numerically investigate the performance for refractive index changes localized at the surface of the holes, a case of particular importance for biosensing.

Polymer Waveguides for Quantum Information

DTIC Science & Technology

2005-01-01

a single photon or a very small amount of light plays a critical role in establishing the quantum nature of the process. These materials offer...realizations of Mach-Zehnder interferometers for use in single- photon quantum communication systems. The Scope of the research for this grant: This...to the waveguide we make. We also intend to investigate the transmission of highly attenuated signals mimicking the single photon , which in turn

Theoretical modeling of a coupled plasmon waveguide resonance sensor based on multimode optical fiber

NASA Astrophysics Data System (ADS)

Liu, Kun; Xue, Meng; Jiang, Junfeng; Wang, Tao; Chang, Pengxiang; Liu, Tiegen

2018-03-01

A coupled plasmon waveguide resonance (CPWR) sensor based on metal/dielectric-coated step index multimode optical fiber is proposed. Theoretical simulations using the four-layer Fresnel equations based on a bi-dimensional optical fiber model were implemented on four structures: Ag-ZnO, Au-ZnO, Ag-TiO2 and Au-TiO2. By controlling the thickness of dielectric layer, we managed to manipulate the CPWR resonance wavelengths. When a CPWR resonance dip is in the short wavelength region, it is insensitive to the change of surrounding refractive index (SRI) and can be used as a reference to improve the sensing accuracy of surface plasmon resonance (SPR) mode. With the increase of the thickness of the dielectric layer, the CPWR resonance dips shift to longer wavelength and the corresponding sensitivities increase. When the 1st CPWR resonance wavelength is near 1550 nm and SRI is around 1.333, the sensitivities of four structures reach 1360.61 nm/RIU, 1375.76 nm/RIU, 1048.48 nm/RIU and 1015.15 nm/RIU, respectively. The values are close to that of the conventional SPR optical fiber sensor while the spectral bandwidths of the optical fiber CPWR sensors are narrower.

Design challenges of EO polymer based leaky waveguide deflector for 40 Gs/s all-optical analog-to-digital converters

NASA Astrophysics Data System (ADS)

Hadjloum, Massinissa; El Gibari, Mohammed; Li, Hongwu; Daryoush, Afshin S.

2016-08-01

Design challenges and performance optimization of an all-optical analog-to-digital converter (AOADC) is presented here. The paper addresses both microwave and optical design of a leaky waveguide optical deflector using electro-optic (E-O) polymer. The optical deflector converts magnitude variation of the applied RF voltage into variation of deflection angle out of a leaky waveguide optical beam using the linear E-O effect (Pockels effect) as part of the E-O polymer based optical waveguide. This variation of deflection angle as result of the applied RF signal is then quantized using optical windows followed by an array of high-speed photodetectors. We optimized the leakage coefficient of the leaky waveguide and its physical length to achieve the best trade-off between bandwidth and the deflected optical beam resolution, by improving the phase velocity matching between lightwave and microwave on one hand and using pre-emphasis technique to compensate for the RF signal attenuation on the other hand. In addition, for ease of access from both optical and RF perspective, a via-hole less broad bandwidth transition is designed between coplanar pads and coupled microstrip (CPW-CMS) driving electrodes. With the best reported E-O coefficient of 350 pm/V, the designed E-O deflector should allow an AOADC operating over 44 giga-samples-per-seconds with an estimated effective resolution of 6.5 bits on RF signals with Nyquist bandwidth of 22 GHz. The overall DC power consumption of all components used in this AOADC is of order of 4 W and is dominated by power consumption in the power amplifier to generate a 20 V RF voltage in 50 Ohm system. A higher sampling rate can be achieved at similar bits of resolution by interleaving a number of this elementary AOADC at the expense of a higher power consumption.

Optical waveguide circuit board with a surface-mounted optical receiver array

NASA Astrophysics Data System (ADS)

Thomson, J. E.; Levesque, Harold; Savov, Emil; Horwitz, Fred; Booth, Bruce L.; Marchegiano, Joseph E.

1994-03-01

A photonic circuit board is fabricated for potential application to interchip and interboard parallel optical links. The board comprises photolithographically patterned polymer optical waveguides on a conventional glass-epoxy electrical circuit board and a surface-mounted integrated circuit (IC) package that optically and electrically couples to an optoelectronic IC. The waveguide circuits include eight-channel arrays of straights, cross-throughs, curves, self- aligning interconnects to multi-fiber ribbon, and out-of-plane turning mirrors. A coherent, fused bundle of optical fibers couples light between 45-deg waveguide mirrors and a GaAs receiver array in the IC package. The fiber bundle is easily aligned to the mirrors and the receivers and is amenable to surface mounting and hermetic sealing. The waveguide-receiver- array board achieved error-free data rates up to 1.25 Gbits/s per channel, and modal noise was shown to be negligible.

Synthesis of Hadamard transformers by use of multimode interference optical waveguides.

PubMed

Gupta, Atma Ram; Tsutsumi, Kiyoshi; Nakayama, Junichi

2003-05-20

We propose a synthesis method of optical Hadamard transformer using multimode interference (MMI) couplers. By using the signal transfer matrix of 2 x 2, 4 x 4, and 8 x 8 MMI couplers, we show that sum and difference units of input signals can be synthesized. An interchange unit of two signals can also be synthesized. One synthesis method of Hadamard transformers is a combination of only 2 x 2 units, and the other is a combination of N x N(N > or = 4) units as well as 2 x 2 units. The design examples of operation units are shown, and the size and the output power of Hadamard transformers are estimated.

Ultra-small, self-holding, optical gate switch using Ge2Sb2Te5 with a multi-mode Si waveguide.

PubMed

Tanaka, Daiki; Shoji, Yuya; Kuwahara, Masashi; Wang, Xiaomin; Kintaka, Kenji; Kawashima, Hitoshi; Toyosaki, Tatsuya; Ikuma, Yuichiro; Tsuda, Hiroyuki

2012-04-23

We report a multi-mode interference-based optical gate switch using a Ge(2)Sb(2)Te(5) thin film with a diameter of only 1 µm. The switching operation was demonstrated by laser pulse irradiation. This switch had a very wide operating wavelength range of 100 nm at around 1575 nm, with an average extinction ratio of 12.6 dB. Repetitive switching over 2,000 irradiation cycles was also successfully demonstrated. In addition, self-holding characteristics were confirmed by observing the dynamic responses, and the rise and fall times were 130 ns and 400 ns, respectively. © 2012 Optical Society of America

Optical Forces on Non-Spherical Nanoparticles Trapped by Optical Waveguides

NASA Astrophysics Data System (ADS)

Hasan Ahmed, Dewan; Sung, Hyung Jin

2011-07-01

Numerical simulations of a solid-core polymer waveguide structure were performed to calculate the trapping efficiencies of particles with nanoscale dimensions smaller than the wavelength of the trapping beam. A three-dimensional (3-D) finite element method was employed to calculate the electromagnetic field. The inlet and outlet boundary conditions were obtained using an eigenvalue solver to determine the guided and evanescent mode profiles. The Maxwell stress tensor was considered for the calculation of the transverse and downward trapping efficiencies. A particle at the center of the waveguide showed minimal transverse trapping efficiency and maximal downward trapping efficiency. This trend gradually reversed as the particle moved away from the center of the waveguide. Particles with larger surface areas exhibited higher trapping efficiencies and tended to be trapped near the waveguide. Particles displaced from the wave input tended to be trapped at the waveguide surface. Simulation of an ellipsoidal particle showed that the orientation of the major axis along the waveguide's lateral z-coordinate significantly influenced the trapping efficiency. The particle dimensions along the z-coordinate were more critical than the gap distance (vertical displacement from the floor of the waveguide) between the ellipsoid particle and the waveguide. The present model was validated using the available results reported in the literature for different trapping efficiencies.

Multifunctional PHPMA-Derived Polymer for Ratiometric pH Sensing, Fluorescence Imaging, and Magnetic Resonance Imaging.

PubMed

Su, Fengyu; Agarwal, Shubhangi; Pan, Tingting; Qiao, Yuan; Zhang, Liqiang; Shi, Zhengwei; Kong, Xiangxing; Day, Kevin; Chen, Meiwan; Meldrum, Deirdre; Kodibagkar, Vikram D; Tian, Yanqing

2018-01-17

In this paper, we report synthesis and characterization of a novel multimodality (MRI/fluorescence) probe for pH sensing and imaging. A multifunctional polymer was derived from poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) and integrated with a naphthalimide-based-ratiometric fluorescence probe and a gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex (Gd-DOTA complex). The polymer was characterized using UV-vis absorption spectrophotometry, fluorescence spectrofluorophotometry, magnetic resonance imaging (MRI), and confocal microscopy for optical and MRI-based pH sensing and cellular imaging. In vitro labeling of macrophage J774 and esophageal CP-A cell lines shows the polymer's ability to be internalized in the cells. The transverse relaxation time (T 2 ) of the polymer was observed to be pH-dependent, whereas the spin-lattice relaxation time (T 1 ) was not. The pH probe in the polymer shows a strong fluorescence-based ratiometric pH response with emission window changes, exhibiting blue emission under acidic conditions and green emission under basic conditions, respectively. This study provides new materials with multimodalities for pH sensing and imaging.

Controlled waveguide coupling for photon emission from colloidal PbS quantum dot using tunable microcavity made of optical polymer and silicon

NASA Astrophysics Data System (ADS)

Nozaka, Takahiro; Mukai, Kohki

2016-04-01

A tunable microcavity device composed of optical polymer and Si with a colloidal quantum dot (QD) is proposed as a single-photon source for planar optical circuit. Cavity size is controlled by electrostatic micromachine behavior with the air bridge structure to tune timing of photon injection into optical waveguide from QD. Three-dimensional positioning of a QD in the cavity structure is available using a nanohole on Si processed by scanning probe microscope lithography. We fabricated the prototype microcavity with PbS-QD-mixed polymenthyl methacrylate on a SOI (semiconductor-on-insulator) substrate to show the tunability of cavity size as the shift of emission peak wavelength of QD ensemble.

Generation of optical vortices in an integrated optical circuit

NASA Astrophysics Data System (ADS)

Tudor, Rebeca; Kusko, Mihai; Kusko, Cristian

2017-09-01

In this work, the generation of optical vortices in an optical integrated circuit is numerically demonstrated. The optical vortices with topological charge m = ±1 are obtained by the coherent superposition of the first order modes present in a waveguide with a rectangular cross section, where the phase delay between these two propagating modes is Δφ = ±π/2. The optical integrated circuit consists of an input waveguide continued with a y-splitter. The left and the right arms of the splitter form two coupling regions K1 and K2 with a multimode output waveguide. In each coupling region, the fundamental modes present in the arms of the splitter are selectively coupled into the output waveguide horizontal and vertical first order modes, respectively. We showed by employing the beam propagation method simulations that the fine tuning of the geometrical parameters of the optical circuit makes possible the generation of optical vortices in both transverse electric (TE) and transverse magnetic (TM) modes. Also, we demonstrated that by placing a thermo-optical element on one of the y-splitter arms, it is possible to switch the topological charge of the generated vortex from m = 1 to m = -1.

Numerical study of phase conjugation in stimulated Brillouin scattering from an optical waveguide

NASA Astrophysics Data System (ADS)

Lehmberg, R. H.

1983-05-01

Stimulated Brillouin scattering (SBS) in a multimode optical waveguide is examined, and the parameters that affect the wavefront conjugation fidelity are studied. The nonlinear propagation code is briefly described and the calculated quantities are defined. The parameter study in the low reflectivity limit is described, and the effects of pump depletion are considered. The waveguide produced significantly higher fidelities than the focused configuration, in agreement with several experimental studies. The light scattered back through the phase aberrator exhibited a farfield intenstiy profile closely matching that of the incident beam; however, the nearfield intensity exhibited large and rapid spatial inhomogeneities across the entire aberrator, even for conjugation fidelities as high as 98 percent. In the absence of pump depletion, the fidelity increased with average pump intensity for amplitude gains up to around e to the 10th and then decreased slowly and monotonically with higher intensity. For all cases, pump depletion significantly enhanced the fidelity of the wavefront conjugation by inhibiting the small-scale pulling effect.

Methodology for the design, production, and test of plastic optical displacement sensors

NASA Astrophysics Data System (ADS)

Rahlves, Maik; Kelb, Christian; Reithmeier, Eduard; Roth, Bernhard

2016-08-01

Optical displacement sensors made entirely from plastic materials offer various advantages such as biocompatibility and high flexibility compared to their commonly used electrical and glass-based counterparts. In addition, various low-cost and large-scale fabrication techniques can potentially be utilized for their fabrication. In this work we present a toolkit for the design, production, and test of such sensors. Using the introduced methods, we demonstrate the development of a simple all-optical displacement sensor based on multimode plastic waveguides. The system consists of polymethylmethacrylate and cyclic olefin polymer which serve as cladding and core materials, respectively. We discuss several numerical models which are useful for the design and simulation of the displacement sensors as well as two manufacturing methods capable of mass-producing such devices. Prior to fabrication, the sensor layout and performance are evaluated by means of a self-implemented ray-optical simulation which can be extended to various other types of sensor concepts. Furthermore, we discuss optical and mechanical test procedures as well as a high-precision tensile testing machine especially suited for the characterization of the opto-mechanical performance of such plastic optical displacement sensors.

Ultracompact splitter for submicrometer silicon-on-insulator rib waveguides.

PubMed

Koster, Alain; Cassan, Eric; Laval, Suzanne; Vivien, Laurent; Pascal, Daniel

2004-11-01

An ultracompact and efficient 1 x 2 splitter for submicrometer silicon-on-insulator rib waveguides using a star coupler is reported. The structure proposed here is decidedly smaller than the usual splitters such as multi-mode interference or Y-branch devices and much less sensitive to technological fluctuations. Design of the compact splitter is optimized at lambda = 1.31 microm with the effective-index method and a two-dimensional beam-propagation method. The excess losses are lower than 0.15 dB, and the dependence of the losses on wavelength between 1.23 and 1.63 microm is almost flat (variation less than 0.04 dB), which makes the device very interesting for coarse wavelength-division multiplexing applications within the silicon photonic technology.

Glass light pipes for solar concentration

NASA Astrophysics Data System (ADS)

Madsen, C. K.; Dogan, Y.; Morrison, M.; Hu, C.; Atkins, R.

2018-02-01

Glass waveguides are fabricated using laser processing techniques that have low optical loss with >90% optical throughput. Advanced light pipes are demonstrated, including angled facets for turning mirrors used for lens-to-light pipe coupling, tapers that increase the concentration, and couplers for combining the outputs from multiple lens array elements. Because they are fabricated from glass, these light pipes can support large optical concentrations and propagate broadband solar over long distances with minimal loss and degradation compared to polymer waveguides. Applications include waveguiding solar concentrators using multi-junction PV cells, solar thermal applications and remoting solar energy, such as for daylighting. Ray trace simulations are used to estimate the surface smoothness required to achieve low loss. Optical measurements for fabricated light pipes are reported for use in waveguiding solar concentrator architectures.

Polymer film-nanoparticle composites as new multimodality, non-migrating breast biopsy markers.

PubMed

Kaplan, Jonah A; Grinstaff, Mark W; Bloch, B Nicolas

2016-03-01

To develop a breast biopsy marker that resists fast and slow migration and has permanent visibility under commonly used imaging modalities. A polymer-nanoparticle composite film was prepared by embedding superparamagnetic iron oxide nanoparticles and a superelastic Nitinol wire within a flexible polyethylene matrix. MRI, mammography, and ultrasound were used to visualize the marker in agar, ex vivo chicken breast, bovine liver, brisket, and biopsy training phantoms. Fast migration caused by the "accordion effect" was quantified after simulated stereotactic, vacuum-assisted core biopsy/marker placement, and centrifugation was used to simulate accelerated long-term (i.e., slow) migration in ex vivo bovine tissue phantoms. Clear marker visualization under MRI, mammography, and ultrasound was observed. After deployment, the marker partially unfolds to give a geometrically constrained structure preventing fast and slow migration. The marker can be deployed through an 11G introducer without fast migration occurring, and shows substantially less slow migration than conventional markers. The polymer-nanoparticle composite biopsy marker is clearly visible on all clinical imaging modalities and does not show substantial migration, which ensures multimodal assessment of the correct spatial information of the biopsy site, allowing for more accurate diagnosis and treatment planning and improved breast cancer patient care. Polymer-nanoparticle composite biopsy markers are visualized using ultrasound, MRI, and mammography. Embedded iron oxide nanoparticles provide tuneable contrast for MRI visualization. Permanent ultrasound visibility is achieved with a non-biodegradable polymer having a distinct ultrasound signal. Flexible polymer-based biopsy markers undergo shape change upon deployment to minimize migration. Non-migrating multimodal markers will help improve accuracy of pre/post-treatment planning studies.

Design issues for directional coupler- and MMI-based optical microring resonator filters on InP

NASA Astrophysics Data System (ADS)

Themistos, Christos; Kalli, Kyriacos; Komodromos, Michalis; Rajarajan, Muttukrishnan; Rahman, B. M. A.; Grattan, Kenneth T. V.

2004-08-01

The characterization and optimization of optical microring resonator-based optical filters on deeply etched GaInAsP-Inp waveguides, using the finite element-based beam propagation approach is presented here. Design issues for directional coupler- and multimode interference coupler-based devices, such as field evolution, optical power, phase, fabrication tolerance and wavelength dependence have been investigated.

A possible approach to optimization of parameters of sound-absorbing structures for multimode waveguides

NASA Astrophysics Data System (ADS)

Mironov, M. A.

2011-11-01

A method of allowing for the spatial sound field structure in designing the sound-absorbing structures for turbojet aircraft engine ducts is proposed. The acoustic impedance of a duct should be chosen so as to prevent the reflection of the primary sound field, which is generated by the sound source in the absence of the duct, from the duct walls.

Colloidal PbS nanocrystals integrated to Si-based photonics for applications at telecom wavelengths

NASA Astrophysics Data System (ADS)

Humer, M.; Guider, R.; Jantsch, W.; Fromherz, T.

2013-05-01

In the last decade, Si based photonics has made major advances in terms of design, fabrication, and device implementation. But due to Silicon's indirect bandgap, it still remains a challenge to create efficient Si-based light emitting devices. In order to overcome this problem, an approach is to develop hybrid systems integrating light-emitting materials into Si. A promising class of materials for this purpose is the class of semiconducting nanocrystal quantum dots (NCs) that are synthesized by colloidal chemistry. As their absorption and emission wavelength depends on the dot size, which can easily be controlled during synthesis, they are extremely attractive as building blocks for nanophotonic applications. For applications in telecom wavelength, Lead chalcogenide colloidal NCs are optimum materials due to their unique optical, electronic and nonlinear properties. In this work, we experimentally demonstrate the integration of PbS nanocrystals into Si-based photonic structures like slot waveguides and ring resonators as optically pumped emitters for room temperature applications. In order to create such hybrid structures, the NCs were dissolved into polymer resists and drop cast on top of the device. Upon optical pumping, intense photoluminescence emission from the resonating modes is recorded at the output of the waveguide with transmission quality factors up to 14000. The polymer host material was investigated with respect to its ability to stabilize the NC's photoluminescence emission against degradation under ambient conditions. The waveguide-ring coupling efficiency was also investigated as function of the NCs concentrations blended into the polymer matrix. The integration of colloidal quantum dots into Silicon photonic structures as demonstrated in this work is a very versatile technique and thus opens a large range of applications utilizing the linear and nonlinear optical properties of PbS NCs at telecom wavelengths.

Polymer microfiber bridging Bi-tapered refractive index sensor based on evanescent field

NASA Astrophysics Data System (ADS)

Lv, Ri-Qing; Wang, Qi; Wang, Bo-Tao; Liu, Yu; Kong, Lingxin

2018-05-01

A PDMS/graphene enhanced PMMA micro optical waveguide sensor is reported in terms of fabrication method and optical characteristics. The micro optical waveguide with a diameter of 6 μm and a length of 800 μm is used as the sensing probe to realize refractive index (RI) measurement suspended in NaCl solutions with different concentrations. Experimental results show that the refractive index sensing sensitivity can reach 2027.97 nm/RIU within the refractive index ranging from 1.3333-1.3426. Research results show that PMMA/graphene micro optical waveguide doped with PDMS is an excellent high sensitive sensing technology in refractive index detection field.

Joint Services Electronics Program - JSEP. Research in Electronics.

DTIC Science & Technology

1985-04-30

5 6 7’ TIME (SEC) T5us 󈨇 5C .4 6. 3[ 13 s ua -5 os 4 .7 4 C T7 r 4 9 Torr SU8 6200C P - 1 𔄃 lcF To AS1 0 c- .9-S p 7 -9 . 4 co - * 9 ’V...Lightwave Technology. Other studies have involved measuring polymer film waveguides using a leaky waveguide method, published by Ding and Garmire

Synthetic Engineering of Spider Silk Fiber as Implantable Optical Waveguides for Low-Loss Light Guiding.

PubMed

Qiao, Xin; Qian, Zhigang; Li, Junjie; Sun, Hongji; Han, Yao; Xia, Xiaoxia; Zhou, Jin; Wang, Chunlan; Wang, Yan; Wang, Changyong

2017-05-03

A variety of devices used for biomedical engineering have been fabricated using protein polymer because of their excellent properties, such as strength, toughness, biocompatibility, and biodegradability. In this study, we fabricated an optical waveguide using genetically engineered spider silk protein. This method has two significant advantages: (1) recombinant spider silk optical waveguide exhibits excellent optical and biological properties and (2) biosynthesis of spider silk protein can overcome the limitation to the research on spider silk optical waveguide due to the low yield of natural spider silk. In detail, two kinds of protein-based optical waveguides made from recombinant spider silk protein and regenerative silkworm silk protein were successfully prepared. Results suggested that the recombinant spider silk optical waveguide showed a smoother surface and a higher refractive index when compared with regenerative silkworm silk protein. The optical loss of recombinant spider silk optical waveguide was 0.8 ± 0.1 dB/cm in air and 1.9 ± 0.3 dB/cm in mouse muscles, which were significantly lower than those of regenerative silkworm silk optical waveguide. Moreover, recombinant spider silk optical waveguide can meet the demand to guide and efficiently deliver light through biological tissue. In addition, recombinant spider silk optical waveguide showed low toxicity to cells in vitro and low-level inflammatory reaction with surrounding tissue in vivo. Therefore, recombinant spider silk optical waveguide is a promising implantable device to guide and deliver light with low loss.

Magnetic nanofiber composite materials and devices using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xing; Zhou, Ziyao

2017-04-11

A nonreciprocal device is described. It includes a housing, a waveguide layer and at least one layer of magnetic nanofiber composite. The magnetic nanofiber composite layer is made up of a polymer base layer, a dielectric matrix comprising magnetic nanofibers. The nanofibers have a high aspect ratio and wherein said dielectric matrix is embedded in the polymer base layer.

Design for beam splitting components employing silicon-on-insulator rib waveguide structures.

PubMed

Hsiao, C S; Wang, Likarn

2005-12-01

We present a new design for beam splitting components employing a silicon-on-insulator rib waveguide structures. In the new design, a high-index thin-film layer is deposited in the rib section to reduce the wave field dispersive tails in the slab section and accordingly render the mode field a confined spot. This in turn improves the beam splitting performance of some conventional waveguide components such as y branches and multimode interference couplers (MMICs), in terms of the excess loss, fiber coupling loss, and compactness of these components. For a 1 x 2 y-branch beam splitter, the excess loss can be as small as 0.43 dB in the new design, which is much lower than that for a conventional rib waveguide structure (which is 1.28 dB). For a 1 x 2 MMIC in our example, the new rib waveguide structure presents an excess loss of 0.064 dB for the TE mode and 0.046 dB for the TM mode, with negligible nonuniformity in dimensions of 30 microm x 1040 microm, whereas its counterpart (i.e., the one with the same dimensions but without a thin-film layer) presents an excess loss of approximately 0.86 dB for both modes. A conventional MMIC must have dimensions larger than 70 microm x 5650 microm to maintain almost the same low excess loss.

Fabrication process for polymer PLC platforms with V-grooves for passive alignment

NASA Astrophysics Data System (ADS)

Park, Suntak; Lee, Jong-Moo; Ahn, Joon Tae; Baek, Yong-Soon

2005-12-01

A method for polymer planar lightwave circuit (PLC) devices fabricated on a substrate with V-grooves is developed for passive alignment of an optical fiber to a polymer waveguide. In order to minimize thickness nonuniformity of polymer layers caused by the V-grooves, dry film resist (DFR) is used. The V-grooves are covered with the DFR before the polymer layers are spin-coated on the substrate. The DFR prevents the polymer from being filled in the V-grooves as well as from being spin-coated nonuniformly on the substrate. This process provides a simple and cost-effective fabrication method of polymer PLCs or platforms for passive alignment.

Design and fabrication of N x N optical couplers based on organic polymer optical waveguides

NASA Astrophysics Data System (ADS)

Krchnavek, Robert R.; Rode, Daniel L.

1994-08-01

In this report, we examine the design and fabrication of a planar, 10x10 optical coupler utilizing photopolymerizable organic polymers. Background information on the theory of operation of the coupler culminating in a set of design equations is presented. The details of the material processing are described, including the preparation of monomer mixtures that result in single-mode polymer waveguides (lambda = 1300 nm) that have core dimensions approximately equal to those of single-mode fiber. This is necessary to insure high coupling efficiency between the planar device and optical fiber. A unique method of aligning and attaching optical fibers to the coupler is demonstrated. This method relies on patterned alignment ways, a transcision cut, and single-mode D-fiber. A theoretical analysis of the in situ monitoring technique used to fabricate the single-mode D-fiber is presented and compared favorably with the experimental results. Finally, the 10x10 coupler is characterized. We have measured an excess loss of approximately 8 dB.

Polymer based resonant waveguide grating photonic filter with on-chip thermal tuning

NASA Astrophysics Data System (ADS)

Chaudhuri, Ritesh Ray; Enemuo, Amarachukwu N.; Song, Youngsik; Seo, Sang-Woo

2018-07-01

In this paper, we present the development of a multilayer polymer resonant waveguide grating (RWG)-based optical filter with an integrated microheater for on-chip thermal spectral tuning. RWG optical filter is fabricated using polymer-based materials. Therefore, its integration can be applied to different material platforms. Typical RWG structure is sensitive to back optical reflection from the structures below. To reduce the effect of back reflection from the metal heater and improve the quality of the integrated RWG filter output, an intermediate absorption layer was implemented utilizing an epoxy based carbon coating. This approach effectively suppresses the background noise in the RWG characteristics. The central wavelength of the reported filter was designed around 1550 nm. Experimentally, wavelength tuning of 21.96 nm was achieved for operating temperature range of 81 °C with approximately 150mW power consumption. Based on the layer-by-layer fabrication approach, the presented thermally tunable RWG filter on a chip has potential for use in low cost hybrid communication systems and spectral sensing applications.

Broadband arrayed waveguide grating multiplexers on indium phosphide

NASA Astrophysics Data System (ADS)

Rausch, Kameron

2005-11-01

Coarse Wavelength Division Multiplexing (CWDM) is becoming a popular way to increase the optical throughput of fibers for short to medium haul networks at a reduced cost. The International Telecommunications Union (ITU) has defined the CWDM network to consist of eighteen channels with channel spacings of 20 nm starting at 1270 nm and ending at 1610 nm. Four and eight channel AWGs suitable for CWDM were fabricated using a versatile S-shape design novel to InP. The standard horseshoe layout will not work on semiconductor for AWGs with a free spectral range (FSR) larger than 30 nm. The AWG design provides operation insensitive to thermal and polarization fluctuations; which is key for low cost operation and packaging. It will be shown that, refractive index changes over the large operating wavelength band produced negligible effects in the transmission spectrum. Standard AWG design assumes refractive index is a constant over the operating wavelength band. As a result, the output waveguide separations are held constant on the second star coupler. As the channel number increases, secondary focal dispersion caused from a changing refractive index can have detrimental effects on performance. A new design method will be introduced which includes refractive index dispersion by allowing the output waveguide separations to vary. The new design is consistent with standard design but is applicable in materials with a linear index dispersion over an arbitrarily large wavelength band. Lastly, a method for increasing the transmission using multimode waveguides is discussed. Traditionally, single mode waveguides are required in order to prevent higher order waveguide modes creating ghost images in the output spectrum. Using bend loss and waveguide junction offsets, higher order modes can be filtered from the output, thereby eliminating ghost images and at the same time, increase transmission.

Metal-capped silicon organic micro-ring electro-optical modulator (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zaki, Aya O.; Kirah, Khaled A.; Swillam, Mohamed A.

2017-02-01

An ultra-compact hybrid plasmonic waveguide ring electro-optical modulator is designed to be easily fabricated on silicon on insulator (SOI) substrates using standard silicon photonics technology. The proposed waveguide is based on a buried standard silicon waveguide of height 220 nm topped with polymer and metal. The key advantage of this novel design is that only the silicon layer of the waveguide is structured as a coupled ring resonator. Then, the device is covered with electro-optical polymer and metal in post processes with no need for lithography or accurate mask alignment techniques. The simple fabrication method imposes many design challenges to obtain a resonator of reasonable loaded quality factor and high extinction ratio. Here, the performance of the resonator is optimized in the telecom wavelength range around 1550 nm using 3D FDTD simulations. The design of the coupling junction between the access waveguide and the tightly bent ring is thoroughly studied. The extension of the metal over the coupling region is exploited to make the critical dimension of the design geometry at least 2.5 times larger than conventional plasmonic resonators and the design is thus more robust. In this paper, we demonstrate an electro-optical modulator that offers an insertion loss < 1 dB, a modulation depth of 12 dB for an applied peak to peak voltage of only 2 V and energy consumption of 1.74 fJ/bit. The performance is superior to previously reported hybrid plasmonic ring resonator based modulators while the design shows robustness and low fabrication cost.

Waveguides in Thin Film Polymeric Materials

NASA Technical Reports Server (NTRS)

Sakisov, Sergey; Abdeldayem, Hossin; Venkateswarlu, Putcha; Teague, Zedric

1996-01-01

Results on the fabrication of integrated optical components in polymeric materials using photo printing methods will be presented. Optical waveguides were fabricated by spin coating preoxidized silicon wafers with organic dye/polymer solution followed by soft baking. The waveguide modes were studied using prism coupling technique. Propagation losses were measured by collecting light scattered from the trace of a propagation mode by either scanning photodetector or CCD camera. We observed the formation of graded index waveguides in photosensitive polyimides after exposure of UV light from a mercury arc lamp. By using a theoretical model, an index profile was reconstructed which is in agreement with the profile reconstructed by the Wentzel-Kramers-Brillouin calculation technique using a modal spectrum of the waveguides. Proposed mechanism for the formation of the graded index includes photocrosslinking followed by UV curing accompanied with optical absorption increase. We also developed the prototype of a novel single-arm double-mode interferometric sensor based on our waveguides. It demonstrates high sensitivity to the chance of ambient temperature. The device can find possible applications in aeropropulsion control systems.

Photo-induced reduction of graphene oxide coating on optical waveguide and consequent optical intermodulation

PubMed Central

Chong, W. Y.; Lim, W. H.; Yap, Y. K.; Lai, C. K.; De La Rue, R. M.; Ahmad, H.

2016-01-01

Increased absorption of transverse-magnetic (TM) - polarised light by a graphene-oxide (GO) coated polymer waveguide has been observed in the presence of transverse-electric (TE) - polarised light. The GO-coated waveguide exhibits very strong photo-absorption of TE-polarised light - and acts as a TM-pass waveguide polariser. The absorbed TE-polarised light causes a significant temperature increase in the GO film and induces thermal reduction of the GO, resulting in an increase in optical-frequency conductivity and consequently increased optical propagation loss. This behaviour in a GO-coated waveguide gives the action of an inverted optical switch/modulator. By varying the incident TE-polarised light power, a maximum modulation efficiency of 72% was measured, with application of an incident optical power level of 57 mW. The GO-coated waveguide was able to respond clearly to modulated TE-polarised light with a pulse duration of as little as 100 μs. In addition, no wavelength dependence was observed in the response of either the modulation (TE-polarised light) or the signal (TM-polarised light). PMID:27034015

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

DOE PAGES

Bobbitt, Jonathan M.; Smith, Emily A.

2017-11-09

There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and SA Raman spectroscopy in combination with appropriate data models can provide this information. A scanning angle (SA) Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7–80-nm axial spatial resolution. The SA Raman method measures Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene ormore » poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330-1260 nm. The interface locations were varied by altering the individual layer thicknesses between 140-680 nm. The Raman amplitude ratio of the 1605 cm -1 peak for PS and 812 cm -1 peak for PMMA was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.« less

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobbitt, Jonathan M.; Smith, Emily A.

There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and SA Raman spectroscopy in combination with appropriate data models can provide this information. A scanning angle (SA) Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7–80-nm axial spatial resolution. The SA Raman method measures Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene ormore » poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330-1260 nm. The interface locations were varied by altering the individual layer thicknesses between 140-680 nm. The Raman amplitude ratio of the 1605 cm -1 peak for PS and 812 cm -1 peak for PMMA was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.« less

Two-channel highly sensitive sensors based on 4 × 4 multimode interference couplers

NASA Astrophysics Data System (ADS)

Le, Trung-Thanh

2017-12-01

We propose a new kind of microring resonators (MRR) based on 4 × 4 multimode interference (MMI) couplers for multichannel and highly sensitive chemical and biological sensors. The proposed sensor structure has advantages of compactness and high sensitivity compared with the reported sensing structures. By using the transfer matrix method (TMM) and numerical simulations, the designs of the sensor based on silicon waveguides are optimized and demonstrated in detail. We apply our structure to detect glucose and ethanol concentrations simultaneously. A high sensitivity of 9000 nm/RIU, detection limit of 2 × 10‒4 for glucose sensing and sensitivity of 6000 nm/RIU, detection limit of 1.3 × 10‒5 for ethanol sensing are achieved.

Experimental study on the statistic characteristics of a 3x3 RF MIMO channel over a single conventional multimode fiber.

PubMed

Lei, Yi; Li, Jianqiang; Wu, Rui; Fan, Yuting; Fu, Songnian; Yin, Feifei; Dai, Yitang; Xu, Kun

2017-06-01

Based on the observed random fluctuation phenomenon of speckle pattern across multimode fiber (MMF) facet and received optical power distribution across three output ports, we experimentally investigate the statistic characteristics of a 3×3 radio frequency multiple-input multiple-output (MIMO) channel enabled by mode division multiplexing in a conventional 50 µm MMF using non-mode-selective three-dimensional waveguide photonic lanterns as mode multiplexer and demultiplexer. The impacts of mode coupling on the MIMO channel coefficients, channel matrix, and channel capacity have been analyzed over different fiber lengths. The results indicate that spatial multiplexing benefits from the greater fiber length with stronger mode coupling, despite a higher optical loss.

Development of components for IFOG-based inertial measurement units using polymer waveguide fabrication technologies

NASA Astrophysics Data System (ADS)

Ashley, P. R.; Temmen, M. G.; Diffey, W. M.; Sanghadasa, M.; Bramson, M. D.

2007-10-01

Active and passive polymer materials have been successfully used in the development of highly accurate, compact and low cost guided-wave components: an optical transceiver and a phase modulator, for inertial measurement units (IMUs) based on the interferometric fibre optic gyroscope (IFOG) technology for precision guidance in navigation systems. High performance and low noise transceivers with high optical power and good spectral quality were fabricated using a silicon-bench architecture. Low loss phase modulators with low halfwave drive voltage (Vπ) have been fabricated with a backscatter compensated design using polarizing waveguides consisting of CLD- and FTC-type high performance electro-optic (E-O) chromophores. Gyro bias stability of less than 0.02° h-1 has been demonstrated with these guided-wave components.

Multimode harmonic power measurement of 40 MW pulsed S-band klystrons

NASA Astrophysics Data System (ADS)

Fowkes, W. R.; Wu, E. S.

1984-08-01

An array of 12 calibrated RF electric field probes on the waveguide walls are used to sample the complex field profile at the second and third harmonics where the fundamental power is in the 40 MW range at 2856 MHz. The measured amplitude and phase signals from these are Fourier analyzed to determine with good accuracy the power in each of the many possible propagating modes.

Cascaded-focus laser writing of low-loss waveguides in polymers.

PubMed

Pätzold, Welm M; Reinhardt, Carsten; Demircan, Ayhan; Morgner, Uwe

2016-03-15

Waveguide writing in poly (methyl methacrylate) (PMMA) with femtosecond laser radiation is presented. An adequate refractive index change is induced in the border area below the irradiated focal volume. It supports an almost symmetric fundamental mode with propagation losses down to 0.5  dB/cm, the lowest losses observed so far in this class of materials. The writing process with a cascaded focus is demonstrated to be highly reliable over a large parameter range.

Mid-infrared materials and devices on a Si platform for optical sensing

PubMed Central

Singh, Vivek; Lin, Pao Tai; Patel, Neil; Lin, Hongtao; Li, Lan; Zou, Yi; Deng, Fei; Ni, Chaoying; Hu, Juejun; Giammarco, James; Soliani, Anna Paola; Zdyrko, Bogdan; Luzinov, Igor; Novak, Spencer; Novak, Jackie; Wachtel, Peter; Danto, Sylvain; Musgraves, J David; Richardson, Kathleen; Kimerling, Lionel C; Agarwal, Anuradha M

2014-01-01

In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiNx waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors. PMID:27877641

Spin coating and plasma process for 2.5D and hybrid 3D micro-resonators on multilayer polymers

NASA Astrophysics Data System (ADS)

Bêche, B.; Gaviot, E.; Godet, C.; Zebda, A.; Potel, A.; Barbe, J.; Camberlein, L.; Vié, V.; Panizza, P.; Loas, G.; Hamel, C.; Zyss, J.; Huby, N.

2009-05-01

We have designed and realized three integrated photonic families of micro-resonators (MR) on multilayer organic materials. Such so-called 2.5D-MR and 3D-MR structures show off radius values ranging from 40 to 200μm. Both first and second families are especially designed on organic multilayer materials and shaped as ring- and disk-MR organics structures arranged upon (and coupled with) a pair of SU8-organic waveguides. The third family is related to hybrid 3D-MR structures composed of spherical glass-MR coupled to organic waveguides by a Langmuir-Blodgett lipid film about three nanometers in thickness. At first, polymer spin coating, surface plasma treatment and selective UV-lithography processes have been developed to realize 2.5D photonic micro-resonators. Secondly, we have designed and characterized photonic-quadripoles made of 3D-glass-MR arranged upon a pair of SU8 waveguides. Such structures are defined by a 4-ports or 4-waveguides coupled by the spherical glass-MR. We have achieved an evanescent photonic coupling between the 3D-MR and the 4-ports structure. Spectral resonances have been measured for 4-whispering gallery-modes (WGM) into such 3D-structures respectively characterized by a 0.97 nm free spectral range (FSR) and a high quality Q-factor up to 4.104.

Efficient active waveguiding properties of Mo6 nano-cluster-doped polymer nanotubes

NASA Astrophysics Data System (ADS)

Bigeon, J.; Huby, N.; Amela-Cortes, M.; Molard, Y.; Garreau, A.; Cordier, S.; Bêche, B.; Duvail, J.-L.

2016-06-01

We investigate 1D nanostructures based on a Mo6@SU8 hybrid nanocomposite in which photoluminescent Mo6 clusters are embedded in the photosensitive SU8 resist. Tens of micrometers long Mo6@SU8-based tubular nanostructures were fabricated by the wetting template method, enabling the control of the inner and outer diameter to about 190 nm and 240 nm respectively, as supported by structural and optical characterizations. The image plane optical study of these nanotubes under optical pumping highlights the efficient waveguiding phenomenon of the red luminescence emitted by the clusters. Moreover, the wave vector distribution in the Fourier plane determined by leakage radiation microscopy gives additional features of the emission and waveguiding. First, the anisotropic red luminescence of the whole system can be attributed to the guided mode along the nanotube. Then, a low-loss propagation behavior is evidenced in the Mo6@SU8-based nanotubes. This result contrasts with the weaker waveguiding signature in the case of UV210-based nanotubes embedding PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)). It is attributed to the strong reabsorption phenomenon, owing to overlapping between absorption and emission bands in the semi-conducting conjugated polymer PFO. These results make this Mo6@SU8 original class of nanocomposite a promising candidate as nanosources for submicronic photonic integration.

Efficient active waveguiding properties of Mo6 nano-cluster-doped polymer nanotubes.

PubMed

Bigeon, J; Huby, N; Amela-Cortes, M; Molard, Y; Garreau, A; Cordier, S; Bêche, B; Duvail, J-L

2016-06-24

We investigate 1D nanostructures based on a Mo6@SU8 hybrid nanocomposite in which photoluminescent Mo6 clusters are embedded in the photosensitive SU8 resist. Tens of micrometers long Mo6@SU8-based tubular nanostructures were fabricated by the wetting template method, enabling the control of the inner and outer diameter to about 190 nm and 240 nm respectively, as supported by structural and optical characterizations. The image plane optical study of these nanotubes under optical pumping highlights the efficient waveguiding phenomenon of the red luminescence emitted by the clusters. Moreover, the wave vector distribution in the Fourier plane determined by leakage radiation microscopy gives additional features of the emission and waveguiding. First, the anisotropic red luminescence of the whole system can be attributed to the guided mode along the nanotube. Then, a low-loss propagation behavior is evidenced in the Mo6@SU8-based nanotubes. This result contrasts with the weaker waveguiding signature in the case of UV210-based nanotubes embedding PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)). It is attributed to the strong reabsorption phenomenon, owing to overlapping between absorption and emission bands in the semi-conducting conjugated polymer PFO. These results make this Mo6@SU8 original class of nanocomposite a promising candidate as nanosources for submicronic photonic integration.

Improvement of both bandwidth and driving voltage of polymer phase modulators using buried in-plane coupled micro-strip driving electrodes

NASA Astrophysics Data System (ADS)

Hadjloum, Massinissa; El Gibari, Mohammed; Li, Hongwu; Daryoush, Afshin S.

2017-06-01

A large performance improvement of polymer phase modulators is reported by using buried in-plane coupled microstrip (CMS) driving electrodes, instead of standard vertical Micro-Strip electrodes. The in-plane CMS driving electrodes have both low radio frequency (RF) losses and high overlap integral between optical and RF waves compared to the vertical designs. Since the optical waveguide and CMS electrodes are located in the same plane, optical injection and microwave driving access cannot be separated perpendicularly without intersection between them. A via-less transition between grounded coplanar waveguide access and CMS driving electrodes is introduced in order to provide broadband excitation of optical phase modulators and avoid the intersection of the optical core and the electrical probe. Simulation and measurement results of the benzocyclobutene polymer as a cladding material and the PMMI-CPO1 polymer as an optical core with an electro-optic coefficient of 70 pm/V demonstrate a broadband operation of 67 GHz using travelling-wave driving electrodes with a half-wave voltage of 4.5 V, while satisfying its low RF losses and high overlap integral between optical and RF waves of in-plane CMS electrodes.

NONLINEAR AND FIBER OPTICS: Analysis of the mode noise in interference fiber channels used for the distribution of microwave signals

NASA Astrophysics Data System (ADS)

Bratchikov, A. N.; Glukhov, I. P.

1991-03-01

The results are given of a statistical theory of the speckle generalized to interference channels used for the distribution of microwave signals using multimode fiber waveguides with step and graded refractive-index profiles. A method is described for estimating the mode noise level in the open and closed regimes with one longitudinal speckle. The influence of the degree of mode filtering, losses at microbends, and spectral properties of a laser source on the statistical properties and the mode noise level is demonstrated. Numerical estimates are obtained of the ratio of the powers of the signal and mode noise for interference channels with typical parameters of fiber waveguides and a qualitative description is given of the effect of the mode noise.

Photonic integrated circuits based on silica and polymer PLC

NASA Astrophysics Data System (ADS)

Izuhara, T.; Fujita, J.; Gerhardt, R.; Sui, B.; Lin, W.; Grek, B.

2013-03-01

Various methods of hybrid integration of photonic circuits are discussed focusing on merits and challenges. Material platforms discussed in this report are mainly polymer and silica. We categorize the hybridization methods using silica and polymer waveguides into two types, chip-to-chip and on-chip integration. General reviews of these hybridization technologies from the past works are reviewed. An example for each method is discussed in details. We also discuss current status of our silica PLC hybrid integration technology.

Free-standing membrane polymer laser on the end of an optical fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, Tianrui, E-mail: trzhai@bjut.edu.cn, E-mail: zhangxinping@bjut.edu.cn; Li, Songtao; Hu, Yujie

2016-01-25

One- and two-dimensional distributed feedback cavities were constructed on free-standing polymer membranes using spin-coating and lift-off techniques. Low threshold lasing was generated through feedback amplification when the 290-nm membrane device was optically pumped, which was attributed to the strong confinement mechanism provided by the active waveguide layer without a substrate. The free-standing membrane polymer laser is flexible and can be transplanted. Single- and dual-wavelength fiber lasers were achieved by directly attaching the membrane polymer laser on the optical fiber end face. This technique provides potential to fabricate polymer lasers on surfaces with arbitrary shapes.

Overmoded subterahertz surface wave oscillator with pure TM{sub 01} mode output

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Guangqiang; Zeng, Peng; Wang, Dongyang

2016-02-15

Overmoded O-type Cerenkov generators using annular electron beams are facing the problem of multi-modes output due to the inevitable structural discontinuities. A simple but effective method to achieve the pure TM{sub 01} mode output is applied on the 0.14 THz overmoded surface wave oscillator (SWO) in this paper. In spite of still using an overmoded slow wave structure to ensure the easy fabrication, the followed smooth circular waveguide is shrinkingly tapered to the output waveguide with appropriate radius that it cuts off other higher modes except TM{sub 01} mode. Moreover, the modified device here has the same power capacity as themore » previous one according to the numerical analysis. By optimized lengths of the transition waveguide and tapered waveguide, particle-in-cell simulation results indicate that the subterahertz wave with output power increased 14.2% at the same frequency is obtained from the proposed SWO under the previous input conditions, and importantly, the output power is all carried by TM{sub 01} mode as expected. Further simulation results in the pulse regime confirm the feasibility of the optimized structure in the actual experiments. This simple and viable design is also applicable to overmoded devices in the lower frequency band of subterahertz wave.« less

Analysis of the bending radius of the cylindrical waveguide of polydimethylsiloxane for the purpose of lighting

NASA Astrophysics Data System (ADS)

Novak, M.; Jargus, J.; Fajkus, M.; Bednarek, L.; Vasinek, V.

2017-10-01

Polydimethylsiloxane (PDMS) can be used for its optical properties and its composition offers the possibility of use in the dangerous environments. Therefore authors of this article focused on more detailed working with this material. The authors describe the use of PDMS polymer for the light transmission over short distances (up to tens of centimeters). PDMS offers good prerequisites (mechanical properties) for the creating cylindrical lighting waveguide e.g. for the purpose of the automotive industry. The objective is to determine the maximum bending radius of the cylindrical waveguide of polydimethylsiloxane for different wavelengths of the visible spectrum and thus extend the knowledge for subsequent use in lighting. The created cylindrical waveguide consist of a core and a cladding. Cladding was formed by a PDMS having a lower refractive index in order to respect the condition of total reflection.

Traveling-Wave Tube Amplifier Second Harmonic as Millimeter-Wave Beacon Source for Atmospheric Propagation Studies

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.

2014-01-01

This paper presents the design and test results of a CW millimeter-wave satellite beacon source, based on the second harmonic from a traveling-wave tube amplifier and utilizes a novel waveguide multimode directional coupler. A potential application of the beacon source is for investigating the atmospheric effects on Q-band (37 to 42 GHz) and V/W-band (71 to 76 GHz) satellite-to-ground signals.

Traveling-Wave Tube Amplifier Second Harmonic as Millimeter-Wave Beacon Source for Atmospheric Propagation Studies

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.

2014-01-01

This paper presents the design and test results of a CW millimeter-wave satellite beacon source, based on the second harmonic from a traveling-wave tube amplifier and utilizes a novel waveguide multimode directional coupler. A potential application of the beacon source is for investigating the atmospheric effects on Q-band (37-42 GHz) and V/W-band (71- 76 GHz) satellite-to-ground signals.

Optical fiber endface biosensor based on resonances in dielectric waveguide gratings

NASA Astrophysics Data System (ADS)

Wawro, Debra D.; Tibuleac, Sorin; Magnusson, Robert; Liu, Hanli

2000-05-01

A new fiber optic sensor integrating dielectric diffraction gratings and thin films on optical fiber endfaces is prosed for biomedical sensing applications. This device utilizes a resonant dielectric waveguide grating structure fabricated on an optical fiber endface to probe reactions occurring in a sensing layer deposited on its surface. The operation of this sensor is based upon a fundamental resonance effect that occurs in waveguide gratings. An incident broad- spectrum signal is guided within an optical fiber and is filtered to reflect or transmit a desired spectral band by the diffractive thin film structure on its endface. Slight changes in one or more parameters of the waveguide grating, such as refractive index or thickness, can result in a responsive shift of the reflected or transmitted spectral peak that can be detected with spectroscopic instruments. This new sensor concept combines improved sensitivity and accuracy with attractive features found separately in currently available fiber optic sensors, such as large dynamic range, small sensing proximity, real time operation, and remote sensing. Diffractive elements of this type consisting of a photoresist grating on a Si3N4 waveguide have been fabricated on multimode optical fiber endfaces with 100 micrometers cores. Preliminary experimental tests using a tunable Ti:sapphire laser indicate notches of 18 percent in the transmission spectrum of the fiber endface guided-mode resonance devices. A theoretical analysis of the device performance capabilities is presented and applied to evaluate the feasibility and potential advantages of this bioprobe.

Crystalline Stratification in Semiconducting Polymer Thin Film Quantified by Grazing Incidence X-ray Scattering

NASA Astrophysics Data System (ADS)

Gann, Eliot; Caironi, Mario; Noh, Yong-Young; Kim, Yun-Hi; McNeill, Christopher R.

The depth dependence of crystalline structure within thin films is critical for many technological applications, but has been impossible to measure directly using common techniques. In this work, by monitoring diffraction peak intensity and location and utilizing the highly angle-dependent waveguiding effects of X-rays near grazing incidence we quantitatively measure the thickness, roughness and orientation of stratified crystalline layers within thin films of a high-performance semiconducting polymer. In particular, this diffractive X-ray waveguiding reveals a self-organized 5-nm-thick crystalline surface layer with crystalline orientation orthogonal to the underlying 65-nm-thick layer. While demonstrated for an organic semiconductor film, this approach is applicable to any thin film material system where stratified crystalline structure and orientation can influence important interfacial processes such as charge injection and field-effect transport.

Electromagnetic Design of a Magnetically-Coupled Spatial Power Combiner

NASA Technical Reports Server (NTRS)

Bulcha, B.; Cataldo, G.; Stevenson, T. R.; U-Yen, K.; Moseley, S. H.; Wollack, E. J.

2017-01-01

The design of a two-dimensional beam-combining network employing a parallel-plate superconducting waveguide with a mono-crystalline silicon dielectric is presented. This novel beam-combining network structure employs an array of magnetically coupled antenna elements to achieve high coupling efficiency and full sampling of the intensity distribution while avoiding diffractive losses in the multi-mode region defined by the parallel-plate waveguide. These attributes enable the structures use in realizing compact far-infrared spectrometers for astrophysical and instrumentation applications. When configured with a suitable corporate-feed power-combiner, this fully sampled array can be used to realize a low-sidelobe apodized response without incurring a reduction in coupling efficiency. To control undesired reflections over a wide range of angles in the finite-sized parallel-plate waveguide region, a wideband meta-material electromagnetic absorber structure is implemented. This adiabatic structure absorbs greater than 99 of the power over the 1.7:1 operational band at angles ranging from normal (0 degree) to near parallel (180 degree) incidence. Design, simulations, and application of the device will be presented.

Investigation on optical properties of Bi2.85La0.15TiNbO9 thin films by prism coupling technique

NASA Astrophysics Data System (ADS)

Zhang, Mingfu; Chen, Hengzhi; Yang, Bin; Cao, Wenwu

2009-12-01

Layered-perovskite ferroelectric Bi2.85La0.15TiNbO9 (LBTN) optical waveguiding thin films were grown on fused silica substrates by pulsed laser deposition (PLD). X-ray diffraction (XRD) revealed that the film is highly (00 l) textured. We observed sharp and distinct transverse electric (TE) and transverse magnetic (TM) multimodes and measured the refractive indices of LBTN thin films at 632.8 nm. The ordinary and extraordinary refractive indices were calculated to be n TE=2.358 and n TM=2.464, respectively. The film homogeneity and the film-substrate interface were analyzed using an improved version of the inverse Wentzel-Kramer-Brillouin (iWKB) method. The refractive index of the film remains constant at n 0 within the waveguiding layer. The average transmittance of the film is 70% in the wavelength range of 400-1400 nm and the optical waveguiding properties were evaluated by the optical prism coupling method. Our results showed that the LBTN films are very good electro-optical active material.

Fourier Transform-Plasmon Waveguide Spectroscopy: A Nondestructive Multifrequency Method for Simultaneously Determining Polymer Thickness and Apparent Index of Refraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobbitt, Jonathan M; Weibel, Stephen C; Elshobaki, Moneim

2014-12-16

Fourier transform (FT)-plasmon waveguide resonance (PWR) spectroscopy measures light reflectivity at a waveguide interface as the incident frequency and angle are scanned. Under conditions of total internal reflection, the reflected light intensity is attenuated when the incident frequency and angle satisfy conditions for exciting surface plasmon modes in the metal as well as guided modes within the waveguide. Expanding upon the concept of two-frequency surface plasmon resonance developed by Peterlinz and Georgiadis [ Opt. Commun. 1996, 130, 260], the apparent index of refraction and the thickness of a waveguide can be measured precisely and simultaneously by FT-PWR with an averagemore » percent relative error of 0.4%. Measuring reflectivity for a range of frequencies extends the analysis to a wide variety of sample compositions and thicknesses since frequencies with the maximum attenuation can be selected to optimize the analysis. Additionally, the ability to measure reflectivity curves with both p- and s-polarized light provides anisotropic indices of refraction. FT-PWR is demonstrated using polystyrene waveguides of varying thickness, and the validity of FT-PWR measurements are verified by comparing the results to data from profilometry and atomic force microscopy (AFM).« less

Fourier transform-plasmon waveguide spectroscopy: a nondestructive multifrequency method for simultaneously determining polymer thickness and apparent index of refraction.

PubMed

Bobbitt, Jonathan M; Weibel, Stephen C; Elshobaki, Moneim; Chaudhary, Sumit; Smith, Emily A

2014-12-16

Fourier transform (FT)-plasmon waveguide resonance (PWR) spectroscopy measures light reflectivity at a waveguide interface as the incident frequency and angle are scanned. Under conditions of total internal reflection, the reflected light intensity is attenuated when the incident frequency and angle satisfy conditions for exciting surface plasmon modes in the metal as well as guided modes within the waveguide. Expanding upon the concept of two-frequency surface plasmon resonance developed by Peterlinz and Georgiadis [Opt. Commun. 1996, 130, 260], the apparent index of refraction and the thickness of a waveguide can be measured precisely and simultaneously by FT-PWR with an average percent relative error of 0.4%. Measuring reflectivity for a range of frequencies extends the analysis to a wide variety of sample compositions and thicknesses since frequencies with the maximum attenuation can be selected to optimize the analysis. Additionally, the ability to measure reflectivity curves with both p- and s-polarized light provides anisotropic indices of refraction. FT-PWR is demonstrated using polystyrene waveguides of varying thickness, and the validity of FT-PWR measurements are verified by comparing the results to data from profilometry and atomic force microscopy (AFM).

Single Mode SU8 Polymer Based Mach-Zehnder Interferometer for Bio-Sensing Application

NASA Astrophysics Data System (ADS)

Boiragi, Indrajit; Kundu, Sushanta; Makkar, Roshan; Chalapathi, Krishnamurthy

2011-10-01

This paper explains the influence of different parameters to the sensitivity of an optical waveguide Mach-Zehnder Interferometer (MZI) for real time detection of biomolecules. The sensing principle is based on the interaction of evanescence field with the biomolecules that get immobilized on sensing arm. The sensitivity has been calculated by varying the sensing window length, wavelength and concentration of bio-analyte. The maximum attainable sensitivity for the preferred design is the order of 10-8 RIU at 840 nm wavelength with a sensing window length of 1cm. All the simulation work has been carried out with Opti-BPMCAD for the optimization of MZI device parameters. The SU8 polymers are used as a core and clad material to fabricate the waveguide. The refractive index of cladding layer is optimized by varying the curing temperature for a fixed time period and the achieved index difference between core and clad is Δn = 0.0151. The fabricated MZI device has been characterized with LASER beam profiler at 840 nm wavelength. This study demonstrates the effectiveness of the different parameter to the sensitivity of a single mode optical waveguide Mach-Zehnder Interferometer for bio-sensing application.

Mode and polarization state selected guided wave spectroscopy of orientational anisotrophy in model membrane cellulosic polymer films: relevance to lab-on-a-chip

NASA Astrophysics Data System (ADS)

Andrews, Mark P.; Kanigan, Tanya

2007-06-01

Orientation anisotropies in structural properties relevant to the use of cellulosic polymers as membranes for lab-on-chips were investigated for cellulose acetate (CA) and regenerated cellulose (RC) films deposited as slab waveguides. Anisotropy was probed with mode and polarization state selected guided wave Raman spectroscopy. CA exhibits partial chain orientation in the plane of the film, and this orientation is independent of sample substrate and film preparation conditions. RC films also show in-plane anisotropy, where the hexose sugar rings lie roughly in the plane of the film. Explanations are given of the role of artifacts in interpreting waveguide Raman spectra, including anomalous contributions to Raman spectra that arise from deviations from right angle scattering geometry, mode-dependent contributions to longitudinal electric field components and TE<-->TM mode conversion. We explore diffusion profiles of small molecules in cellulosic films by adaptations of an inverse-Wentzel-Kramers-Brillouin (iWKB) recursive, noninteger virtual mode index algorithm. Perturbations in the refractive index distribution, n(z), are recovered from the measured relative propagation constants, neffective,m, of the planar waveguide. The refractive index distribution then yields the diffusion profile.

Ultra-broad range organic solid-state laser from a dye-doped holographic grating quasi-waveguide configuration

NASA Astrophysics Data System (ADS)

Liu, Minghuan; Liu, Yonggang; Peng, Zenghui; Mu, Quanquan; Cao, Zhaoliang; Lu, Xinghai; Ma, Ji; Xuan, Li

2017-08-01

This paper reports the ultra-broad 149.1 nm lasing emission from 573.2 to 722.3 nm using a simple [4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran] (DCM)-doped holographic polymer-dispersed liquid crystal (HPDLC) grating quasi-waveguide configuration by varying the grating period. The lasing emission beams show s-polarization property. The quasi-waveguide structure, which contained the cover glass, the DCM-doped HPDLC grating, the semiconducting polymer film poly[-methoxy-5-(2‧-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), and the substrate were confirmed to decrease lasing threshold and broaden lasing wavelength. The operational lifetime of the device is 240 000 pulses, which corresponds to an overall laser duration of more than 6 h at a repetition rate of 10 Hz. In addition, the dual-wavelength lasing range from the 8th and 9th order is over 40 nm. The electrical tunability of the dual-wavelength lasing emission is over 1 nm. The experimental results facilitated the decreased lasing threshold and broadened lasing wavelength range of organic solid-state lasers.

Directional multimode coupler for planar magnonics: Side-coupled magnetic stripes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A.; Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009

We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices suchmore » as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.« less

Single-Arm Double-Mode Double-Order Planar Waveguide Interferometric Sensor

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S.

2000-01-01

We have met the goals stated in section one for the project. We have demonstrated the feasibility of a single-arm double-mode double-order waveguide interferometer as a cost efficient alternative to an optical chemical sensor. Experimental prototype was built as a dye-doped polymer waveguide with propagating modes of orders <<0>> and <<1>> of the same TM polarization. The prototype demonstrated sensitivity to ammonia of the order of 200 ppm per one full oscillation of the signal. Sensor based on polyimide doped with BCP can operate at elevated temperature up to 150 C. Upon the future funding, we are planning to optimize the light source, material and the design in order to achieve sensitivity of the order of 1 ppm per full oscillations.

TiO2 surface functionalization of COC based planar waveguide Bragg gratings for refractive index sensing

NASA Astrophysics Data System (ADS)

Rosenberger, M.; Girschikofsky, M.; Förthner, M.; Belle, S.; Rommel, M.; Frey, L.; Schmauss, B.; Hellmann, R.

2018-01-01

We demonstrate the applicability of a planar waveguide Bragg grating in cyclo-olefin copolymer (COC) for refractive index sensing. The polymer planar waveguide Bragg grating fabricated using a single writing step technique is coated with a high-index layer of titanium dioxide (TiO2) leading to a distinct birefringence. This in turn results in the splitting of the Bragg reflection into two distinct Bragg wavelengths, which strongly differ regarding their refractive index sensitivities. Where one wavelength is only slightly affected by the ambient refractive index, the second Bragg peak shows a strong sensitivity. Furthermore, we investigate the temperature behaviour of the functionalized sensor and discuss it with respect to applications in refractive index sensing.

SiN-assisted polarization-insensitive multicore fiber to silicon photonics interface

NASA Astrophysics Data System (ADS)

Poulopoulos, Giannis N.; Kalavrouziotis, Dimitrios; Mitchell, Paul; Macdonald, John R.; Bakopoulos, Paraskevas; Avramopoulos, Hercules

2015-06-01

We demonstrate a polarization-insensitive coupler interfacing multicore-fiber (MCF) to silicon waveguides. It comprises a 3D glass fanout transforming the circular MCF core-arrangement to linear and performing initial tapering, followed by a Spot-Size-Converter on the silicon chip. Glass waveguides are formed of multiple overlapped modification elements and appropriate offsetting thereof yields tapers with symmetric cross-section. The Spot-Size-Converter is an inverselytapered silicon waveguide with a tapered polymer overcladding where light is initially coupled, whereas phase-matching gradually shifts it towards the silicon core. Co-design of the glass fanout and Spot-Size-Converter obtains theoretical loss below 1dB for the overall Si-to-MCF transition in both polarizations.

Chiral spiral waveguides based on MMI crossings: theory and experiments

NASA Astrophysics Data System (ADS)

Cherchi, Matteo; Ylinen, Sami; Harjanne, Mikko; Kapulainen, Markku; Vehmas, Tapani; Aalto, Timo

2016-03-01

We introduce a novel type of chiral spiral waveguide where the usual waveguide crossings are replaced by 100:0 Multimode Interferometers (MMIs), i.e. 2x2 splitters that couple all the input light in the cross output port. Despite the topological equivalence with the standard configuration, we show how resorting to long MMIs has non-trivial advantages in terms of footprint and propagation length. An accurate analytic model is also introduced to show the impact of nonidealities on the spiral performances, including propagation loss and cross-talk. We have designed and fabricated three chiral spirals on our platform, based on 3 μm thick silicon strip waveguides with 0.13 dB/cm propagation loss, and 1.58 mm long MMIs. The fabricated spirals have 7, 13 and 49 loops respectively, corresponding to the effective lengths 6.6 cm, 12.5 cm and 47.9 cm. The proposed model is successfully applied to the experimental results, highlighting MMI extinction ratio of about 16.5 dB and MMI loss of about 0.08 dB, that are much worse compared to the simulated 50 dB extinction and 0.01 dB loss. This imposes an upper limit to the number of rounds, because light takes shortcuts through the bar MMI ports. Nevertheless, the novel chiral spiral waveguides outperform what is achievable in mainstream silicon photonics platforms based on submicron waveguides in terms of length and propagation losses, and they are promising candidates for the realization of integrated gyroscopes. They can be significantly further improved by replacing the MMIs with adiabatic 100:0 splitters, ensuring lower cross-talk and broader bandwidth.

Multimodal switching of conformation and solubility in homocysteine derived polypeptides.

PubMed

Kramer, Jessica R; Deming, Timothy J

2014-04-16

We report the design and synthesis of poly(S-alkyl-L-homocysteine)s, which were found to be a new class of readily prepared, multiresponsive polymers that possess the unprecedented ability to respond in different ways to different stimuli, either through a change in chain conformation or in water solubility. The responsive properties of these materials are also effected under mild conditions and are completely reversible for all pathways. The key components of these polymers are the incorporation of water solubilizing alkyl functional groups that are integrated with precisely positioned, multiresponsive thioether linkages. This promising system allows multimodal switching of polypeptide properties to obtain desirable features, such as coupled responses to multiple external inputs.

Side-polished fiber based gain-flattening filter for erbium doped fiber amplifiers

NASA Astrophysics Data System (ADS)

Varshney, R. K.; Singh, A.; Pande, K.; Pal, B. P.

2007-03-01

A simple and accurate novel normal mode analysis has been developed to take into account the effect of the non-uniform depth of polishing in the study of the transmission characteristics of optical waveguide devices based on loading of a side-polished fiber half-coupler with a multimode planar waveguide. We apply the same to design and fabricate a gain-flattening filter suitable for fiber amplifiers. The wavelength dependent filtering action of the overall device could demonstrate flattening of an EDFA gain spectrum within ±0.7 dB over a bandwidth of 30 nm in the C-band. Results obtained by the present analysis agree very well with our experimental results. This present analysis should be very useful in the accurate design and analysis of any SPF-MMOW device/component including side-polished fiber based sensors.

Subdiffractional focusing and guiding of polaritonic rays in a natural hyperbolic material

PubMed Central

Dai, S.; Ma, Q.; Andersen, T.; Mcleod, A. S.; Fei, Z.; Liu, M. K.; Wagner, M.; Watanabe, K.; Taniguchi, T.; Thiemens, M.; Keilmann, F.; Jarillo-Herrero, P.; Fogler, M. M.; Basov, D. N.

2015-01-01

Uniaxial materials whose axial and tangential permittivities have opposite signs are referred to as indefinite or hyperbolic media. In such materials, light propagation is unusual leading to novel and often non-intuitive optical phenomena. Here we report infrared nano-imaging experiments demonstrating that crystals of hexagonal boron nitride, a natural mid-infrared hyperbolic material, can act as a ‘hyper-focusing lens' and as a multi-mode waveguide. The lensing is manifested by subdiffractional focusing of phonon–polaritons launched by metallic disks underneath the hexagonal boron nitride crystal. The waveguiding is revealed through the modal analysis of the periodic patterns observed around such launchers and near the sample edges. Our work opens new opportunities for anisotropic layered insulators in infrared nanophotonics complementing and potentially surpassing concurrent artificial hyperbolic materials with lower losses and higher optical localization. PMID:25902364

Optical interconnects for in-plane high-speed signal distribution at 10 Gb/s: Analysis and demonstration

NASA Astrophysics Data System (ADS)

Chang, Yin-Jung

With decreasing transistor size, increasing chip speed, and larger numbers of processors in a system, the performance of a module/system is being limited by the off-chip and off-module bandwidth-distance products. Optical links have moved from fiber-based long distance communications to the cabinet level of 1m--100m, and recently to the backplane-level (10cm--1m). Board-level inter-chip parallel optical interconnects have been demonstrated recently by researchers from Intel, IBM, Fujitsu, NTT and a few research groups in universities. However, the board-level signal/clock distribution function using optical interconnects, the lightwave circuits, the system design, a practically convenient integration scheme committed to the implementation of a system prototype have not been explored or carefully investigated. In this dissertation, the development of a board-level 1 x 4 optical-to-electrical signal distribution at 10Gb/s is presented. In contrast to other prototypes demonstrating board-level parallel optical interconnects that have been drawing much attention for the past decade, the optical link design for the high-speed signal broadcasting is even more complicated and the pitch between receivers could be varying as opposed to fixed-pitch design that has been widely-used in the parallel optical interconnects. New challenges for the board-level high-speed signal broadcasting include, but are not limited to, a new optical link design, a lightwave circuit as a distribution network, and a novel integration scheme that can be a complete radical departure from the traditional assembly method. One of the key building blocks in the lightwave circuit is the distribution network in which a 1 x 4 multimode interference (MMI) splitter is employed. MMI devices operating at high data rates are important in board-level optical interconnects and need to be characterized in the application of board-level signal broadcasting. To determine the speed limitations of MMI devices, the ultra-short pulse response of these devices is modeled based on the guided-mode theory incorporated with Fourier transform technique. For example, for 50 fs Gaussian input pulses into a 1 x 16 splitter, the output pulses are severely degraded in coupling efficiency (48%) and completely broken up in time primarily due to inter-modal and intra-modal (waveguide) dispersion. Material dispersion is found to play only a minor role in the pulse response of MMI devices. However, for 1ps input pulses into the same 1 x 16 splitter, the output pulses are only moderately degraded in coupling efficiency (86%) and only slightly degraded in shape. With the understanding of the necessary condition of the distortionless high-speed signal transmission through MMI devices, high-speed data transmission at 40Gb/s per channel with a total bandwidth of 320Gb/s for 8 output ports is demonstrated for the first time on a 1 x 8 photo-definable polymer-based MMI power splitter. The device is designed with multimode input/output waveguides of 10mum in width and 7.6mum in height for a better input coupling efficiency for which the high-speed testing demands. The eye diagrams are all clear and fully open with an extinction ratio of 10.1dB and a jitter of 1.65 ps. The transmission validity is further confirmed by the bit-error-rate testing at the pseudoramdom binary sequence of 27--1. The fabrication process developed lays the cornerstone of the integration scheme and system design for the prototype of hybrid interconnects. An important problem regarding the guided-mode attenuation associated with optical-interconnect-polymer waveguides fabricated on FR-4 printed-circuit boards is also quantified for the first time. On-board optical waveguides are receiving more attention recently from Fujitsu American Laboratory, IBM Watson Research Center, and Packaging Research Center here at Georgia Tech. This branch of research work is part of the effort in investigating, scientifically, the attenuation mechanism and the effects of the buffer layer thickness on board-level in-plane optical interconnects. The rigorous transmission-line network approach is used and the FR-4 substrate is treated as a long-period substrate grating. A quantitative metric for an appropriate matrix truncation is presented. The peaks of attenuation are shown to occur near the Bragg conditions that characterize the leaky-wave stop bands. For a typical 400mum period FR-4 substrate with an 8mum corrugation depth, a buffer layer thickness of about 40mum is found to be needed to make the attenuation negligibly small. An experimental prototype for on-board optical-to-electrical signal broadcasting operating at 10Gb/s per channel over an interconnect distance of 10cm is demonstrated. An improved 1 x 4 multimode interference (MMI) splitter at 1550nm with linearly-tapered output facet is heterogeneously integrated with four p-i-n photodetectors (PDs) on a Silicon (Si) bench. The Si bench itself is hybrid integrated onto an FR-4 printed-circuit board with four receiver channels. A novel fabrication/integration approach demonstrates the simultaneous alignment between the four waveguides and the four PDs during the MMI fabrication process. The entire system is fully functional at 10Gb/s.

Two-dimensional interferometric characterization of laser-induced refractive index profiles in bulk Topas polymer

NASA Astrophysics Data System (ADS)

Hessler, Steffen; Rosenberger, Manuel; Schmauss, Bernhard; Hellmann, Ralf

2018-01-01

In this paper we precisely determine laser-induced refractive index profiles created in cyclic olefin copolymer Topas 6017 employing a sophisticated phase shifting Mach-Zehnder interferometry approach. Beyond the usual one-dimensional modification depth measurement we highlight that for straight waveguide structures also a two-dimensional refractive index distribution can be directly obtained providing full information of a waveguide's exact cross section and its gradient refractive index contrast. Deployed as direct data input in optical waveguide simulation, the evaluated 2D refractive index profiles permit a detailed calculation of the waveguides' actual mode profiles. Furthermore, conventional one-dimensional interferometric measurements for refractive index depth profiles with varying total imposed laser fluence of a 248 nm KrF excimer laser are included to investigate the effect on refractive index modification depth. Maximum surface refractive index increase turns out to attain up to 1.86 ·10-3 enabling laser-written optical waveguide channels. Additionally, a comprehensive optical material characterization in terms of dispersion, thermo-optic coefficient and absorption measurement of unmodified and UV-modified Topas 6017 is carried out.

Electro Optic Modulation In a Polymer Ringresonator

NASA Astrophysics Data System (ADS)

Leinse, A.; Driessen, A.; Diemeer, M. B. J.

2004-05-01

A thermo optic and electro optic (EO) tunable polymer ringresonator was realized and tested. The device consisted of a microring resonator made of the 4-dimethylamino-4‵-nitrostilbene (DANS) containing polymer and measurements were done on the through port of this device. The ring was used in a vertical coupling structure. The port waveguides were made of the photo-definable epoxy (SU8). The rings used had a diameter of 100 μm and thermo optic tuning of about 170 pm/°C was measured. EO modulation was measured for TE polarization.

Tuned alexandrite laser for dentistry

NASA Astrophysics Data System (ADS)

Sulc, Jan; Jelinkova, Helena; Dostalova, Tatjana; Miyagi, Mitsunobu

2000-04-01

For medical applications tunable solid state laser system emitting a visible light in a region from 710 to 775 nm was developed. Laser head of this system was composed of alexandrite crystal rod (4 mm in diameter, 90 mm of length), two dielectric mirrors and tuning element (dispersing prism or thin-film polarizer). For Q-switching, three different optics shutters were proved: a saturable NC-dye or LiF crystal, LiNbO3 Pockels cell, and rotating prism. Maximum output energy in free-running and Q-switching regime was 400 mJ and 70 mJ, respectively. The pulse duration was 70 microsecond(s) in the free-running and 45 - 250 ns in Q-switching regime. The output free running laser radiation was guided via a multimode quartz fiber (1 m of length, core diameter 600 micrometers ) or via a special fluorocarbon polymer-coated silver hollow glass waveguide (0.62 m of length, inner diameter 1 mm). At first, this radiation with a laser fluence of 2.5 J/cm2 was used for an ablation of a dental calculus. Next, the laser radiation propagation in a root canal and its effect on bacteria was proved. The dissipated energy measurement was made inside and outside of the tooth. From the results follow that the alexandrite laser could be useful for medical applications.

Traveling-Wave Tube Amplifier Second Harmonic as Millimeter-Wave Beacon Source for Atmospheric Propagation Studies

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.

2014-01-01

The design and test results of a novel waveguide multimode directional coupler for a CW millimeter-wave satellite beacon source are presented. The coupler separates the second harmonic power from the fundamental output power of a traveling-wave tube amplifier. A potential application of the beacon source is for investigating the atmospheric effects on Q-band (37 to 42 GHz) and VW-band (71 to 76 GHz) satellite-to-ground signals.

Characterization of a multimode coplanar waveguide parametric amplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simoen, M., E-mail: simoen@chalmers.se; Krantz, P.; Bylander, Jonas

2015-10-21

We characterize a Josephson parametric amplifier based on a flux-tunable quarter-wavelength resonator. The fundamental resonance frequency is ∼1 GHz, but we use higher modes of the resonator for our measurements. An on-chip tuning line allows for magnetic flux pumping of the amplifier. We investigate and compare degenerate parametric amplification, involving a single mode, and nondegenerate parametric amplification, using a pair of modes. We show that we reach quantum-limited noise performance in both cases.

Calibration of a speckle-based compressive sensing receiver

NASA Astrophysics Data System (ADS)

Sefler, George A.; Shaw, T. Justin; Stapleton, Andrew D.; Valley, George C.

2017-02-01

Optical speckle in a multimode waveguide has been proposed to perform the function of a compressive sensing (CS) measurement matrix (MM) in a receiver for GHz-band radio frequency (RF) signals. Unlike other devices used for the CS MM, e.g. the digital micromirror device (DMD) used in the single pixel camera, the elements of the speckle MM are not known before use and must be measured and calibrated. In our system, the RF signal is modulated on a repetitively pulsed chirped wavelength laser source, generated from mode-locked laser pulses that have been dispersed in time or from an electrically addressed distributed Bragg reflector laser. Next, the optical beam with RF propagates through a multimode fiber or waveguide, which applies different weights in wavelength (or equivalently time) and space and performs the function of the CS MM. The output of the guide is directed to or imaged on a bank of photodiodes with integration time set to the pulse length of the chirp waveform. The output of each photodiode is digitized by an analog-to-digital converter (ADC), and the data from these ADCs are used to form the CS measurement vector. Accurate recovery of the RF signal from CS measurements depends critically on knowledge of the weights in the MM. Here we present results using a stable wavelength laser source to probe the guide.

Nanophotonics: Energy Transfer towards Enhanced Luminescent Chemosensing

PubMed Central

Aad, Roy; Couteau, Christophe; Lérondel, Gilles

2015-01-01

We discuss a recently proposed novel photonic approach for enhancing the fluorescence of extremely thin chemosensing polymer layers. We present theoretical and experimental results demonstrating the concept of gain-assisted waveguided energy transfer (G-WET) on a very thin polymer nanolayer spincoated on an active ZnO thin film. The G-WET approach is shown to result in an 8-fold increase in polymer fluorescence. We then extend the G-WET concept to nanostructured media. The benefits of using active nanostructured substrates on the sensitivity and fluorescence of chemosensing polymers are discussed. Preliminary theoretical results on enlarged sensing surface and photonic band-gap are presented. PMID:28788025

Reflection and Transmission Coefficient of Yttrium Iron Garnet Filled Polyvinylidene Fluoride Composite Using Rectangular Waveguide at Microwave Frequencies

PubMed Central

Soleimani, Hassan; Abbas, Zulkifly; Yahya, Noorhana; Shameli, Kamyar; Soleimani, Hojjatollah; Shabanzadeh, Parvaneh

2012-01-01

The sol-gel method was carried out to synthesize nanosized Yttrium Iron Garnet (YIG). The nanomaterials with ferrite structure were heat-treated at different temperatures from 500 to 1000 °C. The phase identification, morphology and functional groups of the prepared samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. The YIG ferrite nanopowder was composited with polyvinylidene fluoride (PVDF) by a solution casting method. The magnitudes of reflection and transmission coefficients of PVDF/YIG containing 6, 10 and 13% YIG, respectively, were measured using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in X-band frequencies. The results indicate that the presence of YIG in polymer composites causes an increase in reflection coefficient and decrease in transmission coefficient of the polymer. PMID:22942718

A hybrid electro-optic polymer and TiO2 double-slot waveguide modulator

PubMed Central

Qiu, Feng; Spring, Andrew M.; Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke; Otomo, Akira; Aoki, Isao; Yokoyama, Shiyoshi

2015-01-01

An electro-optic (EO) modulator using a TiO2 slot hybrid waveguide has been designed and fabricated. Optical mode calculations revealed that the mode was primarily confined within the slots when using a double-slot configuration, thus achieving a high EO activity experimentally. The TiO2 slots also acted as an important barrier to induce an enhanced DC field during the poling of the EO polymer and the driving of the EO modulator. The hybrid phase modulator exhibited a driving voltage (Vπ) of 1.6 V at 1550 nm, which can be further reduced to 0.8 V in a 1 cm-long push-pull Mach–Zehnder interferometer (MZI) structure. The modulator demonstrated a low propagation loss of 5 dB/cm and a relatively high end-fire coupling efficiency. PMID:25708425

Optical Anisotropy and Waveguiding in Thin Films of a Conjugated Polymer Which Exhibits Stimulated Emission.

NASA Astrophysics Data System (ADS)

Miller, E. Kirk; McGehee, Michael; Diaz-Garcia, Maria; Srikant, V.; Heeger, Alan J.

1998-03-01

We report variable angle spectroscopic ellipsometry (VASE) measurements on thin films of poly(2-butyl-5(2-ethyl-hexyl)-1,4- phenylenevinylene) (BuEH-PPV) in the spectral region below the electronic absorption edge. We find that the films are best described as uniaxially anisotropic, with the optical axis perpendicular to the plane of the film, consistent with the notion that the polymer chains lie preferentially in the plane of the film. Due to the anisotropic distribution of chromophores, the in-plane index of refraction is found to be significantly higher and more dispersive than the out-of- plane index, implying a higher effective index for transverse-electric (TE) waveguide modes than for the corresponding transverse- magnetic (TM) modes. The implications of these data for amplified spontaneous emission (ASE) experiments and in-plane laser structures are discussed.

Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Xunlin

2010-07-01

Polymers with strong piezo-, pyro-, and ferroelectricity are attractive for a wide range of applications. In particular, semicrystalline ferroelectric polymers are suitable for a large variety of piezo- and pyroelectric transducers or sensors, while amorphous polymers containing chromophore molecules are particularly interesting for photonic devices. Recently, a new class of polymer materials has been added to this family: internally charged cellular space-charge polymer electrets (so-called “ferroelectrets”), whose piezoelectricity can be orders of magnitude higher than that of conventional ferroelectric polymers. Suitable patterning of these materials leads to improved or unusual macroscopic piezo-, pyro-, and ferroelectric or nonlinear optical properties thatmore » may be particularly useful for advanced transducer or waveguide applications. In the present paper, the piezo-, pyro-, and ferroelectricity of poled polymers is briefly introduced, an overview on the preparation of polymer electrets with patterned piezo-, pyro-, and ferroelectricity is provided and a survey of selected applications is presented.« less

Cross-fiber Bragg grating transducer

NASA Technical Reports Server (NTRS)

Albin, Sacharia (Inventor); Zheng, Jianli (Inventor); Lavarias, Arnel (Inventor)

2000-01-01

A transducer has been invented that uses specially-oriented gratings in waveguide a manner that allows the simultaneous measurement of physical phenomena (such as shear force, strain and temperature) in a single sensing element. The invention has a highly sensitive, linear response and also has directional sensitivity with regard to strain. The transducer has a waveguide with a longitudinal axis as well as two Bragg gratings. The transducer has a first Bragg grating associated with the waveguide that has an angular orientation .theta..sub.a relative to a perpendicular to the longitudinal axis such that 0.degree.<.theta..sub.a <.theta..sub.max. The second Bragg grating is associated with the waveguide in such a way that the angular orientation .theta..sub.b of the grating relative to a perpendicular to the longitudinal axis is (360.degree.-.theta..sub.max)<.theta..sub.b <360.degree.. The first Bragg grating can have a periodicity .LAMBDA..sub.a and the second Bragg grating can have a periodicity .LAMBDA..sub.b such that the periodicity .LAMBDA..sub.a of the first Bragg grating does not equal the periodicity .LAMBDA..sub.b of the second Bragg grating. The angle of the gratings can be such that .theta..sub.a =360.degree.-.theta..sub.b. The waveguide can assume a variety of configurations, including an optical fiber, a rectangular waveguide and a planar waveguide. The waveguide can be fabricated of a variety of materials, including silica and polymer material.

Characterization of CMOS metal based dielectric loaded surface plasmon waveguides at telecom wavelengths.

PubMed

Weeber, J-C; Arocas, J; Heintz, O; Markey, L; Viarbitskaya, S; Colas-des-Francs, G; Hammani, K; Dereux, A; Hoessbacher, C; Koch, U; Leuthold, J; Rohracher, K; Giesecke, A L; Porschatis, C; Wahlbrink, T; Chmielak, B; Pleros, N; Tsiokos, D

2017-01-09

Dielectric loaded surface plasmon waveguides (DLSPPWs) comprised of polymer ridges deposited on top of CMOS compatible metal thin films are investigated at telecom wavelengths. We perform a direct comparison of the properties of copper (Cu), aluminum (Al), titanium nitride (TiN) and gold (Au) based waveguides by implementing the same plasmonic waveguiding configuration for each metal. The DLSPPWs are characterized by leakage radiation microscopy and a fiber-to-fiber configuration mimicking the cut-back method. We introduce the ohmic loss rate (OLR) to analyze quantitatively the properties of the CMOS metal based DLSPPWs relative to the corresponding Au based waveguides. We show that the Cu, Al and TiN based waveguides feature extra ohmic loss compared to Au of 0.027 dB/μm, 0.18 dB/μm and 0.52 dB/μm at 1550nm respectively. The dielectric function of each metal extracted from ellipsometric spectroscopic measurements is used to model the properties of the DLSP-PWs. We find a fairly good agreement between experimental and modeled DLSPPWs properties except for Al featuring a large surface roughness. Finally, we conclude that TiN based waveguides sustaining intermediate effective index (in the range 1.05-1.25) plasmon modes propagate over very short distances restricting the the use of those modes in practical situations.

Spectral and mode properties of surface plasmon polariton waveguides studied by near-field excitation and leakage-mode radiation measurement

PubMed Central

2014-01-01

We present a method to couple surface plasmon polariton (SPP) guiding mode into dielectric-loaded SPP waveguide (DLSPPW) devices with spectral and mode selectivity. The method combined a transmission-mode near-field spectroscopy to excite the SPP mode and a leakage radiation optical microscope for direct visualization. By using a near-field fiber tip, incident photons with different wavelengths were converted into SPPs at the metal/dielectric interface. Real-time SPP radiation images were taken through leakage radiation images. The wavelength-dependent propagation lengths for silver- and gold-based DLSPPWs were measured and compared. It confirms that silver-based SPP has a propagation length longer than a gold-based one by 1.25, 1.38, and 1.52 times for red, green, and blue photons. The resonant coupling as a function of wavelength in dual DLSPPWs was measured. The coupling lengths measured from leakage radiation images were in good agreement with finite-difference time domain simulations. In addition, the propagation profile due to multi-SPP modes interference was studied by changing position of the fiber tip. In a multimode DLSPPW, SPP was split into two branches with a gap of 2.237 μm when the tip was at the center of the waveguide. It became a zigzag profile when the SPP was excited at the corner of the waveguide. PMID:25177228

Multimode quantum interference of photons in multiport integrated devices

PubMed Central

Peruzzo, Alberto; Laing, Anthony; Politi, Alberto; Rudolph, Terry; O'Brien, Jeremy L.

2011-01-01

Photonics is a leading approach in realizing future quantum technologies and recently, optical waveguide circuits on silicon chips have demonstrated high levels of miniaturization and performance. Multimode interference (MMI) devices promise a straightforward implementation of compact and robust multiport circuits. Here, we show quantum interference in a 2×2 MMI coupler with visibility of V=95.6±0.9%. We further demonstrate the operation of a 4×4 port MMI device with photon pairs, which exhibits complex quantum interference behaviour. We have developed a new technique to fully characterize such multiport devices, which removes the need for phase-sensitive measurements and may find applications for a wide range of photonic devices. Our results show that MMI devices can operate in the quantum regime with high fidelity and promise substantial simplification and concatenation of photonic quantum circuits. PMID:21364563

Modeling of Optical Waveguide Poling and Thermally Stimulated Discharge (TSD) Charge and Current Densities for Guest/Host Electro Optic Polymers

NASA Technical Reports Server (NTRS)

Watson, Michael D.; Ashley, Paul R.; Abushagur, Mustafa

2004-01-01

A charge density and current density model of a waveguide system has been developed to explore the effects of electric field electrode poling. An optical waveguide may be modeled during poling by considering the dielectric charge distribution, polarization charge distribution, and conduction charge generated by the poling field. These charge distributions are the source of poling current densities. The model shows that boundary charge current density and polarization current density are the major source of currents measured during poling and thermally stimulated discharge These charge distributions provide insight into the poling mechanisms and are directly related to E(sub A), and, alpha(sub r). Initial comparisons with experimental data show excellent correlation to the model results.

Polymer film strain gauges for measuring large elongations

NASA Astrophysics Data System (ADS)

Kondratov, A. P.; Zueva, A. M.; Varakin, R. S.; Taranec, I. P.; Savenkova, I. A.

2018-02-01

The paper shows the possibility to print polymer strain gages, microstrip lines, coplanar waveguides, and other prints for avionics using printing technology and equipment. The methods of screen and inkjet printing have been complemented by three new operations of preparing print films for application of an electrically conductive ink layer. Such additional operations make it possible to enhance the conductive ink layer adhesion to the film and to manufacture strain gages for measuring large elongations.

Reconfigurable Optical Elements Based on Single and Coupled Microdisk Resonators with Quantum Dot Active Media

DTIC Science & Technology

2009-08-31

Firstly we investigated the bend loss mechanism in a waveguide made using SU8 - a negative photosensitive polymer . Simulations were performed using...present demonstration, the polymer used was SU8 (Microchem Corp.), a negative photoresist. Patterning of the microdisks were achieved using both soft...Proposed All-optical flip flop which uses a passive microring resonator integrated with active elements. Also shown is the crossesction of the SU8

Micro-resonators based on integrated polymer technology for optical sensing

NASA Astrophysics Data System (ADS)

Girault, Pauline; Lemaitre, Jonathan; Guendouz, Mohammed; Lorrain, Nathalie; Poffo, Luiz; Gadonna, Michel; Bosc, Dominique

2014-05-01

Research on sensors has experienced a noticeable development over the last decades especially in label free optical biosensors. However, compact sensors without markers for rapid, reliable and inexpensive detection of various substances induce a significant research of new technological solutions. The context of this work is the development of a sensor based on easily integrated and inexpensive micro-resonator (MR) component in integrated optics, highly sensitive and selective mainly in the areas of health and food. In this work, we take advantage of our previous studies on filters based on micro-resonators (MR) to experiment a new couple of polymers in the objective to use MR as a sensing function. MRs have been fabricated by processing SU8 polymer as core and PMATRIFE polymer as cladding layer of the waveguide. The refractive index contrast reaches 0.16 @ 1550 nm. Sub-micronic ring waveguides gaps from 0.5 to 1 μm have been successfully achieved with UV (i-line) photolithography. This work confirms our forecasts, published earlier, about the resolution that can be achieved. First results show a good extinction coefficient of ~17 dB, a quality factor around 104 and a finesse of 12. These results are in concordance with the theoretical study and they allow us to validate our technology with this couple of polymers. Work is going on with others lower cladding materials that will be used to further increase refractive index contrast for sensing applications.

A Proposal for a High-Voltage Transmission Line Directional Coupler

DOE PAGES

Olsen, R. G.; Li, Zhi

2017-02-01

Directional couplers are devices generally used in high frequency transmission lines and waveguides that respond to forward and reverse traveling waves separately. Hence they can be used to either measure standing wave ratio in the steady state or to determine the direction of a propagating transient wave. Here, a design is proposed for a directional coupler to be used on multimode high voltage transmission lines. Its performance is analyzed and several suggestions are made for improving its design.

Ultra-low-loss and broadband mode converters in Si3N4 technology

NASA Astrophysics Data System (ADS)

Mu, Jinfeng; Dijkstra, Meindert; de Goede, Michiel; Yong, Yean-Sheng; García-Blanco, Sonia M.

2017-02-01

Si3N4 grown by low pressure chemical vapor deposition (LPCVD) on thermally oxidized silicon wafers is largely utilized for creating integrated photonic devices due to its ultra-low propagation loss and large transparency window (400 nm to 2350 nm). In this paper, an ultra-low-loss and broadband mode converter for monolithic integration of different materials onto the passive Si3N4 photonic technology platform is presented. The mode size converter is constructed with a vertically tapered Si3N4 waveguide that is then buried by a polymer or an Al2O3 waveguide. The influence of the various design parameters on the converter characteristics are investigated. Optimal designs are proposed, in which the thickness of the Si3N4 waveguide is tapered from 200 nm to 40 nm. The calculated losses of the mode converters at 976 nm and 1550 nm wavelengths are well below 0.1 dB for the Si3N4-polymer coupler and below 0.3 dB for the Si3N4-Al2O3 coupler. The preliminary experimental results show good agreement with the design values, indicating that the mode converters can be utilized for the low-loss integration of different materials.

Electromagnetic Design of a Magnetically Coupled Spatial Power Combiner

NASA Astrophysics Data System (ADS)

Bulcha, B. T.; Cataldo, G.; Stevenson, T. R.; U-Yen, K.; Moseley, S. H.; Wollack, E. J.

2018-04-01

The design of a two-dimensional spatial beam-combining network employing a parallel-plate superconducting waveguide filled with a monocrystalline silicon dielectric substrate is presented. This component uses arrays of magnetically coupled antenna elements to achieve high coupling efficiency and full sampling of the intensity distribution while avoiding diffractive losses in the multimode waveguide region. These attributes enable the structure's use in realizing compact far-infrared spectrometers for astrophysical and instrumentation applications. If unterminated, reflections within a finite-sized spatial beam combiner can potentially lead to spurious couplings between elements. A planar meta-material electromagnetic absorber is implemented to control this response within the device. This broadband termination absorbs greater than 0.99 of the power over the 1.7:1 operational band at angles ranging from normal to near-parallel incidence. The design approach, simulations and applications of the spatial power combiner and meta-material termination structure are presented.

Optofluidic wavelength division multiplexing for single-virus detection

PubMed Central

Ozcelik, Damla; Parks, Joshua W.; Wall, Thomas A.; Stott, Matthew A.; Cai, Hong; Parks, Joseph W.; Hawkins, Aaron R.; Schmidt, Holger

2015-01-01

Optical waveguides simultaneously transport light at different colors, forming the basis of fiber-optic telecommunication networks that shuttle data in dozens of spectrally separated channels. Here, we reimagine this wavelength division multiplexing (WDM) paradigm in a novel context––the differentiated detection and identification of single influenza viruses on a chip. We use a single multimode interference (MMI) waveguide to create wavelength-dependent spot patterns across the entire visible spectrum and enable multiplexed single biomolecule detection on an optofluidic chip. Each target is identified by its time-dependent fluorescence signal without the need for spectral demultiplexing upon detection. We demonstrate detection of individual fluorescently labeled virus particles of three influenza A subtypes in two implementations: labeling of each virus using three different colors and two-color combinatorial labeling. By extending combinatorial multiplexing to three or more colors, MMI-based WDM provides the multiplexing power required for differentiated clinical tests and the growing field of personalized medicine. PMID:26438840

Electro-optical logic gates based on graphene-silicon waveguides

NASA Astrophysics Data System (ADS)

Chen, Weiwei; Yang, Longzhi; Wang, Pengjun; Zhang, Yawei; Zhou, Liqiang; Yang, Tianjun; Wang, Yang; Yang, Jianyi

2016-08-01

In this paper, designs of electro-optical AND/NAND, OR/ NOR, XOR/XNOR logic gates based on cascaded silicon graphene switches and regular 2×1 multimode interference combiners are presented. Each switch consists of a Mach-Zehnder interferometer in which silicon slot waveguides embedded with graphene flakes are designed for phase shifters. High-speed switching function is achieved by applying an electrical signal to tune the Fermi levels of graphene flakes causing the variation of modal effective index. Calculation results show the crosstalk in the proposed optical switch is lower than -22.9 dB within a bandwidth from 1510 nm to 1600 nm. The designed six electro-optical logic gates with the operation speed of 10 Gbit/s have a minimum extinction ratio of 35.6 dB and a maximum insertion loss of 0.21 dB for transverse electric modes at 1.55 μm.

An all-optical fiber optic photoacoustic transducer

NASA Astrophysics Data System (ADS)

Thathachary, Supriya V.; Motameni, Cameron; Ashkenazi, Shai

2018-02-01

A highly sensitive fiber-optic Fabry-Perot photoacoustic transducer is proposed in this work. The transducer will consist of separate transmit and receive fibers. The receiver will be composed of a Fabry-Perot Ultrasound sensor with a selfwritten waveguide with all-optical ultrasound detection with high sensitivity. In previous work, we have shown an increase in resonator Q-factor from 1900 to 3200 for a simulated Fabry-Perot ultrasound detector of 45 μm thickness upon including a waveguide to limit lateral power losses. Subsequently, we demonstrated a prototype device with 30nm gold mirrors and a cavity composed of the photosensitive polymer Benzocyclobutene. This 80 µm thick device showed an improvement in its Q-factor from 2500 to 5200 after a selfaligned waveguide was written into the cavity using UV exposure. Current work uses a significantly faster fabrication technique using a combination of UV-cured epoxies for the cavity medium, and the waveguide within it. This reduces the fabrication time from several hours to a few minutes, and significantly lowers the cost of fabrication. We use a dip-coating technique to deposit the polymer layer. Future work will include the use of Dielectric Bragg mirrors in place of gold to achieve better reflectivity, thereby further improving the Q-factor of the device. The complete transducer presents an ideal solution for intravascular imaging in cases where tissue differentiation is desirable, an important feature in interventional procedures where arterial perforation is a risk. The final design proposed comprises the transducer within a guidewire to guide interventions for Chronic Total Occlusions, a disease state for which there are currently no invasive imaging options.

Predicting bone strength with ultrasonic guided waves

PubMed Central

Bochud, Nicolas; Vallet, Quentin; Minonzio, Jean-Gabriel; Laugier, Pascal

2017-01-01

Recent bone quantitative ultrasound approaches exploit the multimode waveguide response of long bones for assessing properties such as cortical thickness and stiffness. Clinical applications remain, however, challenging, as the impact of soft tissue on guided waves characteristics is not fully understood yet. In particular, it must be clarified whether soft tissue must be incorporated in waveguide models needed to infer reliable cortical bone properties. We hypothesize that an inverse procedure using a free plate model can be applied to retrieve the thickness and stiffness of cortical bone from experimental data. This approach is first validated on a series of laboratory-controlled measurements performed on assemblies of bone- and soft tissue mimicking phantoms and then on in vivo measurements. The accuracy of the estimates is evaluated by comparison with reference values. To further support our hypothesis, these estimates are subsequently inserted into a bilayer model to test its accuracy. Our results show that the free plate model allows retrieving reliable waveguide properties, despite the presence of soft tissue. They also suggest that the more sophisticated bilayer model, although it is more precise to predict experimental data in the forward problem, could turn out to be hardly manageable for solving the inverse problem. PMID:28256568

Parity-time symmetry optics for modal selection in transverse and longitudinal waves (Conference Presentation)

NASA Astrophysics Data System (ADS)

Benisty, Henri; Lupu, Anatole

2017-05-01

The evolving field of optics for information and communication is currently seeking directions to expand the data rates in all concerned devices, fiber-based or on chips. We describe here two possibilities where the new concept of PT-symmetry in optics [1,2] can be exploited to help high data rate operation, considering either transverse or longitudinal aspects of modal selection, and assuming that data are carried using precise modes. The first aspect is transverse multimode transport. In this case, a fiber or a waveguide carries a few modes, say 4 to 16, and at nodes, they have to undergo a demux/mux operation to add or drop a subset of them, as much as possible without affecting the others. We shall consider to this end the operation as described in ref. [3] : if a PT-symmetric "potential", which essentially consists of a transverse gain-loss profile with antisymmetry, is applied to a waveguide, it has a very different impact on the different modes and mode families in the waveguide. One can in particular find situations where only two modes of the passive waveguide to be analyzed may enter into a gain regime, and not the other ones. From this scheme and others [4], we will discuss what is the road left towards an actual device, either in dielectrics or in case plasmonics is envisioned [5], i.e. with rather constant losses, but the possible advantage of miniaturization. The second aspect is longitudinal mode selection. The special transport properties of PT-symmetric Bragg gratings are now well established. In order to be used within a data management system, attention has to be paid to the rejection rate of Bragg gratings, and to the flatness of their response in the targeted window. To this end, a slow modulation of both real and imaginary parts of the periodic pattern of the basically PT-symmetric waveguide can help, in the general spirit of "apodization", but now with more parameters. We will detail some aspects of the designs introduced in [6] , notably their ease of implementation in established optoelectronic fabrication platforms. To conclude these considerations, the perspectives offered by the combination of transverse multimode systems and PT-symmetric type of periodicity will be discussed. [1] C. M. Bender and S. Boettcher, "Real spectra in non-Hermitian Hamiltonians having PT-symmetry," Phys. Rev. Lett. 80, 5243 (1998). [2] J. Čtyroký, V. Kuzmiak, and S. Eyderman, "Waveguide structures with antisymmetric gain/loss profile," Opt. Express 18, 21585-21593 (2010). [3] H. Benisty, A. Lupu, A. Degiron, "Transverse periodic PT symmetry for modal demultiplexing in optical waveguides," Phys. Rev. A 91, 053825 (2015). [4] N. Rivolta, B. Maes, "Symmetry recovery for coupled photonic modes with transversal PT symmetry", Opt. Letters, 40, 16, 3922-3925, (2015) [5] A. Lupu, H. Benisty, A. Degiron, "Switching using PT symmetry in plasmonic systems: positive role of the losses," Opt. Express 21, 21651-21668 (2013). [6] A. Lupu, H. Benisty, A. Lavrinenko, "Tailoring spectral properties of binary PT-symmetric gratings by using duty cycle methods," JSTQE 22, 35-41 (2016).

Polarization independent polymer waveguide tunable receivers incorporating a micro-optic circulator

NASA Astrophysics Data System (ADS)

Wu, Xiaoping; Park, Tae-Hyun; Park, Su-Hyun; Seo, Jun-Kyu; Oh, Min-Cheol

2018-06-01

In order to simplify the receiver configuration in a wavelength division multiplexed optical fiber network, compact wavelength tunable filters have long been expected to be used as channel selectors. Bragg reflector inherently has the most suitable reflection spectrum for filtering a single wavelength from the densely multiplexed wavelength signal. Polymer has high thermo-optic coefficient and good thermal insulation property compared to the other optical waveguide materials such as silicon and silica materials. This can be used to broadly tune the reflection spectrum of Bragg reflector using a simple micro-heater. In this work, a micro-optic circulator component and a polymeric Bragg reflector device are assembled to produce a small form factor tunable receiver. Compared to the integrated-optical versions, the micro-optics are based on well-developed manufacturing processes and can achieve competitive production yields. The device exhibits high reflectivity with a flat top passband, and a polarization dependence of 0.06 nm achieved by virtue of the low birefringence of LFR polymer, which make a significant contribution to the implementation of polarization independent tunable receiver. The wavelength tuning range of 40 nm is demonstrated by using a bottom located heater with a groove for heat isolation.

High sensitivity waveguide micro-displacement sensor based on intermodal interference

NASA Astrophysics Data System (ADS)

Ji, Lanting; He, Guobing; Gao, Yang; Xu, Yan; Liang, Honglei; Sun, Xiaoqiang; Wang, Xibin; Yi, Yunji; Chen, Changming; Wang, Fei; Zhang, Daming

2017-11-01

An optical waveguide displacement sensor according to core-cladding modes interference is theoretically proposed and experimentally demonstrated. Ultraviolet sensitive SU-8 polymer on silica is used as the guiding layer. It is covered by a 12 nm thick planar gold grating. The air gap sensing head which consists of the waveguide end and the single-mode fiber facet can realize the displacement detection by monitoring the wavelength dip shifting in transmission spectra. Cladding modes propagating in the exposed SU-8 can be effectively excited by the end-fire coupling because of the mode field mismatch between the SU-8 waveguide and lead-in fiber. A sinusoidal pattern transmission spectrum in C-band with the depth of over 14 dB can be observed due to the interference between the core and cladding modes. Peaks in the transmission spectrum vary continuously with the position offset of input fiber facet from the center of waveguide end. Both the sensitivity and the stability of sensing are enhanced by the introduction of nanometric gold gratings. The fabricated displacement sensor exhibits a high sensitivity of 2.3 nm μm-1, promising potentials for micromechanical processing and integrated optics application.

Simultaneous RGB lasing from a single-chip polymer device.

PubMed

Yamashita, Kenichi; Takeuchi, Nobutaka; Oe, Kunishige; Yanagi, Hisao

2010-07-15

This Letter describes the fabrication and operation of a single-chip white-laser device. The laser device has a multilayered structure consisting of three laser layers. Each laser layer comprises polymer claddings and a waveguide core doped with organic dye. In each laser layer, grating corrugations were fabricated by UV-nanoimprint lithography that act as distributed-feedback cavity structures. Under optical pumping, lasing output with red, green, and blue colors was simultaneously obtained from the sample edge.

Scanning angle Raman spectroscopy: A nondestructive method for simultaneously determining mixed polymer fractional composition and film thickness

DOE PAGES

Bobbitt, Jonathan M.; Mendivelso-Pérez, Deyny; Smith, Emily A.

2016-11-03

A scanning angle (SA) Raman spectroscopy method was developed to simultaneously measure the chemical composition and thickness of waveguide mixed polymer films with varying fractional compositions. In order to test the method, six films of polystyrene-block-poly(methyl methacrylate), some mixed with poly(methyl methacrylate) homopolymer (PS-b-PMMA:PMMA), and two films of poly(2-vinylnapthalene)-block-poly(methyl methacrylate) (P2VN-b-PMMA) were prepared. The film thickness ranged from 495 to 971 nm. The chemical composition and thickness of PS-b-PMMA:PMMA films was varied by the addition of the PMMA homopolymer and annealing the films in toluene. SA Raman peak amplitude ratios (1001 cm -1 for PS, 812 cm -1 for PMMA,more » and 1388 cm -1 for P2VN) were used to calculate the refractive index of the polymer film, an input parameter in calculations of the sum square electric field (SSEF). The film thickness was determined by SSEF models of the experimental Raman amplitudes versus the incident angle of light. The average film thickness determined by the developed SA Raman spectroscopy method was within 5% of the value determined by optical profilometry. In conclusion, SA Raman spectroscopy will be useful for in situ label-free analyses of mixed polymer waveguide films.« less

Optics Communications: Special issue on Polymer Photonics and Its Applications

NASA Astrophysics Data System (ADS)

Zhang, Ziyang; Pitwon, Richard C. A.; Feng, Jing

2016-03-01

In the last decade polymer photonics has witnessed a tremendous boost in research efforts and practical applications. Polymer materials can be engineered to exhibit unique optical and electrical properties. Extremely transparent and reliable passive optical polymers have been made commercially available and paved the ground for the development of various waveguide components. Advancement in the research activities regarding the synthesis of active polymers has enabled devices such as ultra-fast electro-optic modulators, efficient white light emitting diodes, broadband solar cells, flexible displays, and so on. The fabrication technology is not only fast and cost-effective, but also provides flexibility and broad compatibility with other semiconductor processing technologies. Reports show that polymers have been integrated in photonic platforms such as silicon-on-insulator (SOI), III-V semiconductors, and silica PLCs, and vice versa, photonic components made from a multitude of materials have been integrated, in a heterogeneous/hybrid manner, in polymer photonic platforms.

Fabrication and characterization of on-chip optical nonlinear chalcogenide nanofiber devices.

PubMed

Zhang, Qiming; Li, Ming; Hao, Qiang; Deng, Dinghuan; Zhou, Hui; Zeng, Heping; Zhan, Li; Wu, Xiang; Liu, Liying; Xu, Lei

2010-11-15

Chalcogenide (As(2)S(3)) nanofibers as narrow as 200 nm in diameter are drawn by the fiber pulling method, are successfully embedded in SU8 polymer, and form on-chip waveguides and high-Q microknot resonators (Q = 3.9 × 10(4)) with smooth cleaved end faces. Resonance tuning of resonators is realized by localized laser irradiation. Strong supercontinuum generation with a bandwidth of 500 nm is achieved in a 7-cm-long on-chip chalcogenide waveguide. Our result provides a method for the development of compact, high-optical-quality, and robust photonic devices.

Synthesis and Characterization of Electroresponsive Materials with Applications In: Part I. Second Harmonic Generation. Part II. Organic-Lanthanide Ion Complexes for Electroluminescence and Optical Amplifiers.

NASA Astrophysics Data System (ADS)

Claude, Charles

1995-01-01

Materials for optical waveguides were developed from two different approaches, inorganic-organic composites and soft gel polymers. Inorganic-organic composites were developed from alkoxysilane and organically modified silanes based on nonlinear optical chromophores. Organically modified silanes based on N-((3^' -trialkoxysilyl)propyl)-4-nitroaniline were synthesized and sol-gelled with trimethoxysilane. After a densification process at 190^circC with a corona discharge, the second harmonic of the film was measured with a Nd:YAG laser with a fundamental wavelength of 1064nm, d_{33} = 13pm/V. The decay of the second harmonic was expressed by a stretched bi-exponential equation. The decay time (tau _2) was equal to 3374 hours, and was comparable to nonlinear optical systems based on epoxy/Disperse Orange 1. The processing temperature of the organically modified silane was limited to 200^circC due to the decomposition of the organic chromophore. Soft gel polymers were synthesized and characterized for the development of optical waveguides with dc-electrical field assisted phase-matching. Polymers based on 4-nitroaniline terminated poly(ethylene oxide-co-propylene oxide) were shown to exhibit second harmonic generation that were optically phase-matched in an electrical field. The optical signals were stable and reproducible. Siloxane polymers modified with 1-mercapto-4-nitrobenzene and 1-mercapto-4-methylsulfonylstilbene nonlinear optical chromophores were synthesized. The physical and the linear and nonlinear optical properties of the polymers were characterized. Waveguides were developed from the polymers which were optically phase -matched and had an efficiency of 8.1%. The siloxane polymers exhibited optical phase-matching in an applied electrical field and can be used with a semiconductor laser. Organic lanthanide ion complexes for electroluminescence and optical amplifiers were synthesized and characterized. The complexes were characterized for their thermal and oxidative stability and for their optical properties. Organic-europium ion complexes based on derivatives of 2-benzoyl benzoate are stable to a temperature 70^circ C higher than the europium beta -diketonate complexes. The optical and fluorescence properties of the organic-europium ion complexes were characterized. The methoxy and the t-butyl derivatives of the europium 2-benzoylbenzoate complexes exhibited fluorescence quantum efficiencies that were comparable to europium tris(thenoyl trifluoroacetonate) in methylene chloride but the extinction coefficient was two-thirds of the europium thenoyltrifluoroacetonate complexes. The last complex characterized was the europium bis(diphenylphosphino)imine complex. The complex exhibited thermal stability to 550 ^circC under nitrogen.

Chemical sensors fabricated by a photonic integrated circuit foundry

NASA Astrophysics Data System (ADS)

Stievater, Todd H.; Koo, Kee; Tyndall, Nathan F.; Holmstrom, Scott A.; Kozak, Dmitry A.; Goetz, Peter G.; McGill, R. Andrew; Pruessner, Marcel W.

2018-02-01

We describe the detection of trace concentrations of chemical agents using waveguide-enhanced Raman spectroscopy in a photonic integrated circuit fabricated by AIM Photonics. The photonic integrated circuit is based on a five-centimeter long silicon nitride waveguide with a trench etched in the top cladding to allow access to the evanescent field of the propagating mode by analyte molecules. This waveguide transducer is coated with a sorbent polymer to enhance detection sensitivity and placed between low-loss edge couplers. The photonic integrated circuit is laid-out using the AIM Photonics Process Design Kit and fabricated on a Multi-Project Wafer. We detect chemical warfare agent simulants at sub parts-per-million levels in times of less than a minute. We also discuss anticipated improvements in the level of integration for photonic chemical sensors, as well as existing challenges.

External electro-optic sampling utilizing a poled polymer asymmetric Fabry Perot cavity as an electro-optical probe tip

NASA Astrophysics Data System (ADS)

Chen, Kaixin; Zhang, Hongbo; Zhang, Daming; Yang, Han; Yi, Maobin

2002-09-01

External electro-optic sampling utilizing a poled polymer asymmetry Fabry-Perot cavity as electro-optic probe tip has been demonstrated. Electro-optical polymer spin coated on the high-reflectivity mirror (HRM) was corona poled. Thus, an asymmetric F-P cavity was formed based on the different reflectivity of the polymer and HRM and it converted the phase modulation that originates from electro-optic effect of the poled polymer to amplitude modulation, so only one laser beam is needed in this system. The principle of the sampling was analyzed by multiple reflection and index ellipsoid methods. A 1.2 GHz microwave signal propagating on coplanar waveguide transmission line was sampled, and the voltage sensitivity about 0.5 mV/ Hz was obtained.

Health monitoring of carbon cantilever using femtosecond laser inscribed FBG array in gradient-index CYTOP polymer fibre

NASA Astrophysics Data System (ADS)

Theodosiou, Antreas; Kalli, Kyriacos; Komodromos, Michael

2017-04-01

We report on the femtosecond laser inscription of a fibre Bragg grating array in multimode, gradient-index, CYTOP polymer optical fibre and its demonstration as a quasi-distributed sensor for cantilever health monitoring measurements. We exploit the key advantage of polymer optical fibres, having a significantly lower Young's modulus compared with silica fibres, for vibration measurements. We also modify the typical multi-mode Bragg grating spectrum through control of the femtosecond laser inscription process, thereby producing gratings having single peak wavelength spectra. The sensor array is used to recover the time-dependent, wavelength response from each Bragg grating sensor and extract the mode shape of the beam. The mode shapes of the beam were used to observe "damage" introduced to the cantilever by adding masses to its surface; adjusting the level of damage by using different weights and placing them at different point across the beam. We show that health monitoring measurements are feasible with polymer based fibre Bragg gratings. The accurate and rapid detection of damage points on structural beams and the damage level is an important parameter for improved maintenance and servicing of beams under load and for the prevention of long-term damage.

Analysis of multimode BDK doped POF gratings for temperature sensing

NASA Astrophysics Data System (ADS)

Luo, Yanhua; Wu, Wenxuan; Wang, Tongxin; Cheng, Xusheng; Zhang, Qijin; Peng, Gang-Ding; Zhu, Bing

2012-10-01

We report a temperature sensor based on a Bragg grating written in a benzil dimethyl ketal (BDK) doped multimode (MM) polymer optical fiber (POF) for the first time to our knowledge. The thermal response was further analyzed in view of theory and experiment. In theory, with the order of the reflected mode increasing from 1st to 60th order, for MM silica fiber Bragg grating (FBG) the temperature sensitivity will increase linearly from 16.2 pm/°C to 17.5 pm/°C, while for MM polymer FBG the temperature sensitivity (absolute value) will increase linearly from -79.5 pm/°C to -104.4 pm/°C. In addition, temperature sensitivity of MM polymer FBG exhibits almost 1 order larger mode order dependence than that of MM silica FBG. In experiment, the Bragg wavelength shift will decline linearly as the temperature rises, contrary to that of MM silica FBG. The temperature sensitivity of MM polymer FBG is ranged from -0.097 nm/°C to -0.111 nm/°C, more than 8 times that of MM silica FBG, showing great potential used as a temperature sensor.

A novel wavelength multiplexer/demutiplexer based on side-port multimode interference coupler

NASA Astrophysics Data System (ADS)

Wei, Shile; Jian, Wu; Zhao, Lingjuan; Qiu, Jifang; Yin, Zuoshan; Hui, Rongqing

2014-05-01

Based on side-port multimode interference coupler, a novel design of 1.31/1.55-μm wavelength multiplexer/demutiplexer on SOI platform with conventional channel waveguides is proposed and analyzed by using wide-angle beam propagation method. With a 25.9μm long ultra-short MMI section, nearly an order of magnitude shorter than that of the previously reported 1.31/1.55-μm wavelength MMI splitters on SOI, simulation results exhibit contrasts of 28dB and 25dB at wavelength 1.31 and 1.55 μm, respectively, and the insertion losses are both below 0.55dB. Meanwhile, the analysis shows that the proposed structure has larger fabrication tolerances than restricted MMI based structures and the present design methodology also applies to split other wavelengths and in different material platforms, such as InP, GaAs and PLC guides, etc.

Brightness enhancement limits in pulsed cladding-pumped fiber Raman amplifiers

NASA Astrophysics Data System (ADS)

Ji, Junhua; Codemard, Christophe A.; Nilsson, Johan

2010-02-01

We analyze theoretically limitations on brightness enhancement of a multimode pump beam into a diffraction-limited Stokes beam in efficient cladding-pumped fiber Raman amplifiers. Firstly, the power-scaling of the 1st Stokes (hence the brightness enhancement) is limited by the generation of the 2nd order Stokes. Thus using a spectral waveguide filter such as a W-type fiber core, it is possible to improve this limit to nearly five times that of a normal fiber without spectral filter. Secondly, we analyze limits set by glass damage, propagation loss, and pump-signal pulse walk-off in the multimode fiber. We show that a well-designed fiber with a propagation loss of 3.5 dB/km allows for a pump-to-signal brightness improvement of over 1000 times for pulses longer than 40 ns and up to 3500 times in the cw regime.

Hybrid organic-inorganic sol-gel materials and components for integrated optoelectronics

NASA Astrophysics Data System (ADS)

Lu, Dong

On the technical platform of hybrid organic-inorganic sol-gel, the integrated optoelectronics in the forms of heterogeneous integration between the hybrid sol-gel waveguide and the high refractive index semiconductors and the nonlinear functional doping of disperse red chromophore into hybrid sol-gel is developed. The structure of hybrid sol-gel waveguide on high index semiconductor substrate is designed with BPM-CAD software. A hybrid sol-gel based on MAPTMS and TEOS suitable for lower cladding for the waveguide is developed. The multi-layer hybrid sol-gel waveguide with good mode confinement and low polarization dependence is fabricated on Si and InP. As proof of concept, a 1 x 12 beam splitter based on multimode interference is fabricated on silicon substrate. The device shows excess loss below 0.65 dB and imbalance below 0.28 dB for both TE and TM polarization. A nonlinear active hybrid sol-gel doped with disperse red 13 has been developed by simple co-solvent method. It permits high loading concentration and has low optical loss at 1550 nm. The second-order nonlinear property of the active sol-gel is induced with corona poling and studied with second harmonic generation. A 3-fold of enhancement in the poling efficiency is achieved by blue light assisted corona poling. The chromophore alignment stability is improved by reducing the free volume of the formed inorganic network from the sol-gel condensation reaction. An active sol-gel channel waveguide has been fabricated using active and passive hybrid sol-gel materials by only photopatterning and spin-coating. An amplitude modulator based on the active sol-gel containing 30 wt.% of DR13 shows an electro-optic coefficient of 14 pm/V at 1550 nm and stable operation within the observation time of 24 days.

All optical controlled photonic integrated circuits using azo dye functionized sol-gel material

NASA Astrophysics Data System (ADS)

Ke, Xianjun

The main focus of this dissertation is development and characterization of all-optical controllable azo dye functionized sol gel material, demonstrating a PIC fabrication technique on glass substrate using such material, and exploration and feasibility demonstration of three PIC functional devices namely optical variable attenuator, optical switches, and optical tunable filters using the material. The realization of all the devices in this dissertation are based on one material: dye functionalized sol-gel material. A photochromic sol-gel material functionalized with azo dye was synthesized and characterized. It possesses a photochromic characteristic under the control of green laser beam illumination. The material characteristics suggest the possibility of a new promising material platform candidate for the fabrication of alloptical controlled photonic integrated circuits. As the first potential application of the dye functionalized sol-gel material, an alloptical variable attenuator was designed and demonstrated. The optical variable attenuation is achieved in Mach-Zehnder interferometric configuration through all-optical modulation of sol-gel waveguide phase shifters. A 2 x 2 optical switch based on multimode interference (MMI) waveguide structure is proposed in the dissertation. The schematic configuration of the optical switch consists of a cascade of two identical MMIs with two all-optical controlled phase shifters realized by using the photochromic sol-gel material. The cross or bar switch state of the optical switch is determined by the phase difference between the two sol-gel waveguide phase shifters. An all-optical tunable filter is designed and its feasibility demonstrated by using the sol-gel photochromic material. Except for the phase change demonstrated on sol-gel waveguide phase shifters, dynamic gratings were observed on sol-gel film when exposed to two interference beams. This reveals the possibility of realizing Bragg grating-based tunable filters. The schematic configuration of proposed tunable filters consists of a single straight waveguide embedded with a sol-gel waveguide. The wavelength tuning of the tunable filters is accomplished by varying the grating period.

On-chip free beam optics on a polymer-based photonic integration platform.

PubMed

Happach, M; de Felipe, D; Conradi, H; Friedhoff, V N; Schwartz, E; Kleinert, M; Brinker, W; Zawadzki, C; Keil, N; Hofmann, W; Schell, M

2017-10-30

This paper presents on-chip free beam optics on polymer-based photonic components. Due to the circumstance that waveguide-based optics allows no direct beam access we use Gradient index (GRIN) lenses assembled into the chip to collimate the beam from the waveguides. This enables low loss power transmission over a length of 1432 µm. Even though the beam propagates through air it is possible to create a resonator with a wavelength shift of 0.002 nm/°C, hence the allowed deviations from the ITU-T grid (100 GHz) are met for ± 20 °C. In order to guarantee reliable laser stability, it is necessary to implement optical isolators at the output of the laser. This requires the insertion of bulk material into the chip and is realized by a 1050 µm thick coated glass. Due to the large gap of the free-space section, it is possible to combine different resonators together. This demonstrates the feasibility of an integrated wavelength-meter.

Demonstration of pulse controlled all-optical switch/modulator.

PubMed

Akin, Osman; Dinleyici, M S

2014-03-15

An all-optical pulse controlled switch/modulator based on evanescent coupling between a polymer slab waveguide and a single mode fiber is demonstrated. Very fast all-optical modulation/switching is achieved via Kerr effect of the nonlinear polymer placed in the evanescent region of the optical fiber. Local refractive index perturbation (Δn=-1.45612×10(-5)) on the thin film leads to 0.374 nW power modulation at the fiber output, which results in a switching efficiency of ≈1.5%.

Electrical and Nonlinear Optical Studies of Specific Organic Molecular and Nonconjugated Conductive Polymeric Systems

NASA Astrophysics Data System (ADS)

Narayanan, Ananthakrishnan

In this research, structural, electrical and nonlinear optical characteristics of: (a) single crystal films involving a noncentrosymmetric molecule DAST and a laser dye IR125 and (b) specific nonconjugated conducting polymers including poly(beta-pinene) and polynorbornene have been studied. 4'-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) is a well known second order nonlinear optical material. This material has exceptionally high electro-optic coefficients, high thermal stability and ultrafast response time. In this work single crystal films involving a combination of DAST and IR125 have been prepared using modified shear method and the films have been characterized using polarized optical microscopy, X-ray diffraction, polarization dependent optical absorption and photoluminescence spectroscopy. The electro-optic coefficient of these films measured at 633nm was found to be 300pm/V. Since IR-125 has a strong absorption band from 500nm to 800nm, these films are promising for various applications in nonlinear optics at longer wavelength and for light emission. Nonconjugated conducting polymers are a class of polymers that have at least one double bond in their repeat units. 1,4-cis polyisoprene, polyalloocimene, styrene butadiene rubber, poly(ethylenepyrrolediyl) derivatives, and poly(beta-pinene) are some of the well known examples of nonconjugated conducting polymers. In this work, polynorborne, a new addition to the class of nonconjugated conducting polymers is discussed. Like other polymers in this class, polynorbornene exhibits increase in electrical conductivity by many orders of magnitude upon doping with iodine. The maximum electrical conductivity of this material is 0.01 S/cm. As shown by using FTIR microscopy, the C=C bonds are transformed into cation radicals when polynorborne is doped. This is due to the charge-transfer from the double bond to the dopant (iodine). These materials like other nonconjugated conducting polymers have significant applications in electro-optics and photonics. Electron paramagnetic resonance measurements on poly(beta-pinene) before and after doping with iodine are reported in this work. The EPR signal of this polymer increases proportionally with the iodine concentration due to the formation of cation radicals upon doping and charge-transfer. The results agree well with the doping mechanism of nonconjugated conducting polymers discussed earlier in literature. Hyperfine splitting in heavily doped polymers is observed due to the reduced distance between the cation radical and the iodine anion. Off-resonant electro-optic measurements in doped poly(beta-pinene) at 790nm, 800nm, 810nm and 1.55microm using field-induced birefringence technique have been studied. The results show that this material exhibits the highest cubic nonlinearities of all known materials. The Kerr coefficient measured at 1.55microm is 1.6x10-10 m/V2 which is about 30 times higher than that of conjugated polymers. Results of two photon measurements in this doped polymer using pump-probe technique with a pulsed, mode-locked (150 fs pulses) beam from a Ti-Sapphire laser are reported. The measured value of alpha2 at 790 nm and 795 nm were found to be 2.28+/-0.1 cm/MW and 2.5+/-0.1 cm/MW respectively. The data confirms that the nonlinearity in this material is ultrafast and electronic in nature. Such large nonlinearities in these materials are attributed the charge confinement in these materials in a sub-nanometer domain (upon doping) resulting in a metal-like quantum dot structure. Photovoltaic measurements in a composite involving poly(beta-pinene) and C60 are discussed. This is the first time a nonconjugated conducting polymer based photovoltaic cell has been fabricated. A composite involving 4% C60 by weight produced a photovoltage of 280mV for an incident light intensity of 6mW/sq.cm. These low cost devices have applications in solar cells, photodetectors etc. A nonlinear optical waveguide was prepared by casting a thin film of poly(beta-pinene) on bare multi-mode optical fiber and doping it with iodine. The doped fibers were of excellent optical quality. Two-photon absorption experiments were conducted using these waveguides and large changes in transmission upto 28% was observed in 15cm long fiber. More work needs to be done to confirm this result. This is a significant step in the direction of making these materials a viable choice for ultrafast (femtosecond time-scale) optical devices. To summarize, these works included detailed investigations of structural, electrical and nonlinear optical characteristics of specific molecular crystal films and nonconjugated conducting polymers.

Passive fiber alignment to single-mode plastic waveguides fabricated by injection molding

NASA Astrophysics Data System (ADS)

Pompe, Guido; Lehmacher, Stefan; Rudolph, Stefan; Kalveram, Stefan; Joenck, Matthias; Neyer, Andreas

1998-04-01

Passive fibre-waveguide coupling is a promising alternative to expensive active coupling in single-mode fibre-optics. The idea to utilize replication techniques in transparent polymeric materials for waveguide and alignment structure fabrication has led to the SIGA-process (Silizium, Galvanik und Abformung) which allows a cost effective production of low loss polymer waveguides in the near IR. Major difficulties in passive fibre coupling are caused by the high lateral alignment accuracy (of about 1 micrometer) in fibre positioning. In the SIGA process, the exact position of the V- grooves relative to the waveguide trenches is defined by the etch mask for the silicon master wafer. The width of the V- grooves is determined by the KOH etching time. It is controlled precisely at various stages in the etching process by means of a microscope based piezo driven measurement system with a resolution better than 0.5 micrometer, thus allowing a final vertical precision of fibre positioning of 350 nm. In order to specify the capability of our technology we have measured the position of dozens of fibres glued into V- grooves. The result was that an amount of 55% of the fibre cores was closer than 1.5 micrometer to the waveguide centre. As the experience has shown, a two-step process for the fabrication of passively fibre coupled waveguides is necessary. First, the waveguides are produced by filling the waveguide trenches with an IR-transparent monomer and by polymerizing it using UV curing. The waveguides are inspected with visible and IR light by clamping a fibre ribbon mechanically into the integrated plastic V-grooves. In a second step the fibre ribbon is fixed irreversibly in the V- grooves. By that way we have reached an insertion loss of 3.5 dB at 1300nm and 1550nm for passively coupled 22mm single mode waveguides. Most of the losses are attributed to waveguide imperfections. More details concerning the coupling losses and the device performances will be reported at the conference.

Design and construction of a VHGT-attached WDM-type triplex transceiver module using polymer PLC hybrid integration technology

NASA Astrophysics Data System (ADS)

Jerábek, Vitezslav; Hüttel, Ivan; Prajzler, Václav; Busek, K.; Seliger, P.

2008-11-01

We report about design and construction of the bidirectional transceiver TRx module for subscriber part of the passive optical network PON for a fiber to the home FTTH topology. The TRx module consists of a epoxy novolak resin polymer planar lightwave circuit (PLC) hybrid integration technology with volume holographic grating triplex filter VHGT, surface-illuminated photodetectors and spot-size converted Fabry-Pérot laser diode in SMD package. The hybrid PLC has composed from a two parts-polymer optical waveguide including VHGT filter section and a optoelectronic microwave section. The both parts are placed on the composite substrate.

Highly tunable birefringent microstructured optical fiber.

PubMed

Kerbage, C; Steinvurzel, P; Reyes, P; Westbrook, P S; Windeler, R S; Hale, A; Eggleton, B J

2002-05-15

We demonstrate a method for introducing and dynamically tuning birefringence in a microstructured optical fiber. Waveguide asymmetry in the fiber is obtained by selective filling of air holes with polymer, and tunability is achieved by temperature tuning of the polymer's index. The fiber is tapered such that the mode field expands into the cladding and efficiently overlaps the polymer that has been infused into the air holes, ensuring enhanced tunability and low splice loss. Experimental results are compared with numerical simulations made with the beam propagation method and confirm birefringence tuning that corresponds to a phase change of 6pi for a 1-cm length of fiber.

Silicon Mach-Zehnder interferometer racetrack microring for sensing

NASA Astrophysics Data System (ADS)

Xiong, Yule; Ye, Winnie N.

2014-03-01

SOI-based microring resonators (MRRs) have attracted extensive attentions as ultra-compact sensors. Recently, a new structure design combining a ring and a Mach-Zehnder interferometer (MZI) was proposed as sensors for biomedical applications, and as modulators for communications applications. In this design, the MZI uses two identical couplers, where one arm is formed by connecting the access waveguide of the couplers, while the other arm is part of the microring. Such a device may have only one major resonance with a high extinction ratio in a very broad wavelength span (quasi-free spectral range, quasi-FSR), which offers a very large measurement range for sensing applications. 2×2 multimode interference (MMI) couplers are used to couple the microring and the bus waveguides as MMI couplers have broader wavelength responses. We present the first experimental demonstration of the MMI-coupled MZI racetrack microrings for sensing applications. Two types of MMI-coupled MZI racetrack microrings are discussed: one with wire waveguides, and the other using slotted waveguides. For the MZI racetrack microring using wire waveguides, we achieve a quasi-FSR of 34.3 nm near the wavelength of 1520 nm. The corresponding major resonance of the MZI racetrack microring demonstrates a high extinction ratio of ~22.4 dB with a full-width-half-maximum (FWHM) of 1.94 nm, and a quality factor Q of ~800. On the other hand, the quasi-FSR of the MZI racetrack microring with slot waveguides is 23.2 nm near the wavelength of 1540 nm; and the extinction ratio of the major resonance is ~24.5 dB with λFWHM=0.82 nm and Q=~1,900. To demonstrate the uses for sensing applications, we measure the resonance shifts corresponding to the concentration change of the ambient aqueous solutions of sucrose. DI water is used as the reference for calibration to avoid any other variations, e.g. temperature change. Experiments show that the sensitivities of the MZI racetrack microring sensors with wire and slot waveguides are 101.7 nm/RIU and 166.7 nm/RIU, respectively.

Optical printed circuit board (O-PCB) and VLSI photonic integrated circuits: visions, challenges, and progresses

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, S. G.; O, B. H.; Park, S. G.; Noh, H. S.; Kim, K. H.; Song, S. H.

2006-09-01

A collective overview and review is presented on the original work conducted on the theory, design, fabrication, and in-tegration of micro/nano-scale optical wires and photonic devices for applications in a newly-conceived photonic systems called "optical printed circuit board" (O-PCBs) and "VLSI photonic integrated circuits" (VLSI-PIC). These are aimed for compact, high-speed, multi-functional, intelligent, light-weight, low-energy and environmentally friendly, low-cost, and high-volume applications to complement or surpass the capabilities of electrical PCBs (E-PCBs) and/or VLSI electronic integrated circuit (VLSI-IC) systems. These consist of 2-dimensional or 3-dimensional planar arrays of micro/nano-optical wires and circuits to perform the functions of all-optical sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards or substrates. The integrated optical devices include micro/nano-scale waveguides, lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices, made of polymer, silicon and other semiconductor materials. For VLSI photonic integration, photonic crystals and plasmonic structures have been used. Scientific and technological issues concerning the processes of miniaturization, interconnection and integration of these systems as applicable to board-to-board, chip-to-chip, and intra-chip integration, are discussed along with applications for future computers, telecommunications, and sensor-systems. Visions and challenges toward these goals are also discussed.

Design and VNA-measurement of coplanar waveguide (CPW) on benzocyclobutene (BCB) at THz frequencies

NASA Astrophysics Data System (ADS)

Cao, Lei; Grimault-Jacquin, Anne-Sophie; Zerounian, Nicolas; Aniel, Frédéric

2014-03-01

The low permittivity and the low loss tangent of the benzocyclobutene polymer (BCB) offers to coplanar waveguides (CPW) a low dispersive propagation properties at THz frequency. These transmission lines have been designed, modeled with a three dimensional (3D) solver of Maxwell equations based on finite element method (FEM) from 20 to 1000 GHz at various characteristic impedances (Zc). Their dispersion and losses (radiation, conduction and dielectric) have been investigated separately versus the waveguide size, the nature of the substrate (dielectric or semiconductor) to optimize the THz signal propagation. Monomode CPW on BCB numerically designed for various Zc were realized and measured with vector network analyzer (VNA). S-parameters of CPW are de-embedded by optimization of the accesses' model. A good agreement is found between experimental and numerical results with low attenuation constants of 2.7 dB/mm and 3.5 dB/mm at 400 GHz and 500 GHz, respectively.

UV/Vis visible optical waveguides fabricated using organic-inorganic nanocomposite layers.

PubMed

Simone, Giuseppina; Perozziello, Gerardo

2011-03-01

Nanocomposite layers based on silica nanoparticles and a methacrylate matrix are synthesized by a solvent-free process and characterized in order to realize UV/Vis transparent optical waveguides. Chemical functionalization of the silica nanoparticles permits to interface the polymers and the silica. The refractive index, roughness and wettability and the machinability of the layers can be tuned changing the silica nanoparticle concentration and chemical modification of the surface of the nanoparticles. The optical transparency of the layers is affected by the nanoparticles organization between the organic chains, while it increased proportionally with respect to silica concentration. Nanocomposite layers with a concentration of 40 wt% in silica reached UV transparency for a wavelength of 250 nm. UV/Vis transparent waveguides were micromilled through nanocomposite layers and characterized. Propagation losses were measured to be around 1 dB cm(-1) at a wavelength of 350 nm.

1x3 beam splitter for TE polarization based on self-imaging phenomena in photonic crystal waveguides.

PubMed

Zhang, Min; Malureanu, Radu; Krüger, Asger Christian; Kristensen, Martin

2010-07-05

Based on inspiration from multi-mode interference self-imaging and theoretical FDTD simulations, a 1x3 beam splitter was designed, fabricated and characterized. Measurements show that for TE-polarized incident light the power is distributed equally between the output ports within 1dB in the range from 1541nm to 1552nm, and the total transmission of the 1x3 splitter is equal to the corresponding length of a single-line-defect PhCW within the measurement uncertainty.

Dynamical Casimir Effect for Gaussian Boson Sampling.

PubMed

Peropadre, Borja; Huh, Joonsuk; Sabín, Carlos

2018-02-28

We show that the Dynamical Casimir Effect (DCE), realized on two multimode coplanar waveg-uide resonators, implements a gaussian boson sampler (GBS). The appropriate choice of the mirror acceleration that couples both resonators translates into the desired initial gaussian state and many-boson interference in a boson sampling network. In particular, we show that the proposed quantum simulator naturally performs a classically hard task, known as scattershot boson sampling. Our result unveils an unprecedented computational power of DCE, and paves the way for using DCE as a resource for quantum simulation.

All-Union Conference on Laser Optics, 4th, Leningrad, USSR, January 13-18, 1984, Proceedings

NASA Astrophysics Data System (ADS)

Bukhenskii, M. F.

1984-08-01

The papers presented in this volume provide an overview of current theoretical and experimental research in laser optics. Topics discussed include electronically controlled tunable lasers, nonlinear phenomena in fiber-optic waveguides, holographic distributed-feedback dye lasers, and new developments in solid-state lasers. Papers are also presented on the generation of picosecond pulses through self-Q-switching in a distributed-feedback laser, temporal compression of light pulses during stimulated backscattering, and optimization of second harmonic generation in a multimode Nd:glass laser.

Sound reflection by a resonator array in a multimode cylindrical waveguide

NASA Astrophysics Data System (ADS)

Lapin, A. D.

2012-09-01

The paper considers the problem of scattering of the mth symmetric mode by an array of Q rings of identical, closely located Helmholtz resonators joined by necks to the walls of a wide circular pipe. The distance between rings is equal to half the wavelength of this mode at frequency ω, equal or close to the eigen-frequency of the resonator ring with allowance for the connected mass and interaction of neighboring rings via inhomogeneous modes. The coefficient of reflection of the mth mode from this grating array is calculated.

Formation of Polarized Beams in Chains of Dielectric Spheres and Cylinders

DTIC Science & Technology

2013-10-15

Three different types of coupling to the PFMs. (a) Collimated rays, (b) spherical emitter, and (c) a multimode fiber inserted inside a hollow waveguide...oscillating along the (a) y axis and (b) z axis. (c) The intensity profiles of the focused beams calculated 0.62 μm away from the tip of the end cylinder...ray. In a geometrical optics limit (D ≫ 10λ) the results are not depen- dent on D and λ. (b) d HWG Fiber (c) S Polarizer+Detectors (a) x z y Fig. 3

Delivery of high-energy radiation in midinfrared spectral region by hollow waveguides

NASA Astrophysics Data System (ADS)

Nemec, Michal; Jelinkova, Helena; Sulc, Jan; Cerny, Pavel; Miyagi, Mitsunobu; Iwai, Katsumasa; Abe, Yukio; Shi, Yi-Wei; Matsuura, Yuji

2003-07-01

Due to increasing number of requirements dealing with the application of a high energy mid-infrared radiation in various branches of medicine (cardiology, dentistry, dermatology, urology, gastroenterology), an enough flexible and lossless delivery system is required. For a transport of this high energy pulses in a mid-infrared region special cyclic olefin polymer-coated silver (COP/Ag) hollow glass waveguides were prepared and tested. A length of the waveguides was 0.5 m and inner diameter 1 mm. As a radiation source, an Er:YAG laser was used. The system generated the energy up to 2.16 J or 2.35 J (in dependence on a repetition rate used - 3 Hz or 4 Hz, respectively). The length of transmitted pulses was measured to be from 110 up to 550 usec in dependence on output energy used. The output radiation was coupled into the COP/Ag waveguide and a throughput and losses values were measured in dependence to input radiation parameters. The transmission obtained was 91%. The maximum delivered energy was dependent on a damage threshold of the waveguide. It was found that the damage threshold is dependent on the repetition rate which shows the dependences on the heat dissipated in the waveguide wall. The value of the damage was 1.7 J and 1.5 J for 3 Hz and 4 Hz repetition rate, respectively. The safe delivered power reached the value of 5 W. The characteristics obtained make this specially constructed COP/Ag hollow glass waveguide promising for the delivery of high-energy laser pulses in medicine and also in other applications.

Optical interconnects based on VCSELs and low-loss silicon photonics

NASA Astrophysics Data System (ADS)

Aalto, Timo; Harjanne, Mikko; Karppinen, Mikko; Cherchi, Matteo; Sitomaniemi, Aila; Ollila, Jyrki; Malacarne, Antonio; Neumeyr, Christian

2018-02-01

Silicon photonics with micron-scale Si waveguides offers most of the benefits of submicron SOI technology while avoiding most of its limitations. In particular, thick silicon-on-insulator (SOI) waveguides offer 0.1 dB/cm propagation loss, polarization independency, broadband single-mode (SM) operation from 1.2 to >4 µm wavelength and ability to transmit high optical powers (>1 W). Here we describe the feasibility of Thick-SOI technology for advanced optical interconnects. With 12 μm SOI waveguides we demonstrate efficient coupling between standard single-mode fibers, vertical-cavity surface-emitting lasers (VCSELs) and photodetectors (PDs), as well as wavelength multiplexing in small footprint. Discrete VCSELs and PDs already support 28 Gb/s on-off keying (OOK), which shows a path towards 50-100 Gb/s bandwidth per wavelength by using more advanced modulation formats like PAM4. Directly modulated VCSELs enable very power-efficient optical interconnects for up to 40 km distance. Furthermore, with 3 μm SOI waveguides we demonstrate extremely dense and low-loss integration of numerous optical functions, such as multiplexers, filters, switches and delay lines. Also polarization independent and athermal operation is demonstrated. The latter is achieved by using short polymer waveguides to compensate for the thermo-optic effect in silicon. New concepts for isolator integration and polarization rotation are also explained.

Broadband Energy Harvester Using Non-linear Polymer Spring and Electromagnetic/Triboelectric Hybrid Mechanism

PubMed Central

Gupta, Rahul Kumar; Shi, Qiongfeng; Dhakar, Lokesh; Wang, Tao; Heng, Chun Huat; Lee, Chengkuo

2017-01-01

Over the years, several approaches have been devised to widen the operating bandwidth, but most of them can only be triggered at high accelerations. In this work, we investigate a broadband energy harvester based on combination of non-linear stiffening effect and multimodal energy harvesting to obtain high bandwidth over wide range of accelerations (0.1 g–2.0 g). In order to achieve broadband behavior, a polymer based spring exhibiting multimodal energy harvesting is used. Besides, non-linear stiffening effect is introduced by using mechanical stoppers. At low accelerations (<0.5 g), the nearby mode frequencies of polymer spring contribute to broadening characteristics, while proof mass engages with mechanical stoppers to introduce broadening by non-linear stiffening at higher accelerations. The electromagnetic mechanism is employed in this design to enhance its output at low accelerations when triboelectric output is negligible. Our device displays bandwidth of 40 Hz even at low acceleration of 0.1 g and it is increased up to 68 Hz at 2 g. When non-linear stiffening is used along with multimodal energy-harvesting, the obtained bandwidth increases from 23 Hz to 68 Hz with percentage increment of 295% at 1.8 g. Further, we have demonstrated the triboelectric output measured as acceleration sensing signals in terms of voltage and current sensitivity of 4.7 Vg−1 and 19.7 nAg−1, respectively. PMID:28120924

Broadband Energy Harvester Using Non-linear Polymer Spring and Electromagnetic/Triboelectric Hybrid Mechanism

NASA Astrophysics Data System (ADS)

Gupta, Rahul Kumar; Shi, Qiongfeng; Dhakar, Lokesh; Wang, Tao; Heng, Chun Huat; Lee, Chengkuo

2017-01-01

Over the years, several approaches have been devised to widen the operating bandwidth, but most of them can only be triggered at high accelerations. In this work, we investigate a broadband energy harvester based on combination of non-linear stiffening effect and multimodal energy harvesting to obtain high bandwidth over wide range of accelerations (0.1 g-2.0 g). In order to achieve broadband behavior, a polymer based spring exhibiting multimodal energy harvesting is used. Besides, non-linear stiffening effect is introduced by using mechanical stoppers. At low accelerations (<0.5 g), the nearby mode frequencies of polymer spring contribute to broadening characteristics, while proof mass engages with mechanical stoppers to introduce broadening by non-linear stiffening at higher accelerations. The electromagnetic mechanism is employed in this design to enhance its output at low accelerations when triboelectric output is negligible. Our device displays bandwidth of 40 Hz even at low acceleration of 0.1 g and it is increased up to 68 Hz at 2 g. When non-linear stiffening is used along with multimodal energy-harvesting, the obtained bandwidth increases from 23 Hz to 68 Hz with percentage increment of 295% at 1.8 g. Further, we have demonstrated the triboelectric output measured as acceleration sensing signals in terms of voltage and current sensitivity of 4.7 Vg-1 and 19.7 nAg-1, respectively.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobbitt, Jonathan M.; Mendivelso-Pérez, Deyny; Smith, Emily A.

A scanning angle (SA) Raman spectroscopy method was developed to simultaneously measure the chemical composition and thickness of waveguide mixed polymer films with varying fractional compositions. In order to test the method, six films of polystyrene-block-poly(methyl methacrylate), some mixed with poly(methyl methacrylate) homopolymer (PS-b-PMMA:PMMA), and two films of poly(2-vinylnapthalene)-block-poly(methyl methacrylate) (P2VN-b-PMMA) were prepared. The film thickness ranged from 495 to 971 nm. The chemical composition and thickness of PS-b-PMMA:PMMA films was varied by the addition of the PMMA homopolymer and annealing the films in toluene. SA Raman peak amplitude ratios (1001 cm -1 for PS, 812 cm -1 for PMMA,more » and 1388 cm -1 for P2VN) were used to calculate the refractive index of the polymer film, an input parameter in calculations of the sum square electric field (SSEF). The film thickness was determined by SSEF models of the experimental Raman amplitudes versus the incident angle of light. The average film thickness determined by the developed SA Raman spectroscopy method was within 5% of the value determined by optical profilometry. In conclusion, SA Raman spectroscopy will be useful for in situ label-free analyses of mixed polymer waveguide films.« less

Polymer Waveguide Fabrication Techniques

NASA Astrophysics Data System (ADS)

Ramey, Delvan A.

1985-01-01

The ability of integrated optic systems to compete in signal processing aplications with more traditional analog and digital electronic systems is discussed. The Acousto-Optic Spectrum Analyzer is an example which motivated the particular work discussed herein. Provided real time processing is more critical than absolute accuracy, such integrated optic systems fulfill a design need. Fan-out waveguide arrays allow crosstalk in system detector arrays to be controlled without directly limiting system resolution. A polyurethane pattern definition process was developed in order to demonstrate fan-out arrays. This novel process is discussed, along with further research needs. Integrated optic system market penetration would be enhanced by development of commercial processes of this type.

All polymer asymmetric Mach-Zehnder interferometer waveguide sensor by imprinting bonding and laser polishing

NASA Astrophysics Data System (ADS)

Liu, Yu; Sun, Yue; Yi, Yun-Ji; Tian, Liang; Cao, Yue; Chen, Chang-Ming; Sun, Xiao-Qiang; Zhang, Da-Ming

2017-12-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 61605057, 61475061, and 61575076), the Science and Technology Development Plan of Jilin Province, China (Grant No. 20140519006JH), and the Excellent Youth Foundation of Jilin Province, China (Grant No. 20170520158JH).

Realization of a compact polarization splitter-rotator on silicon.

PubMed

Dai, Daoxin; Wu, Hao

2016-05-15

A novel compact polarization splitter-rotator (PSR) is proposed and realized with silicon-on-insulator nanowires. The present PSR consists of an adiabatic taper, an asymmetric directional coupler (ADC), and a multimode interference (MMI) mode filter. The adiabatic taper enables an efficient mode conversion from the launched TM₀ mode to the TE₁ mode in a wide waveguide, which is then coupled to the TE₀ mode of a narrow waveguide through the ADC. Meanwhile, the launched TE₀ mode does not have mode conversion and outputs from the through port directly. The MMI mode filter is cascaded at the through port to filter out the residual power of the TE₁ mode so that the extinction ratio of the PSR is improved greatly. The total length of the PSR is ∼70  μm and the fabricated PSR has an extinction ratio of ∼20  dB over a broadband ranging from 1547 to 1597 nm.

Chip-based wide field-of-view nanoscopy

NASA Astrophysics Data System (ADS)

Diekmann, Robin; Helle, Øystein I.; Øie, Cristina I.; McCourt, Peter; Huser, Thomas R.; Schüttpelz, Mark; Ahluwalia, Balpreet S.

2017-04-01

Present optical nanoscopy techniques use a complex microscope for imaging and a simple glass slide to hold the sample. Here, we demonstrate the inverse: the use of a complex, but mass-producible optical chip, which hosts the sample and provides a waveguide for the illumination source, and a standard low-cost microscope to acquire super-resolved images via two different approaches. Waveguides composed of a material with high refractive-index contrast provide a strong evanescent field that is used for single-molecule switching and fluorescence excitation, thus enabling chip-based single-molecule localization microscopy. Additionally, multimode interference patterns induce spatial fluorescence intensity variations that enable fluctuation-based super-resolution imaging. As chip-based nanoscopy separates the illumination and detection light paths, total-internal-reflection fluorescence excitation is possible over a large field of view, with up to 0.5 mm × 0.5 mm being demonstrated. Using multicolour chip-based nanoscopy, we visualize fenestrations in liver sinusoidal endothelial cells.

Surface-Emitting Distributed Feedback Terahertz Quantum-Cascade Lasers in Metal-Metal Waveguides

NASA Technical Reports Server (NTRS)

Kumar, Sushil; Williams, Benjamin S.; Qin, Qi; Lee, Alan W. M.; Hu, Qing; Reno, John L.

2007-01-01

Single-mode surface-emitting distributed feedback terahertz quantumcascade lasers operating around 2.9 THz are developed in metal-metal waveguides. A combination of techniques including precise control of phase of reflection at the facets, and u e of metal on the sidewalls to eliminate higher-order lateral modes allow robust single-mode operation over a range of approximately 0.35 THz. Single-lobed far-field radiation pattern is obtained using a pi phase-shift in center of the second-order Bragg grating. A grating device operating at 2.93 THz lased up to 149 K in pulsed mode and a temperature tuning of 19 .7 GHz was observed from 5 K to 147 K. The same device lased up to 78 K in continuous-wave (cw) mode emitting more than 6 m W of cw power at 5 K. ln general, maximum temperature of pulsed operation for grating devices was within a few Kelvin of that of multi-mode Fabry-Perot ridge lasers

Thin-film magnetless Faraday rotators for compact heterogeneous integrated optical isolators

NASA Astrophysics Data System (ADS)

Karki, Dolendra; Stenger, Vincent; Pollick, Andrea; Levy, Miguel

2017-06-01

This report describes the fabrication, characterization, and transfer of ultra-compact thin-film magnetless Faraday rotators to silicon photonic substrates. Thin films of magnetization latching bismuth-substituted rare-earth iron garnets were produced from commercially available materials by mechanical lapping, dice polishing, and crystal-ion-slicing. Eleven- μ m -thick films were shown to retain the 45 ° Faraday rotation of the bulk material to within 2 ° at 1.55 μ m wavelength without re-poling. Anti-reflection coated films evince 0.09 dB insertion loses and better than -20 dB extinction ratios. Lower extinction ratios than the bulk are ascribed to multimode propagation. Significantly larger extinction ratios are predicted for single-mode waveguides. Faraday rotation, extinction ratios, and insertion loss tests on He-ion implanted slab waveguides of the same material yielded similar results. The work culminated with bond alignment and transfer of 7 μ m -thick crystal-ion-sliced 50 × 480 μ m 2 films onto silicon photonic substrates.

CO2 laser induced refractive index changes in optical polymers.

PubMed

Liu, Qing; Chiang, Kin Seng; Reekie, Laurence; Chow, Yuk Tak

2012-01-02

We study the infrared photosensitivity properties of two optical polymer materials, benzocyclobutene (BCB) and epoxy OPTOCAST 3505, with a 10.6 μm CO2 laser. We discover that the CO2 laser radiation can lower the refractive index of BCB by as much as 5.5 × 10(-3), while inducing no measurable index change in the epoxy. As confirmed by Fourier transform infrared spectroscopy, the observed index change in BCB can be attributed to photothermal modification of chemical bonds in the material by the CO2 laser radiation. Our findings open up a new possibility of processing polymer materials with a CO2 laser, which could be further developed for application in the areas of post-processing and direct-writing of polymer waveguide devices.

High sensitivity optical biosensor based on polymer materials and using the Vernier effect.

PubMed

Azuelos, Paul; Girault, Pauline; Lorrain, Nathalie; Poffo, Luiz; Guendouz, Mohammed; Thual, Monique; Lemaître, Jonathan; Pirasteh, Parastesh; Hardy, Isabelle; Charrier, Joël

2017-11-27

We demonstrate the fabrication of a Vernier effect SU8/PMATRIFE polymer optical biosensor with high homogeneous sensitivity using a standard photolithography process. The sensor is based on one micro-resonator embedded on each arm of a Mach-Zehnder interferometer. Measurements are based on the refractive index variation of the optical waveguide superstrate with different concentrations of glucose solutions. The sensitivity of the sensor has been measured as 17558 nm/RIU and the limit of detection has been estimated to 1.1.10 -6 RIU.

Free space and waveguide Talbot effect: phase relations and planar light circuit applications

NASA Astrophysics Data System (ADS)

Nikkhah, H.; Zheng, Q.; Hasan, I.; Abdul-Majid, S.; Hall, T. J.

2012-10-01

Optical fields that are periodic in the transverse plane self-image periodically as they propagate along the optical axis: a phenomenon known as the Talbot effect. A transfer matrix may be defined that relates the amplitude and phase of point sources placed on a particular grid at the input to their respective multiple images at an image plane. The free-space Talbot effect may be mapped to the waveguide Talbot effect. Applying this mapping to the transfer matrix enables the prediction of the phase and amplitude relations between the ports of a Multimode Interference (MMI) coupler- a planar waveguide device. The transfer matrix approach has not previously been applied to the free-space case and its mapping to the waveguide case provides greater clarity and physical insight into the phase relationships than previous treatments. The paper first introduces the underlying physics of the Talbot effect in free space with emphasis on the positions along the optical axis at which images occur; their multiplicity; and their relative phase relations determined by the Gauss Quadratic Sum of number theory. The analysis is then adapted to predict the phase relationships between the ports of an MMI. These phase relationships are critical to planar light circuit (PLC) applications such as 90° optical hybrids for coherent optical receiver front-ends, external optical I-Q modulators for coherent optical transmitters; and optical phased array switches. These applications are illustrated by results obtained from devices that have been fabricated and tested by the PTLab in Si micro-photonic integration platforms.

Multiwaveguide implantable probe for light delivery to sets of distributed brain targets.

PubMed

Zorzos, Anthony N; Boyden, Edward S; Fonstad, Clifton G

2010-12-15

Optical fibers are commonly inserted into living tissues such as the brain in order to deliver light to deep targets for neuroscientific and neuroengineering applications such as optogenetics, in which light is used to activate or silence neurons expressing specific photosensitive proteins. However, an optical fiber is limited to delivering light to a single target within the three-dimensional structure of the brain. We here demonstrate a multiwaveguide probe capable of independently delivering light to multiple targets along the probe axis, thus enabling versatile optical control of sets of distributed brain targets. The 1.45-cm-long probe is microfabricated in the form of a 360-μm-wide array of 12 parallel silicon oxynitride (SiON) multimode waveguides clad with SiO(2) and coated with aluminum; probes of custom dimensions are easily created as well. The waveguide array accepts light from a set of sources at the input end and guides the light down each waveguide to an aluminum corner mirror that efficiently deflects light away from the probe axis. Light losses at each stage are small (input coupling loss, 0.4 ± 0.3 dB; bend loss, negligible; propagation loss, 3.1 ± 1 dB/cm using the outscattering method and 3.2 ± 0.4 dB/cm using the cutback method; corner mirror loss, 1.5 ± 0.4 dB); a waveguide coupled, for example, to a 5 mW source will deliver over 1.5 mW to a target at a depth of 1 cm.

Optical Micromachined Ultrasound Transducers (OMUT)-- A New Approach for High Frequency Ultrasound Imaging

NASA Astrophysics Data System (ADS)

Tadayon, Mohammad Amin

Piezoelectric technology is the backbone of most medical ultrasound imaging arrays, however, in scaling the technology to sizes required for high frequency operation (> 20 MHz), it encounters substantial difficulties in fabrication and signal transduction efficiency. These limitations particularly affect the design of intravascular ultrasound (IVUS) imaging probes whose operating frequency can approach 60 MHz. Optical technology has been proposed and investigated for several decades as an alternative approach for high frequency ultrasound transducers. However, to apply this promising technology in guiding clinical operations such as in interventional cardiology, brain surgery, and laparoscopic surgery further raise in the sensitivity is required. Here, in order to achieve the required sensitivity for an intravascular ultrasound imaging probe, we introduce design changes making use of alternative receiver mechanisms. First, we present an air cavity detector that makes use of a polymer membrane for increased mechanical deflection. We have also significantly raised the thin film detector sensitivity by improving its optical characteristics. This can be achieved by inducing a refractive index feature inside the Fabry-Perot resonator that simply creates a waveguide between the two mirrors. This approach eliminates the loss in energy due to diffraction in the cavity, and therefore the Q-factor is only limited by mirror loss and absorption. To demonstrate this optical improvements, a waveguide Fabry-Perot resonator has been fabricated consisting of two dielectric Bragg reflectors with a layer of photosensitive polymer between them. The measured finesse of the fabricated resonator was 692, and the Q-factor was 55000. The fabrication process of this device has been modified to fabricate an ultrasonically testable waveguide Fabry-Perot resonator. By applying this method, we have achieved a noise equivalent pressure of 178 Pa over a bandwidth of 28 MHz or 0.03 Pa/Hz1/2 which is approximately 20-fold better than a similar device without a waveguide. The finesse of the tested Fabry-Perot resonator was around 200. This result is 5 times higher than the finesse measured in the same device outside the waveguide region. In future, our developed technology can be integrated on the tip of an optical fiber bundle and applied for intravascular ultrasound imaging.

Giant refractive-index modulation by two-photon reduction of fluorescent graphene oxides for multimode optical recording.

PubMed

Li, Xiangping; Zhang, Qiming; Chen, Xi; Gu, Min

2013-10-02

Graphene oxides (GOs) have emerged as precursors offering the potential of a cost-effective and large-scale production of graphene-based materials. Despite that their intrinsic fluorescence property has already brought interest of researchers for optical applications, to date, refractive-index modulation as one of the fundamental aspects of optical properties of GOs has received less attention. Here we reported on a giant refractive-index modulation on the order of 10(-2) to 10(-1), accompanied by a fluorescence intensity change, through the two-photon reduction of GOs. These features enabled a mechanism for multimode optical recording with the fluorescence contrast and the hologram-encoded refractive-index modulation in GO-dispersed polymers for security-enhanced high-capacity information technologies. Our results show that GO-polymer composites may provide a new material platform enabling flexible micro-/nano-photonic information devices.

Ultra-small and broadband polarization splitters based on double-slit interference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Chengwei; Li, Hongyun; Gong, Qihuang

2016-03-07

An ultra-small and broadband polarization splitter is numerically and experimentally demonstrated based on the double-slit interference in a polymer-film-coated double-slit structure. The hybrid slab waveguide (air-polymer-Au) supports both the transverse-magnetic and transverse-electric modes. The incident beam from the back side can excite these two guided modes of orthogonally polarized states in the hybrid structure. By exploiting the difference slit widths and the large mode birefringence, these two guided modes propagate to the opposite directions along the front metal surface. Moreover, the short interference length broadens the operation bandwidth. Experimentally, a polarization splitter with a lateral dimension of only about 1.6 μmmore » and an operation bandwidth of 50 nm is realized. By designing the double-slit structure in a hybrid strip waveguide, the device dimension can be significant downscaled to about 0.3 × 1.3 μm{sup 2}. Such an ultra-small and broadband polarization splitter may find important applications in the integrated photonic circuits.« less

Backplane photonic interconnect modules with optical jumpers

NASA Astrophysics Data System (ADS)

Glebov, Alexei L.; Lee, Michael G.; Yokouchi, Kishio

2005-03-01

Prototypes of optical interconnect (OI) modules for backplane applications are presented. The transceivers attached to the linecards E/O convert the signals that are passed to and from the backplane by optical jumpers terminated with MTP-type connectors. The connectors plug into adaptors attached to the backplane and the microlens arrays mounted in the adaptors couple the light between the fibers and waveguides. Planar polymer channel waveguides with 30-50 μm cross-sections route the optical signals across the board with propagation losses as low as 0.05 dB/cm @ 850 nm. The 45¦-tapered integrated micromirrors reflect the light in and out of the waveguide plane with the loss of 0.8 dB per mirror. The connector displacement measurements indicate that the adaptor lateral assembly accuracy can be at least +/-10 μm for the excess loss not exceeding 1 dB. Insertion losses of the test modules with integrated waveguides, 45¦ mirrors, and pluggable optical jumper connectors are about 5 dB. Eye diagrams at 10.7 Gb/s have typical width and height of 70 ps and 400 mV, respectively, and jitter of about 20 ps.

Polymer/silica hybrid integration waveguide Bragg grating based on surface plasmon polaritons.

PubMed

Tian, Liang; Wang, Fei; Wu, Yuanda; Sun, Xiaoqiang; Yi, Yunji; Zhang, Daming

2018-05-01

We proposed a device composed of a Bragg grating and a long-range surface plasmon polariton waveguide. The waveguide is formed by embedding a thin Au stripe in negative UV photoresist (SU-8 2005). The corrugated grating structure is created on a silica substrate using contact lithography and inductively coupled plasma etching, which is transferred onto the SU-8 2005 film by a spin coating process, producing a periodic modulation of refractive index along the waveguide. We achieve a transmission peak with an extinction ratio of 17 dB and a 3-dB bandwidth of 0.9 nm at a wavelength of 1575.2 nm. We achieve a reflection peak with a side-mode suppression ratio of 9.7 dB, a 3-dB bandwidth of 0.9 nm at a wavelength of 1575.2 nm when the heating electrode isn't working. The shift of the reflection peak with heating power over the range 0-6 mW is approximately 2.9 nm. This thermal dependence exhibits an average slope of -0.48  nm/mW.

Cross-linked polyimides for integrated optics

NASA Astrophysics Data System (ADS)

Singer, Kenneth D.; Kowalczyk, Tony C.; Nguyen, Hung D.; Beuhler, Allyson J.; Wargowski, David A.

1997-01-01

We have investigated a promising class of polyimide materials for both passive and active electro-optic devices, namely crosslinkable polyimides. These fluorinated polyimides are soluble in the imidized form and are both thermally and photo-crosslinkable leading to easy processability into waveguide structures and the possibility of stable electro-optic properties. We have fabricated channel and slab waveguides and investigated the mechanism of optical propagation loss using photothermal deflection spectroscopy and waveguide loss spectroscopy, and found the losses to arise from residual absorption due to the formation of charge transfer states. The absorption is inhibited by fluorination leading to propagation losses as low as 0.3 dB/cm in the near infrared. Because of the ability to photocrosslink, channel waveguides are fabricated using a simple wet-etch process. Channel waveguides so formed are observed to have no excess loss over slab structures. Solubility followed by thermal cross-linking allows the formation of multilayer structures. We have produced electro-optic polymers by doping with the nonlinear optical chromophores, DCM and DADC; and a process of concurrent poling and thermal crosslinking. Multilayer structures have been investigated and poling fields optimized in the active layer by doping the cladding with an anti-static agent. The high glass-transition temperature and cross-linking leads to very stable electro-optic properties. We are currently building electro-optic modulators based on these materials. Progress and results in this area also are reported.

Ultra-broadband THz time-domain spectroscopy of common polymers using THz air photonics.

PubMed

D'Angelo, Francesco; Mics, Zoltán; Bonn, Mischa; Turchinovich, Dmitry

2014-05-19

Terahertz-range dielectric properties of the common polymers low-density polyethylene (LDPE), cyclic olefin/ethylene copolymer (TOPAS®), polyamide-6 (PA6), and polytetrafluoroethylene (PTFE or Teflon®) are characterized in the ultra-broadband frequency window 2-15 THz, using a THz time-domain spectrometer employing air-photonics for the generation and detection of single-cycle sub-50 fs THz transients. The time domain measurements provide direct access to both the absorption and refractive index spectra. The polymers LDPE and TOPAS® demonstrate negligible absorption and spectrally-flat refractive index across the entire spectroscopy window, revealing the high potential of these polymers for applications in THz photonics such as ultra-broadband polymer-based dielectric mirrors, waveguides, and fibers. Resonant high-frequency polar vibrational modes are observed and assigned in polymers PA6 and PTFE, and their dielectric functions in the complete frequency window 2-15 THz are theoretically reproduced. Our results demonstrate the potential of ultra-broadband air-photonics-based THz time domain spectroscopy as a valuable analytic tool for materials science.

Scaling Fiber Lasers to Large Mode Area: An Investigation of Passive Mode-Locking Using a Multi-Mode Fiber

PubMed Central

Ding, Edwin; Lefrancois, Simon; Kutz, Jose Nathan; Wise, Frank W.

2011-01-01

The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg–Landau equations. Simulations show that stable and robust mode-locked pulses can be produced. However, the mode-locking can be destabilized by excessive higher-order mode content. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that mode-locking can be significantly disturbed in the presence of higher-order modes, resulting in lower maximum single-pulse energies. In practice, spatial mode content must be carefully controlled to achieve full pulse energy scaling. This paper demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers. PMID:21731106

Scaling Fiber Lasers to Large Mode Area: An Investigation of Passive Mode-Locking Using a Multi-Mode Fiber.

PubMed

Ding, Edwin; Lefrancois, Simon; Kutz, Jose Nathan; Wise, Frank W

2011-01-01

The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg-Landau equations. Simulations show that stable and robust mode-locked pulses can be produced. However, the mode-locking can be destabilized by excessive higher-order mode content. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that mode-locking can be significantly disturbed in the presence of higher-order modes, resulting in lower maximum single-pulse energies. In practice, spatial mode content must be carefully controlled to achieve full pulse energy scaling. This paper demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers.

Complete spatiotemporal characterization and optical transfer matrix inversion of a 420 mode fiber.

PubMed

Carpenter, Joel; Eggleton, Benjamin J; Schröder, Jochen

2016-12-01

The ability to measure a scattering medium's optical transfer matrix, the mapping between any spatial input and output, has enabled applications such as imaging to be performed through media which would otherwise be opaque due to scattering. However, the scattering of light occurs not just in space, but also in time. We complete the characterization of scatter by extending optical transfer matrix methods into the time domain, allowing any spatiotemporal input state at one end to be mapped directly to its corresponding spatiotemporal output state. We have measured the optical transfer function of a multimode fiber in its entirety; it consists of 420 modes in/out at 32768 wavelengths, the most detailed complete characterization of multimode waveguide light propagation to date, to the best of our knowledge. We then demonstrate the ability to generate any spatial/polarization state at the output of the fiber at any wavelength, as well as predict the temporal response of any spatial/polarization input state.

Demonstration of glass-based photonic interposer for mid-board-optical engines and electrical-optical circuit board (EOCB) integration strategy

NASA Astrophysics Data System (ADS)

Schröder, H.; Neitz, M.; Schneider-Ramelow, M.

2018-02-01

Due to its optical transparency and superior dielectric properties glass is regarded as a promising candidate for advanced applications as active photonic interposer for mid-board-optics and optical PCB waveguide integration. The concepts for multi-mode and single-mode photonic system integration are discussed and related demonstration project results will be presented. A hybrid integrated photonic glass body interposer with integrated optical lenses for multi-mode data communication wavelength of 850 nm have been realized. The paper summarizes process developments which allow cost efficient metallization of TGV. Electro-optical elements like photodiodes and VCSELs can be directly flip-chip mounted on the glass substrate according to the desired lens positions. Furthermore results for a silicon photonic based single-mode active interposer integration onto a single mode glass made EOCB will be compared in terms of packaging challenges. The board level integration strategy for both of these technological approaches and general next generation board level integration concepts for photonic interposer will be introductorily discussed.

Large area single-mode parity-time-symmetric laser amplifiers.

PubMed

Miri, Mohammad-Ali; LiKamWa, Patrik; Christodoulides, Demetrios N

2012-03-01

By exploiting recent developments associated with parity-time (PT) symmetry in optics, we here propose a new avenue in realizing single-mode large area laser amplifiers. This can be accomplished by utilizing the abrupt symmetry breaking transition that allows the fundamental mode to experience gain while keeping all the higher order modes neutral. Such PT-symmetric structures can be realized by judiciously coupling two multimode waveguides, one exhibiting gain while the other exhibits an equal amount of loss. Pertinent examples are provided for both semiconductor and fiber laser amplifiers. © 2012 Optical Society of America

FIBER OPTICS. ACOUSTOOPTICS: Amplification of semiconductor laser radiation in the wavelength range 1.24-1.3 μm by stimulated Raman scattering in an optical fiber

NASA Astrophysics Data System (ADS)

Belotitskiĭ, V. I.; Kuzin, E. A.; Ovsyannikov, D. V.; Petrov, Mikhail P.

1990-07-01

An investigation was made of the influence of weak semiconductor laser radiation on the spectrum of stimulated Raman scattering in a single-mode optical waveguide pumped by a YAG:Nd3+ laser emitting at 1.06 μm. The scattered radiation power increased by a factor exceeding 10 at the semiconductor laser wavelength. A small-signal dynamic gain reached 47 dB. Simultaneous amplification was observed of several modes of multimode semiconductor laser radiation with an intermode spectral interval of 1.3 nm.

Multiplexing of adjacent vortex modes with the forked grating coupler

NASA Astrophysics Data System (ADS)

Nadovich, Christopher T.; Kosciolek, Derek J.; Crouse, David T.; Jemison, William D.

2017-08-01

For vortex fiber multiplexing to reach practical commercial viability, simple silicon photonic interfaces with vortex fiber will be required. These interfaces must support multiplexing. Toward this goal, an efficient singlefed multimode Forked Grating Coupler (FGC) for coupling two different optical vortex OAM charges to or from the TE0 and TE1 rectangular waveguide modes has been developed. A simple, apodized device implemented with e-beam lithography and a conventional dual-etch processing on SOI wafer exhibits low crosstalk and reasonable mode match. Advanced designs using this concept are expected to further improve performance.

Long-range monostatic remote sensing of geomaterial structure weak vibrations

NASA Astrophysics Data System (ADS)

Heifetz, Alexander; Bakhtiari, Sasan; Gopalsami, Nachappa; Elmer, Thomas W.; Mukherjee, Souvik

2018-04-01

We study analytically and numerically signal sensitivity in remote sensing measurements of weak mechanical vibration of structures made of typical construction geomaterials, such as concrete. The analysis includes considerations of electromagnetic beam atmospheric absorption, reflection, scattering, diffraction and losses. Comparison is made between electromagnetic frequencies of 35GHz (Ka-band), 94GHz (W-band) and 260GHz (WR-3 waveguide band), corresponding to atmospheric transparency windows of the electromagnetic spectrum. Numerical simulations indicate that 94GHz frequency is optimal in terms of signal sensitivity and specificity for long-distance (>1.5km) sensing of weak multi-mode vibrations.

Exploring photoreceptor reflectivity via multimodal imaging of outer retinal tubulation in advanced age-related macular degeneration

PubMed Central

Litts, Katie M.; Wang, Xiaolin; Clark, Mark E.; Owsley, Cynthia; Freund, K. Bailey; Curcio, Christine A.; Zhang, Yuhua

2016-01-01

Purpose To investigate the microscopic structure of outer retinal tubulation (ORT) and optical properties of cone photoreceptors in vivo, we studied ORT appearance by multimodal imaging, including spectral domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO). Methods Four eyes of 4 subjects with advanced AMD underwent color fundus photography, infrared reflectance imaging, SD-OCT, and AOSLO with a high-resolution research instrument. ORT was identified in closely spaced (11 μm) SD-OCT volume scans. Results ORT in cross-sectional and en face SD-OCT was a hyporeflective area representing a lumen surrounded by a hyperreflective border consisting of cone photoreceptor mitochondria and external limiting membrane, per previous histology. In contrast, ORT by AOSLO was a hyporeflective structure of the same shape as in en face SD-OCT but lacking visualizable cone photoreceptors. Conclusion Lack of ORT cone reflectivity by AOSLO indicates that cones have lost their normal directionality and waveguiding property due to loss of outer segments and subsequent retinal remodeling. Reflective ORT cones by SD-OCT, in contrast, may depend partly on mitochondria as light scatterers within inner segments of these degenerating cells, a phenomenon enhanced by coherent imaging. Multimodal imaging of ORT provides insight into cone degeneration and reflectivity sources in OCT. PMID:27584549

Optical biosensors for cell adhesion.

PubMed

Ramsden, Jeremy J; Horvath, Robert

2009-01-01

Planar optical waveguides offer an ideal substratum for cells on which to reside. The materials from which the waveguides are made--high refractive index transparent dielectrics--correspond to the coatings of medical implants (e.g., the oxides of niobium, tantalum, and titanium) or the high molecular weight polymers used for culture flasks (e.g., polystyrene). The waveguides can furthermore be modified both chemically and morphologically while retaining their full capability for generating an evanescent optical field that has its greatest strength at the interface between the solid substratum and the liquid phase with which it is invariably in contact (i.e., the culture medium bathing the cells), decaying exponentially perpendicular to the interface at a rate controllable by varying the material parameters of the waveguide. Analysis of the perturbation of the evanescent field by the presence of living cells within it enables their size, number density, shape, refractive index (linked to their constitution) and so forth to be determined, the number of parameters depending on the number of waveguide lightmodes analyzed. No labeling of any kind is necessary, and convenient measurement setups are fully compatible with maintaining the cells in their usual environment. If the temporal evolution of the perturbation is analyzed, even more information can be obtained, such as the amount of material (microexudate) secreted by the cell while residing on the surface. Separation of parallel effects simultaneously contributing to the perturbation of the evanescent field can be accomplished by analysis of coupling peak shape when a grating coupler is used to measure the propagation constants of the waveguide lightmodes.

Process development for waveguide chemical sensors with integrated polymeric sensitive layers

NASA Astrophysics Data System (ADS)

Amberkar, Raghu; Gao, Zhan; Park, Jongwon; Henthorn, David B.; Kim, Chang-Soo

2008-02-01

Due to the proper optical property and flexibility in the process development, an epoxy-based, high-aspect ratio photoresist SU-8 is now attracting attention in optical sensing applications. Manipulation of the surface properties of SU-8 waveguides is critical to attach functional films such as chemically-sensitive layers. We describe a new integration process to immobilize fluorescence molecules on SU-8 waveguide surface for application to intensity-based optical chemical sensors. We use two polymers for this application. Spin-on, hydrophobic, photopatternable silicone is a convenient material to contain fluorophore molecules and to pattern a photolithographically defined thin layer on the surface of SU-8. We use fumed silica powders as an additive to uniformly disperse the fluorophores in the silicone precursor. In general, additional processes are not critically required to promote the adhesion between the SU-8 and silicone. The other material is polyethylene glycol diacrylate (PEGDA). Recently we demonstrated a novel photografting method to modify the surface of SU-8 using a surface bound initiator to control its wettability. The activated surface is then coated with a monomer precursor solution. Polymerization follows when the sample is exposed to UV irradiation, resulting in a grafted PEGDA layer incorporating fluorophores within the hydrogel matrix. Since this method is based the UV-based photografting reaction, it is possible to grow off photolithographically defined hydrogel patterns on the waveguide structures. The resulting films will be viable integrated components in optical bioanalytical sensors. This is a promising technique for integrated chemical sensors both for planar type waveguide and vertical type waveguide chemical sensors.

Coupling Ideality of Integrated Planar High-Q Microresonators

NASA Astrophysics Data System (ADS)

Pfeiffer, Martin H. P.; Liu, Junqiu; Geiselmann, Michael; Kippenberg, Tobias J.

2017-02-01

Chip-scale optical microresonators with integrated planar optical waveguides are useful building blocks for linear, nonlinear, and quantum-optical photonic devices alike. Loss reduction through improving fabrication processes results in several integrated microresonator platforms attaining quality (Q ) factors of several millions. Beyond the improvement of the quality factor, the ability to operate the microresonator with high coupling ideality in the overcoupled regime is of central importance. In this regime, the dominant source of loss constitutes the coupling to a single desired output channel, which is particularly important not only for quantum-optical applications such as the generation of squeezed light and correlated photon pairs but also for linear and nonlinear photonics. However, to date, the coupling ideality in integrated photonic microresonators is not well understood, in particular, design-dependent losses and their impact on the regime of high ideality. Here we investigate design-dependent parasitic losses described by the coupling ideality of the commonly employed microresonator design consisting of a microring-resonator waveguide side coupled to a straight bus waveguide, a system which is not properly described by the conventional input-output theory of open systems due to the presence of higher-order modes. By systematic characterization of multimode high-Q silicon nitride microresonator devices, we show that this design can suffer from low coupling ideality. By performing 3D simulations, we identify the coupling to higher-order bus waveguide modes as the dominant origin of parasitic losses which lead to the low coupling ideality. Using suitably designed bus waveguides, parasitic losses are mitigated with a nearly unity ideality and strong overcoupling (i.e., a ratio of external coupling to internal resonator loss rate >9 ) are demonstrated. Moreover, we find that different resonator modes can exchange power through the coupler, which, therefore, constitutes a mechanism that induces modal coupling, a phenomenon known to distort resonator dispersion properties. Our results demonstrate the potential for significant performance improvements of integrated planar microresonators for applications in quantum optics and nonlinear photonics achievable by optimized coupler designs.

Advances in flexible optrode hardware for use in cybernetic insects

NASA Astrophysics Data System (ADS)

Register, Joseph; Callahan, Dennis M.; Segura, Carlos; LeBlanc, John; Lissandrello, Charles; Kumar, Parshant; Salthouse, Christopher; Wheeler, Jesse

2017-08-01

Optogenetic manipulation is widely used to selectively excite and silence neurons in laboratory experiments. Recent efforts to miniaturize the components of optogenetic systems have enabled experiments on freely moving animals, but further miniaturization is required for freely flying insects. In particular, miniaturization of high channel-count optical waveguides are needed for high-resolution interfaces. Thin flexible waveguide arrays are needed to bend light around tight turns to access small anatomical targets. We present the design of lightweight miniaturized optogentic hardware and supporting electronics for the untethered steering of dragonfly flight. The system is designed to enable autonomous flight and includes processing, guidance sensors, solar power, and light stimulators. The system will weigh less than 200mg and be worn by the dragonfly as a backpack. The flexible implant has been designed to provide stimuli around nerves through micron scale apertures of adjacent neural tissue without the use of heavy hardware. We address the challenges of lightweight optogenetics and the development of high contrast polymer waveguides for this purpose.

Hollow waveguide for giant Er:YAG laser pulses transfer

NASA Astrophysics Data System (ADS)

Nemec, Michal; Jelinkova, Helena; Koranda, Petr; Cech, Miroslav; Sulc, Jan; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

2004-06-01

Short Er:YAG laser pulses were delivered by a cyclic olefin polymer coated silver hollow glass (COP/Ag) waveguide specially designed for a high power radiation. Er:YAG laser was Q-switched by an electro-optic shutter - LiNbO3 Pockels cell with Brewster angle cut input/output faces. The maximum energy output obtained from this system was 29 mJ with the length of pulse 69 ns corresponding to 420 kW output peak power. The system was working with the repetition rate of 1.5 Hz. A delivery system composed of a lens (f = 40 mm), protector and waveguide with the 700/850 μm diameter and 50 cm or 1 m length. The measured maximum delivered intensity was 86 MW/cm2 what corresponds to the transmission of 78.6 % for whole delivery system. Using of a sealed cap, this delivery system gives a possibility of the contact surgical treatment in many medicine branches, for example ophthalmology, urology or dentistry.

Investigating nonlinear distortion in the photopolymer materials

NASA Astrophysics Data System (ADS)

Malallah, Ra'ed; Cassidy, Derek; Muniraj, Inbarasan; Zhao, Liang; Ryle, James P.; Sheridan, John T.

2017-05-01

Propagation and diffraction of a light beam through nonlinear materials are effectively compensated by the effect of selftrapping. The laser beam propagating through photo-sensitive polymer PVA/AA can generate a waveguide of higher refractive index in direction of the light propagation. In order to investigate this phenomenon occurring in light-sensitive photopolymer media, the behaviour of a single light beam focused on the front surface of photopolymer bulk is investigated. As part of this work the self-bending of parallel beams separated in spaces during self-writing waveguides are studied. It is shown that there is strong correlation between the intensity of the input beams and their separation distance and the resulting deformation of waveguide trajectory during channels formation. This self-channeling can be modelled numerically using a three-dimension model to describe what takes place inside the volume of a photopolymer media. Corresponding numerical simulations show good agreement with experimental observations, which confirm the validity of the numerical model that was used to simulate these experiments.

Amphiphilic semiconducting polymer as multifunctional nanocarrier for fluorescence/photoacoustic imaging guided chemo-photothermal therapy.

PubMed

Jiang, Yuyan; Cui, Dong; Fang, Yuan; Zhen, Xu; Upputuri, Paul Kumar; Pramanik, Manojit; Ding, Dan; Pu, Kanyi

2017-11-01

Chemo-photothermal nanotheranostics has the advantage of synergistic therapeutic effect, providing opportunities for optimized cancer therapy. However, current chemo-photothermal nanotheranostic systems generally comprise more than three components, encountering the potential issues of unstable nanostructures and unexpected conflicts in optical and biophysical properties among different components. We herein synthesize an amphiphilic semiconducting polymer (PEG-PCB) and utilize it as a multifunctional nanocarrier to simplify chemo-photothermal nanotheranostics. PEG-PCB has a semiconducting backbone that not only serves as the diagnostic component for near-infrared (NIR) fluorescence and photoacoustic (PA) imaging, but also acts as the therapeutic agent for photothermal therapy. In addition, the hydrophobic backbone of PEG-PCB provides strong hydrophobic and π-π interactions with the aromatic anticancer drug such as doxorubicin for drug encapsulation and delivery. Such a trifunctionality of PEG-PCB eventually results in a greatly simplified nanotheranostic system with only two components but multimodal imaging and therapeutic capacities, permitting effective NIR fluorescence/PA imaging guided chemo-photothermal therapy of cancer in living mice. Our study thus provides a molecular engineering approach to integrate essential properties into one polymer for multimodal nanotheranostics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design Considerations for Monolithic Beam Formers Based on Electro-Optic Polymer Phase Modulators and Strain-Induced Optical Waveguides - Postprint

DTIC Science & Technology

2015-01-01

integrated circuit,” AFRL/SNDP Rome, NY (MIPR#F1ATA06317G002) (2007). [2] S-K. Kim, W. Yun, K. Geary, Y.-C. Hung, and H. R. Fetterman , “Electro-optic...Garner, H. Zhang, V. Chuyanov, L. R. Dalton, F. Wang, A. S. Ren, A. Zhang, G. Todorova, A. Harper, H. R. Fetterman , D. Chen, A. Upupa, D. Bhattacharya... Fetterman , “Push-pull electro-optic polymer modulators with half-wave voltage and low loss at both 1310 and 1550 nm,” Appl. Phys. Lett., 78, 3136-3138

Multimode-singlemode-multimode optical fiber sensor coated with novolac resin for detecting liquid phase alcohol

NASA Astrophysics Data System (ADS)

Marfu'ah, Amalia, Niza Rosyda; Hatta, Agus Muhamad; Pratama, Detak Yan

2018-04-01

Alcohol sensor based on multimode-singlemode-multimode (MSM) optical fiber with novolac resin as the external medium is proposed and demonstrated experimentally. Novolac resin swells when it is exposed by the alcohol. This effect causes a change in the polymer density leading to the refractive index's variation. The transmission light of the sensor depends on the refractive index of external medium. Based on the results, alcohol sensor based on MSM optical fiber structure using novolac resin has a higher sensitivity compared to the sensor without using novolac resin in the mixture of alcohol and distilled water. Alcohol sensor based on MSM optical fiber structure using novolac resin in the mixture of alcohol and distilled water with a singlemode fiber length of 5 mm has a sensitivity of 0.028972 dBm per % V/V, and in the mixture of alcohol and sugar solution of 10% w/w has a sensitivity of 0.005005 dBm per % V/V.

Design of optical metamaterial waveguide structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ortega-Moñux, Alejandro; Halir, Robert; Sánchez-Postigo, Alejandro; Soler-Penadés, Jordi; Ctyroký, Jirí; Luque-González, José Manuel; Sarmiento-Merenguel, José Darío.; Wangüemert-Pérez, Juan Gonzalo; Schmid, Jens H.; Xu, Dan-Xia; Janz, Sigfried; Lapointe, Jean; Molina-Fernández, Iñigo; Nedeljkovic, Milos; Mashanovich, Goran Z.; Cheben, Pavel

2017-05-01

Subwavelength gratings (SWGs) are periodic structures with a pitch (Λ) smaller than the wavelength of the propagating wave (λ), so that diffraction effects are suppressed. These structures thus behave as artificial metamaterials where the refractive index and the dispersion profile can be controlled with a proper design of the geometry of the structure. SWG waveguides have found extensive applications in the field of integrated optics, such as efficient fiber-chip couplers, broadband multimode interference (MMI) couplers, polarization beam splitters or evanescent field sensors, among others. From the point of view of nano-fabrication, the subwavelength condition (Λ << λ) is much easier to meet for long, mid-infrared wavelengths than for the comparatively short near-infrared wavelengths. Since most of the integrated devices based on SWGs have been proposed for the near-infrared, the true potential of subwavelength structures has not yet been completely exploited. In this talk we summarize some valuable guidelines for the design of high performance SWG integrated devices. We will start describing some practical aspects of the design, such as the range of application of semi-analytical methods, the rigorous electromagnetic simulation of Floquet modes, the relevance of substrate leakage losses and the effects of the random jitter, inherent to any fabrication process, on the performance of SWG structures. Finally, we will show the possibilities of the design of SWG structures with two different state-of-the-art applications: i) ultra-broadband MMI beam splitters with an operation bandwidth greater than 300nm for telecom wavelengths and ii) a set of suspended waveguides with SWG lateral cladding for mid-infrared applications, including low loss waveguides, MMI couplers and Mach-Zehnder interferometers.

Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, G.; Miller, R.; Ogden, L.

2016-09-05

Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrummore » with increasing frequency.« less

Widely tunable long-period waveguide grating couplers

NASA Astrophysics Data System (ADS)

Bai, Y.; Liu, Q.; Lor, K. P.; Chiang, K. S.

2006-12-01

We demonstrate experimentally two widely tunable optical couplers formed with parallel long-period polymer waveguide gratings. One of the couplers consists of two parallel gratings and shows a peak coupling efficiency of ~34%. The resonance wavelength of the coupler can be tuned thermally with a sensitivity of 4.7 nm/°C. The experimental results agree well with the coupled-mode analysis. The other coupler consists of an array of ten widely separated gratings. A peak coupling efficiency of ~11% is obtained between the two best matched gratings in the array and the resonance wavelength can be tuned thermally with a sensitivity of -3.8 nm/°C. These couplers have the potential to be further developed into practical broadband add/drop multiplexers and signal dividers.

Arbitrary-ratio power splitter based on nonlinear multimode interference coupler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tajaldini, Mehdi; Young Researchers and Elite Club, Baft Branch, Islamic Azad University, Baft; Jafri, Mohd Zubir Mat

2015-04-24

We propose an ultra-compact multimode interference (MMI) power splitter based on nonlinear effects from simulations using nonlinear modal propagation analysis (NMPA) cooperation with finite difference Method (FDM) to access free choice of splitting ratio. Conventional multimode interference power splitter could only obtain a few discrete ratios. The power splitting ratio may be adjusted continuously while the input set power is varying by a tunable laser. In fact, using an ultra- compact MMI with a simple structure that is launched by a tunable nonlinear input fulfills the problem of arbitrary-ratio in integrated photonics circuits. Silicon on insulator (SOI) is used asmore » the offered material due to the high contrast refractive index and Centro symmetric properties. The high-resolution images at the end of the multimode waveguide in the simulated power splitter have a high power balance, whereas access to a free choice of splitting ratio is not possible under the linear regime in the proposed length range except changes in the dimension for any ratio. The compact dimensions and ideal performance of the device are established according to optimized parameters. The proposed regime can be extended to the design of M×N arbitrary power splitters ratio for programmable logic devices in all optical digital signal processing. The results of this study indicate that nonlinear modal propagation analysis solves the miniaturization problem for all-optical devices based on MMI couplers to achieve multiple functions in a compact planar integrated circuit and also overcomes the limitations of previously proposed methods for nonlinear MMI.« less

Accurate core position control in polymer optical waveguides using the Mosquito method for three-dimensional optical wiring

NASA Astrophysics Data System (ADS)

Date, Kumi; Ishigure, Takaaki

2017-02-01

Polymer optical waveguides with graded-index (GI) circular cores are fabricated using the Mosquito method, in which the positions of parallel cores are accurately controlled. Such an accurate arrangement is of great importance for a high optical coupling efficiency with other optical components such as fiber ribbons. In the Mosquito method that we developed, a core monomer with a viscous liquid state is dispensed into another liquid state monomer for cladding via a syringe needle. Hence, the core positions are likely to shift during or after the dispensing process due to several factors. We investigate the factors, specifically affecting the core height. When the core and cladding monomers are selected appropriately, the effect of the gravity could be negligible, so the core height is maintained uniform, resulting in accurate core heights. The height variance is controlled in +/-2 micrometers for the 12 cores. Meanwhile, larger shift in the core height is observed when the needle-tip position is apart from the substrate surface. One of the possible reasons of the needle-tip height dependence is the asymmetric volume contraction during the monomer curing. We find a linear relationship between the original needle-tip height and the core-height observed. This relationship is implemented in the needle-scan program to stabilize the core height in different layers. Finally, the core heights are accurately controlled even if the cores are aligned on various heights. These results indicate that the Mosquito method enables to fabricate waveguides in which the cores are 3-dimensionally aligned with a high position accuracy.

Toward photostable multiplex analyte detection on a single mode planar optical waveguide

NASA Astrophysics Data System (ADS)

Mukundan, Harshini; Xie, Hongzhi; Anderson, Aaron; Grace, W. Kevin; Martinez, Jennifer S.; Swanson, Basil

2009-02-01

We have developed a waveguide-based optical biosensor for the sensitive and specific detection of biomarkers associated with disease. Our technology combines the superior optical properties of single-mode planar waveguides, the robust nature of functionalized self-assembled monolayer sensing films and the specificity of fluorescence sandwich immunoassays to detect biomarkers in complex biological samples such as serum, urine and sputum. We have previously reported the adaptation of our technology to the detection of biomarkers associated with breast cancer and anthrax. However, these approaches primarily used phospholipid bilayers as the functional film and organic dyes (ex: AlexaFluors) as the fluorescence reporter. Organic dyes are easily photodegraded and are not amenable to multiplexing because of their narrow Stokes' shift. Here we have developed strategies for conjugation of the detector antibodies with quantum dots for use in a multiplex detection platform. We have previously evaluated dihydroxylipoic acid quantum dots for the detection of a breast cancer biomarker. In this manuscript, we investigate the detection of the Bacillus anthracis protective antigen using antibodies conjugated with polymer-coated quantum dots. Kinetics of binding on the waveguide-based biosensor is reported. We compare the sensitivity of quantum dot labeled antibodies to those labeled with AlexaFluor and demonstrate the photostability of the former in our assay platform. In addition, we compare sulfydryl labeling of the antibody in the hinge region to that of nonspecific amine labeling. This is but the first step in developing a multiplex assay for such biomarkers on our waveguide platform.

Structural and waveguiding characteristics of Er3+:Yb3Al5-yGayO12 films grown by the liquid phase epitaxy

NASA Astrophysics Data System (ADS)

Hlásek, T.; Rubešová, K.; Jakeš, V.; Nekvindová, P.; Kučera, M.; Daniš, S.; Veis, M.; Havránek, V.

2015-11-01

Erbium (Er3+) doped ytterbium garnet (Er:Yb3Al5-yGayO12; y = 0, 0.55 and 1.1) single crystalline thick films have been grown by the low-temperature liquid phase epitaxy method (LPE). The composition of the films was determined using the high resolution XRD, the particle-induced X-ray emission spectroscopy (PIXE) and the particle-induced gamma-ray emission spectroscopy (PIGE). The lattice mismatch between films and substrates was investigated by the high-resolution X-ray diffraction. The surface analysis was carried out by the atomic force microscopy (AFM). Pure infrared emission of Er3+ ions was observed in all films containing gallium. The characteristics such as refractive index, thickness and light propagation were studied by the m-line spectroscopy (MLS) using several wavelengths (633, 964, 1311 and 1552 nm). All samples, where y = 1.1, were multimode waveguides. For these reasons, the Er:Yb3Al3.9Ga1.1O12 seems to be a promising material for light amplifiers in the IR region.

Tunable in-line fiber optic comb filter using a side-polished single-mode fiber coupler with LiNbO 3 overlay and intermediate coupling layer

NASA Astrophysics Data System (ADS)

Sohn, Kyung-Rak; Song, Jae-Won

2002-03-01

Using a side-polished single-mode fiber covered with a polished LiNbO 3 overlay and an intermediate coupling layer, tunable fiber-optic comb filters are demonstrated. The device behaviors based on the modal properties of the fiber and the planar LiNbO 3 waveguide are analyzed by two dimensional beam propagation methods (2-D BPM) and discussed the role of an intermediate coupling layer in terms of coupling efficiency. We also show that the thermo-optic effects of this layer can be utilized to tune the comb filter. When the polished x-cut LiNbO 3 with 200 μm thickness is used as a multimode overlay waveguide, the comb output spectra with free spectral range of 4 nm are measured in 1550 nm wavelength range. The tuning rate as a function of the refractive index of an intermediate coupling layer, Δλ/ Δnb, is about -0.129 nm/-0.001. The experimental results are in good agreement with the calculated results.

Nano-composite insert in 1D waveguides for control of elastic power flow

NASA Astrophysics Data System (ADS)

Vignesh, P. S.; Mitra, Mira; Gopalakrishnan, S.

2007-01-01

In this paper, carbon nanotube embedded polymer composite/nano-composites are used to regulate power flow from its source to other parts of the structure. This is done by inserting nano-composite strips in the waveguides which are modelled here as isotropic Euler-Bernoulli beams with axial, transverse and rotational degrees of freedom. The power flow is due to wave propagation resulting from a high frequency broadband impulse load. The underlying concept is that the high stiffness of the insert reduces the wave transmission between different parts of the structures. The simulations are done using a wavelet based spectral finite element (WSFE) technique which is specially tailored for such high frequency wave propagation analysis. Numerical experiments are performed to illustrate the use of inserts in maintaining the power flow in a certain region of the structure below a given threshold value which may be specified depending on various applications. The effects of parameters such as the volume fraction of carbon nanotube (CNT) in the polymer, and the length and position of the inserts are also studied. These studies help in defining the optimal volume fraction of CNT and length of the insert for a specified structural configuration.

Low Loss Graded Index Polymer Optical Fiber for Local Networking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claus, Richard Otto

The objective of this Department of Energy SBIR program has been to develop technology for the advancement of advanced computing systems. NanoSonic worked with two subcontractors, the Polymicro Division of Molex, a U.S.-based manufacturer of specialized optical fiber and fiber components, and Virginia Tech, a research university involved through the Global Environment for Network Innovations (GENI) program in high-speed computer networking research. NanoSonic developed a patented molecular-level self-assembly process to manufacture polymer-based optical fibers in a way similar to the modified chemical vapor deposition (MCVD) approach typically used to make glass optical fibers. Although polymer fiber has a higher attenuationmore » per unit length than glass fiber, short connectorized polymer fiber jumpers offer significant cost savings over their glass counterparts, particularly due to the potential use of low-cost plastic fiber connectors. As part of the SBIR commercialization process, NanoSonic exclusively licensed this technology to a large ($100B+ market cap) U.S.-based manufacturing conglomerate near the end of the first year of the Phase II program. With this base technology developed and licensed, NanoSonic then worked with Polymicro to address secondary program goals of using related but not conflicting production methods to enhance the performance of other specialty optical fiber products and components, and Virginia Tech continued its evaluation of developed polymer fibers in its network infrastructure system on the university campus. We also report our current understanding of the observation during the Phase I program of quantum conductance and partial quantum conductance in metal-insulator-metal (MIM) devices. Such conductance behavior may be modeled as singlemode behavior in one-dimensional electrically conducting waveguides, similar in principle to singlemode optical propagation in dielectric fiber waveguides. Although NanoSonic has not licensed any of the additional technology developed during the second year of the program, several proprietary discussions with major materials companies are underway as of the conclusion of Phase II.« less

Polymeric variable optical attenuators based on magnetic sensitive stimuli materials

NASA Astrophysics Data System (ADS)

de Pedro, S.; Cadarso, V. J.; Ackermann, T. N.; Muñoz-Berbel, X.; Plaza, J. A.; Brugger, J.; Büttgenbach, S.; Llobera, A.

2014-12-01

Magnetically-actuable, polymer-based variable optical attenuators (VOA) are presented in this paper. The design comprises a cantilever which also plays the role of a waveguide and the input/output alignment elements for simple alignment, yet still rendering an efficient coupling. Magnetic properties have been conferred to these micro-opto-electromechanical systems (MOEMS) by implementing two different strategies: in the first case, a magnetic sensitive stimuli material (M-SSM) is obtained by a combination of polydimethylsiloxane (PDMS) and ferrofluid (FF) in ratios between 14.9 wt % and 29.9 wt %. An M-SSM strip under the waveguide-cantilever, defined with soft lithography (SLT), provides the required actuation capability. In the second case, specific volumes of FF are dispensed at the end of the cantilever tip (outside the waveguide) by means of inkjet printing (IJP), obtaining the required magnetic response while holding the optical transparency of the waveguide-cantilever. In the absence of a magnetic field, the waveguide-cantilever is aligned with the output fiber optics and thus the intrinsic optical losses can be obtained. Numerical simulations, validated experimentally, have shown that, for any cantilever length, the VOAs defined by IJP present lower intrinsic optical losses than their SLT counterparts. Under an applied magnetic field (Bapp), both VOA configurations experience a misalignment between the waveguide-cantilever and the output fiber optics. Thus, the proposed VOAs modulate the output power as a function of the cantilever displacement, which is proportional to Bapp. The experimental results for the three different waveguide-cantilever lengths and six different FF concentrations (three per technology) show maximum deflections of 220 µm at 29.9 wt % of FF for VOASLT and 250 µm at 22.3 wt % FF for VOAIJP, at 0.57 kG for both. These deflections provide maximum actuation losses of 16.1 dB and 18.9 dB for the VOASLT and VOAIJP, respectively.

The Talbot effect in a metamaterial

NASA Astrophysics Data System (ADS)

Nikkhah, H.; Hasan, M.; Hall, T. J.

2018-02-01

The effect of anisotropy and spatial dispersion of a metamaterial on the Talbot effect may be engineered in principle. This has profound implications for applications of the Talbot effect such as the design of a multimode interference coupler (MMI). The paper describes how a metamaterial can suppress the modal phase error which otherwise limits the scaling of MMI port dimension. A binary multilayer dielectric material described by the Kronig-Penney model is shown to provide a close approximation to the required dispersion relation. Results of simulations of a multi-slotted waveguide MMI engineered to provide a polarising beam splitter function are given as an example of the method.

The Role of Morphology and Electronic Chain Aggregation on the Optical Gain Properties of Semiconducting Conjugated Polymers

NASA Astrophysics Data System (ADS)

Lampert, Zachary Evan

Conjugated polymers (CPs) are a novel class of materials that exhibit the optical and electrical properties of semiconductors while still retaining the durability and processability of plastics. CPs are also intrinsically 4-level systems with high luminescence quantum efficiencies making them particularly attractive as organic gain media for solid-state laser applications. However, before CPs can emerge as a commercially available laser technology, a more comprehensive understanding of the morphological dependence of the photophysics is required. In this thesis, the morphology and chain conformation dependence of amplified spontaneous emission (ASE) and optical gain in thin films of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) was investigated. By changing the chemical nature of the solvent from which films were cast, as well as the temperature at which films were annealed, CP films with different morphologies, and hence different degrees of interchain interactions were achieved. Contrary to the common perception that polymer morphology plays a decisive role in determining the ASE behavior of thin CP films, we found that chromophore aggregation and degree of conformational order have minimal impact on optical gain. In fact, experimental results indicated that an extremely large fraction of interchain aggregate species and/or exciton dissociating defects are required to significantly alter the optical properties and suppress stimulated emission. These results are pertinent to the fabrication and optimization of an electrically pumped laser device, as improvements in charge carrier mobility through controlled increases in chain aggregation may provide a viable means of optimizing injection efficiency without significantly degrading optical gain. To offset charge-induced absorption losses under electrical pumping, and to enable the use of more compact and economical sources under optical pumping, conjugated polymers exhibiting low lasing thresholds and large net gains are highly desirable. In this thesis, we also discuss novel routes we developed for enhancement of ASE performance in MEH-PPV thin film planar waveguides. The first technique relied on improving the distribution of the TE0 guided mode in the CP gain layer through optimization of waveguide architecture. This was achieved by fabricating symmetric heterostructure waveguides formed from a core layer of MEH-PPV sandwiched between an SiO2 buffer and index matched poly(methyl methacrylate) (PMMA) cover layer. Relative to asymmetric waveguides of Si(100)/SiO2/MEH-PPV/Air, symmetric waveguides exhibited increased optical confinement and reduced propagation loss enabling lower ASE threshold (40%) and higher net gain (50%). Independent of device architecture and degree of aggregation in the films, we discovered that optical gain is also highly dependent on the excitation conditions, specifically the temporal width of the pump laser pulses. A 400% increase in net gain was achieved under transient (25 picosecond pulses), compared to quasi-steady state (8 nanosecond pulses), excitation conditions. This large difference is attributed to low pumping efficiency and increased non-radiative recombination under ns pumping, which reduces the emission cross-section resulting in a net decrease in gain. The gain values we achieved in the ps regime are to the best of our knowledge the largest gain values reported to date for thin conjugated polymer films measured using the variable stripe length (VSL) technique. Films pumped in the transient regime also required 30 times less pump energy density to reach threshold in comparison with films pumped in the quasi-steady state regime, although the excited state densities were essentially the same. These results demonstrate that the pumping efficiency, and hence generation rate of excited states in a gain medium, can be dramatically increased by using pump laser pulses that are shorter than the exciton luminescence lifetime

Silicon Photonics: All-Optical Devices for Linear and Nonlinear Applications

NASA Astrophysics Data System (ADS)

Driscoll, Jeffrey B.

Silicon photonics has grown rapidly since the first Si electro-optic switch was demonstrated in 1987, and the field has never grown more quickly than it has over the past decade, fueled by milestone achievements in semiconductor processing technologies for low loss waveguides, high-speed Si modulators, Si lasers, Si detectors, and an enormous toolbox of passive and active integrated devices. Silicon photonics is now on the verge of major commercialization breakthroughs, and optical communication links remain the force driving integrated and Si photonics towards the first commercial telecom and datacom transceivers; however other potential and future applications are becoming uncovered and refined as researchers reveal the benefits of manipulating photons on the nanoscale. This thesis documents an exploration into the unique guided-wave and nonlinear properties of deeply-scaled high-index-contrast sub-wavelength Si waveguides. It is found that the tight confinement inherent to single-mode channel waveguides on the silicon-on-insulator platform lead to a rich physics, which can be leveraged for new devices extending well beyond simple passive interconnects and electro-optic devices. The following chapters will concentrate, in detail, on a number of unique physical features of Si waveguides and extend these attributes towards new and interesting devices. Linear optical properties and nonlinear optical properties are investigated, both of which are strongly affected by tight optical confinement of the guided waveguide modes. As will be shown, tight optical confinement directly results in strongly vectoral modal components, where the electric and magnetic fields of the guided modes extend into all spatial dimensions, even along the axis of propagation. In fact, the longitudinal electric and magnetic field components can be just as strong as the transverse fields, directly affecting the modal group velocity and energy transport properties since the longitudinal fields are shown to contribute no time-averaged momentum. Furthermore, the vectoral modal components, in conjunction with the tensoral nature of the third-order susceptibility of Si, lead to nonlinear properties which are dependent on waveguide orientation with respect to the Si parent crystal and the construction of the modal electric field components. This consideration is used to maximize effective nonlinearity and realize nonlinear Kerr gratings along specific waveguide trajectories. Tight optical confinement leads to a natural enhancement of the intrinsically large effective nonlinearty of Si waveguides, and in fact, the effective nonlinearty can be made to be almost 106 times greater in Si waveguides than that of standard single-mode fiber. Such a large nonlinearity motivates chip-scale all-optical signal processing techniques. Wavelength conversion by both four-wave-mixing (FWM) and cross-phase-modulation (XPM) will be discussed, including a technique that allows for enhanced broadband discrete FWM over arbitrary spectral spans by modulating both the linear and nonlinear waveguide properties through periodic changes in waveguide geometry. This quasi-phase-matching approach has very real applications towards connecting mature telecom sources detectors and components to other spectral regimes, including the mid-IR. Other signal processing techniques such as all-optical modulation format conversion via XPM will also be discussed. This thesis will conclude by looking at ways to extend the bandwidth capacity of Si waveguide interconnects on chip. As the number of processing cores continues to scale as a means for computational performance gains, on-chip link capacity will become an increasingly important issue. Metallic traces have severe limitations and are envisioned to eventually bow to integrated photonic links. The aggregate bandwidth supported by a single waveguide link will therefore become a crucial consideration as integrated photonics approaches the CPU. One way to increase aggregate bandwidth is to utilize different eigen-modes of a multimode waveguide, and integrated waveguide mode-muxes and demuxes for achieving simultaneous mode-division-multiplexing and wavelength-division-multiplexing will be demonstrated.

Combined electromagnetic and photoreaction modeling of CLD-1 photobleaching in polymer microring resonators

NASA Astrophysics Data System (ADS)

Huang, Yanyi; Poon, Joyce K. S.; Liang, Wei; Yariv, Amnon; Zhang, Cheng; Dalton, Larry R.

2005-08-01

By combining a solid-state photoreaction model with the modal solutions of an optical waveguide, we simulate the refractive index change due to the photobleaching of CLD-1 chromophores in an amorphous polycarbonate microring resonator. The simulation agrees well with experimental results. The photobleaching quantum efficiency of the CLD-1 chromophores is determined to be 0.65%. The combined modeling of the electromagnetic wave propagation and photoreaction precisely illustrates the spatial and temporal evolution of the optical properties of the polymer material as manifested in the refractive index and their effects on the modal and physical properties of the optical devices.

Flexible Transient Optical Waveguides and Surface-Wave Biosensors Constructed from Monocrystalline Silicon.

PubMed

Bai, Wubin; Yang, Hongjun; Ma, Yinji; Chen, Hao; Shin, Jiho; Liu, Yonghao; Yang, Quansan; Kandela, Irawati; Liu, Zhonghe; Kang, Seung-Kyun; Wei, Chen; Haney, Chad R; Brikha, Anlil; Ge, Xiaochen; Feng, Xue; Braun, Paul V; Huang, Yonggang; Zhou, Weidong; Rogers, John A

2018-06-26

Optical technologies offer important capabilities in both biological research and clinical care. Recent interest is in implantable devices that provide intimate optical coupling to biological tissues for a finite time period and then undergo full bioresorption into benign products, thereby serving as temporary implants for diagnosis and/or therapy. The results presented here establish a silicon-based, bioresorbable photonic platform that relies on thin filaments of monocrystalline silicon encapsulated by polymers as flexible, transient optical waveguides for accurate light delivery and sensing at targeted sites in biological systems. Comprehensive studies of the mechanical and optical properties associated with bending and unfurling the waveguides from wafer-scale sources of materials establish general guidelines in fabrication and design. Monitoring biochemical species such as glucose and tracking physiological parameters such as oxygen saturation using near-infrared spectroscopic methods demonstrate modes of utility in biomedicine. These concepts provide versatile capabilities in biomedical diagnosis, therapy, deep-tissue imaging, and surgery, and suggest a broad range of opportunities for silicon photonics in bioresorbable technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dual nature of localization in guiding systems with randomly corrugated boundaries: Anderson-type versus entropic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarasov, Yu.V., E-mail: yutarasov@ire.kharkov.ua; Shostenko, L.D.

A unified theory for the conductance of an infinitely long multimode quantum wire whose finite segment has randomly rough lateral boundaries is developed. It enables one to rigorously take account of all feasible mechanisms of wave scattering, both related to boundary roughness and to contacts between the wire rough section and the perfect leads within the same technical frameworks. The rough part of the conducting wire is shown to act as a mode-specific randomly modulated effective potential barrier whose height is governed essentially by the asperity slope. The mean height of the barrier, which is proportional to the average slopemore » squared, specifies the number of conducting channels. Under relatively small asperity amplitude this number can take on arbitrary small, up to zero, values if the asperities are sufficiently sharp. The consecutive channel cut-off that arises when the asperity sharpness increases can be regarded as a kind of localization, which is not related to the disorder per se but rather is of entropic or (equivalently) geometric origin. The fluctuating part of the effective barrier results in two fundamentally different types of guided wave scattering, viz., inter- and intramode scattering. The intermode scattering is shown to be for the most part very strong except in the cases of (a) extremely smooth asperities, (b) excessively small length of the corrugated segment, and (c) the asperities sharp enough for only one conducting channel to remain in the wire. Under strong intermode scattering, a new set of conducting channels develops in the corrugated waveguide, which have the form of asymptotically decoupled extended modes subject to individual solely intramode random potentials. In view of this fact, two transport regimes only are realizable in randomly corrugated multimode waveguides, specifically, the ballistic and the localized regime, the latter characteristic of one-dimensional random systems. Two kinds of localization are thus shown to coexist in waveguide-like systems with randomly corrugated boundaries, specifically, the entropic localization and the one-dimensional Anderson (disorder-driven) localization. If the particular mode propagates across the rough segment ballistically, the Fabry–Pérot-type oscillations should be observed in the conductance, which are suppressed for the mode transferred in the Anderson-localized regime.« less

Optofluidic devices for biomolecule sensing and multiplexing

NASA Astrophysics Data System (ADS)

Ozcelik, Damla

Optofluidics which integrates photonics and microfluidics, has led to highly compact, sensitive and adaptable biomedical sensors. Optofluidic biosensors based on liquid-core anti-resonant reflecting optical waveguides (LC-ARROWs), have proven to be a highly sensitive, portable, and reconfigurable platform for fluorescence spectroscopy and detection of single biomolecules such as proteins, nucleic acids, and virus particles. However, continued improvements in sensitivity remain a major goal as we approach the ultimate limit of detecting individual bio-particles labeled by single or few fluorophores. Additionally, the ability to simultaneously detect and identify multiple biological particles or biomarkers is one of the key requirements for molecular diagnostic tests. The compactness and adaptability of these platforms can further be advanced by introducing tunability, integrating off-chip components, designing reconfigurable and customizable devices, which makes these platforms very good candidates for many different applications. The goal of this thesis was to introduce new elements in these LC-ARROW optofluidics platforms that provide major enhancements in their functionality, making them more sensitive, compact, customizable and multiplexed. First, a novel integrated tunable spectral filter that achieves effective elimination of background noise on the ARROW platform was demonstrated. A unique dual liquid-core design enabled the independent multi-wavelength tuning of the spectral filter by adjusting the refractive index and chemical properties of the liquid. In order to enhance the detection sensitivity of the platform, Y-splitter waveguides were integrated to create multiple excitation spots for each target molecule. A powerful signal processing algorithm was used to analyze the data to improve the signal-to-noise ratio (SNR) of the collected data. Next, the design, optimization and characterization of the Y-splitter waveguides are presented; and single influenza virus detection with an improved SNR was demonstrated using this platform. Finally, multiplexing capacity is introduced to the ARROW detection platform by integrating multi-mode interference (MMI) waveguides. MMI waveguides create wavelength dependent multiple excitation spots at the excitation region, allowing the spectral multiplexed detection of multiple different target molecules based on the excitation pattern, without the need for additional spectral filters. Successful spectral multiplexed detection of three different types of influenza viruses is achieved by using separate wavelengths and combination of wavelengths. This multiplexing capacity is further enhanced by taking advantage of the spatial properties of the MMI pattern, designing triple liquid-core waveguides that intersect the MMI waveguide in different locations. Furthermore, the spectral and spatial multiplexing capacities are combined in these triple liquid-core MMI platforms, allowing these devices to distinguish multiple different targets and samples simultaneously.

Demonstration of a stand-alone cylindrical fiber coil for optical amplifiers

NASA Astrophysics Data System (ADS)

Laxton, Steven R.; Bravo, Tyler; Madsen, Christi K.

2015-08-01

The design, fabrication and measurement of a cylindrical fiber coil structure is presented that has applications for compact fiber-optic amplifiers. A multimode fiber is used as a surrogate for a dual clad, rare-earth doped fiber for coil fabrication and optical testing. A ray trace algorithm, written in Python, was used to simulate the behavior of light travelling along the waveguide path. An in-house fabrication method was developed using 3D printed parts designed in SolidWorks and assembled with Arduino-controlled stepper motors for coil winding. Ultraviolet-cured epoxy was used to bind the coils into a rigid cylinder. Bend losses are introduced by the coil, and a measurement of the losses for two coil lengths was obtained experimentally. The measurements confirm that bend losses through a multimode fiber, representative of pump light propagating in a dual-clad rare-earth doped fiber, are relatively wavelength independent over a large spectral range and that higher order modes are extinguished quickly while lower order modes transmit through the windings with relatively low loss.

Space-division-multiplexed transmission of 3x3 multiple-input multiple-output wireless signals over conventional graded-index multimode fiber.

PubMed

Lei, Yi; Li, Jianqiang; Fan, Yuting; Yu, Dawei; Fu, Songnian; Yin, Feifei; Dai, Yitang; Xu, Kun

2016-12-12

In this paper, we experimentally demonstrate space-division-multiplexed (SDM) transmission of IEEE 802.11ac-compliant 3-spatial-stream WLAN signals over 3 spatial modes of conventional 50um graded-index (GI) multimode fiber (MMF) employing non-mode-selective 3D-waveguide photonic lantern. Two kinds of scenarios, including fiber-only transmission and fiber-wireless hybrid transmission, were investigated by measuring error vector magnitude (EVM) performance for each stream and condition number (CN) of the channel matrix. The experimental results show that, SDM-based MMF link could offer a CN< 20dB well-conditioned MIMO channel over up to 1km fiber length within 0-6GHz, achieving as low as 2.38%, 2.97% and 2.11% EVM performance for 1km MMF link at 2.4GHz, 5.8GHz, and 200m MMF link followed by 1m air distance at 2.7GHz, respectively. These results indicate the possibility to distribute wireless MIMO signals over existing in-building commercially-available MMFs with enormous cost-saving.

An acousto-optic sensor based on resonance grating waveguide structure

PubMed Central

Xie, Antonio Jou; Song, Fuchuan; Seo, Sang-Woo

2014-01-01

This paper presents an acousto-optic (AO) sensor based on resonance grating waveguide structure. The sensor is fabricated using elastic polymer materials to achieve a good sensitivity to ultrasound pressure waves. Ultrasound pressure waves modify the structural parameters of the sensor and result in the optical resonance shift of the sensor. This converts into a light intensity modulation. A commercial ultrasound transducer at 20 MHz is used to characterize a fabricated sensor and detection sensitivity at different optical source wavelength within a resonance spectrum is investigated. Practical use of the sensor at a fixed optical source wavelength is presented. Ultimately, the geometry of the planar sensor structure is suitable for two-dimensional, optical pressure imaging applications such as pressure wave detection and mapping, and ultrasound imaging. PMID:25045203

Giant nonlinear response at a plasmonic nanofocus drives efficient four-wave mixing

NASA Astrophysics Data System (ADS)

Nielsen, Michael P.; Shi, Xingyuan; Dichtl, Paul; Maier, Stefan A.; Oulton, Rupert F.

2017-12-01

Efficient optical frequency mixing typically must accumulate over large interaction lengths because nonlinear responses in natural materials are inherently weak. This limits the efficiency of mixing processes owing to the requirement of phase matching. Here, we report efficient four-wave mixing (FWM) over micrometer-scale interaction lengths at telecommunications wavelengths on silicon. We used an integrated plasmonic gap waveguide that strongly confines light within a nonlinear organic polymer. The gap waveguide intensifies light by nanofocusing it to a mode cross-section of a few tens of nanometers, thus generating a nonlinear response so strong that efficient FWM accumulates over wavelength-scale distances. This technique opens up nonlinear optics to a regime of relaxed phase matching, with the possibility of compact, broadband, and efficient frequency mixing integrated with silicon photonics.

Nonlinear optical polymers for electro-optic signal processing

NASA Technical Reports Server (NTRS)

Lindsay, Geoffrey A.

1991-01-01

Photonics is an emerging technology, slated for rapid growth in communications systems, sensors, imagers, and computers. Its growth is driven by the need for speed, reliability, and low cost. New nonlinear polymeric materials will be a key technology in the new wave of photonics devices. Electron-conjubated polymeric materials offer large electro-optic figures of merit, ease of processing into films and fibers, ruggedness, low cost, and a plethora of design options. Several new broad classes of second-order nonlinear optical polymers were developed at the Navy's Michelson Laboratory at China Lake, California. Polar alignment in thin film waveguides was achieved by electric-field poling and Langmuir-Blodgett processing. Our polymers have high softening temperatures and good aging properties. While most of the films can be photobleached with ultraviolet (UV) light, some have excellent stability in the 500-1600 nm range, and UV stability in the 290-310 nm range. The optical nonlinear response of these polymers is subpicosecond. Electro-optic switches, frequency doublers, light modulators, and optical data storage media are some of the device applications anticipated for these polymers.

Smoothing Polymer Surfaces by Solvent-Vapor Exposure

NASA Astrophysics Data System (ADS)

Anthamatten, Mitchell

2003-03-01

Ultra-smooth polymer surfaces are of great importance in a large body of technical applications such as optical coatings, supermirrors, waveguides, paints, and fusion targets. We are investigating a simple approach to controlling surface roughness: by temporarily swelling the polymer with solvent molecules. As the solvent penetrates into the polymer, its viscosity is lowered, and surface tension forces drive surface flattening. To investigate sorption kinetics and surface-smoothing phenomena, a series of vapor-deposited poly(amic acid) films were exposed to dimethyl sulfoxide vapors. During solvent exposure, the surface topology was continuously monitored using light interference microscopy. The resulting power spectra indicate that high-frequency defects smooth faster than low-frequency defects. This frequency dependence was studied by depositing polymer films onto a series of 2D sinusoidal surfaces and performing smoothing experiments. Results show that the amplitudes of the sinusoidal surfaces decay exponentially with solvent exposure time, and the exponential decay constants are proportional to surface frequency. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Deep proton writing of high aspect ratio SU-8 micro-pillars on glass

NASA Astrophysics Data System (ADS)

Ebraert, Evert; Rwamucyo, Ben; Thienpont, Hugo; Van Erps, Jürgen

2016-12-01

Deep proton writing (DPW) is a fabrication technology developed for the rapid prototyping of polymer micro-structures. We use SU-8, a negative resist, spincoated in a layer up to 720 μm-thick in a single step on borosilicate glass, for irradiation with a collimated 12 MeV energy proton beam. Micro-pillars with a slightly conical profile are irradiated in the SU-8 layer. We determine the optimal proton fluence to be 1.02 × 104 μm-2, with which we are able to repeatably achieve micro-pillars with a top-diameter of 138 ± 1 μm and a bottom-diameter of 151 ± 3 μm. The smallest fabricated pillars have a top-diameter of 57 ± 5 μm. We achieved a root-mean-square sidewall surface roughness between 19 nm and 35 nm for the fabricated micro-pillars, measured over an area of 5 × 63.7 μm. We briefly discuss initial testing of two potential applications of the fabricated micro-pillars. Using ∼100 μm-diameter pillars as waveguides for gigascale integration optical interconnect applications, has shown a 4.7 dB improvement in optical multimode fiber-to-fiber coupling as compared to the case where an air-gap is present between the fibers at the telecom wavelength of 1550 nm. The ∼140 μm-diameter pillars were used for mold fabrication with silicone casting. The resulting mold can be used for hydrogel casting, to obtain hydrogel replicas mimicking human tissue for in vitro bio-chemical applications.

Design and process development of a photonic crystal polymer biosensor for point-of-care diagnostics

NASA Astrophysics Data System (ADS)

Dortu, F.; Egger, H.; Kolari, K.; Haatainen, T.; Furjes, P.; Fekete, Z.; Bernier, D.; Sharp, G.; Lahiri, B.; Kurunczi, S.; Sanchez, J.-C.; Turck, N.; Petrik, P.; Patko, D.; Horvath, R.; Eiden, S.; Aalto, T.; Watts, S.; Johnson, N. P.; De La Rue, R. M.; Giannone, D.

2011-07-01

In this work, we report advances in the fabrication and anticipated performance of a polymer biosensor photonic chip developed in the European Union project P3SENS (FP7-ICT4-248304). Due to the low cost requirements of point-ofcare applications, the photonic chip is fabricated from nanocomposite polymeric materials, using highly scalable nanoimprint- lithography (NIL). A suitable microfluidic structure transporting the analyte solutions to the sensor area is also fabricated in polymer and adequately bonded to the photonic chip. We first discuss the design and the simulated performance of a high-Q resonant cavity photonic crystal sensor made of a high refractive index polyimide core waveguide on a low index polymer cladding. We then report the advances in doped and undoped polymer thin film processing and characterization for fabricating the photonic sensor chip. Finally the development of the microfluidic chip is presented in details, including the characterisation of the fluidic behaviour, the technological and material aspects of the 3D polymer structuring and the stable adhesion strategies for bonding the fluidic and the photonic chips, with regards to the constraints imposed by the bioreceptors supposedly already present on the sensors.

Design optimization of integrated BiDi triplexer optical filter based on planar lightwave circuit.

PubMed

Xu, Chenglin; Hong, Xiaobin; Huang, Wei-Ping

2006-05-29

Design optimization of a novel integrated bi-directional (BiDi) triplexer filter based on planar lightwave circuit (PLC) for fiber-to-the premise (FTTP) applications is described. A multi-mode interference (MMI) device is used to filter the up-stream 1310nm signal from the down-stream 1490nm and 1555nm signals. An array waveguide grating (AWG) device performs the dense WDM function by further separating the two down-stream signals. The MMI and AWG are built on the same substrate with monolithic integration. The design is validated by simulation, which shows excellent performance in terms of filter spectral characteristics (e.g., bandwidth, cross-talk, etc.) as well as insertion loss.

Design optimization of integrated BiDi triplexer optical filter based on planar lightwave circuit

NASA Astrophysics Data System (ADS)

Xu, Chenglin; Hong, Xiaobin; Huang, Wei-Ping

2006-05-01

Design optimization of a novel integrated bi-directional (BiDi) triplexer filter based on planar lightwave circuit (PLC) for fiber-to-the premise (FTTP) applications is described. A multi-mode interference (MMI) device is used to filter the up-stream 1310nm signal from the down-stream 1490nm and 1555nm signals. An array waveguide grating (AWG) device performs the dense WDM function by further separating the two down-stream signals. The MMI and AWG are built on the same substrate with monolithic integration. The design is validated by simulation, which shows excellent performance in terms of filter spectral characteristics (e.g., bandwidth, cross-talk, etc.) as well as insertion loss.

Frequency doubling in poled polymers using anomalous dispersion phase-matching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kowalczyk, T.C.; Singer, K.D.; Cahill, P.A.

1995-10-01

The authors report on a second harmonic generation in a poled polymer waveguide using anomalous dispersion phase-matching. Blue light ({lambda} = 407 nm) was produced by phase-matching the lowest order fundamental and harmonic modes over a distance of 32 {micro}m. The experimental conversion efficiency was {eta} = 1.2 {times} 10{sup {minus}4}, in agreement with theory. Additionally, they discuss a method of enhancing the conversion efficiency for second harmonic generation using anomalous dispersion phase-matching to optimize Cerenkov second harmonic generation. The modeling shows that a combination of phase-matching techniques creates larger conversion efficiencies and reduces critical fabrication requirements of the individualmore » phase-matching techniques.« less

Fluorene-based macromolecular nanostructures and nanomaterials for organic (opto)electronics.

PubMed

Xie, Ling-Hai; Yang, Su-Hui; Lin, Jin-Yi; Yi, Ming-Dong; Huang, Wei

2013-10-13

Nanotechnology not only opens up the realm of nanoelectronics and nanophotonics, but also upgrades organic thin-film electronics and optoelectronics. In this review, we introduce polymer semiconductors and plastic electronics briefly, followed by various top-down and bottom-up nano approaches to organic electronics. Subsequently, we highlight the progress in polyfluorene-based nanoparticles and nanowires (nanofibres), their tunable optoelectronic properties as well as their applications in polymer light-emitting devices, solar cells, field-effect transistors, photodetectors, lasers, optical waveguides and others. Finally, an outlook is given with regard to four-element complex devices via organic nanotechnology and molecular manufacturing that will spread to areas such as organic mechatronics in the framework of robotic-directed science and technology.

Reversible switching of quantum cascade laser-modes using a pH-responsive polymeric cladding as transducer.

PubMed

Basnar, Bernhard; Schartner, Stephan; Austerer, Maximilian; Andrews, Aaron Maxwell; Roch, Tomas; Schrenk, Werner; Strasser, Gottfried

2008-06-09

We present a novel approach for the reversible switching of the emission wavelength of a quantum cascade laser (QCL) using a halochromic cladding. An air-waveguide laser ridge is coated with a thin layer of polyacrylic acid. This cladding introduces losses corresponding to the absorption spectrum of the polymer. By changing the state of the polymer, the absorption spectrum and losses change, inducing a shift of 7 cm(-1) in the emission wavelength. This change is induced by exposure to acidic or alkaline vapors under ambient conditions and is fully reversible. Such lasers can be used as multi-color light source and as sensor for atmospheric pH.

Production of atmospheric pressure microwave plasma with dielectric half-mirror resonator and its application to polymer surface treatment

NASA Astrophysics Data System (ADS)

Sasai, Kensuke; Keyamura, Kazuki; Suzuki, Haruka; Toyoda, Hirotaka

2018-06-01

For the surface treatment of a polymer tube, a ring-shaped atmospheric pressure microwave plasma (APMP) using a coaxial waveguide is studied. In this APMP, a dielectric plate is used not only as a partial mirror for cavity resonation but also for the precise alignment of the discharge gap for ring-shaped plasma production. The optimum position of the dielectric plate is investigated by electromagnetic wave simulation. On the basis of simulation results, a ring-shaped plasma with good uniformity along the ring is produced. The coaxial APMP is applied to the surface treatment of ethylene tetrafluoroethylene. A very fast surface modification within 3 s is observed.

Coupling Photonics and Coherent Spintronics for Low-Loss Flexible Optical Logic

DTIC Science & Technology

2015-12-02

AFRL-AFOSR-VA-TR-2016-0055 Coupling photonics and coherent spintronics for low-loss flexible optical logic Jesse Berezovsky CASE WESTERN RESERVE UNIV...2012 - 14/06/2015 4. TITLE AND SUBTITLE Coupling photonics and coherent spintronics for low-loss flexible optical logic 5a. CONTRACT NUMBER 5b...into devices, ranging from macroscopic optical cavities, to arrays of microlens cavities, to quantum dot-impregnated integrated polymer waveguides

Design of a compact high-speed optical modulator based on a hybrid plasmonic nanobeam cavity

NASA Astrophysics Data System (ADS)

Javid, Mohammad Reza; Miri, Mehdi; Zarifkar, Abbas

2018-03-01

A hybrid plasmonic electro-optic modulator based on a polymer-filled one dimensional photonic crystal nanobeam (1D PhCNB) cavity is proposed here. In the proposed structure the optical intensity modulation is realized by shifting the resonant wavelength of the cavity through electrically tuning the refractive index of the electro-optic polymer in the hybrid plasmonic waveguide. As a result of the subwavelength light confinement in the hybrid plasmonic waveguide and the compact footprint of the 1D PhCNB cavity, the designed modulator has the small overall footprint of 3 . 6 μm2 and the required wavelength shift can be achieved by applying very small actuating power. Three dimensional finite-difference time-domain (3D-FDTD) simulations show that the modulation depth of 10.9 dB, and insertion loss of 1.14 dB, along with very high modulation speed of 224 GHz can be achieved in the proposed modulator with very low modulation energy of 0.75 fJ/bit. A comparison between the performance parameters of the proposed modulator and those of previously reported PhCNB based modulators reveals the superior performance of the proposed structure in terms of modulation speed, energy consumption and overall footprint.

Optofluidic refractive-index sensors employing bent waveguide structures for low-cost, rapid chemical and biomedical sensing.

PubMed

Liu, I-Chen; Chen, Pin-Chuan; Chau, Lai-Kwan; Chang, Guo-En

2018-01-08

We propose and develop an intensity-detection-based refractive-index (RI) sensor for low-cost, rapid RI sensing. The sensor is composed of a polymer bent ridge waveguide (BRWG) structure on a low-cost glass substrate and is integrated with a microfluidic channel. Different-RI solutions flowing through the BRWG sensing region induce output optical power variations caused by optical bend losses, enabling simple and real-time RI detection. Additionally, the sensors are fabricated using rapid and cost-effective vacuum-less processes, attaining the low cost and high throughput required for mass production. A good RI solution of 5.31 10 -4 × RIU -1 is achieved from the RI experiments. This study demonstrates mass-producible and compact RI sensors for rapid and sensitive chemical analysis and biomedical sensing.

Integrated five-port non-blocking optical router based on mode-selective property

NASA Astrophysics Data System (ADS)

Jia, Hao; Zhou, Ting; Fu, Xin; Ding, Jianfeng; Zhang, Lei; Yang, Lin

2018-05-01

In this paper, we propose and demonstrate a five-port optical router based on mode-selective property. It utilizes different combinations of four spatial modes at input and output ports as labels to distinguish its 20 routing paths. It can direct signals from the source port to the destination port intelligently without power consumption and additional switching time to realize various path steering. The proposed architecture is constructed by asymmetric directional coupler based mode-multiplexers/de-multiplexers, multimode interference based waveguide crossings and single-mode interconnect waveguides. The broad optical bandwidths of these constituents make the device suitable to combine with wavelength division multiplexing signal transmission, which can effectively increase the data throughput. Measurement results show that the insertion loss of its 20 routing paths are lower than 8.5 dB and the optical signal-to-noise ratios are larger than 16.3 dB at 1525-1565 nm. To characterize its routing functionality, a 40-Gbps data transmission with bit-error-rate (BER) measurement is implemented. The power penalties for the error-free switching (BER<10-9) are 1.0 dB and 0.8 dB at 1545 nm and 1565 nm, respectively.

Thermoresponsive core-shell magnetic nanoparticles for combined modalities of cancer therapy.

PubMed

Purushotham, S; Chang, P E J; Rumpel, H; Kee, I H C; Ng, R T H; Chow, P K H; Tan, C K; Ramanujan, R V

2009-07-29

Thermoresponsive polymer-coated magnetic nanoparticles loaded with anti-cancer drugs are of considerable interest for novel multi-modal cancer therapies. Such nanoparticles can be used for magnetic drug targeting followed by simultaneous hyperthermia and drug release. Gamma-Fe(2)O(3) iron oxide magnetic nanoparticles (MNP) with average sizes of 14, 19 and 43 nm were synthesized by high temperature decomposition. Composite magnetic nanoparticles (CNP) of 43 nm MNP coated with the thermoresponsive polymer poly-n-isopropylacrylamide (PNIPAM) were prepared by dispersion polymerization of n-isopropylacrylamide monomer in the presence of the MNP. In vitro drug release of doxorubicin-(dox) loaded dehydrated CNP at temperatures below and above the lower critical solution temperature of PNIPAM (34 degrees C) revealed a weak dependence of drug release on swelling behavior. The particles displayed Fickian diffusion release kinetics; the maximum dox release at 42 degrees C after 101 h was 41%. In vitro simultaneous hyperthermia and drug release of therapeutically relevant quantities of dox was achieved, 14.7% of loaded dox was released in 47 min at hyperthermia temperatures. In vivo magnetic targeting of dox-loaded CNP to hepatocellular carcinoma (HCC) in a buffalo rat model was studied by magnetic resonance imaging (MRI) and histology. In summary, the good in vitro and in vivo performance of the doxorubicin-loaded thermoresponsive polymer-coated magnetic nanoparticles suggests considerable promise for applications in multi-modal treatment of cancer.

Inductively coupled plasma etching of GaAs low loss waveguides for a traveling waveguide polarization converter, using chlorine chemistry

NASA Astrophysics Data System (ADS)

Lu, J.; Meng, X.; Springthorpe, A. J.; Shepherd, F. R.; Poirier, M.

2004-05-01

A traveling waveguide polarization converter [M. Poirier et al.] has been developed, which involves long, low loss, weakly confined waveguides etched in GaAs (epitaxially grown by molecular beam epitaxy), with electroplated ``T electrodes'' distributed along the etched floor adjacent to the ridge walls, and airbridge interconnect metallization. This article describes the development of the waveguide fabrication, based on inductively coupled plasma (ICP) etching of GaAs using Cl2 chemistry; the special processes required to fabricate the electrodes and metallization [X. Meng et al.], and the device characteristics [M. Poirier et al.], are described elsewhere. The required waveguide has dimensions nominally 4 μm wide and 2.1 μm deep, with dimensional tolerances ~0.1 μm across the wafer and wafer to wafer. A vertical etch profile with very smooth sidewalls and floors is required to enable the plated metal electrodes to be fabricated within 0.1 μm of the ridge. The ridges were fabricated using Cl2 ICP etching and a photoresist mask patterned with an I-line stepper; He backside cooling, combined with an electrostatic chuck, was employed to ensure good heat transfer to prevent resist reticulation. The experimental results showed that the ridge profile is very sensitive to ICP power and platen rf power. High ICP power and low platen power tend to result in more isotropic etching, whereas increasing platen power increases the photoresist etch rate, which causes rougher ridge sidewalls. No strong dependence of GaAs etch rate and ridge profile were observed with small changes in process temperature (chuck temperature). However, when the chuck temperature was decreased from 25 to 0 °C, etch uniformity across a 3 in. wafer improved from 6% to 3%. Photoresist and polymer residues present after the ICP etch were removed using a combination of wet and dry processes. .

Hybrid optofluidic biosensors

NASA Astrophysics Data System (ADS)

Parks, Joshua W.

Optofluidics, born of the desire to create a system containing microfluidic environments with integrated optical elements, has seen dramatic increases in popularity over the last 10 years. In particular, the application of this technology towards chip based molecular sensors has undergone significant development. The most sensitive of these biosensors interface liquid- and solid-core antiresonant reflecting optical waveguides (ARROWs). These sensor chips are created using conventional silicon microfabrication. As such, ARROW technology has previously been unable to utilize state-of-the-art microfluidic developments because the technology used--soft polydimethyl siloxane (PDMS) micromolded chips--is unamenable to the silicon microfabrication workflows implemented in the creation of ARROW detection chips. The original goal of this thesis was to employ hybrid integration, or the connection of independently designed and fabricated optofluidic and microfluidic chips, to create enhanced biosensors with the capability of processing and detecting biological samples on a single hybrid system. After successful demonstration of this paradigm, this work expanded into a new direction--direct integration of sensing and detection technologies on a new platform with dynamic, multi-dimensional photonic re-configurability. This thesis reports a number of firsts, including: • 1,000 fold optical transmission enhancement of ARROW optofluidic detection chips through thermal annealing, • Detection of single nucleic acids on a silicon-based ARROW chip, • Hybrid optofluidic integration of ARROW detection chips and passive PDMS microfluidic chips, • Hybrid optofluidic integration of ARROW detection chips and actively controllable PDMS microfluidic chips with integrated microvalves, • On-chip concentration and detection of clinical Ebola nucleic acids, • Multimode interference (MMI) waveguide based wavelength division multiplexing for detection of single influenza virions, • All PDMS platform created from monolithically integrated solid- and liquid-core waveguides with single particle detection efficiency and directly integrated microvalves, featuring: ∘ Tunable/tailorable PDMS MMI waveguides, ∘ Lightvalves (optical switch/fluidic microvalve) with the ability to dynamically control light and fluid flow simultaneously, ∘ Lightvalve trap architecture with the ability to physically trap, detect, and analyze single biomolecules.

Multimodal modeling and validation of simplified vocal tract acoustics for sibilant /s/

NASA Astrophysics Data System (ADS)

Yoshinaga, T.; Van Hirtum, A.; Wada, S.

2017-12-01

To investigate the acoustic characteristics of sibilant /s/, multimodal theory is applied to a simplified vocal tract geometry derived from a CT scan of a single speaker for whom the sound spectrum was gathered. The vocal tract was represented by a concatenation of waveguides with rectangular cross-sections and constant width, and a sound source was placed either at the inlet of the vocal tract or downstream from the constriction representing the sibilant groove. The modeled pressure amplitude was validated experimentally using an acoustic driver or airflow supply at the vocal tract inlet. Results showed that the spectrum predicted with the source at the inlet and including higher-order modes matched the spectrum measured with the acoustic driver at the inlet. Spectra modeled with the source downstream from the constriction captured the first characteristic peak observed for the speaker at 4 kHz. By positioning the source near the upper teeth wall, the higher frequency peak observed for the speaker at 8 kHz was predicted with the inclusion of higher-order modes. At the frequencies of the characteristic peaks, nodes and antinodes of the pressure amplitude were observed in the simplified vocal tract when the source was placed downstream from the constriction. These results indicate that the multimodal approach enables to capture the amplitude and frequency of the peaks in the spectrum as well as the nodes and antinodes of the pressure distribution due to /s/ inside the vocal tract.

Plate-slot polymer waveguide modulator on silicon-on-insulator.

PubMed

Qiu, Feng; Spring, Andrew M; Hong, Jianxun; Yokoyama, Shiyoshi

2018-04-30

Electro-optic (EO) modulators are vital for efficient "electrical to optical" transitions and high-speed optical interconnects. In this work, we applied an EO polymer to demonstrate modulators on silicon-on-insulator substrates. The fabricated Mach-Zehnder interferometer (MZI) and ring resonator consist of a Si and TiO 2 slot, in which the EO polymer was embedded to realize a low-driving and large bandwidth modulation. The designed optical and electrical constructions are able to provide a highly concentrated TM mode with low propagation loss and effective EO properties. The fabricated MZI modulator shows a π-voltage-length product of 0.66 V·cm and a 3-dB bandwidth of 31 GHz. The measured EO activity is advantageous to exploit the ring modulator with a resonant tunability of 0.065 nm/V and a 3-dB modulation bandwidth up to 13 GHz.

Developments in the photonics program at OSC

NASA Astrophysics Data System (ADS)

Peyghambarian, N.

2014-10-01

The photonics program at the College of Optical Sciences started nearly 30 years ago. In 1984, the program was focused on development of femtosecond laser sources and their use in investigating semiconductor carrier dynamics. The program grew into polymer and organic optics in late 1989 and was strengthened by the winning of the CAMP MURI from ONR in 1995 that was focused on multifunctional polymers including photorefractive polymers, organic light emitting diodes and 3D direct laser writing. Also in 1995, the areas of glass waveguide and fiber optic materials and devices were added to the program. In 2008, the optical communication and future internet research was started through winning the CIAN NSF ERC. Expertise in thin films, optical storage and the fundamental aspects of light are elements of the overall research program. Holographic 3D display, autofocus lenses, bio-medical imaging and devices for vision have also been ongoing research areas.

Flat-top MZI filters: a novel robust design based on MMI splitters

NASA Astrophysics Data System (ADS)

Cherchi, Matteo; Harjanne, Mikko; Ylinen, Sami; Kapulainen, Markku; Vehmas, Tapani; Aalto, Timo

2016-03-01

Multimode Interferometers (MMIs) are an attractive alternative to directional couplers, ensuring more relaxed tolerances to fabrication errors and broader operation bandwidth. The drawback is that only a limited discrete set of splitting ratios is achievable with MMIs of constant cross section. This issue clearly limits their use in flat-top interferometric filters, which design requires, in general, free choice of the splitting ratios. Here we show for the first time that it is possible to design 4-stage flat-top interferometers using only standard MMIs with 50:50 and 85:15 splitting ratios. The design approach is based on the representation of the system on the Bloch sphere. Flat-top interleavers with different free spectral ranges have been designed and fabricated on the silicon photonics platform of VTT, based on 3 μm thick rib and strip waveguides. Two different layouts have been explored: one where all components are collinear and a more compact one which elements have been folded in a spiral shape. All interleavers have been designed for TE polarization, and they work in a wavelength range comparable with the 100 nm bandwidth of the MMI splitters. Even though fabrication imperfections and non-ideal behaviour of both waveguide bends and MMIs led to reduced extinction compared to simulations, most devices show in-band extinction exceeding 15 dB. The in-band losses of the most central channels did not exceed 1.5 dB compared to the reference straight waveguide. The designed interleavers can be employed in cascaded configurations to achieve broadband and fabrication tolerant flat-top wavelength (de)multiplexers.

Embedded optical interconnect technology in data storage systems

NASA Astrophysics Data System (ADS)

Pitwon, Richard C. A.; Hopkins, Ken; Milward, Dave; Muggeridge, Malcolm

2010-05-01

As both data storage interconnect speeds increase and form factors in hard disk drive technologies continue to shrink, the density of printed channels on the storage array midplane goes up. The dominant interconnect protocol on storage array midplanes is expected to increase to 12 Gb/s by 2012 thereby exacerbating the performance bottleneck in future digital data storage systems. The design challenges inherent to modern data storage systems are discussed and an embedded optical infrastructure proposed to mitigate this bottleneck. The proposed solution is based on the deployment of an electro-optical printed circuit board and active interconnect technology. The connection architecture adopted would allow for electronic line cards with active optical edge connectors to be plugged into and unplugged from a passive electro-optical midplane with embedded polymeric waveguides. A demonstration platform has been developed to assess the viability of embedded electro-optical midplane technology in dense data storage systems and successfully demonstrated at 10.3 Gb/s. Active connectors incorporate optical transceiver interfaces operating at 850 nm and are connected in an in-plane coupling configuration to the embedded waveguides in the midplane. In addition a novel method of passively aligning and assembling passive optical devices to embedded polymer waveguide arrays has also been demonstrated.

Peptide Integrated Optics.

PubMed

Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil

2018-02-01

Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dry silver electromigration process for optical glass waveguide fabrication and fluxless bonding technology for photonics and MEMS packaging

NASA Astrophysics Data System (ADS)

Chuang, Ricky Wenkuei

2001-07-01

An effectively simple dry silver electromigration technology without the need of evaporating separate gold or aluminum film electrodes onto both sides of glass is reported to fabricate low-loss deep multimode planar and channel waveguides on BK7 and BF450 glass substrates. A relatively high electrical field ranging from 440 to 545 V/mm was applied to the glass to speed up the migration, while at the same time preventing silver ions that were driven into the glass from reducing into silver atom; a major contributor to waveguide loss. The deep planar and channel waveguides thus fabricated showed no discolors or cracks, of which the attenuation losses of less than 2dB/cm and 0.1dB/cm were later measured from channel waveguides constructed on the BK7 and BF450 glass substrates, respectively, using our 0.6328mum He-Ne laser edge-coupling setup. To complete the waveguide studies, the scanning electron microscope (SEM) equipped with energy-dispersive X-ray (EDX) detector was adopted to obtain the concentration profiles of silver and sodium ions distributed in a waveguiding region after the exchange. The EDX measurements acquired hereafter were then utilized along with the Gladstone-Dale relation altogether to deduce the refractive index profile; of which a nearly step-like profile was consistently deduced from every deep planar and channel waveguides fabricated. Finally, a numerical model utilizing the space charge approach was devised to explain the nonlinear current effect often observed during the actual waveguide fabrication. The simulation results have confirmed that the nonlinear current-versus-time profile obtained is mainly attributed to the inhomogeneous distribution of the electric field in the glass substrate due to a space charge region created by the separation between silver- and sodium-ion migration fronts as a result of their unequal mobilities; a phenomenon which is ultimately responsible for the eventual slow down in the ion exchange rate as monitored during the actual electromigration process. A fluxless oxidation-free bonding technology using multilayer composite solders based on the non eutectic binary alloys of indium-tin (In-Sn), silver-indium (Ag-In), gold-tin (Au-Sn), and bismuth-tin (Bi-Sn) has been established and studied to determine its applicability to photonics and MEMS packaging. The scanning acoustic microscopy (SAM) conducted on these solder samples has consistently shown that a nearly void-free joint fabricated from each non-eutectic binary alloy system can be reliably achieved. In addition, the scanning electron microscopy (SEM) equipped with the energy dispersive X-ray (EDX) detector was also performed on the cross section of each sample to determine its joint composition, especially of any sign of intermetallic compounds. These results will demonstrate that any intermetallic compound or phase present in a joint fabricated with a pre-determined multilayer composition based on a specific binary alloy system can be well understood and fully justified by correlating the experimental outcome with its respective binary phase diagram.

High-Reliability Waveguide Vacuum/Pressure Window

NASA Technical Reports Server (NTRS)

Britcliffe, Michael J.; Hanson, Theodore R.; Long, Ezra M.; Montanez, Steven

2013-01-01

The NASA Deep Space Network (DSN) uses commercial waveguide windows on the output waveguide of Ka-band (32 GHz) low-noise amplifiers. Mechanical failure of these windows resulted in an unacceptable loss in tracking time. To address this issue, a new Ka-band WR-28 waveguide window has been designed, fabricated, and tested. The window uses a slab of low-loss, low-dielectric constant foam that is bonded into a 1/2-wave-thick waveguide/flange. The foam is a commercially available, rigid, closed-cell polymethacrylimide. It has excellent electrical properties with a dielectric constant of 1.04, and a loss tangent of 0.01. It is relatively strong with a tensile strength of 1 MPa. The material is virtually impermeable to helium. The finished window exhibits a leak rate of less than 3x10(exp -3)cu cm/s with helium. The material is also chemically resistant and can be cleaned with acetone. The window is constructed by fabricating a window body by brazing a short length of WR-28 copper waveguide into a standard rectangular flange, and machining the resulting part to a thickness of 4.6 mm. The foam is machined to a rectangular shape with a dimension of 7.06x3.53 mm. The foam is bonded into the body with a two-part epoxy. After curing, the excess glue and foam are knife-trimmed by hand. The finished window has a loss of less than 0.08 dB (2%) and a return loss of greater than 25 dB at 32 GHz. This meets the requirements for the DSN application. The window is usable for most applications over the entire 26-to-40-GHz waveguide band. The window return loss can be tuned to a required frequency by var y in g the thickness of the window slightly. Most standard waveguide windows use a thin membrane of material bonded into a recess in a waveguide flange, or sandwiched between two flanges with a polymer seal. Designs using the recessed window are prone to mechanical failure over time due to constraints on the dimensions of the recess that allow the bond to fail. Designs using the sandwich method are often permeable to helium, which prohibits the use of helium leak detection. At the time of this reporting, 40 windows have been produced. Twelve are in operation with a combined operating time of over 30,000 hours without a failure.

Sensor chip and apparatus for tactile and/or flow sensing

NASA Technical Reports Server (NTRS)

Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

2008-01-01

A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.

Sensor chip and apparatus for tactile and/or flow sensing

NASA Technical Reports Server (NTRS)

Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

2009-01-01

A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.

Scalable 3D bicontinuous fluid networks: polymer heat exchangers toward artificial organs.

PubMed

Roper, Christopher S; Schubert, Randall C; Maloney, Kevin J; Page, David; Ro, Christopher J; Yang, Sophia S; Jacobsen, Alan J

2015-04-17

A scalable method for fabricating architected materials well-suited for heat and mass exchange is presented. These materials exhibit unprecedented combinations of small hydraulic diameters (13.0-0.09 mm) and large hydraulic-diameter-to-thickness ratios (5.0-30,100). This process expands the range of material architectures achievable starting from photopolymer waveguide lattices or additive manufacturing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukundan, Harshini; Xei, Hongshi; Anderson, Aaron S

We have developed a waveguide-based optical biosensor for the sensitive and specific detection of biomarkers associated with disease. Our technology combines the superior optical properties of single-mode planar waveguides, the robust nature of functionalized self-assembled monolayer sensing films and the specificity of fluorescence sandwich immunoassays to detect biomarkers in complex biological samples such as serum, urine and sputum. We have previously reported the adaptation of our technology to the detection of biomarkers associated with breast cancer and anthrax. However, these approaches primarily used phospholipid bilayers as the functional film and organic dyes (ex: AlexaFluors) as the fluorescence reporter. Organic dyesmore » are easily photodegraded and are not amenable to multiplexing because of their narrow Stokes' shift. Here we have developed strategies for conjugation of the detector antibodies with quantum dots for use in a multiplex detection platform. We have previously evaluated dihydroxylipoic acid quantum dots for the detection of a breast cancer biomarker. In this manuscript, we investigate the detection of the Bacillus anthracis protective antigen using antibodies conjugated with polymer-coated quantum dots. Kinetics of binding on the waveguide-based biosensor is reported. We compare the sensitivity of quantum dot labeled antibodies to those labeled with AlexaFluor and demonstrate the photostability of the former in our assay platform. In addition, we compare sulfydryl labeling of the antibody in the hinge region to that of nonspecific amine labeling. This is but the first step in developing a multiplex assay for such biomarkers on our waveguide platform.« less

Practical microstructured and plasmonic terahertz waveguides

NASA Astrophysics Data System (ADS)

Markov, Andrey

The terahertz frequency range, with frequencies lying between 100 GHz and 10 THz, has strong potential for various technological and scientific applications such as sensing, imaging, communications, and spectroscopy. Most terahertz (THz) sources are immobile and THz systems use free-space propagation in dry air where losses are minimal. Designing efficient THz waveguides for flexible delivery of broadband THz radiation is an important step towards practical applications of terahertz techniques. THz waveguides can be very useful on the system integration level when used for connection of the diverse THz point devices, such as sources, filters, sensor cells, detectors, etc. The most straightforward application of waveguides is to deliver electromagnetic waves from the source to the point of detection. Cumbersome free-space optics can be replaced by waveguides operating in the THz range, which could lead to the development of compact THz time domain spectroscopy systems. Other promising applications of THz waveguides are in sensing and imaging. THz waveguides have also been shown to operate in subwavelength regimes, offering mode confinement in waveguide structures with a size smaller than the diffraction limit, and thus, surpassing the resolution of free-space THz imaging systems. In order to design efficient terahertz waveguides, the frequency dependent loss and dispersion of the waveguide must be minimized. A possible solution would be to increase the fraction of mode power propagating through air. In this thesis, the usage of planar porous air/dielectric waveguides and metal wire/dielectric hybrid terahertz fibers will be discussed. First, I present a novel design of a planar porous low-loss waveguide, describe its fabrication, and characterize it in view of its potential applications as a low-loss waveguide and sensor in the THz spectral range. The waveguide structure features a periodic sequence of layers of thin (25-50 mum) polyethylene film that are separated by low-loss air layers of comparable thickness. A large fraction of the modal fields in these waveguides is guided in the low-loss air region, thus effectively reducing the waveguide transmission losses. I consider that such waveguides can be useful not only for low-loss THz wave delivery, but also for sensing of biological and chemical specimens in the terahertz region, by placing the recognition elements directly into the waveguide microstructure. The main advantage of the proposed planar porous waveguide is the convenient access to its optical mode, since the major portion of THz power launched into such a waveguide is confined within the air layers. Moreover, small spacing between the layers promotes rapid loading of the analyte into the waveguide due to strong capillary effect (< 1 s filling of a 10 cm long waveguide with an analyte). The transmission and absorption properties of such waveguides have been investigated both experimentally using THz-TDS spectroscopy and theoretically using finite element software. The modal refractive index of porous waveguides is smaller compared to pure polymer and it is easy to adjust by changing the air spacing between the layers, as well as the number of layers in the core. The porous waveguide exhibits considerably smaller transmission losses than bulk material. In the following chapters I review another promising approach towards designing of low-loss, low-dispersion THz waveguides. The hybrid metal/dielectric waveguides use a plasmonic mode guided in the gap between two parallel wires that are, in turn, encapsulated inside a low-loss, low-refractive index, micro-structured cladding that provides mechanical stability and isolation from the environment. I describe several promising techniques that can be used to encapsulate the two-wire waveguides, while minimizing the negative impact of dielectric cladding on the waveguide optical properties. In particular, I detail the use of low-density foams and microstructured plastic claddings as two enabling materials for the two-wire waveguide encapsulation. The hybrid fiber design is more convenient for practical applications than a classic two metal wire THz waveguide as it allows direct manipulations of the fiber without the risk of perturbing its core-guided mode. I present a detailed analysis of the modal properties of the hybrid metal/dielectric waveguides, compare them with the properties of a classic two-wire waveguide, and then present strategies for the improvement of hybrid waveguide performance by using higher cladding porosity or utilizing inherently porous cladding material. I study coupling efficiency into hybrid waveguides and conclude that it can be relatively high (>50%) in the broad frequency range ˜0.5 THz. Not surprisingly, optical properties of such fibers are inferior to those of a classic two-wire waveguide due to the presence of lossy dielectric near an inter-wire gap. At the same time, composite fibers outperform porous fibers of the same geometry both in bandwidth of operation and in lower dispersion. I demonstrate that hybrid metal/dielectric porous waveguides can have a very large operational bandwidth, while supporting tightly confined, air-bound modes both at high and low frequencies. This is possible as, at higher frequencies, hybrid fibers can support ARROW-like low-loss air-bound modes, while changing their guidance mechanism to plasmonic confinement in the inter-wire air gap at lower frequencies. Finally, I describe an intriguing resonant property of some hybrid plasmonic modes of metal / dielectric waveguides that manifests itself in the strong frequency dependent change in the modal confinement from dielectric-bound to air-bound. I discuss how this property can be used to construct THz refractometers. Introduction of even lossless analytes into the fiber core leads to significant changes in the modal losses, which is used as a transduction mechanism. The resolution of the refractometer has been investigated numerically as a function of the operation frequency and the geometric parameters of the fiber. With a refractive index resolution on the order of ˜10-3 RIU, the composite fiber-based sensor is capable of identifying various gaseous analytes and aerosols or measuring the concentration of dust particles in the air.

A reprogrammable multifunctional chalcogenide guided-wave lens.

PubMed

Cao, Tun; Wei, Chen-Wei; Cen, Meng-Jia; Guo, Bao; Kim, Yong-June; Zhang, Shuang; Qiu, Cheng-Wei

2018-06-05

The transformation optics (TO) technique, which establishes an equivalence between a curved space and a spatial distribution of inhomogeneous constitutive parameters, has enabled an extraordinary paradigm for manipulating wave propagation. However, extreme constitutive parameters, as well as a static nature, inherently limit the simultaneous achievement of broadband performance, ultrafast reconfigurability and versatile reprogrammable functions. Here, we integrate the TO technique with an active phase-change chalcogenide to achieve a reconfigurable multi-mode guided-wave lens. The lens is made of a Rinehart-shaped curved waveguide with an effective refractive index gradient profile through partially crystallizing Ge2Sb2Te5. Upon changing the bias time of the external voltage imparted to the Ge2Sb2Te5 segments, the refractive index gradient profile can be tuned with a transformative platform for various functions for visible light. The electrically reprogrammable multi-mode guided-wave lens is capable of dynamically acquiring various functionalities with an ultrafast response time. Our findings may offer a significant step forward by providing a universal method to obtain ultrafast and highly versatile guided-wave manipulation, such as in Einstein rings, cloaking, Maxwell fish-eye lenses and Luneburg lenses.

Development of hierarchical, tunable pore size polymer foams for ICF targets

DOE PAGES

Hamilton, Christopher E.; Lee, Matthew Nicholson; Parra-Vasquez, A. Nicholas Gerardo

2016-08-01

In this study, one of the great challenges of inertial confinement fusion experiments is poor understanding of the effects of reactant heterogeneity on fusion reactions. The Marble campaign, conceived at Los Alamos National Laboratory, aims to gather new insights into this issue by utilizing target capsules containing polymer foams of variable pore sizes, tunable over an order of magnitude. Here, we describe recent and ongoing progress in the development of CH and CH/CD polymer foams in support of Marble. Hierarchical and tunable pore sizes have been achieved by utilizing a sacrificial porogen template within an open-celled poly(divinylbenzene) or poly(divinylbenzene-co-styrene) aerogelmore » matrix, resulting in low-density foams (~30 mg/ml) with continuous multimodal pore networks.« less

Superconducting Vacuum-Gap Crossovers for High Performance Microwave Applications

NASA Technical Reports Server (NTRS)

Denis, Kevin L.; Brown, Ari D.; Chang, Meng-Ping; Hu, Ron; U-Yen, Kongpop; Wollack, Edward J.

2016-01-01

The design and fabrication of low-loss wide-bandwidth superconducting vacuum-gap crossovers for high performance millimeter wave applications are described. In order to reduce ohmic and parasitic losses at millimeter wavelengths a vacuum gap is preferred relative to dielectric spacer. Here, vacuum-gap crossovers were realized by using a sacrificial polymer layer followed by niobium sputter deposition optimized for coating coverage over an underlying niobium signal layer. Both coplanar waveguide and microstrip crossover topologies have been explored in detail. The resulting fabrication process is compatible with a bulk micro-machining process for realizing waveguide coupled detectors, which includes sacrificial wax bonding, and wafer backside deep reactive ion etching for creation of leg isolated silicon membrane structures. Release of the vacuum gap structures along with the wax bonded wafer after DRIE is implemented in the same process step used to complete the detector fabrication. ?

Electro-optical modulator in a polymerinfiltrated silicon slotted photonic crystal waveguide heterostructure resonator.

PubMed

Wülbern, Jan Hendrik; Petrov, Alexander; Eich, Manfred

2009-01-05

We present a novel concept of a compact, ultra fast electro-optic modulator, based on photonic crystal resonator structures that can be realized in two dimensional photonic crystal slabs of silicon as core material employing a nonlinear optical polymer as infiltration and cladding material. The novel concept is to combine a photonic crystal heterostructure cavity with a slotted defect waveguide. The photonic crystal lattice can be used as a distributed electrode for the application of a modulation signal. An electrical contact is hence provided while the optical wave is kept isolated from the lossy metal electrodes. Thereby, well known disadvantages of segmented electrode designs such as excessive scattering are avoided. The optical field enhancement in the slotted region increases the nonlinear interaction with an external electric field resulting in an envisaged switching voltage of approximately 1 V at modulation speeds up to 100 GHz.

Polymeric PLC-type thermo-optic optical attenuator fabricated by UV imprint technique

NASA Astrophysics Data System (ADS)

Kim, Jin Tae; Choi, Choon-Gi

2006-01-01

A planar lightwave circuit-type polymer thermo-optic optical attenuator was fabricated via a UV imprint technique. In order to reduce the step for filling of cores and minimize the detrimental residual slab waveguide, convex ridge-type micro cores for guidance of light were defined with an accuracy of ±0.5 μm on the under-clad by a single step of imprinting. The voltage-controlled polymer optical attenuator showed 30-dB attenuation with 80-mW electrical input power at a wavelength of 1.55 μm. The rise and fall times are less than 5 ms. It displays about 0.2- and 1-dB polarization dependence at 0- and 10-dB attenuations, respectively.

Realization of an ultra-compact polarization beam splitter using asymmetric MMI based on silicon nitride / silicon-on-insulator platform.

PubMed

Sun, Xiao; Aitchison, J Stewart; Mojahedi, Mo

2017-04-03

We have experimentally demonstrated a compact polarization beam splitter (PBS) based on the silicon nitride/silicon-on-insulator platform using the recently proposed augmented-low-index-guiding (ALIG) waveguide structure. The two orthogonal polarizations are split in an asymmetric multimode interference (MMI) section, which was 1.6 μm wide and 4.8 μm long. The device works well over the entire C-band wavelength range and has a measured low insertion loss of less than 1 dB. The polarization extinction ratio at the Bar Port is approximately 17 dB and at the Cross Port is approximately 25 dB. The design of the device is robust and has a good fabrication tolerance.

Optically active Er-Yb doped glass films prepared by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Serna, R.; Ballesteros, J. M.; Jiménez de Castro, M.; Solis, J.; Afonso, C. N.

1998-08-01

Active rare-earth Er3+-Yb3+ co-doped phosphate glass films are produced in a single step by pulsed laser deposition. The films are multimode waveguides and exhibit the highest refractive index, optical density and 1.54 μm photoluminescence intensity and lifetime when deposited at low oxygen pressure (Pox⩽4×10-5 Torr). The density of the films obtained under these conditions is higher than that of the target material as a consequence of the high kinetic energy of the species generated during ablation. Luminescent emission can be excited by optical pumping the Er3+ ions either directly or through cross-relaxation of the Yb3+. Post-deposition annealing allows us to improve the luminescence performance.

Integrated polymer-based Mach-Zehnder interferometer label-free streptavidin biosensor compatible with injection molding.

PubMed

Bruck, R; Melnik, E; Muellner, P; Hainberger, R; Lämmerhofer, M

2011-05-15

We report the development of a Mach-Zehnder interferometer biosensor based on a high index contrast polymer material system and the demonstration of label-free online measurement of biotin-streptavidin binding on the sensor surface. The surface of the polyimide waveguide core layer was functionalized with 3-mercaptopropyl trimethoxy silane and malemide tagged biotin. Several concentrations of Chromeon 642-streptavidin dissolved in phosphate buffered saline solution were rinsed over the functionalized sensor surface by means of a fluidic system and the biotin-streptavidin binding process was observed in the output signal of the interferometer at a wavelength of 1310 nm. Despite the large wavelength and the comparatively low surface sensitivity of the sensor system due to the low index contrast in polymer material systems compared to inorganic material systems, we were able to resolve streptavidin concentrations of down to 0.1 μg/ml. The polymer-based optical sensor design is fully compatible with cost-efficient mass production technologies such as injection molding and spin coating, which makes it an attractive alternative to inorganic optical sensors. Copyright © 2011 Elsevier B.V. All rights reserved.

Direct laser writing of polymer micro-ring resonator ultrasonic sensors

NASA Astrophysics Data System (ADS)

Wei, Heming; Krishnaswamy, Sridhar

2017-04-01

With the development of photoacoustic technology in recent years, ultrasound-related sensors play a vital role in a number of areas ranging from scientific research to nondestructive testing. Compared with the traditional PZT transducer as ultrasonic sensors, novel ultrasonic sensors based on optical methods such as micro-ring resonators have gained increasing attention. The total internal reflection of the light along the cavity results in light propagating in microcavities as whispering gallery modes (WGMs), which are extremely sensitive to change in the radius and refractive index of the cavity induced by ultrasound strain field. In this work, we present a polymer optical micro-ring resonator based ultrasonic sensor fabricated by direct laser writing optical lithography. The design consists of a single micro-ring and a straight tapered waveguide that can be directly coupled by single mode fibers (SMFs). The design and fabrication of the printed polymer resonator have been optimized to provide broad bandwidth and high optical quality factor to ensure high detection sensitivity. The experiments demonstrate the potential of the polymer micro-ring resonator to works as a high-performance ultrasonic sensor.

Refractometers for different refractive index range by surface plasmon resonance sensors in multimode optical fibers with different metals

NASA Astrophysics Data System (ADS)

Zuppella, P.; Corso, Alain J.; Pelizzo, Maria G.; Cennamo, N.; Zeni, L.

2016-09-01

We have realized a plasmonic sensor based on Au/Pd metal bilayer in a multimode plastic optical fiber. This metal bilayer, based on a metal with high imaginary part of the refractive index and gold, shows interesting properties in terms of sensitivity and performances, in different refractive index ranges. The development of highly sensitive platforms for high refractive index detection (higher than 1.38) is interesting for chemical applications based on molecularly imprinted polymer as receptors, while the aqueous medium is the refractive index range of biosensors based on bio-receptors. In this work we have presented an Au/Pd metal bilayer optimized for 1.38-1.42 refractive index range.

Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

PubMed Central

Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

2017-01-01

By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU. PMID:29232841

Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers.

PubMed

Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

2017-12-09

By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

NASA Astrophysics Data System (ADS)

Fisher, Mark E.; la Grone, Marcus; Sikes, John

2003-09-01

A sensor (known as Fido) that utilizes amplification of fluorescence quenching as the transduction mechanism for ultra-trace detection of nitroaromatic compounds associated with landmines has been described previously. Previous sensor prototypes utilized a single band of amplifying polymer deployed inside a capillary waveguide to form the sensing element of the detector. A new prototype has been developed that incorporates multiple, discrete bands of different amplifying polymers deployed in a linear array inside the capillary. Vapor-phase samples are introduced into the sensor as a sharp pulse via a gated inlet. As the vapor pulse is swept through the capillary by flow of a carrier gas, the pulse of analyte encounters the bands of polymer sequentially. If the sample contains nitroaromatic explosives, the bands of polymer will respond with a reduction in emission intensity proportional to the mass of analyte in the sample. Because the polymer bands are deployed serially, the analyte pulse does not reach the bands of polymer simultaneously. Hence, a temporal response pattern will be observed as the analyte pulse traverses the length of the capillary. In addition, the intensity of response for each band will vary, producing a ratiometric response. The temporal and ratiometric responses are characteristic of a given analyte, enhancing discrimination of target analytes from potential interferents. This should translate into a reduction in sensor false alarm rates.

Processing soft materials for integrated photonic and macroelectronic components and devices

NASA Astrophysics Data System (ADS)

Tsay, Candice Ruth

Incorporating soft materials into micro-fabrication processes opens up new functionalities for fabricated devices, but requires unique processing routes. This thesis presents our development of integrated photonic and macroelectronic structures through processing innovations that unite disparate inorganic/organic, and soft/rigid materials systems. For the integrated photonic system, we focus our efforts on chalcogenide glasses, dielectric materials that exhibit a variety of optical properties that make them desirable for near- and mid-infrared communications and sensing applications. However, processing limitations for these relatively fragile materials have made the direct integration of waveguides with sources or detectors challenging. Here we demonstrate the viability of several additive methods for patterning chalcogenide glass waveguides from solution. In particular, we focus on two complementary soft lithography methods. The first, micro-molding in capillaries (MIMIC), is shown to fabricate multi-mode As2S 3 waveguides which are directly integrated with quantum cascade lasers (QCLs). In a second method, we demonstrate the ability of micro-transfer molding (muTM), to produce arrays of single mode rib waveguides over large areas while maintaining low surface and edge roughness. These methods form a suite of processes that can be applied to chalcogenide solutions to create a diverse array of mid-IR photonic structures ranging from less than 5 to 10's of mum in cross-sectional dimension. Optical characterization, including measurement of waveguide loss by cut-back, is carried out in the mid-IR using QCLs. In addition, materials characterization of the chalcogenide glass structures is carried out to determine loss mechanisms and optimize processing. While we use soft polymeric materials as molds to pattern chalcogenide glasses, we also employ them as substrate material for stretchable electronic systems, which comprise a new class of flexible macroelectronics. These devices must undergo elastic deformation to large strain (>10%), for applications in which electronics are conformally shaped around surfaces of arbitrary shape, like many biological surfaces. We develop strategies for processing stretchable metallic electrodes and study the mechanism of their stretchability via careful observation of thin film micro-structures. Our macroelectronic work culminates in fabrication of stretchable microelectrode arrays that interface with brain tissue, laying the groundwork for future development of advanced bio-electronic interfaces.

Low-cost fused taper polymer optical fiber (LFT-POF) splitters for environmental and home-networking solution

NASA Astrophysics Data System (ADS)

Supian, L. S.; Ab-Rahman, Mohammad Syuhaimi; Harun, Mohd Hazwan; Gunab, Hadi; Sulaiman, Malik; Naim, Nani Fadzlina

2017-08-01

In visible optical communication over the multimode PMMA fibers, the overall cost of optical network can be reduced by deploying economical splitters for distributing the optical data signals from a point to multipoint in transmission network. The low-cost splitters shall have two main characteristics; good uniformity and high power efficiency. The most cost-effective and environmental friendly optical splitter having those characteristics have been developed. The device material is 100% purely based on the multimode step-index PMMA Polymer Optical Fiber (POF). The region which all fibers merged as single fiber is called as fused-taper POF. This ensures that all fibers are melted and fused properly. The results for uniformity and power efficiency of all splitters have been revealed by injecting red LED transmitter with 650 nm wavelength into input port while each end of output fibers measured by optical power meter. Final analysis shows our fused-taper splitter has low excess loss 0.53 dB and each of the output port has low insertion loss, which the average value is below 7 dB. In addition, the splitter has good uniformity that is 32:37:31% in which it is suitably used for demultiplexer fabrication.

Constitutive Parameter Measurement Using Double Ridge Waveguide

DTIC Science & Technology

2013-03-01

different microwave absorbers. The sample constructed by AFRL is a polymer known commercially as VeroP and was fabricated in a Polyjet 3D printer . The...local 3D printer resources. The acrylic was able to fit similarly to the AFRL sample. The absorber material was formed using laser cut plastic as a...samples. During the sample fabrication process, the 3D printer from Air Force Institute of Technology (AFIT) was used to verify the sample size. The

Displacement sensing based on modal interference in polymer optical fibers with partially applied strain

NASA Astrophysics Data System (ADS)

Mizuno, Yosuke; Hagiwara, Sonoko; Kawa, Tomohito; Lee, Heeyoung; Nakamura, Kentaro

2018-05-01

Strain sensing based on modal interference in multimode fibers (MMFs) has been extensively studied, but no experimental or theoretical reports have been given as to how the system works when strain is applied not to the whole MMF but only to part of the MMF. Here, using a perfluorinated graded-index polymer optical fiber as the MMF, we investigate the strain sensing characteristics of this type of sensor when strain is partially applied to fiber sections with different lengths. The strain sensitivity dependence on the length of the strained section reveals that this strain sensor actually behaves as a displacement sensor.

Chip-scale integrated optical interconnects: a key enabler for future high-performance computing

NASA Astrophysics Data System (ADS)

Haney, Michael; Nair, Rohit; Gu, Tian

2012-01-01

High Performance Computing (HPC) systems are putting ever-increasing demands on the throughput efficiency of their interconnection fabrics. In this paper, the limits of conventional metal trace-based inter-chip interconnect fabrics are examined in the context of state-of-the-art HPC systems, which currently operate near the 1 GFLOPS/W level. The analysis suggests that conventional metal trace interconnects will limit performance to approximately 6 GFLOPS/W in larger HPC systems that require many computer chips to be interconnected in parallel processing architectures. As the HPC communications bottlenecks push closer to the processing chips, integrated Optical Interconnect (OI) technology may provide the ultra-high bandwidths needed at the inter- and intra-chip levels. With inter-chip photonic link energies projected to be less than 1 pJ/bit, integrated OI is projected to enable HPC architecture scaling to the 50 GFLOPS/W level and beyond - providing a path to Peta-FLOPS-level HPC within a single rack, and potentially even Exa-FLOPSlevel HPC for large systems. A new hybrid integrated chip-scale OI approach is described and evaluated. The concept integrates a high-density polymer waveguide fabric directly on top of a multiple quantum well (MQW) modulator array that is area-bonded to the Silicon computing chip. Grayscale lithography is used to fabricate 5 μm x 5 μm polymer waveguides and associated novel small-footprint total internal reflection-based vertical input/output couplers directly onto a layer containing an array of GaAs MQW devices configured to be either absorption modulators or photodetectors. An external continuous wave optical "power supply" is coupled into the waveguide links. Contrast ratios were measured using a test rider chip in place of a Silicon processing chip. The results suggest that sub-pJ/b chip-scale communication is achievable with this concept. When integrated into high-density integrated optical interconnect fabrics, it could provide a seamless interconnect fabric spanning the intra-

Numerical simulation of viscoelastic layer rearrangement in polymer melts using OpenFOAM®

DOE Office of Scientific and Technical Information (OSTI.GOV)

Köpplmayr, Thomas, E-mail: tkoepplmayr@gmail.com; Mayrhofer, Elias

In addition to their shear-thinning behavior, polymer melts are characterized by first and second normal stress differences, which cause secondary motions. Polymer coextrusion processes involve viscoelastic two-phase flows that influence layer formation. Using polymer melts with different pigmentation makes visible the layers deformed by second normal stress differences. We used a new solver for the OpenFOAM CFD toolbox which handles viscoelastic two-phase flows. A derivative of the volume-of-fluid (VoF) methodology was employed to describe the interface. Different types of polymer melt, such as polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were investigated. In a coextrusion process, the less viscousmore » phase usually tends to encapsulate the more viscous one. However, the different viscoelastic properties of the melts also influence interface deformation. The materials were characterized by small-amplitude oscillatory-shear rheometry, and a multimode Giesekus model was used to fit shear viscosity, storage and loss modulus. Our simulations also took interfacial tension into account. Experimental observations and corresponding numerical simulations were found to be in good accordance.« less

Novel photonics polymer and its application in IT

NASA Astrophysics Data System (ADS)

Koike, Yasuhiro

2003-07-01

In the field of LANs, transmission systems based on a multimode silica fiber network is heading towards capacities of Gb/s. We have proposed a low-loss, high-bandwidth and large-core graded-index plastic optical fiber (GI POF) in data-com. area. We sill show that GI POF enables to virtually eliminate the "modal noise" problem cased by the medium-core silica fibers. Therefore, stable high-speed data transmission is realized by GI POF rather than silica fibers. Furthermore, advent of perfluorinated (PF) polymer based GI POF network can support higher transmission than silica fibers network because of the small material dispersion of PF polymer compared with silica. In addition, we proposed a "highly scattering optical transmission (HSOT) polymer" and applied it to a light guide plate of a liquid crystal display (LCD) backlight. The advanced HSOT polymer backlight that was proposed using the HSOT designing simulation program demonstrated approximately three times higher luminance than the conventional flat-type HSOT backlight of 14.1-inch diagonal because of the microscopic prism structures at the bottom of the advanced HSOT light guide plate. The HSOT polymer containing the optimized heterogeneous structures produced homogeneous scattered light with forward directivity and sufficient color uniformity.

Polymer-Based Therapeutics: Nanoassemblies and Nanoparticles for Management of Atherosclerosis

PubMed Central

Lewis, Daniel R.; Kamisoglu, Kubra; York, Adam; Moghe, Prabhas V.

2012-01-01

Coronary arterial disease, one of the leading causes of adult mortality, is triggered by atherosclerosis. A disease with complex etiology, atherosclerosis results from the progressive long-term combination of atherogenesis, the accumulation of modified lipoproteins within blood vessel walls, along with vascular and systemic inflammatory processes. The management of atherosclerosis is challenged by the localized flare-up of several multipronged signaling interactions between activated monocytes, atherogenic macrophages and inflamed or dysfunctional endothelial cells. A new generation of approaches is now emerging founded on multifocal, targeted therapies that seek to reverse or ameliorate the athero-inflammatory cascade within the vascular intima. This article reviews the various classes and primary examples of bioactive configurations of nanoscale assemblies. Of specific interest are polymer-based or polymer-lipid micellar assemblies designed as multimodal receptor-targeted blockers or drug carriers whose activity can be tuned by variations in polymer hydrophobicity, charge, and architecture. Also reviewed are emerging reports on multifunctional nanoassemblies and nanoparticles for improved circulation and enhanced targeting to athero-inflammatory lesions and atherosclerotic plaques. PMID:21523920

Micro-optical elements produced using an photo-embossing technique in photopolymers

NASA Astrophysics Data System (ADS)

O'Neill, Feidhlim T.; Rowsome, Ita C.; Carr, Alun J.; Daniels, Stephen M.; Gleeson, Michael R.; Kelly, John V.; Close, Ciara; Lawrence, Justin R.; Sheridan, John T.

2005-09-01

Micro-optical devices are very important in current high-tech consumer items. The development of future products depends on both the evolution of fabrication techniques and on the development of new low cost mass production methods. Polymers offer ease of fabrication and low cost and are therefore excellent materials for the development of micro-optical devices. Polymer optical devices include passive optical elements, such as microlens arrays and waveguides, as well as active devices such as polymer based lasers. One of the most important areas of micro-optics is that of microlens design, manufacture and testing. The wide diversity of fabrication methods used for the production of these elements indicates their importance. One of these fabrication techniques is photo-embossing. The use of the photo-embossing technique and a photopolymer holographic recording material will be examined in this paper. A discussion of current attempts to model the fabrication process and a review of the experimental method will be given.

Modeling and prediction of relaxation of polar order in high-activity nonlinear optical polymers

NASA Astrophysics Data System (ADS)

Guenthner, Andrew J.; Lindsay, Geoffrey A.; Wright, Michael E.; Fallis, Stephen; Ashley, Paul R.; Sanghadasa, Mohan

2007-09-01

Mach-Zehnder optical modulators were fabricated using the CLD and FTC chromophores in polymer-on-silicon optical waveguides. Up to 17 months of oven-ageing stability are reported for the poled polymer films. Modulators containing an FTC-polyimide had the best over all aging performance. To model and extrapolate the ageing data, a relaxation correlation function attributed to A. K. Jonscher was compared to the well-established stretched exponential correlation function. Both models gave a good fit to the data. The Jonscher model predicted a slower relaxation rate in the out years. Analysis showed that collecting data for a longer period relative to the relaxation time was more important for generating useful predictions than the precision with which individual model parameters could be estimated. Thus from a practical standpoint, time-temperature superposition must be assumed in order to generate meaningful predictions. For this purpose, Arrhenius-type expressions were found to relate the model time constants to the ageing temperatures.

Synchronously Pumped Optical Parametric Oscillator with Intracavity Difference Frequency Mixing

DTIC Science & Technology

1998-06-29

Phys. B, vol. 63, no. 5, pp. 437-441, 1996. [11] T. Töpfer, K. P. Petrov, Y. Mine, L. E. Myers, and R. W. Wallace , "Room- temperature midinfrared...generation in diazo-dye-substitured polymer channel waveguides," IEEE J. of Quant. Electron., vol. 33, no. 3, pp. 349-357, 1997. [56] A. Szilagyi ...periodically poled lithium- niobate," Opt. Lett, vol. 23, no. 9, pp. 664-666, 1998. [119] W. R. Bosenberg, J. I. Alexander, L. E. Myers, and R. W. Wallace

The family of micro sensors for remote control the pollution in liquids and gases

NASA Astrophysics Data System (ADS)

Tulaikova, Tamara; Kocharyun, Gevorg; Rogerson, Graham; Burmistrova, Ludmyla; Sychugov, Vladimir; Dorojkin, Peter

2005-10-01

There are the results for the 3 groups of fiber-optical sensors. First is the fiber-optical sensor with changed sensitive heads on the base on porous polymer with clamped activated dye. Vibration method for fiber-optical sensors provides more convenient output measurements of resonant frequency changes, in comparison with the first device. The self-focusing of the living sells into optical wave-guides in laser road in water will be considered as a new touch method for environment remote sensing.

Wavelength-controlled external-cavity laser with a silicon photonic crystal resonant reflector

NASA Astrophysics Data System (ADS)

Gonzalez-Fernandez, A. A.; Liles, Alexandros A.; Persheyev, Saydulla; Debnath, Kapil; O'Faolain, Liam

2016-03-01

We report the experimental demonstration of an alternative design of external-cavity hybrid lasers consisting of a III-V Semiconductor Optical Amplifier with fiber reflector and a Photonic Crystal (PhC) based resonant reflector on SOI. The Silicon reflector comprises a polymer (SU8) bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and sidemode suppression ratio of more than 25 dB.

Analysis of liquid-phase chemical detection using guided shear horizontal-surface acoustic wave sensors.

PubMed

Li, Zhonghui; Jones, Yolanda; Hossenlopp, Jeanne; Cernosek, Richard; Josse, Fabien

2005-07-15

Direct chemical sensing in liquid environments using polymer-guided shear horizontal surface acoustic wave sensor platforms on 36 degrees rotated Y-cut LiTaO3 is investigated. Design considerations for optimizing these devices for liquid-phase detection are systematically explored. Two different sensor geometries are experimentally and theoretically analyzed. Dual delay line devices are used with a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemically sensitive polymer, which acts as both a guiding layer and a sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layer model provides higher sensitivity than the four-layer model. Contributions from mass loading and coating viscoelasticity changes to the sensor response are evaluated, taking into account the added mass, swelling, and plasticization. Chemically sensitive polymers are investigated in the detection of low concentrations (1-60 ppm) of toluene, ethylbenzene, and xylenes in water. A low-ppb level detection limit is estimated from the present experimental measurements. Sensor properties are investigated by varying the sensor geometries, coating thickness combinations, coating properties, and curing temperature for operation in liquid environments. Partition coefficients for polymer-aqueous analyte pairs are used to explain the observed trend in sensitivity for the polymers PMMA, poly(isobutylene), poly(epichlorohydrin), and poly(ethyl acrylate) used in this work.

Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S.

1997-01-01

All the goals of the research effort for the first year were met by the accomplishments. Additional efforts were done to speed up the process of development and construction of the experimental gas chamber which will be completed by the end of 1997. This chamber incorporates vacuum sealed multimode optical fiber lines which connect the sensor to the remote light source and signal processing equipment. This optical fiber line is a prototype of actual optical communication links connecting real sensors to a control unit within an aircraft or spacecraft. An important problem which we are planning to focus on during the second year is coupling of optical fiber line to the sensor. Currently this problem is solved using focusing optics and prism couplers. More reliable solutions are planned to be investigated.