Bidirectional optical bistability in a dual-pumped erbium doped fiber ring laser.

PubMed

Lai, W J; Shum, P; Binh, L

2004-11-15

We investigate bidirectional optical wave propagations in a dual-pumped erbium doped fiber ring laser without isolator, and observe optical bistability behaviors. Consequently, we propose and construct a NOLM-NALM fiber ring laser to demonstrate and exploit this bidirectional optical bistability phenomenon in optical switching by introducing two tunable variable ratio couplers in the system. Numerical analyses based on the proposed laser structure have also been demonstrated corroborated with the experimental results.

Universal method for constructing N-port non-blocking optical router based on 2 × 2 optical switch for photonic networks-on-chip.

PubMed

Chen, Qiaoshan; Zhang, Fanfan; Ji, Ruiqiang; Zhang, Lei; Yang, Lin

2014-05-19

We propose a universal method for constructing N-port non-blocking optical router for photonic networks-on-chip, in which all microring (MR) optical switches or Mach-Zehnder (M-Z) optical switches behave as 2 × 2 optical switches. The optical router constructed by the proposed method has minimum optical switches, in which the number of the optical switches is reduced about 50% compared to the reported optical routers based on MR optical switches and more than 30% compared to the reported optical routers based on M-Z optical switches, and therefore is more compact in footprint and more power-efficient. We also present a strict mathematical proof of the non-blocking routing of the proposed N-port optical router.

Plastic Transition to Switch Nonlinear Optical Properties Showing the Record High Contrast in a Single-Component Molecular Crystal.

PubMed

Sun, Zhihua; Chen, Tianliang; Liu, Xitao; Hong, Maochun; Luo, Junhua

2015-12-23

To switch bulk nonlinear optical (NLO) effects represents an exciting new branch of NLO material science, whereas it remains a great challenge to achieve high contrast for "on/off" of quadratic NLO effects in crystalline materials. Here, we report the supereminent NLO-switching behaviors of a single-component plastic crystal, 2-(hydroxymethyl)-2-nitro-1,3-propanediol (1), which shows a record high contrast of at least ∼150, exceeding all the known crystalline switches. Such a breakthrough is clearly elucidated from the slowing down of highly isotropic molecular motions during plastic-to-rigid transition. The deep understanding of its intrinsic plasticity and superior NLO property allows the construction of a feasible switching mechanism. As a unique class of substances with short-range disorder embedded in long-range ordered crystalline lattice, plastic crystals enable response to external stimuli and fulfill specific photoelectric functions, which open a newly conceptual avenue for the designing of new functional materials.

Optically Driven Q-Switches For Lasers

NASA Technical Reports Server (NTRS)

Hemmati, Hamid

1994-01-01

Optically driven Q-switches for pulsed lasers proposed, taking place of acousto-optical, magneto-optical, and electro-optical switches. Optical switching beams of proposed Q-switching most likely generated in pulsed diode lasers or light-emitting diodes, outputs of which are amplitude-modulated easily by direct modulation of relatively small input currents. Energy efficiencies exceed those of electrically driven Q-switches.

Noise-driven switching and chaotic itinerancy among dynamic states in a three-mode intracavity second-harmonic generation laser operating on a Λ transition

NASA Astrophysics Data System (ADS)

Otsuka, Kenju; Ohtomo, Takayuki; Maniwa, Tsuyoshi; Kawasaki, Hazumi; Ko, Jing-Yuan

2003-09-01

We studied the antiphase self-pulsation in a globally coupled three-mode laser operating in different optical spectrum configurations. We observed locking of modal pulsation frequencies, quasiperiodicity, clustering behaviors, and chaos, resulting from the nonlinear interaction among modes. The robustness of [p:q:r] three-frequency locking states and quasiperiodic oscillations against residual noise has been examined by using joint time-frequency analysis of long-term experimental time series. Two sharply antithetical types of switching behaviors among different dynamic states were observed during temporal evolutions; noise-driven switching and self-induced switching, which manifests itself in chaotic itinerancy. The modal interplay behind observed behaviors was studied by using the statistical dynamic quantity of the information circulation. Well-organized information flows among modes, which correspond to the number of degeneracies of modal pulsation frequencies, were found to be established in accordance with the inherent antiphase dynamics. Observed locking behaviors, quasiperiodic motions, and chaotic itinerancy were reproduced by numerical simulation of the model equations.

All-optical switch with two periodically modulated nonlinear waveguides.

PubMed

Xie, Qiongtao; Luo, Xiaobing; Wu, Biao

2010-02-01

We propose a type of all-optical switch which consists of two periodically modulated nonlinear optical waveguides placed in parallel. Compared to the all-optical switch based on the traditional nonlinear directional coupler without periodic modulation, this all-optical switch has much lower switching threshold power and sharper switching width.

High-power microwave generation using optically activated semiconductor switches

NASA Astrophysics Data System (ADS)

Nunnally, William C.

1990-12-01

The two prominent types of optically controlled switches, the optically controlled linear (OCL) switch and the optically initiated avalanche (OIA) switch, are described, and their operating parameters are characterized. Two transmission line approaches, one using a frozen-wave generator and the other using an injected-wave generator, for generation of multiple cycles of high-power microwave energy using optically controlled switches are discussed. The point design performances of the series-switch, frozen-wave generator and the parallel-switch, injected-wave generator are compared. The operating and performance limitations of the optically controlled switch types are discussed, and additional research needed to advance the development of the optically controlled, bulk, semiconductor switches is indicated.

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

Method to optimize optical switch topology for photonic network-on-chip

NASA Astrophysics Data System (ADS)

Zhou, Ting; Jia, Hao

2018-04-01

In this paper, we propose a method to optimize the optical switch by substituting optical waveguide crossings for optical switching units and an optimizing algorithm to complete the optimization automatically. The functionality of the optical switch remains constant under optimization. With this method, we simplify the topology of optical switch, which means the insertion loss and power consumption of the whole optical switch can be effectively minimized. Simulation result shows that the number of switching units of the optical switch based on Spanke-Benes can be reduced by 16.7%, 20%, 20%, 19% and 17.9% for the scale from 4 × 4 to 8 × 8 respectively. As a proof of concept, the experimental demonstration of an optimized six-port optical switch based on Spanke-Benes structure by means of silicon photonics chip is reported.

Comparative study of 2-DOF micromirrors for precision light manipulation

NASA Astrophysics Data System (ADS)

Young, Johanna I.; Shkel, Andrei M.

2001-08-01

Many industry experts predict that the future of fiber optic telecommunications depends on the development of all-optical components for switching of photonic signals from fiber to fiber throughout the networks. MEMS is a promising technology for providing all-optical switching at high speeds with significant cost reductions. This paper reports on the the analysis of two designs for 2-DOF electrostatically actuated MEMS micromirrors for precision controllable large optical switching arrays. The behavior of the micromirror designs is predicted by coupled-field electrostatic and modal analysis using a finite element analysis (FEA) multi-physics modeling software. The analysis indicates that the commonly used gimbal type mirror design experiences electrostatic interference and would therefore be difficult to precisely control for 2-DOF motion. We propose a new design approach which preserves 2-DOF actuation while minimizing electrostatic interference between the drive electrodes and the mirror. Instead of using two torsional axes, we use one actuator which combines torsional and flexural DOFs. A comparative analysis of the conventional gimbal design and the one proposed in this paper is performed.

Electro-optical 1 x 2, 1 x N and N x N fiber-optic and free-space switching over 1.55 to 3.0 μm using a Ge-Ge(2)Sb(2)Te(5)-Ge prism structure.

PubMed

Hendrickson, Joshua; Soref, Richard; Sweet, Julian; Majumdar, Arka

2015-01-12

New device designs are proposed and theoretical simulations are performed on electro-optical routing switches in which light beams enter and exit the device either from free space or from lensed fibers. The active medium is a ~100 nm layer of phase change material (Ge(2)Sb(2)Te(5) or GeTe) that is electrically "triggered" to change its phase, giving "self-holding" behavior in each of two phases. Electrical current is supplied to that film by a pair of transparent highly doped conducting Ge prisms on both sides of the layer. For S-polarized light incident at ~80° on the film, a three-layer Fabry-Perot analysis, including dielectric loss, predicts good 1 x 2 and 2 x 2 switch performance at infrared wavelengths of 1.55, 2.1 and 3.0 μm, although the performance at 1.55 μm is degraded by material loss and prism mismatch. Proposals for in-plane and volumetric 1 x 4 and 4 x 4 switches are also presented. An unpolarized 1 x 2 switch projects good performance at mid infrared.

Latching micro optical switch

DOEpatents

Garcia, Ernest J; Polosky, Marc A

2013-05-21

An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

Optical Circuit Switched Protocol

NASA Technical Reports Server (NTRS)

Monacos, Steve P. (Inventor)

2000-01-01

The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

Construction of large scale switch matrix by interconnecting integrated optical switch chips with EDFAs

NASA Astrophysics Data System (ADS)

Liao, Mingle; Wu, Baojian; Hou, Jianhong; Qiu, Kun

2018-03-01

Large scale optical switches are essential components in optical communication network. We aim to build up a large scale optical switch matrix by the interconnection of silicon-based optical switch chips using 3-stage CLOS structure, where EDFAs are needed to compensate for the insertion loss of the chips. The optical signal-to-noise ratio (OSNR) performance of the resulting large scale optical switch matrix is investigated for TE-mode light and the experimental results are in agreement with the theoretical analysis. We build up a 64 ×64 switch matrix by use of 16 ×16 optical switch chips and the OSNR and receiver sensibility can respectively be improved by 0.6 dB and 0.2 dB by optimizing the gain configuration of the EDFAs.

Feasibility study of an integrated optic switching center. [satellite tracking application

NASA Technical Reports Server (NTRS)

1979-01-01

The design of a high data rate switching center for a satellite tracking station is discussed. The feasibility of a switching network using an integrated switching matrix is assessed. The preferred integrated optical switching scheme was found to be an electro-optic Bragg diffraction switch. To ascertain the advantages of the integrated optics switching center, its properties are compared to those of opto-electronic and to electronics switching networks.

Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

NASA Technical Reports Server (NTRS)

Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

1986-01-01

After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

Improved Electro-Optical Switches

NASA Technical Reports Server (NTRS)

Nelson, Bruce N.; Cooper, Ronald F.

1994-01-01

Improved single-pole, double-throw electro-optical switches operate in switching times less than microsecond developed for applications as optical communication systems and networks of optical sensors. Contain no moving parts. In comparison with some prior electro-optical switches, these are simpler and operate with smaller optical losses. Beam of light switched from one output path to other by applying, to electro-optical crystal, voltage causing polarization of beam of light to change from vertical to horizontal.

Demonstration of 720×720 optical fast circuit switch for intra-datacenter networks

NASA Astrophysics Data System (ADS)

Ueda, Koh; Mori, Yojiro; Hasegawa, Hiroshi; Matsuura, Hiroyuki; Ishii, Kiyo; Kuwatsuka, Haruhiko; Namiki, Shu; Sato, Ken-ichi

2016-03-01

Intra-datacenter traffic is growing more than 20% a year. In typical datacenters, many racks/pods including servers are interconnected via multi-tier electrical switches. The electrical switches necessitate power-consuming optical-to- electrical (OE) and electrical-to-optical (EO) conversion, the power consumption of which increases with traffic. To overcome this problem, optical switches that eliminate costly OE and EO conversion and enable low power consumption switching are being investigated. There are two major requirements for the optical switch. First, it must have a high port count to construct reduced tier intra-datacenter networks. Second, switching speed must be short enough that most of the traffic load can be offloaded from electrical switches. Among various optical switches, we focus on those based on arrayed-waveguide gratings (AWGs), since the AWG is a passive device with minimal power consumption. We previously proposed a high-port-count optical switch architecture that utilizes tunable lasers, route-and-combine switches, and wavelength-routing switches comprised of couplers, erbium-doped fiber amplifiers (EDFAs), and AWGs. We employed conventional external cavity lasers whose wavelength-tuning speed was slower than 100 ms. In this paper, we demonstrate a large-scale optical switch that offers fast wavelength routing. We construct a 720×720 optical switch using recently developed lasers whose wavelength-tuning period is below 460 μs. We evaluate the switching time via bit-error-ratio measurements and achieve 470-μs switching time (includes 10-μs guard time to handle EDFA surge). To best of our knowledge, this is the first demonstration of such a large-scale optical switch with practical switching time.

128×128 three-dimensional MEMS optical switch module with simultaneous optical path connection for optical cross-connect systems.

PubMed

Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru; Kawajiri, Yuko; Hirata, Hirooki; Uchiyama, Shingo; Makihara, Mitsuhiro; Sakata, Tomomi; Shimoyama, Nobuhiro; Oda, Kazuhiro

2011-07-20

A 128×128 three-dimensional MEMS optical switch module and a switching-control algorithm for high-speed connection and optical power stabilization are described. A prototype switch module enables the simultaneous switching of all optical paths. The insertion loss is less than 4.6 dB and is 2.3 dB on average. The switching time is less than 38 ms and is 8 ms on average. We confirmed that the maximum optical power can be obtained and optical power stabilization control is possible. The results confirm that the module is suitable for practical use in optical cross-connect systems. © 2011 Optical Society of America

Design of a digital, ultra-broadband electro-optic switch for reconfigurable optical networks-on-chip.

PubMed

Van Campenhout, Joris; Green, William M J; Vlasov, Yurii A

2009-12-21

We present a novel design for a noise-tolerant, ultra-broadband electro-optic switch, based on a Mach-Zehnder lattice (MZL) interferometer. We analyze the switch performance through rigorous optical simulations, for devices implemented in silicon-on-insulator with carrier-injection-based phase shifters. We show that such a MZL switch can be designed to have a step-like switching response, resulting in improved tolerance to drive-voltage noise and temperature variations as compared to a single-stage Mach-Zehnder switch. Furthermore, we show that degradation in switching crosstalk and insertion loss due to free-carrier absorption can be largely overcome by a MZL switch design. Finally, MZL switches can be designed for having an ultra-wide, temperature-insensitive optical bandwidth of more than 250 nm. The proposed device shows good potential as a broadband optical switch in reconfigurable optical networks-on-chip.

On-chip broadband silicon thermo-optic 2☓2 four-mode optical switch for optical space and local mode switching.

PubMed

Zhou, Ting; Jia, Hao; Ding, Jianfeng; Zhang, Lei; Fu, Xin; Yang, Lin

2018-04-02

We present a silicon thermo-optic 2☓2 four-mode optical switch optimized for optical space switching plus local optical mode switching. Four asymmetric directional couplers are utilized for mode multiplexing and de-multiplexing. Sixteen 2☓2 single-mode optical switches based on balanced thermally tunable Mach-Zehnder interferometers are exploited for switching function. The measured insertion losses are 8.0~12.2 dB and the optical signal-to-noise ratios are larger than 11.2 dB in the wavelength range of 1525~1565 nm. The optical links in "all-bar" and "all-cross" states exhibit less than 2.0 dB and 1.4 dB power penalties respectively below 10 -9 bit error rates for 40 Gbps data transmission.

Transparent electrode for optical switch

DOEpatents

Goldhar, J.; Henesian, M.A.

1984-10-19

The invention relates generally to optical switches and techniques for applying a voltage to an electro-optical crystal, and more particularly, to transparent electodes for an optical switch. System architectures for very large inertial confinement fusion (ICF) lasers require active optical elements with apertures on the order of one meter. Large aperture optical switches are needed for isolation of stages, switch-out from regenerative amplifier cavities and protection from target retroreflections.

Alternative Controller for a Fiber-Optic Switch

NASA Technical Reports Server (NTRS)

Peters, Robert

2007-01-01

A simplified diagram of a relatively inexpensive controller for a DiCon VX (or equivalent) fiber-optic switch -- an electromechanically actuated switch for optically connecting one or two input optical fibers to any of a number of output optical fibers is shown. DiCon VX fiber-optic switches are used primarily in research and development in the telecommunication industry. This controller can control any such switch having up to 32 output channels.

Light-induced new memory states in electronic resistive switching of NiO/NSTO junction

NASA Astrophysics Data System (ADS)

Wei, Ling; Li, G. Q.; Zhang, W. F.

2016-02-01

n-type and p-type NiO films were prepared on SrTiO3:Nb (NSTO) by controlling oxygen pressures during the process of pulsed laser deposition. The results of current-voltage (I-V) characteristics and photocurrent investigation indicate that the junction shows a typical electronic bipolar resistive switching (RS) behavior and the optical injection can add new resistance states. Photocurrents can obviously be modulated by different resistance states of NiO/NSTO junction. The linear fitting results of I-V curves reveal that the low resistance state follows Ohmic behavior and the high resistance state follows Schottky-emission mechanism. The depletion widths under forward and reverse bias in the dark and with the illumination were estimated respectively. Combined with the energy band structure, the mechanism of RS and photoresponse in the NiO/NSTO junction can be attributed to the variance of interfacial barrier during electrical and optical injection. These results pave the way for the application of the NiO/NSTO junction in the multilevel storage of optical-electrical devices.

Optical switching using IP protocol

NASA Astrophysics Data System (ADS)

Utreras, Andres J.; Gusqui, Luis; Reyes, Andres; Mena, Ricardo I.; Licenko, Gennady L.; Amirgaliyev, Yedilkhan; Komada, Paweł; Luganskaya, Saule; Kashaganova, Gulzhan

2017-08-01

To understand and evaluate the Optical Layer, and how it will affect the IP protocols over WDM (Switching), the present analyse is proposed. Optical communications have attractive proprieties, but also have some disadvantages, so the challenge is to combine the best of both branches. In this paper, general concepts for different options of switching are reviewed as: optical burst switching (OBS) and automatically switching optical network (ASON). Specific details such as their architectures are also discussed. In addition, the relevant characteristics of each variation for switching are reviewed.

Magneto-optic garnet and liquid crystal optical switches

NASA Technical Reports Server (NTRS)

Krawczak, J. A.; Torok, E. J.; Harvey, W. A.; Hewitt, F. G.; Nelson, G. L.

1984-01-01

Magnetic stripe domain and liquid crystal devices are being developed and evaluated as fiber optic switches that can be utilized for nonblocking type nxm optical matrix switches in networking and optical processing. Liquid crystal switches are characterized by very low insertion loss and crosstalk, while stripe domain switches commutate in less than one microsecond. Both switches operate on multimode, randomly polarized fiber light with potentially large values for (n,m). The applications of these magnetic stripe domain and liquid crystal devices are discussed.

Optical switch based on thermocapillarity

NASA Astrophysics Data System (ADS)

Sakata, Tomomi; Makihara, Mitsuhiro; Togo, Hiroyoshi; Shimokawa, Fusao; Kaneko, Kazumasa

2001-11-01

Space-division optical switches are essential for the protection, optical cross-connects (OXCs), and optical add/drop multiplexers (OADMs) needed in future fiber-optic communication networks. For applications in these areas, we proposed a thermocapillarity switch called oil-latching interfacial-tension variation effect (OLIVE) switch. An OLIVE switch is a micro-mechanical optical switch fabricated on planar lightwave circuits (PLC) using micro-electro-mechanical systems (MEMS) technology. It consists of a crossing waveguide that has a groove at each crossing point and a pair of microheaters. The groove is partially filled with the refractive-index-matching liquid, and optical signals are switched according to the liquid's position in the groove, i.e., whether it is passing straight through the groove or reflecting at the sidewall of the groove. The liquid is driven by thermocapillarity and latched by capillarity. Using the total internal reflection to switch the optical path, the OLIVE switch exhibits excellent optical characteristics, such as high transparency (insertion loss: < 2 dB), high extinction ratio (> 50 dB), and low crosstalk (< -50 dB). Moreover, since this switch has a simple structure and bi-stability, it has wide variety of applications in wavelength division multiplexing (WDM) networks.

Time dependent and temperature dependent properties of the forward voltage characteristic of InGaN high power LEDs

NASA Astrophysics Data System (ADS)

Fulmek, P. L.; Haumer, P.; Wenzl, F. P.; Nemitz, W.; Nicolics, J.

2017-03-01

Estimating the junction temperature and its dynamic behavior in dependence of various operating conditions is an important issue, since these properties influence the optical characteristics as well as the aging processes of a light-emitting diode (LED). Particularly for high-power LEDs and pulsed operation, the dynamic behavior and the resulting thermal cycles are of interest. The forward voltage method relies on the existence of a time-independent unique triple of forward-voltage, forward-current, and junction temperature. These three figures should as well uniquely define the optical output power and spectrum, as well as the loss power of the LED, which is responsible for an increase of the junction temperature. From transient FEM-simulations one may expect an increase of the temperature of the active semiconductor layer of some 1/10 K within the first 10 μs. Most of the well-established techniques for junction temperature measurement via forward voltage method evaluate the measurement data several dozens of microseconds after switching on or switching off and estimate the junction temperature by extrapolation towards the time of switching. In contrast, the authors developed a measurement procedure with the focus on the first microseconds after switching. Besides a fast data acquisition system, a precise control of the switching process is required, i.e. a precisely defined current pulse amplitude with fast rise-time and negligible transient by-effects. We start with a short description of the measurement setup and the newly developed control algorithm for the generation of short current pulses. The thermal characterization of the LED chip during the measurement procedures is accomplished by an IR thermography system and transient finite element simulations. The same experimental setup is used to investigate the optical properties of the LED in an Ulbricht-sphere. Our experiments are performed on InGaN LED chips mounted on an Al based insulated metal substrate (IMS), giving a comprehensive picture of the transient behavior of the forward voltage of this type of high power LED.

Organic Materials For Optical Switching

NASA Technical Reports Server (NTRS)

Cardelino, Beatriz H.

1993-01-01

Equations predict properties of candidate materials. Report presents results of theoretical study of nonlinear optical properties of organic materials. Such materials used in optical switching devices for computers and telecommunications, replacing electronic switches. Optical switching potentially offers extremely high information throughout in compact hardware.

Compound semiconductor optical waveguide switch

DOEpatents

Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

2003-06-10

An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

QKD-Based Secured Burst Integrity Design for Optical Burst Switched Networks

NASA Astrophysics Data System (ADS)

Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

2016-03-01

The field of optical transmission has undergone numerous advancements and is still being researched mainly due to the fact that optical data transmission can be done at enormous speeds. It is quite evident that people prefer optical communication when it comes to large amount of data involving its transmission. The concept of switching in networks has matured enormously with several researches, architecture to implement and methods starting with Optical circuit switching to Optical Burst Switching. Optical burst switching is regarded as viable solution for switching bursts over networks but has several security vulnerabilities. However, this work exploited the security issues associated with Optical Burst Switching with respect to integrity of burst. This proposed Quantum Key based Secure Hash Algorithm (QKBSHA-512) with enhanced compression function design provides better avalanche effect over the conventional integrity algorithms.

Experimental demonstration of tunable multiple optical orthogonal codes sequences-based optical label for optical packets switching

NASA Astrophysics Data System (ADS)

Zhang, Chongfu; Qiu, Kun; Zhou, Heng; Ling, Yun; Wang, Yawei; Xu, Bo

2010-03-01

In this paper, the tunable multiple optical orthogonal codes sequences (MOOCS)-based optical label for optical packet switching (OPS) (MOOCS-OPS) is experimentally demonstrated for the first time. The tunable MOOCS-based optical label is performed by using fiber Bragg grating (FBG)-based optical en/decoders group and optical switches configured by using Field Programmable Gate Array (FPGA), and the optical label is erased by using Semiconductor Optical Amplifier (SOA). Some waveforms of the MOOCS-based optical label, optical packet including the MOOCS-based optical label and the payloads are obtained, the switching control mechanism and the switching matrix are discussed, the bit error rate (BER) performance of this system is also studied. These experimental results show that the tunable MOOCS-OPS scheme is effective.

Samarium Monosulfide (SmS): Reviewing Properties and Applications

PubMed Central

Sousanis, Andreas

2017-01-01

In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducting and metallic states could be exploited in several applications, such as high density optical storage and memory materials, thermovoltaic devices, infrared sensors and more. We discuss the electronic, optical and magnetic properties of SmS, its switching behavior, as well as the thin film deposition techniques which have been used, such as e-beam evaporation and sputtering. Moreover, applications and possible ideas for future work on this material are presented. Our scope is to present the properties of SmS, which were mainly measured in bulk crystals, while at the same time we describe the possible deposition methods that will push the study of SmS to nanoscale dimensions, opening an intriguing range of applications for low-dimensional, pressure-induced semiconductor–metal transition compounds. PMID:28813006

A low-latency optical switch architecture using integrated μm SOI-based contention resolution and switching

NASA Astrophysics Data System (ADS)

Mourgias-Alexandris, G.; Moralis-Pegios, M.; Terzenidis, N.; Cherchi, M.; Harjanne, M.; Aalto, T.; Vyrsokinos, K.; Pleros, N.

2018-02-01

The urgent need for high-bandwidth and high-port connectivity in Data Centers has boosted the deployment of optoelectronic packet switches towards bringing high data-rate optics closer to the ASIC, realizing optical transceiver functions directly at the ASIC package for high-rate, low-energy and low-latency interconnects. Even though optics can offer a broad range of low-energy integrated switch fabrics for replacing electronic switches and seamlessly interface with the optical I/Os, the use of energy- and latency-consuming electronic SerDes continues to be a necessity, mainly dictated by the absence of integrated and reliable optical buffering solutions. SerDes undertakes the role of optimally synergizing the lower-speed electronic buffers with the incoming and outgoing optical streams, suggesting that a SerDes-released chip-scale optical switch fabric can be only realized in case all necessary functions including contention resolution and switching can be implemented on a common photonic integration platform. In this paper, we demonstrate experimentally a hybrid Broadcast-and-Select (BS) / wavelength routed optical switch that performs both the optical buffering and switching functions with μm-scale Silicon-integrated building blocks. Optical buffering is carried out in a silicon-integrated variable delay line bank with a record-high on-chip delay/footprint efficiency of 2.6ns/mm2 and up to 17.2 nsec delay capability, while switching is executed via a BS design and a silicon-integrated echelle grating, assisted by SOA-MZI wavelength conversion stages and controlled by a FPGA header processing module. The switch has been experimentally validated in a 3x3 arrangement with 10Gb/s NRZ optical data packets, demonstrating error-free switching operation with a power penalty of <5dB.

All-optical quantum fluid spin beam splitter

NASA Astrophysics Data System (ADS)

Askitopoulos, A.; Nalitov, A. V.; Sedov, E. S.; Pickup, L.; Cherotchenko, E. D.; Hatzopoulos, Z.; Savvidis, P. G.; Kavokin, A. V.; Lagoudakis, P. G.

2018-06-01

We investigate the spin behavior of the first excited state of a polariton condensate in an optical trap by means of polarization resolved spectroscopy. The interplay between the repulsive polariton interactions and the gain saturation results in a nontrivial spontaneous switching between the two quasidegenerate spatial modes of the polariton condensate. As a result, the polarization pattern of the emitted light dramatically changes. Successful harnessing of this effect can lead to a spin-demultiplexing device for polariton-based optical integrated circuits.

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared

NASA Astrophysics Data System (ADS)

Fischer, Marco P.; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J.; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-01

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared.

PubMed

Fischer, Marco P; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-22

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

Ultralow-intensity magneto-optical and mechanical effects in metal nanocolloids.

PubMed

Moocarme, M; Domínguez-Juárez, J L; Vuong, L T

2014-03-12

Magneto-plasmonics is a designation generally associated with ferromagnetic-plasmonic materials because such optical responses from nonmagnetic materials alone are considered weak. Here, we show that there exists a switching transition between linear and nonlinear magneto-optical behaviors in noble-metal nanocolloids that is observable at ultralow illumination intensities and direct current magnetic fields. The response is attributed to polarization-dependent nonzero-time-averaged plasmonic loops, vortex power flows, and nanoparticle magnetization. This work identifies significant mechanical effects that subsequently exist via magnetic-dipole interactions.

An all-optical switch based on a surface plasmon polariton resonator

NASA Astrophysics Data System (ADS)

Pan, Zijuan; Lang, Peilin; Duan, Gaoyan

2018-04-01

All-optical switch is one of the key parts of optical circuit. We employ a temperature-sensitive resonator to form an optical switch. The resonator deforms under the applied light and adjusts the transmittance of the structure. To our knowledge, this is the first design of an all-optical surface plasmon polariton (SPP) switch based on the heat deformation effect.

Impact of optical feedback on current-induced polarization behavior of 1550 nm vertical-cavity surface-emitting lasers.

PubMed

Deng, Tao; Wu, Zheng-Mao; Xie, Yi-Yuan; Wu, Jia-Gui; Tang, Xi; Fan, Li; Panajotov, Krassimir; Xia, Guang-Qiong

2013-06-01

Polarization switching (PS) between two orthogonal linearly polarized fundamental modes is experimentally observed in commercial free-running 1550 nm vertical-cavity surface-emitting lasers (VCSELs) (Raycan). The characteristics of this PS are strongly modified after introducing a polarization-preserved (PP) or polarization-orthogonal (PO) optical feedback. Under the case that the external cavity is approximately 30 cm, the PP optical feedback results in the PS point shifting toward a lower injection current, and the region within which the two polarization modes coexist is enlarged with the increase of the PP feedback strength. Under too-strong PP feedback levels, the PS disappears. The impact of PO optical feedback on VCSEL polarization behavior is quite similar to that of PP optical feedback, but larger feedback strength is needed to obtain similar results.

International Conference on Integrated Optical Circuit Engineering, 1st, Cambridge, MA, October 23-25, 1984, Proceedings

NASA Astrophysics Data System (ADS)

Ostrowsky, D. B.; Sriram, S.

Aspects of waveguide technology are explored, taking into account waveguide fabrication techniques in GaAs/GaAlAs, the design and fabrication of AlGaAs/GaAs phase couplers for optical integrated circuit applications, ion implanted GaAs integrated optics fabrication technology, a direct writing electron beam lithography based process for the realization of optoelectronic integrated circuits, and advances in the development of semiconductor integrated optical circuits for telecommunications. Other subjects examined are related to optical signal processing, optical switching, and questions of optical bistability and logic. Attention is given to acousto-optic techniques in integrated optics, acousto-optic Bragg diffraction in proton exchanged waveguides, optical threshold logic architectures for hybrid binary/residue processors, integrated optical modulation and switching, all-optic logic devices for waveguide optics, optoelectronic switching, high-speed photodetector switching, and a mechanical optical switch.

Highly integrated 3×3 silicon thermo-optical switch using a single combined phase shifter for optical interconnects.

PubMed

Wang, Wanjun; Zhou, Haifeng; Yang, Jianyi; Wang, Minghua; Jiang, Xiaoqing

2012-06-15

We report on an experimental 3×3 thermo-optical switch on silicon on insulator. By controlling a single combined phase shifter, light from any input waveguide can be directed to any output waveguide, showing a simple control method and highly integrated structure as compared to the conventional multiway optical switches. Furthermore, the proposed optical switch can be generalized to be a 1×N and N×N optical switch without an extra phase shifter. The switch is fabricated by complementary metal oxide semiconductor technology. By experiment, full 3×3 switching functionality is demonstrated at a wavelength of 1.55 μm, with an average cross talk of -11.1  dB and a power consumption of 97.5 mW.

Analysis of optical route in a micro high-speed magneto-optic switch

NASA Astrophysics Data System (ADS)

Weng, Zihua; Yang, Guoguang; Huang, Yuanqing; Chen, Zhimin; Zhu, Yun; Wu, Jinming; Lin, Shufen; Mo, Weiping

2005-02-01

A novel micro high-speed 2x2 magneto-optic switch and its optical route, which is used in high-speed all-optical communication network, is designed and analyzed in this paper. The study of micro high-speed magneto-optic switch mainly involves the optical route and high-speed control technique design. The optical route design covers optical route design of polarization in optical switch, the performance analysis and material selection of magneto-optic crystal and magnetic path design in Faraday rotator. The research of high-speed control technique involves the study of nanosecond pulse generator, high-speed magnetic field and its control technique etc. High-speed current transients from nanosecond pulse generator are used to switch the magnetization of the magneto-optic crystal, which propagates a 1550nm optical beam. The optical route design schemes and electronic circuits of high-speed control technique are both simulated on computer and test by the experiments respectively. The experiment results state that the nanosecond pulse generator can output the pulse with rising edge time 3~35ns, voltage amplitude 10~90V and pulse width 10~100ns. Under the control of CPU singlechip, the optical beam can be stably switched and the switching time is less than 1μs currently.

Proposal of optical mode switch

NASA Astrophysics Data System (ADS)

Takakura, Ryuta; Jizodo, Makoto; Fujino, Asuka; Tanaka, Tatsushi; Hamamoto, Kiichi

2014-08-01

Here, we propose a novel optical mode switch, which is a new concept of the optical switch. It can overcome the matrix size limitation issue, which has been a general issue for the waveguide optical space switch, because of its simple fiber coupling configuration. In addition, it contributes to the lossless mux/demux function such as wavelength multiplexing with powerless mode conversion unlike wavelength conversion. In this paper, we propose the principle of the optical mode switch. The simulation results showed less than -30 dB mode crosstalk, with less than only 0.1 dB excess loss for a two-mode optical switch. Moreover, the scalable configuration up to four modes is also proposed in this paper.

A novel fast optical switch based on two cascaded Terahertz Optical Asymmetric Demultiplexers (TOAD).

PubMed

Wang, Bing; Baby, Varghese; Tong, Wilson; Xu, Lei; Friedman, Michelle; Runser, Robert; Glesk, Ivan; Prucnal, Paul

2002-01-14

A novel optical switch based on cascading two terahertz optical asymmetric demultiplexers (TOAD) is presented. By utilizing the sharp edge of the asymmetric TOAD switching window profile, two TOAD switching windows are overlapped to produce a narrower aggregate switching window, not limited by the pulse propagation time in the SOA of the TOAD. Simulations of the cascaded TOAD switching window show relatively constant window amplitude for different window sizes. Experimental results on cascading two TOADs, each with a switching window of 8ps, but with the SOA on opposite sides of the fiber loop, show a minimum switching window of 2.7ps.

All-optical switching for 10-Gb/s packet data by using an ultralow-power optical bistability of photonic-crystal nanocavities.

PubMed

Nozaki, Kengo; Lacraz, Amedee; Shinya, Akihiko; Matsuo, Shinji; Sato, Tomonari; Takeda, Koji; Kuramochi, Eiichi; Notomi, Masaya

2015-11-16

An all-optical packet switching using bistable photonic crystal nanocavity memories was demonstrated for the first time. Nanocavity-waveguide coupling systems were configured for 1 × 1, 1 × 2, and 1 × 3 switches for 10-Gb/s optical packet, and they were all operated with an optical bias power of only a few μW. The power is several magnitudes lower than that of previously reported all-optical packet switches incorporating all-optical memories. A theoretical investigation indicated the optimum design for reducing the power consumption even further, and for realizing a higher data-rate capability and higher extinction. A small footprint and integrability are also features of our switches, which make them attractive for constructing an all-optical packet switching subsystem with a view to realizing optical routing on a chip.

Pump-Induced, Dual-Frequency Switching in a Short-Cavity, Ytterbium-Doped Fiber Laser

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

Guan, W.; Marciante, J.R.

2008-07-23

Using a short linear cavity composed of a section of highly ytterbium-doped fiber surrounded by two fiber Bragg gratings, dual frequency switching is achieved by tuning the pump power of the laser. The dual-frequency switching is generated by the thermal effects of the absorbed pump in the ytterbium-doped fiber. At each frequency, the laser shows single-longitudinal-mode behavior. In each single-mode regime, the optical signal-to-noise ratio of the laser is greater than 50 dB. The dual-frequency, switchable, fiber laser can be designed for various applications by the careful selection of the two gratings.

All-optical switching of magnetoresistive devices using telecom-band femtosecond laser

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

He, Li; Chen, Jun-Yang; Wang, Jian-Ping, E-mail: jpwang@umn.edu, E-mail: moli@umn.edu

Ultrafast all-optical switching of the magnetization of various magnetic systems is an intriguing phenomenon that can have tremendous impact on information storage and processing. Here, we demonstrate all-optical switching of GdFeCo alloy films using a telecom-band femtosecond fiber laser. We further fabricate Hall cross devices and electrically readout all-optical switching by measuring anomalous Hall voltage changes. The use of a telecom laser and the demonstrated all-optical switching of magnetoresistive devices represent the first step toward integration of opto-magnetic devices with mainstream photonic devices to enable novel optical and spintronic functionalities.

Development, implementation, and test results on integrated optics switching matrix

NASA Technical Reports Server (NTRS)

Rutz, E.

1982-01-01

A small integrated optics switching matrix, which was developed, implemented, and tested, indicates high performance. The matrix serves as a model for the design of larger switching matrices. The larger integrated optics switching matrix should form the integral part of a switching center with high data rate throughput of up to 300 megabits per second. The switching matrix technique can accomplish the design goals of low crosstalk and low distortion. About 50 illustrations help explain and depict the many phases of the integrated optics switching matrix. Many equations used to explain and calculate the experimental data are also included.

Advanced optical components for next-generation photonic networks

NASA Astrophysics Data System (ADS)

Yoo, S. J. B.

2003-08-01

Future networks will require very high throughput, carrying dominantly data-centric traffic. The role of Photonic Networks employing all-optical systems will become increasingly important in providing scalable bandwidth, agile reconfigurability, and low-power consumptions in the future. In particular, the self-similar nature of data traffic indicates that packet switching and burst switching will be beneficial in the Next Generation Photonic Networks. While the natural conclusion is to pursue Photonic Packet Switching and Photonic Burst Switching systems, there are significant challenges in realizing such a system due to practical limitations in optical component technologies. Lack of a viable all-optical memory technology will continue to drive us towards exploring rapid reconfigurability in the wavelength domain. We will introduce and discuss the advanced optical component technologies behind the Photonic Packet Routing system designed and demonstrated at UC Davis. The system is capable of packet switching and burst switching, as well as circuit switching with 600 psec switching speed and scalability to 42 petabit/sec aggregated switching capacity. By utilizing a combination of rapidly tunable wavelength conversion and a uniform-loss cyclic frequency (ULCF) arrayed waveguide grating router (AWGR), the system is capable of rapidly switching the packets in wavelength, time, and space domains. The label swapping module inside the Photonic Packet Routing system containing a Mach-Zehnder wavelength converter and a narrow-band fiber Bragg-grating achieves all-optical label swapping with optical 2R (potentially 3R) regeneration while maintaining optical transparency for the data payload. By utilizing the advanced optical component technologies, the Photonic Packet Routing system successfully demonstrated error-free, cascaded, multi-hop photonic packet switching and routing with optical-label swapping. This paper will review the advanced optical component technologies and their role in the Next Generation Photonic Networks.

Flexible-rate optical packet generation/detection and label swapping for optical label switching networks

NASA Astrophysics Data System (ADS)

Wu, Zhongying; Li, Juhao; Tian, Yu; Ge, Dawei; Zhu, Paikun; Chen, Yuanxiang; Chen, Zhangyuan; He, Yongqi

2017-03-01

In recent years, optical label switching (OLS) gains lots of attentions due to its intrinsic advantages to implement protocol, bit-rate, granularity and data format transparency packet switching. In this paper, we propose a novel scheme to realize flexible-rate optical packet switching for OLS networks. At the transmitter node, flexible-rate packet is generated by parallel modulating different combinations of optical carriers generated from the optical multi-carrier generator (OMCG), among which the low-speed optical label occupies one carrier. At the switching node, label is extracted and re-generated in label processing unit (LPU). The payloads are switched based on routing information and new label is added after switching. At the receiver node, another OMCG serves as local oscillators (LOs) for optical payloads coherent detection. The proposed scheme offers good flexibility for dynamic optical packet switching by adjusting the payload bandwidth and could also effectively reduce the number of lasers, modulators and receivers for packet generation/detection. We present proof-of-concept demonstrations of flexible-rate packet generation/detection and label swapping in 12.5 GHz grid. The influence of crosstalk for cascaded label swapping is also investigated.

Optical control demonstrates switch-like PIP3 dynamics underlying the initiation of immune cell migration

PubMed Central

Karunarathne, W. K. Ajith; Giri, Lopamudra; Patel, Anilkumar K.; Venkatesh, Kareenhalli V.; Gautam, N.

2013-01-01

There is a dearth of approaches to experimentally direct cell migration by continuously varying signal input to a single cell, evoking all possible migratory responses and quantitatively monitoring the cellular and molecular response dynamics. Here we used a visual blue opsin to recruit the endogenous G-protein network that mediates immune cell migration. Specific optical inputs to this optical trigger of signaling helped steer migration in all possible directions with precision. Spectrally selective imaging was used to monitor cell-wide phosphatidylinositol (3,4,5)-triphosphate (PIP3), cytoskeletal, and cellular dynamics. A switch-like PIP3 increase at the cell front and a decrease at the back were identified, underlying the decisive migratory response. Migration was initiated at the rapidly increasing switch stage of PIP3 dynamics. This result explains how a migratory cell filters background fluctuations in the intensity of an extracellular signal but responds by initiating directionally sensitive migration to a persistent signal gradient across the cell. A two-compartment computational model incorporating a localized activator that is antagonistic to a diffusible inhibitor was able to simulate the switch-like PIP3 response. It was also able simulate the slow dissipation of PIP3 on signal termination. The ability to independently apply similar signaling inputs to single cells detected two cell populations with distinct thresholds for migration initiation. Overall the optical approach here can be applied to understand G-protein–coupled receptor network control of other cell behaviors. PMID:23569254

Optical control demonstrates switch-like PIP3 dynamics underlying the initiation of immune cell migration.

PubMed

Karunarathne, W K Ajith; Giri, Lopamudra; Patel, Anilkumar K; Venkatesh, Kareenhalli V; Gautam, N

2013-04-23

There is a dearth of approaches to experimentally direct cell migration by continuously varying signal input to a single cell, evoking all possible migratory responses and quantitatively monitoring the cellular and molecular response dynamics. Here we used a visual blue opsin to recruit the endogenous G-protein network that mediates immune cell migration. Specific optical inputs to this optical trigger of signaling helped steer migration in all possible directions with precision. Spectrally selective imaging was used to monitor cell-wide phosphatidylinositol (3,4,5)-triphosphate (PIP3), cytoskeletal, and cellular dynamics. A switch-like PIP3 increase at the cell front and a decrease at the back were identified, underlying the decisive migratory response. Migration was initiated at the rapidly increasing switch stage of PIP3 dynamics. This result explains how a migratory cell filters background fluctuations in the intensity of an extracellular signal but responds by initiating directionally sensitive migration to a persistent signal gradient across the cell. A two-compartment computational model incorporating a localized activator that is antagonistic to a diffusible inhibitor was able to simulate the switch-like PIP3 response. It was also able simulate the slow dissipation of PIP3 on signal termination. The ability to independently apply similar signaling inputs to single cells detected two cell populations with distinct thresholds for migration initiation. Overall the optical approach here can be applied to understand G-protein-coupled receptor network control of other cell behaviors.

Optically-switched submillimeter-wave oscillator and radiator having a switch-to-switch propagation delay

NASA Technical Reports Server (NTRS)

Spencer, Michael G. (Inventor); Maserjian, Joseph (Inventor)

1995-01-01

A submillimeter wave-generating integrated circuit includes an array of N photoconductive switches biased across a common voltage source and an optical path difference from a common optical pulse of repetition rate f sub 0 providing a different optical delay to each of the switches. In one embodiment, each incoming pulse is applied to successive ones of the N switches with successive delays. The N switches are spaced apart with a suitable switch-to-switch spacing so as to generate at the output load or antenna radiation of a submillimeter wave frequency f on the order of N f sub 0. Preferably, the optical pulse has a repetition rate of at least 10 GHz and N is of the order of 100, so that the circuit generates radiation of frequency of the order of or greater than 1 Terahertz.

Asymmetric noise sensitivity of pulse trains in an excitable microlaser with delayed optical feedback

NASA Astrophysics Data System (ADS)

Terrien, Soizic; Krauskopf, Bernd; Broderick, Neil G. R.; Andréoli, Louis; Selmi, Foued; Braive, Rémy; Beaudoin, Grégoire; Sagnes, Isabelle; Barbay, Sylvain

2017-10-01

A semiconductor micropillar laser with delayed optical feedback is considered. In the excitable regime, we show that a single optical perturbation can trigger a train of pulses that is sustained for a finite duration. The distribution of the pulse train duration exhibits an exponential behavior characteristic of a noise-induced process driven by uncorrelated white noise present in the system. The comparison of experimental observations with theoretical and numerical analysis of a minimal model yields excellent agreement. Importantly, the random switch-off process takes place between two attractors of different nature: an equilibrium and a periodic orbit. Our analysis shows that there is a small time window during which the pulsations are very sensitive to noise, and this explains the observed strong bias toward switch-off. These results raise the possibility of all optical control of the pulse train duration that may have an impact for practical applications in photonics and may also apply to the dynamics of other noise-driven excitable systems with delayed feedback.

Free-Space Optical Switch Modules Using Risley Optical Beam Deflectors

NASA Astrophysics Data System (ADS)

Matsui, Takashi; Oohira, Fumikazu; Hosogi, Maho; Yamamoto, Tsuyoshi

2006-03-01

This paper describes new optical switch modules based on Risley optical beam deflectors. The Risley deflector consists of two wedge-shaped prisms and precisely controllable rotation mechanisms. An optical beam can be deflected to the direction of two axes by rotating each prism independently. The deflectors potentially have a self-latching function, which provides a reliable switching operation, and a large-deflection angle of 19.2°, which makes the switch compact. We experimentally confirmed that prototype switch modules, hardware volume: 15× 15× 31 mm3, deflection angle: <19.2°, have a scalability of the switch up to 256 ports, low-loss characteristics of 1.0-1.5 dB, and switching time of within 6 s.

Switching fields and their distributions in rounded-rectangle [Co/Pd]8 nanodots and nanorings with identical configuration

NASA Astrophysics Data System (ADS)

Ren, Y.; Wang, Y.; He, X. D.; Adeyeye, A. O.

2018-04-01

We present two different types of magnetization reversal behaviors for the identically-configured Co/Pd multilayers with rounded-rectangular nanodots and nanorings for various edge-to-edge distances (s), by using focused magneto-optic Kerr measurements and magnetic force microscopy measurements. For the nanodots with a fixed outer diameter of d = 580 nm, the switching field Hsw and switching field distribution (SFD) are almost invariant with respect to s. However, the Hsw and SFD for the nanodot arrays could be easily modulated by varying d, which is ascribed to the size effect. In contrast, the Hsw and SFD are strongly dependent on s for the nanorings. Compared to the strongly coupled magnetic moments of the closely-packed nanorings, the magnetostatic interaction among nanodots is negligible, which should be responsible for the observed different magnetization reversal behaviors.

Ultra-fast all-optical plasmonic switching in near infra-red spectrum using a Kerr nonlinear ring resonator

NASA Astrophysics Data System (ADS)

Nurmohammadi, Tofiq; Abbasian, Karim; Yadipour, Reza

2018-03-01

In this paper, an all-optical plasmonic switch based on metal-insulator-metal (MIM) nanoplasmonic waveguide with a Kerr nonlinear ring resonator is introduced and studied. Two-dimensional simulations utilizing the finite-difference time-domain algorithm are used to demonstrate an apparent optical bistability and significant switching mechanisms (in enabled-low condition: T(ON/OFF) =21.9 and in enabled-high condition: T(ON/OFF) =24.9) of the signal light arisen by altering the pump-light intensity. The proposed all-optical switching demonstrates femtosecond-scale feedback time (90 fs) and then ultra-fast switching can be achieved. The offered all-optical switch may recognize potential significant applications in integrated optical circuits.

Optical switches and switching methods

DOEpatents

Doty, Michael

2008-03-04

A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

Architecture design and performance evaluation of multigranularity optical networks based on optical code division multiplexing

NASA Astrophysics Data System (ADS)

Huang, Shaowei; Baba, Ken-Ichi; Murata, Masayuki; Kitayama, Ken-Ichi

2006-12-01

In traditional lambda-based multigranularity optical networks, a lambda is always treated as the basic routing unit, resulting in low wavelength utilization. On the basis of optical code division multiplexing (OCDM) technology, a novel OCDM-based multigranularity optical cross-connect (MG-OXC) is proposed. Compared with the traditional lambda-based MG-OXC, its switching capability has been extended to support fiber switching, waveband switching, lambda switching, and OCDM switching. In a network composed of OCDM-based MG-OXCs, a single wavelength can be shared by distinct label switched paths (LSPs) called OCDM-LSPs, and OCDM-LSP switching can be implemented in the optical domain. To improve the network flexibility for an OCDM-LSP provisioning, two kinds of switches enabling hybrid optical code (OC)-wavelength conversion are designed. Simulation results indicate that a blocking probability reduction of 2 orders can be obtained by deploying only five OCs to a single wavelength. Furthermore, compared with time-division-multiplexing LSP (TDM-LSP), owing to the asynchronous accessibility and the OC conversion, OCDM-LSPs have been shown to permit a simpler switch architecture and achieve better blocking performance than TDM-LSPs.

Quantum Zeno Blockade for Next Generation Optical Switching in Fiber Systems

DTIC Science & Technology

2013-09-01

and utilized a self - referential quantum process tomography method to observe the Zeno effect in optical fiber using the ultrafast all- optical switch...controllable and can be used as a knob to study the core physics behind the Zeno-based switching. For this experiment, we developed a self - referential ...efficient optical communications. The quantum Zeno effect can be used to induce or inhibit optical switching through a variety of processes , all of

Measurement of magnetic property of FePt granular media at near Curie temperature

NASA Astrophysics Data System (ADS)

Yang, H. Z.; Chen, Y. J.; Leong, S. H.; An, C. W.; Ye, K. D.; Hu, J. F.

2017-02-01

The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature (Tc) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity 25 kOe) at near Tc with a home built HAMR testing instrument. The local area of HAMR media is heated to near Tc by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field (Hc) of the FePt granular media and their dependence on the optical heating power at near Tc were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the Tc distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, Hc of the HAMR media at near Tc in a static manner. The present methodology will facilitate the HAMR media testing.

Optical switching property of electromagnetically induced transparency in a Λ system

NASA Astrophysics Data System (ADS)

Zhang, Lianshui; Wang, Jian; Feng, Xiaomin; Yang, Lijun; Li, Xiaoli; Zhao, Min

2008-12-01

In this paper we study the coherent transient property of a Λ-three-level system (Ωd = 0) and a quasi- Λ -four-level system (Ωd>0). Optical switching of the probe field can be achieved by applying a pulsed coupling field or rf field. In Λ -shaped three-level system, when the coupling field was switched on, there is a almost total transparency of the probe field and the time required for the absorption changing from 90% to 10% of the maximum absorption is 2.9Γ0 (Γ0 is spontaneous emission lifetime). When the coupling field was switched off, there is an initial increase of the probe field absorption and then gradually evolves to the maximum of absorption of the two-level absorption, the time required for the absorption of the system changing from 10% to 90% is 4.2Γ0. In four-level system, where rf driving field is used as switching field, to achieve the same depth of the optical switching, the time of the optical switching is 2.5Γ0 and 6.1Γ0, respectively. The results show that with the same depth of the optical switching, the switch-on time of the four-level system is shorter than that of the three-level system, while the switch-off time of the four-level system is longer. The depth of the optical switching of the four-level system was much larger than that of the three-level system, where the depth of the optical switching of the latter is merely 14.8% of that of the former. The speed of optical switching of the two systems can be increased by the increase of Rabi frequency of coupling field or rf field.

Characteristics of silicon-based Sagnac optical switches using magneto-optical micro-ring array

NASA Astrophysics Data System (ADS)

Ni, Shuang; Wu, Baojian; Liu, Yawen

2018-01-01

The miniaturization and integration of optical switches are necessary for photonic switching networks and the utilization of magneto optical effects is a promising candidate. We propose a Sagnac optical switch chip based on the principle of nonreciprocal phase shift (NPS) of the magneto-optical (MO) micro-ring (MOMR) array, composed of SiO2/Si/Ce:YIG/SGGG. The MO switching function is realized by controlling the drive current in the snake-like metal microstrip circuit layered on the MOMRs. The transmission characteristics of the Sagnac MO switch chip dependent on magnetization intensity, waveguide coupling coefficient and waveguide loss are simulated. By optimizing the coupling coefficients, we design an MO switch using two serial MOMRs with a circumference of 38.37 μm, and the 3dB bandwidth and the extinction ratio are respectively up to 1.6 nm and 50dB for the waveguide loss coefficient of ?. And the switching magnetization can be further reduced by increasing the number of parallel MOMRs. The frequency response of the MO Sagnac switch is analyzed as well.

Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

NASA Astrophysics Data System (ADS)

Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

2014-08-01

Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

High-speed optical switch fabrics with large port count.

PubMed

Yeo, Yong-Kee; Xu, Zhaowen; Wang, Dawei; Liu, Jianguo; Wang, Yixin; Cheng, Tee-Hiang

2009-06-22

We report a novel architecture that can be used to construct optical switch fabrics with very high port count and nanoseconds switching speed. It is well known that optical switch fabrics with very fast switching time and high port count are challenging to realize. Currently, one of the most promising solutions is based on a combination of wavelength-tunable lasers and the arrayed waveguide grating router (AWGR). To scale up the number of ports in such switches, a direct method is to use AWGRs with a high channel count. However, such AWGRs introduce very large crosstalk noise due to the close wavelength channel spacing. In this paper, we propose an architecture for realizing a high-port count optical switch fabric using a combination of low-port count AWGRs, optical ON-OFF gates and WDM couplers. Using this new methodology, we constructed a proof-of concept experiment to demonstrate the feasibility of a 256 x 256 optical switch fabric. To our knowledge, this port count is the highest ever reported for switch fabrics of this type.

Numerical investigation of an all-optical switch in a graded nonlinear plasmonic grating.

PubMed

Wang, Guoxi; Lu, Hua; Liu, Xueming; Gong, Yongkang

2012-11-09

We have proposed and numerically investigated an all-optical switch based on a metal-insulator-metal waveguide with graded nonlinear plasmonic gratings. The influences of grating depth and refractive index of a Kerr nonlinear medium on the transmission of the switch are exactly analyzed by utilizing transmission line theory. The finite-difference time-domain simulation results show that the highly compact structure possesses excellent switch function by tuning the incident electric field intensity. In addition, the simulation results show that this all-optical switch has an ultrawide operating frequency regime and femtosecond-scale response time (~130 fs). Such a switch can find potential applications for all-optical signal processing and optical communication.

High bandwidth all-optical 3×3 switch based on multimode interference structures

NASA Astrophysics Data System (ADS)

Le, Duy-Tien; Truong, Cao-Dung; Le, Trung-Thanh

2017-03-01

A high bandwidth all-optical 3×3 switch based on general interference multimode interference (GI-MMI) structure is proposed in this study. Two 3×3 multimode interference couplers are cascaded to realize an all-optical switch operating at both wavelengths of 1550 nm and 1310 nm. Two nonlinear directional couplers at two outer-arms of the structure are used as all-optical phase shifters to achieve all switching states and to control the switching states. Analytical expressions for switching operation using the transfer matrix method are presented. The beam propagation method (BPM) is used to design and optimize the whole structure. The optimal design of the all-optical phase shifters and 3×3 MMI couplers are carried out to reduce the switching power and loss.

Temporal switching jitter in photoconductive switches

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

GAUDET,JOHN A.; SKIPPER,MICHAEL C.; ABDALLA,MICHAEL D.

This paper reports on a recent comparison made between the Air Force Research Laboratory (AFRL) gallium arsenide, optically-triggered switch test configuration and the Sandia National Laboratories (SNL) gallium arsenide, optically-triggered switch test configuration. The purpose of these measurements was to compare the temporal switch jitter times. It is found that the optical trigger laser characteristics are dominant in determining the PCSS jitter.

Apollo Ring Optical Switch

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

Maestas, J.H.

1987-03-01

An optical switch was designed, built, and installed at Sandia National Laboratories in Albuquerque, New Mexico, to facilitate the integration of two Apollo computer networks into a single network. This report presents an overview of the optical switch as well as its layout, switch testing procedure and test data, and installation.

Call for Papers: Photonics in Switching

NASA Astrophysics Data System (ADS)

Wosinska, Lena; Glick, Madeleine

2006-04-01

Call for Papers: Photonics in Switching

Guest Editors:

Lena Wosinska, Royal Institute of Technology (KTH) / ICT Sweden Madeleine Glick, Intel Research, Cambridge, UK

Scope of Submission

• WDM node architectures
• Novel device technologies enabling photonics in switching, such as optical switch fabrics, optical memory, and wavelength conversion
• Routing protocols
• WDM switching and routing
• Quality of service
• Performance measurement and evaluation
• Next-generation optical networks: architecture, signaling, and control
• Traffic measurement and field trials
• Optical burst and packet switching
• OBS/OPS node architectures
• Burst/Packet scheduling and routing algorithms
• Contention resolution/avoidance strategies
• Services and applications for OBS/OPS (e.g., grid networks, storage-area networks, etc.)
• Burst assembly and ingress traffic shaping
• Hybrid OBS/TDM or OBS/wavelength routing

Manuscript Submission

Light-Gated Memristor with Integrated Logic and Memory Functions.

PubMed

Tan, Hongwei; Liu, Gang; Yang, Huali; Yi, Xiaohui; Pan, Liang; Shang, Jie; Long, Shibing; Liu, Ming; Wu, Yihong; Li, Run-Wei

2017-11-28

Memristive devices are able to store and process information, which offers several key advantages over the transistor-based architectures. However, most of the two-terminal memristive devices have fixed functions once made and cannot be reconfigured for other situations. Here, we propose and demonstrate a memristive device "memlogic" (memory logic) as a nonvolatile switch of logic operations integrated with memory function in a single light-gated memristor. Based on nonvolatile light-modulated memristive switching behavior, a single memlogic cell is able to achieve optical and electrical mixed basic Boolean logic of reconfigurable "AND", "OR", and "NOT" operations. Furthermore, the single memlogic cell is also capable of functioning as an optical adder and digital-to-analog converter. All the memlogic outputs are memristive for in situ data storage due to the nonvolatile resistive switching and persistent photoconductivity effects. Thus, as a memdevice, the memlogic has potential for not only simplifying the programmable logic circuits but also building memristive multifunctional optoelectronics.

Room temperature operation of electro-optical bistability in the edge-emitting tunneling-collector transistor laser

NASA Astrophysics Data System (ADS)

Feng, M.; Holonyak, N.; Wang, C. Y.

2017-09-01

Optical bistable devices are fundamental to digital photonics as building blocks of switches, logic gates, and memories in future computer systems. Here, we demonstrate both optical and electrical bistability and capability for switching in a single transistor operated at room temperature. The electro-optical hysteresis is explained by the interaction of electron-hole (e-h) generation and recombination dynamics with the cavity photon modulation in different switching paths. The switch-UP and switch-DOWN threshold voltages are determined by the rate difference of photon generation at the base quantum-well and the photon absorption via intra-cavity photon-assisted tunneling controlled by the collector voltage. Thus, the transistor laser electro-optical bistable switching is programmable with base current and collector voltage, and the basis for high speed optical logic processors.

Remote Optical Switch for Localized and Selective Control of Gene Interference

PubMed Central

Lee, Somin Eunice; Liu, Gang Logan; Kim, Franklin; Lee, Luke P.

2009-01-01

Near infrared-absorbing gold nanoplasmonic particles (GNPs) are used as optical switches of gene interference and are remotely controlled using light. We have tuned optical switches to a wavelength where cellular photodamage is minimized. Optical switches are functionalized with double-stranded oligonucleotides. At desired times and at specific intracellular locations, remote optical excitation is used to liberate gene-interfering oligonucleotides. We demonstrate a novel gene-interfering technique offering spatial and temporal control, which is otherwise impossible using conventional gene-interfering techniques. PMID:19128006

Compact wavelength-selective optical switch based on digital optical phase conjugation.

PubMed

Li, Zhiyang; Claver, Havyarimana

2013-11-15

In this Letter, we show that digital optical phase conjugation might be utilized to construct a new kind of wavelength-selective switches. When incorporated with a multimode interferometer, these switches have wide bandwidth, high tolerance for fabrication error, and low polarization dependency. They might help to build large-scale multiwavelength nonblocking switching systems, or even to fabricate an optical cross-connecting or routing system on a chip.

OPTICAL PROCESSING OF INFORMATION: Multistage optoelectronic two-dimensional image switches

NASA Astrophysics Data System (ADS)

Fedorov, V. B.

1994-06-01

The implementation principles and the feasibility of construction of high-throughput multistage optoelectronic switches, capable of transmitting data in the form of two-dimensional images along interconnected pairs of optical channels, are considered. Different ways of realising compact switches are proposed. They are based on the use of polarisation-sensitive elements, arrays of modulators of the plane of polarisation of light, arrays of objectives, and free-space optics. Optical systems of such switches can theoretically ensure that the resolution and optical losses in two-dimensional image transmission are limited only by diffraction. Estimates are obtained of the main maximum-performance parameters of the proposed optoelectronic image switches.

Micro-Ball-Lens Optical Switch Driven by SMA Actuator

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok

2003-01-01

The figure is a simplified cross section of a microscopic optical switch that was partially developed at the time of reporting the information for this article. In a fully developed version, light would be coupled from an input optical fiber to one of two side-by-side output optical fibers. The optical connection between the input and the selected output fiber would be made via a microscopic ball lens. Switching of the optical connection from one output fiber to another would be effected by using a pair of thin-film shape-memory-alloy (SMA) actuators to toggle the lens between two resting switch positions. There are many optical switches some made of macroscopic parts by conventional fabrication techniques and some that are microfabricated and, hence, belong to the class of microelectromechanical systems (MEMS). Conventionally fabricated optical switches tend to be expensive. MEMS switches can be mass-produced at relatively low cost, but their attractiveness has been diminished by the fact that, heretofore, MEMS switches have usually been found to exhibit high insertion losses. The present switch is intended to serve as a prototype of low-loss MEMS switches. In addition, this is the first reported SMA-based optical switch. The optical fibers would be held in V grooves in a silicon frame. The lens would have a diameter of 1 m; it would be held by, and positioned between, the SMA actuators, which would be made of thin films of TiNi alloy. Although the SMA actuators are depicted here as having simple shapes for the sake of clarity of illustration, the real actuators would have complex, partly net-like shapes. With the exception of the lens and the optical fibers, the SMA actuators and other components of the switch would be made by microfabrication techniques. The components would be assembled into a sandwich structure to complete the fabrication of the switch. To effect switching, an electric current would be passed through one of the SMA actuators to heat it above its transition temperature, thereby causing it to deform to a different "remembered" shape. The two SMA actuators would be stiff enough that once switching had taken place and the electrical current was turned off, the lens would remain latched in the most recently selected position. In a test, the partially developed switch exhibited an insertion loss of only -1.9 dB and a switching contrast of 70 dB. One the basis of prior research on SMA actuators and assuming a lens displacement of 125 m between extreme positions, it has been estimated that the fully developed switch would be capable of operating at a frequency as high as 10 Hz.

Converged photonic data storage and switch platform for exascale disaggregated data centers

NASA Astrophysics Data System (ADS)

Pitwon, R.; Wang, K.; Worrall, A.

2017-02-01

We report on a converged optically enabled Ethernet storage, switch and compute platform, which could support future disaggregated data center architectures. The platform includes optically enabled Ethernet switch controllers, an advanced electro-optical midplane and optically interchangeable generic end node devices. We demonstrate system level performance using optically enabled Ethernet disk drives and micro-servers across optical links of varied lengths.

Enhanced Thermo-Optical Switching of Paraffin-Wax Composite Spots under Laser Heating

PubMed Central

Said, Asmaa; Salah, Abeer; Abdel Fattah, Gamal

2017-01-01

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin’s rather low thermal conductivity. In this paper, the use of different carbon fillers as thermal conductivity enhancers for paraffin has been investigated, and a novel structure based on spot of paraffin wax as a thermo-optic switch is presented. Thermo-optical switching parameters are enhanced with the addition of graphite and graphene, due to the extreme thermal conductivity of the carbon fillers. Differential Scanning Calorimetry (DSC) and Scanning electron microscope (SEM) are performed on paraffin wax composites, and specific heat capacities are calculated based on DSC measurements. Thermo-optical switching based on transmission is measured as a function of the host concentration under conventional electric heating and laser heating of paraffin-carbon fillers composites. Further enhancements in thermo-optical switching parameters are studied under Nd:YAG laser heating. This novel structure can be used in future networks with huge bandwidth requirements and electric noise free remote aerial laser switching applications. PMID:28772884

Enhanced Thermo-Optical Switching of Paraffin-Wax Composite Spots under Laser Heating.

PubMed

Said, Asmaa; Salah, Abeer; Fattah, Gamal Abdel

2017-05-12

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin's rather low thermal conductivity. In this paper, the use of different carbon fillers as thermal conductivity enhancers for paraffin has been investigated, and a novel structure based on spot of paraffin wax as a thermo-optic switch is presented. Thermo-optical switching parameters are enhanced with the addition of graphite and graphene, due to the extreme thermal conductivity of the carbon fillers. Differential Scanning Calorimetry (DSC) and Scanning electron microscope (SEM) are performed on paraffin wax composites, and specific heat capacities are calculated based on DSC measurements. Thermo-optical switching based on transmission is measured as a function of the host concentration under conventional electric heating and laser heating of paraffin-carbon fillers composites. Further enhancements in thermo-optical switching parameters are studied under Nd:YAG laser heating. This novel structure can be used in future networks with huge bandwidth requirements and electric noise free remote aerial laser switching applications.

Efficient high repetition rate electro-optic Q-switched laser with an optically active langasite crystal

PubMed Central

Ma, Shihui; Yu, Haohai; Zhang, Huaijin; Han, Xuekun; Lu, Qingming; Ma, Changqin; Boughton, Robert I.; Wang, Jiyang

2016-01-01

With an optically active langasite (LGS) crystal as the electro-optic Q-switch, we demonstrate an efficient Q-switched laser with a repetition rate of 200 kHz. Based on the theoretical analysis of the interaction between optical activity and electro-optic property, the optical activity of the crystal has no influence on the birefringence during Q-switching if the quarter wave plate used was rotated to align with the polarization direction. With a Nd:LuVO4 crystal possessing a large emission cross-section and a short fluorescence lifetime as the gain medium, a stable LGS Q-switched laser was designed with average output power of 4.39 W, corresponding to a slope efficiency of 29.4% and with a minimum pulse width of 5.1 ns. This work represents the highest repetition rate achieved so far in a LGS Q-switched laser and it can provide a practical Q-switched laser with a tunable high repetition rates for many applications, such as materials processing, laser ranging, medicine, military applications, biomacromolecule materials, remote sensing, etc. PMID:27461819

Submicron bidirectional all-optical plasmonic switches

PubMed Central

Chen, Jianjun; Li, Zhi; Zhang, Xiang; Xiao, Jinghua; Gong, Qihuang

2013-01-01

Ultra-small all-optical switches are of importance in highly integrated optical communication and computing networks. However, the weak nonlinear light-matter interactions in natural materials present an enormous challenge to realize efficiently switching for the ultra-short interaction lengths. Here, we experimentally demonstrate a submicron bidirectional all-optical plasmonic switch with an asymmetric T-shape single slit. Sharp asymmetric spectra as well as significant field enhancements (about 18 times that in the conventional slit case) occur in the symmetry-breaking structure. Consequently, both of the surface plasmon polaritons propagating in the opposite directions on the metal surface are all-optically controlled inversely at the same time with the on/off switching ratios of >6 dB for the device lateral dimension of <1 μm. Moreover, in such a submicron structure, the coupling of free-space light and the on-chip bidirectional switching are integrated together. This submicron bidirectional all-optical switch may find important applications in the highly integrated plasmonic circuits. PMID:23486232

Optical MEMS platform for low-cost on-chip integration of planar light circuits and optical switching

NASA Astrophysics Data System (ADS)

German, Kristine A.; Kubby, Joel; Chen, Jingkuang; Diehl, James; Feinberg, Kathleen; Gulvin, Peter; Herko, Larry; Jia, Nancy; Lin, Pinyen; Liu, Xueyuan; Ma, Jun; Meyers, John; Nystrom, Peter; Wang, Yao Rong

2004-07-01

Xerox Corporation has developed a technology platform for on-chip integration of latching MEMS optical waveguide switches and Planar Light Circuit (PLC) components using a Silicon On Insulator (SOI) based process. To illustrate the current state of this new technology platform, working prototypes of a Reconfigurable Optical Add/Drop Multiplexer (ROADM) and a l-router will be presented along with details of the integrated latching MEMS optical switches. On-chip integration of optical switches and PLCs can greatly reduce the size, manufacturing cost and operating cost of multi-component optical equipment. It is anticipated that low-cost, low-overhead optical network products will accelerate the migration of functions and services from high-cost long-haul markets to price sensitive markets, including networks for metropolitan areas and fiber to the home. Compared to the more common silica-on-silicon PLC technology, the high index of refraction of silicon waveguides created in the SOI device layer enables miniaturization of optical components, thereby increasing yield and decreasing cost projections. The latching SOI MEMS switches feature moving waveguides, and are advantaged across multiple attributes relative to alternative switching technologies, such as thermal optical switches and polymer switches. The SOI process employed was jointly developed under the auspice of the NIST APT program in partnership with Coventor, Corning IntelliSense Corp., and MicroScan Systems to enable fabrication of a broad range of free space and guided wave MicroOptoElectroMechanical Systems (MOEMS).

Power inverter with optical isolation

DOEpatents

Duncan, Paul G.; Schroeder, John Alan

2005-12-06

An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

A single-stage optical load-balanced switch for data centers.

PubMed

Huang, Qirui; Yeo, Yong-Kee; Zhou, Luying

2012-10-22

Load balancing is an attractive technique to achieve maximum throughput and optimal resource utilization in large-scale switching systems. However current electronic load-balanced switches suffer from severe problems in implementation cost, power consumption and scaling. To overcome these problems, in this paper we propose a single-stage optical load-balanced switch architecture based on an arrayed waveguide grating router (AWGR) in conjunction with fast tunable lasers. By reuse of the fast tunable lasers, the switch achieves both functions of load balancing and switching through the AWGR. With this architecture, proof-of-concept experiments have been conducted to investigate the feasibility of the optical load-balanced switch and to examine its physical performance. Compared to three-stage load-balanced switches, the reported switch needs only half of optical devices such as tunable lasers and AWGRs, which can provide a cost-effective solution for future data centers.

Electrical and Optical Characteristics of Undoped and Se-Doped Bi2S3 Transistors

NASA Astrophysics Data System (ADS)

Kilcoyne, Colin; Alsaqqa, Ali; Rahman, Ajara A.; Whittaker-Brooks, Luisa; Sambandamurthy, G.

Semiconducting chalcogenides have been drawing increased attention due to their interesting physical properties, especially in low dimensional structures. Bi2S3 has demonstrated a high optical absorption coefficient, a large bulk mobility, small bandgap, high Seebeck coefficient, and low thermal conductivity. These properties make it a good candidate for optical, electric and thermoelectric applications. However, control over the electrical properties for enhanced thermoelectric performance and optical applications is desired. We present electrical transport and optical properties from individual nanowire and few-layer transistors of single crystalline undoped and Se-doped Bi2S3-xSex. All devices exhibit n-type semiconducting behavior and the ON/OFF ratio, mobility, and conductivity noise behavior are studied as functions of dopant concentration, temperature, and charge carrier density in different conduction regimes. The roles of dopant driven scattering mechanisms and mobility/carrier density fluctuations will be discussed. The potential for this series of materials as optical and electrical switches will be presented. NSF DMR.

A nonlinear plasmonic waveguide based all-optical bidirectional switching

NASA Astrophysics Data System (ADS)

Bana, Xiaoqiang; Pang, Xingxing; Li, Xiaohui; Hu, Bin; Guo, Yixuan; Zheng, Hairong

2018-01-01

In this paper, an all-optical switching with a nanometer coupled ring resonator is demonstrated based on the nonlinear material. By adjusting the light intensity, we implement the resonance wavelength from 880 nm to 940 nm in the nonlinear material structure monocyclic. In the bidirectional switch structure, the center wavelength (i.e. 880 nm) is fixed. By changing the light intensity from I = 0 to I = 53 . 1 MW /cm2, the function of optical switching can be obtained. The results demonstrate that both the single-ring cavity and the T-shaped double-ring structure can realize the optical switching effect. This work takes advantage of the simple structure. The single-ring cavity plasmonic switches have many advantages, such as nanoscale size, low pumping light intensity, ultrafast response time (femtosecond level), etc. It is expected that the proposed all-optical integrated devices can be potentially applied in optical communication, signal processing, and signal sensing, etc.

Preparation and thermo-optic switch properties based on chiral azobenzene-containing polyurethane

NASA Astrophysics Data System (ADS)

Ye, Feiyan; Qiu, Fengxian; Yang, Dongya; Cao, Guorong; Guan, Yijun; Zhuang, Lin

2013-07-01

A chiral azo chromophore compound 4-(4'-nitro-phenyl-diazenyl)-phenyl-1,2-propanediol ether (NPDPPE) was prepared with p-nitroaniline, phenol and R(-)-3-chloro-1,2-propanediol by the diazo-coupling reaction. Then, the chromophore molecule NPDPPE was polymerized with isophorone diisocyanate (IPDI) to obtain novel chiral azobenzene-containing polyurethane (CACPU). The chemical structures of chromophore molecule and CACPU were characterized by the FT-IR and UV-visible spectroscopy. The physical properties (thermal conductivity, thermal diffusion coefficient, and specific heat capacity) and mechanical properties (tensile strength, elongation at break and hardness) of CACPU thin films were measured. The refractive index and thermo-optic (TO) coefficient (dn/dT) of CACPU thin film was investigated for TE (transversal electric) polarizations by using an attenuated total reflection (ATR) configuration at the wavelengths of 532, 650 and 850 nm. The transmission loss of film was measured using the charge coupled device (CCD) digital imaging devices. A Y-branch switch and Mach-Zehnder interferometer (MZI) thermo-optic switches based on thermo-optic effect were proposed and the performances of switches were simulated. The results showed that the power consumption of the Y-branch thermo-optic switch was only 3.28 mW. The rising and falling times of Y-branch and MZI switches were 12.0 ms and 2.0 ms, respectively. The conclusion has potential significance to improve and develop new Y-branch digital optical switch (DOS), MZI thermo-optic switch, directional coupler (DC) switch and optical modulators.

Synthesis, physical properties and simulation of thermo-optic switch based on azo benzothiazole heterocyclic polymer

NASA Astrophysics Data System (ADS)

Qiu, Fengxian; Chen, Caihong; Zhou, Qiaolan; Cao, Zhijuan; Cao, Guorong; Guan, Yijun; Yang, Dongya

2014-05-01

A chromophore molecule 4-[(benzothiazole-2-yl)diazenyl]phenyl-1,3-diamine (BTPD) was prepared with 2-amino benzothiazole and m-phenylenediamine by diazo-coupling reaction. Then, the BTPD was polymerized with polyether polyol (NJ-220) and isophorone diisocyanate (IPDI) to obtain novel azo benzothiazole polyurethane-urea (BTPUU). The chemical structures of BTPD and BTPUU were characterized by FT-IR and UV-visible spectroscopy. The thermal and mechanical properties of BTPUU film were investigated. The refractive index and transmission loss of BTPUU film were measured at different temperatures and different laser wavelengths (532 nm, 650 nm and 850 nm) by an attenuated total reflection (ATR) technique and CCD digital imaging devices. The thermo-optic coefficients of BTPUU are -4.7086 × 10-4 °C-1 (532 nm), -6.5257 × 10-4 °C-1 (650 nm) and -5.1029 × 10-4 °C-1 (850 nm), respectively. A Y-branch switch and Mach-Zehnder interferometer (MZI) thermo-optic switches based on thermo-optic effect were proposed and the performances of the switches were simulated, respectively. The results show that the power consumption of the Y-branch thermo-optic switch is only 3.28 mW. The response times of Y-branch and MZI switches are 8.0 ms and 2.0 ms, respectively. The results indicate that the prepared BTPUU has high potential for the applications of the Y-branch digital optical switch (DOS), MZI thermo-optic switch, directional coupler (DC) switch and optical modulators.

Development of optical packet and circuit integrated ring network testbed.

PubMed

Furukawa, Hideaki; Harai, Hiroaki; Miyazawa, Takaya; Shinada, Satoshi; Kawasaki, Wataru; Wada, Naoya

2011-12-12

We developed novel integrated optical packet and circuit switch-node equipment. Compared with our previous equipment, a polarization-independent 4 × 4 semiconductor optical amplifier switch subsystem, gain-controlled optical amplifiers, and one 100 Gbps optical packet transponder and seven 10 Gbps optical path transponders with 10 Gigabit Ethernet (10GbE) client-interfaces were newly installed in the present system. The switch and amplifiers can provide more stable operation without equipment adjustments for the frequent polarization-rotations and dynamic packet-rate changes of optical packets. We constructed an optical packet and circuit integrated ring network testbed consisting of two switch nodes for accelerating network development, and we demonstrated 66 km fiber transmission and switching operation of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10GbE frames. Error-free (frame error rate < 1×10(-4)) operation was achieved with optical packets of various packet lengths and packet rates, and stable operation of the network testbed was confirmed. In addition, 4K uncompressed video streaming over OPS links was successfully demonstrated. © 2011 Optical Society of America

Piezoelectric Diffraction-Based Optical Switches

NASA Technical Reports Server (NTRS)

Spremo, Stevan; Fuhr, Peter; Schipper, John

2003-01-01

Piezoelectric diffraction-based optoelectronic devices have been invented to satisfy requirements for switching signals quickly among alternative optical paths in optical communication networks. These devices are capable of operating with switching times as short as microseconds or even nanoseconds in some cases.

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Dynamics of optical matter creation and annihilation in colloidal liquids controlled by laser trapping power.

PubMed

Liu, Jin; Dai, Qiao-Feng; Huang, Xu-Guang; Wu, Li-Jun; Guo, Qi; Hu, Wei; Yang, Xiang-Bo; Lan, Sheng; Gopal, Achanta Venu; Trofimov, Vyacheslav A

2008-11-15

We investigate the dynamics of optical matter creation and annihilation in a colloidal liquid that was employed to construct an all-optical switch. It is revealed that the switching-on process can be characterized by the Fermi-Dirac distribution function, while the switching-off process can be described by a steady state followed by a single exponential decay. The phase transition times exhibit a strong dependence on trapping power. With an increasing trapping power, while the switching-on time decreases rapidly, the switch-off time increases significantly, indicating the effects of optical binding and van der Waals force on the lifetime of the optical matter.

Optical switching and photoluminescence in erbium-implanted vanadium dioxide thin films

NASA Astrophysics Data System (ADS)

Lim, Herianto; Stavrias, Nikolas; Johnson, Brett C.; Marvel, Robert E.; Haglund, Richard F.; McCallum, Jeffrey C.

2014-03-01

Vanadium dioxide (VO2) is under intensive consideration for optical switching due to its reversible phase transition, which features a drastic and rapid shift in infrared reflectivity. Classified as an insulator-to-metal transition, the phase transition in VO2 can be induced thermally, electrically, and optically. When induced optically, the transition can occur on sub-picosecond time scales. It is interesting to dope VO2 with erbium ions (Er3+) and observe their combined properties. The first excited-state luminescence of Er3+ lies within the wavelength window of minimal transmission-loss in silicon and has been widely utilized for signal amplification and generation in silicon photonics. The incorporation of Er3+ into VO2 could therefore result in a novel photonic material capable of simultaneous optical switching and amplification. In this work, we investigate the optical switching and photoluminescence in Er-implanted VO2 thin films. Thermally driven optical switching is demonstrated in the Er-implanted VO2 by infrared reflectometry. Photoluminescence is observed in the thin films annealed at ˜800 °C or above. In addition, Raman spectroscopy and a statistical analysis of switching hysteresis are carried out to assess the effects of the ion implantation on the VO2 thin films. We conclude that Er-implanted VO2 can function as an optical switch and amplifier, but with reduced switching quality compared to pure VO2.

Novel all-optical logic gate using an add/drop filter and intensity switch.

PubMed

Threepak, T; Mitatha, S; Yupapin, P P

2011-12-01

A novel design of all-optical logic device is proposed. An all-optical logic device system composes of an optical intensity switch and add/drop filter. The intensity switch is formed to switch signal by using the relationship between refraction angle and signal intensity. In operation, two input signals are coupled into one with some coupling loss and attenuation, in which the combination of add/drop with intensity switch produces the optical logic gate. The advantage is that the proposed device can operate the high speed logic function. Moreover, it uses low power consumption. Furthermore, by using the extremely small component, this design can be put into a single chip. Finally, we have successfully produced the all-optical logic gate that can generate the accurate AND and NOT operation results.

Cost-effective optical switch matrix for microwave phased-array

NASA Technical Reports Server (NTRS)

Pan, J. J.; Chia, S. L.; Li, W. Z.; Grove, C. H.

1991-01-01

An all-fiber (6x6) optical shutter switch matrix with the control system for microwave phased array has been demonstrated. The device offers the advantages of integrated configuration, low cost, low power consumption, small size, and light weight. The maximum extinction ratio (among 36 individual pixel) of this switch matrix at 840 nm is 24.2 dB, and the switching time is less than 120 microsec. In addition to phased array application, this low cost switch matrix is extremely attractive for fiber optic switching networks.

All-optical switch using optically controlled two mode interference coupler.

PubMed

Sahu, Partha Pratim

2012-05-10

In this paper, we have introduced optically controlled two-mode interference (OTMI) coupler having silicon core and GaAsInP cladding as an all-optical switch. By taking advantage of refractive index modulation by launching optical pulse into cladding region of TMI waveguide, we have shown optically controlled switching operation. We have studied optical pulse-controlled coupling characteristics of the proposed device by using a simple mathematical model on the basis of sinusoidal modes. The device length is less than that of previous work. It is also seen that the cross talk of the OTMI switch is not significantly increased with fabrication tolerances (±δw) in comparison with previous work.

Tuning electro-optic susceptibity via strain engineering in artificial PZT multilayer films for high-performance broadband modulator

NASA Astrophysics Data System (ADS)

Zhu, Minmin; Du, Zehui; Li, Hongling; Chen, Bensong; Jing, Lin; Tay, Roland Ying Jie; Lin, Jinjun; Tsang, Siu Hon; Teo, Edwin Hang Tong

2017-12-01

A series of Pb(Zr1-xTix)O3 multilayer films alternatively stacked by Pb(Zr0.52Ti0.48)O3 and Pb(Zr0.35Ti0.65)O3 layers have been deposited on corning glass by magnetron sputtering. The films demonstrate pure perovskite structure and good crystallinity. A large tetragonality (c/a) of ∼1.061 and a shift of ∼0.08 eV for optical bandgap were investigated at layer engineered films. In addition, these samples exhibited a wild tunable electro-optic behavior from tens to ∼250.2 pm/V, as well as fast switching time of down to a few microseconds. The giant EO coefficient was attribute the strain-polarization coupling effect and also comparable to that of epitaxial (001) single crystal PZT thin films. The combination of high transparency, large EO effect, fast switching time, and huge phase transition temperature in PZT-based thin films show the potential on electro-optics from laser to information telecommunication.

Optically triggered high voltage switch network and method for switching a high voltage

DOEpatents

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Electro-optic Q-switch

NASA Technical Reports Server (NTRS)

Zou, Yingyin (Inventor); Chen, Qiushui (Inventor); Zhang, Run (Inventor); Jiang, Hua (Inventor)

2006-01-01

An electro-optic Q-switch for generating sequence of laser pulses was disclosed. The Q-switch comprises a quadratic electro-optic material and is connected with an electronic unit generating a radio frequency wave with positive and negative pulses alternatively. The Q-switch is controlled by the radio frequency wave in such a way that laser pulse is generated when the radio frequency wave changes its polarity.

Ultra-fast all-optical plasmon induced transparency in a metal–insulator–metal waveguide containing two Kerr nonlinear ring resonators

NASA Astrophysics Data System (ADS)

Nurmohammadi, Tofiq; Abbasian, Karim; Yadipour, Reza

2018-05-01

In this work, an ultra-fast all-optical plasmon induced transparency based on a metal–insulator–metal nanoplasmonic waveguide with two Kerr nonlinear ring resonators is studied. Two-dimensional simulations utilizing the finite-difference time-domain method are used to show an obvious optical bistability and significant switching mechanisms of the signal light by varying the pump-light intensity. The proposed all-optical switching based on plasmon induced transparency demonstrates femtosecond-scale feedback time (90 fs), meaning ultra-fast switching can be achieved. The presented all-optical switch may have potential significant applications in integrated optical circuits.

Optical computer switching network

NASA Technical Reports Server (NTRS)

Clymer, B.; Collins, S. A., Jr.

1985-01-01

The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

All-optical switching application based on optical nonlinearity of Yb(3+) doped aluminosilicate glass fiber with a long-period fiber gratings pair.

PubMed

Kim, Yune; Kim, Nam; Chung, Youngjoo; Paek, Un-Chul; Han, Won-Taek

2004-02-23

We propose a new fiber-type all-optical switching device based on the optical nonlinearity of Yb(3+) doped fiber and a long-period fiber gratings(LPG) pair. The all-optical ON-OFF switching with the continuous wave laser signal at ~1556nm in the LPG pair including the 25.5cm long Yb(3+) doped fiber was demonstrated up to ~200Hz upon pumping with the modulated square wave pulses at 976nm, where a full optical switching with the ~18dB extinction ratio was obtained at the launched pump power of ~35mW.

Six-port optical switch for cluster-mesh photonic network-on-chip

NASA Astrophysics Data System (ADS)

Jia, Hao; Zhou, Ting; Zhao, Yunchou; Xia, Yuhao; Dai, Jincheng; Zhang, Lei; Ding, Jianfeng; Fu, Xin; Yang, Lin

2018-05-01

Photonic network-on-chip for high-performance multi-core processors has attracted substantial interest in recent years as it offers a systematic method to meet the demand of large bandwidth, low latency and low power dissipation. In this paper we demonstrate a non-blocking six-port optical switch for cluster-mesh photonic network-on-chip. The architecture is constructed by substituting three optical switching units of typical Spanke-Benes network to optical waveguide crossings. Compared with Spanke-Benes network, the number of optical switching units is reduced by 20%, while the connectivity of routing path is maintained. By this way the footprint and power consumption can be reduced at the expense of sacrificing the network latency performance in some cases. The device is realized by 12 thermally tuned silicon Mach-Zehnder optical switching units. Its theoretical spectral responses are evaluated by establishing a numerical model. The experimental spectral responses are also characterized, which indicates that the optical signal-to-noise ratios of the optical switch are larger than 13.5 dB in the wavelength range from 1525 nm to 1565 nm. Data transmission experiment with the data rate of 32 Gbps is implemented for each optical link.

Demonstration of the feasibility of large-port-count optical switching using a hybrid Mach-Zehnder interferometer-semiconductor optical amplifier switch module in a recirculating loop.

PubMed

Cheng, Q; Wonfor, A; Wei, J L; Penty, R V; White, I H

2014-09-15

For what we believe is the first time, the feasibility of large-port-count nanosecond-reconfiguration-time optical switches is demonstrated using a hybrid approach, where Mach-Zehnder interferometric (MZI) switches provide low-loss, high-speed routing with short semiconductor optical amplifiers (SOAs) being integrated to enhance extinction. By repeatedly passing signals through a monolithic hybrid dilated 2×2 switch module in a recirculating loop, the potential performance of high-port-count switches using the hybrid approach is demonstrated. Experimentally, a single pass switch penalty of only 0.1 dB is demonstrated for the 2×2 module, while even after seven passes through the switch, equivalent to a 128×128 router, a penalty of only 2.4 dB is recorded at a data rate of 10 Gb/s.

All-optical switch consisting of two-stage interferometers controlled by using saturable absorption of monolayer graphene.

PubMed

Oya, Masayuki; Kishikawa, Hiroki; Goto, Nobuo; Yanagiya, Shin-ichiro

2012-11-19

At routing nodes in future photonic networks, pico-second switching will be a key function. We propose an all-optical switch consisting of two-stage Mach-Zehnder interferometers, whose arms contain graphene saturable absorption films. Optical amplitudes along the interferometers are controlled to perform switching between two output ports instead of phase control used in conventional switches. Since only absorption is used for realizing complete switching, insertion loss of 10.2 dB is accompanied in switching. Picosecond response can be expected because of the fast response of saturable absorption of graphene. The switching characteristics are theoretically analyzed and numerically simulated by the finite-difference beam propagation method (FD-BPM).

Performance of highly connected photonic switching lossless metro-access optical networks

NASA Astrophysics Data System (ADS)

Martins, Indayara Bertoldi; Martins, Yara; Barbosa, Felipe Rudge

2018-03-01

The present work analyzes the performance of photonic switching networks, optical packet switching (OPS) and optical burst switching (OBS), in mesh topology of different sizes and configurations. The "lossless" photonic switching node is based on a semiconductor optical amplifier, demonstrated and validated with experimental results on optical power gain, noise figure, and spectral range. The network performance was evaluated through computer simulations based on parameters such as average number of hops, optical packet loss fraction, and optical transport delay (Am). The combination of these elements leads to a consistent account of performance, in terms of network traffic and packet delivery for OPS and OBS metropolitan networks. Results show that a combination of highly connected mesh topologies having an ingress e-buffer present high efficiency and throughput, with very low packet loss and low latency, ensuring fast data delivery to the final receiver.

Multi-function all optical packet switch by periodic wavelength arrangement in an arrayed waveguide grating and wideband optical filters.

PubMed

Feng, Kai-Ming; Wu, Chung-Yu; Wen, Yu-Hsiang

2012-01-16

By utilizing the cyclic filtering function of an NxN arrayed waveguide grating (AWG), we propose and experimentally demonstrate a novel multi-function all optical packet switching (OPS) architecture by applying a periodical wavelength arrangement between the AWG in the optical routing/buffering unit and a set of wideband optical filters in the switched output ports to achieve the desired routing and buffering functions. The proposed OPS employs only one tunable wavelength converter at the input port to convert the input wavelength to a designated wavelength which reduces the number of active optical components and thus the complexity of the traffic control is simplified in the OPS. With the proposed OPS architecture, multiple optical packet switching functions, including arbitrary packet switching and buffering, first-in-first-out (FIFO) packet multiplexing, packet demultiplexing and packet add/drop multiplexing, have been successfully demonstrated.

Photoswitching Behavior of 5-Phenylazopyrimidines: In Situ Irradiation NMR and Optical Spectroscopy Combined with Theoretical Methods.

PubMed

Čechová, Lucie; Kind, Jonas; Dračínský, Martin; Filo, Juraj; Janeba, Zlatko; Thiele, Christina M; Cigáň, Marek; Procházková, Eliška

2018-05-11

The photoswitching behavior of 5-phenylazopyrimidines was investigated by optical methods and NMR spectroscopy with in situ irradiation sustained by mathematical modeling and DFT calculations. Irradiation of various compounds with electron-donating groups on the pyrimidine ring and substituents with electron-withdrawing as well as electron-donating substituent in the para-position of the phenyl ring were examined. All compounds could be successfully converted to the cis isomer; this isomerization and the subsequent thermal fading were studied. Switching cycles can be repeated without signs of photodegradation for most of the compounds, which makes them adept to molecular photoswitches. Interestingly, the chloro and cyano derivatives can be switched without UV light, which makes them vis(π → π*)-vis(n → π*) photoswitches. Surprisingly equal trans-to- cis photoisomerization quantum yields for π → π* and n → π* excitation indicate the blocking of the inversion pathway following π → π* excitation. In contrast to that, DFT computations suggest the inversion mechanism for the reverse thermal cis-to- trans isomerization of 5-phenylazopyrimidines.

Three-tier multi-granularity switching system based on PCE

NASA Astrophysics Data System (ADS)

Wang, Yubao; Sun, Hao; Liu, Yanfei

2017-10-01

With the growing demand for business communications, electrical signal processing optical path switching can't meet the demand. The multi-granularity switch system that can improve node routing and switching capabilities came into being. In the traditional network, each node is responsible for calculating the path; synchronize the whole network state, which will increase the burden on the network, so the concept of path calculation element (PCE) is proposed. The PCE is responsible for routing and allocating resources in the network1. In the traditional band-switched optical network, the wavelength is used as the basic routing unit, resulting in relatively low wavelength utilization. Due to the limitation of wavelength continuity, the routing design of the band technology becomes complicated, which directly affects the utilization of the system. In this paper, optical code granularity is adopted. There is no continuity of the optical code, and the number of optical codes is more flexible than the wavelength. For the introduction of optical code switching, we propose a Code Group Routing Entity (CGRE) algorithm. In short, the combination of three-tier multi-granularity optical switching system and PCE can simplify the network structure, reduce the node load, and enhance the network scalability and survivability. Realize the intelligentization of optical network.

Optical switch compatible with wavelength division multiplexing and mode division multiplexing for photonic networks-on-chip.

PubMed

Jia, Hao; Zhou, Ting; Zhang, Lei; Ding, Jianfeng; Fu, Xin; Yang, Lin

2017-08-21

We propose a 2 × 2 multimode optical switch, which is composed of two mode de-multiplexers, n 2 × 2 single-mode optical switches where n is the number of the supported spatial modes, and two mode multiplexers. As a proof of concept, asymmetric directional couplers are employed to construct the mode multiplexers and de-multiplexers, balanced Mach-Zehnder interferometer is utilized to construct the 2 × 2 single-mode optical switches. The fabricated silicon 2 × 2 multimode optical switch has a broad optical bandwidth and can support four spatial modes. The link-crosstalk for all four modes is smaller than -18.8 dB. The inter-mode crosstalk for the same optical link is less than -22.1 dB. 40 Gbps data transmission is performed for all spatial modes and all optical links. The power penalties for the error-free switching (BER<10 -9 ) at 25 Gbps are less than 1.8 dB for all channels at the wavelength of 1550 nm. The power consumption of the device is 117.9 mW in the "cross" state and 116.2 mW in the "bar" state. The switching time is about 21 μs. This work enables large-capacity multimode photonic networks-on-chip.

Scalable Active Optical Access Network Using Variable High-Speed PLZT Optical Switch/Splitter

NASA Astrophysics Data System (ADS)

Ashizawa, Kunitaka; Sato, Takehiro; Tokuhashi, Kazumasa; Ishii, Daisuke; Okamoto, Satoru; Yamanaka, Naoaki; Oki, Eiji

This paper proposes a scalable active optical access network using high-speed Plumbum Lanthanum Zirconate Titanate (PLZT) optical switch/splitter. The Active Optical Network, called ActiON, using PLZT switching technology has been presented to increase the number of subscribers and the maximum transmission distance, compared to the Passive Optical Network (PON). ActiON supports the multicast slot allocation realized by running the PLZT switch elements in the splitter mode, which forces the switch to behave as an optical splitter. However, the previous ActiON creates a tradeoff between the network scalability and the power loss experienced by the optical signal to each user. It does not use the optical power efficiently because the optical power is simply divided into 0.5 to 0.5 without considering transmission distance from OLT to each ONU. The proposed network adopts PLZT switch elements in the variable splitter mode, which controls the split ratio of the optical power considering the transmission distance from OLT to each ONU, in addition to PLZT switch elements in existing two modes, the switching mode and the splitter mode. The proposed network introduces the flexible multicast slot allocation according to the transmission distance from OLT to each user and the number of required users using three modes, while keeping the advantages of ActiON, which are to support scalable and secure access services. Numerical results show that the proposed network dramatically reduces the required number of slots and supports high bandwidth efficiency services and extends the coverage of access network, compared to the previous ActiON, and the required computation time for selecting multicast users is less than 30msec, which is acceptable for on-demand broadcast services.

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%.

All-optical clocked delay flip-flop using a single terahertz optical asymmetric demultiplexer-based switch: a theoretical study.

PubMed

Chattopadhyay, Tanay

2010-10-01

A flip-flop (FF) is a kind of latch and the simplest form of memory device, which stores various values either temporarily or permanently. Optical FF memories form a fundamental building block for all-optical packet switches in next-generation communication networks. An all-optical clocked delay FF using a single terahertz optical asymmetric demultiplexer-based interferometric switch is proposed and described. Numerical simulation results are also reported.

A cross-stacked plasmonic nanowire network for high-contrast femtosecond optical switching.

PubMed

Lin, Yuanhai; Zhang, Xinping; Fang, Xiaohui; Liang, Shuyan

2016-01-21

We report an ultrafast optical switching device constructed by stacking two layers of gold nanowires into a perpendicularly crossed network, which works at a speed faster than 280 fs with an on/off modulation depth of about 22.4%. The two stacks play different roles in enhancing consistently the optical switching performance due to their different dependence on the polarization of optical electric fields. The cross-plasmon resonance based on the interaction between the perpendicularly stacked gold nanowires and its Fano-coupling with Rayleigh anomaly is the dominant mechanism for such a high-contrast optical switching device.

Low-power, 2 x 2 silicon electro-optic switch with 110-nm bandwidth for broadband reconfigurable optical networks.

PubMed

Van Campenhout, Joris; Green, William M J; Assefa, Solomon; Vlasov, Yurii A

2009-12-21

We present an ultra-broadband Mach-Zehnder based optical switch in silicon, electrically driven through carrier injection. Crosstalk levels lower than -17 dB are obtained for both the 'on' and 'off' switching states over an optical bandwidth of 110 nm, owing to the implementation of broadband 50% couplers. Full 2 x 2 switching functionality is demonstrated, with low power consumption (approximately 3 mW) and a fast switching time (< 4 ns). The utilization of standard CMOS metallization results in a low drive voltage (approximately 1 V) and a record-low V(pi)L (approximately 0.06 V x mm). The wide optical bandwidth is maintained for temperature variations up to 30 K.

High-performance flat data center network architecture based on scalable and flow-controlled optical switching system

NASA Astrophysics Data System (ADS)

Calabretta, Nicola; Miao, Wang; Dorren, Harm

2016-03-01

Traffic in data centers networks (DCNs) is steadily growing to support various applications and virtualization technologies. Multi-tenancy enabling efficient resource utilization is considered as a key requirement for the next generation DCs resulting from the growing demands for services and applications. Virtualization mechanisms and technologies can leverage statistical multiplexing and fast switch reconfiguration to further extend the DC efficiency and agility. We present a novel high performance flat DCN employing bufferless and distributed fast (sub-microsecond) optical switches with wavelength, space, and time switching operation. The fast optical switches can enhance the performance of the DCNs by providing large-capacity switching capability and efficiently sharing the data plane resources by exploiting statistical multiplexing. Benefiting from the Software-Defined Networking (SDN) control of the optical switches, virtual DCNs can be flexibly created and reconfigured by the DCN provider. Numerical and experimental investigations of the DCN based on the fast optical switches show the successful setup of virtual network slices for intra-data center interconnections. Experimental results to assess the DCN performance in terms of latency and packet loss show less than 10^-5 packet loss and 640ns end-to-end latency with 0.4 load and 16- packet size buffer. Numerical investigation on the performance of the systems when the port number of the optical switch is scaled to 32x32 system indicate that more than 1000 ToRs each with Terabit/s interface can be interconnected providing a Petabit/s capacity. The roadmap to photonic integration of large port optical switches will be also presented.

Low threshold all-optical crossbar switch on GaAs-GaAlAs channel waveguide arrays

NASA Astrophysics Data System (ADS)

Jannson, Tomasz; Kostrzewski, Andrew

1994-09-01

During the Phase 2 project entitled 'Low Threshold All-Optical Crossbar Switch on GaAs - GaAlAs Channel Waveguide Array,' Physical Optics Corporation (POC) developed the basic principles for the fabrication of all-optical crossbar switches. Based on this development. POC fabricated a 2 x 2 GaAs/GaAlAs switch that changes the direction of incident light with minimum insertion loss and nonlinear distortion. This unique technology can be used in both analog and digital networks. The applications of this technology are widespread. Because the all-optical network does not have any speed limitations (RC time constant), POC's approach will be beneficial to SONET networks, phased array radar networks, very high speed oscilloscopes, all-optical networks, IR countermeasure systems, BER equipment, and the fast growing video conferencing network market. The novel all-optical crossbar switch developed in this program will solve interconnect problems. and will be a key component in the widely proposed all-optical 200 Gb/s SONET/ATM networks.

Intelligent switches of integrated lightwave circuits with core telecommunication functions

NASA Astrophysics Data System (ADS)

Izhaky, Nahum; Duer, Reuven; Berns, Neil; Tal, Eran; Vinikman, Shirly; Schoenwald, Jeffrey S.; Shani, Yosi

2001-05-01

We present a brief overview of a promising switching technology based on Silica on Silicon thermo-optic integrated circuits. This is basically a 2D solid-state optical device capable of non-blocking switching operation. Except of its excellent performance (insertion loss<5dB, switching time<2ms...), the switch enables additional important build-in functionalities. It enables single-to- single channel switching and single-to-multiple channel multicasting/broadcasting. In addition, it has the capability of channel weighting and variable output power control (attenuation), for instance, to equalize signal levels and compensate for unbalanced different optical input powers, or to equalize unbalanced EDFA gain curve. We examine the market segments appropriate for the switch size and technology, followed by a discussion of the basic features of the technology. The discussion is focused on important requirements from the switch and the technology (e.g., insertion loss, power consumption, channel isolation, extinction ratio, switching time, and heat dissipation). The mechanical design is also considered. It must take into account integration of optical fiber, optical planar wafer, analog electronics and digital microprocessor controls, embedded software, and heating power dissipation. The Lynx Photon.8x8 switch is compared to competing technologies, in terms of typical market performance requirements.

Micro electro mechanical system optical switching

DOEpatents

Thorson, Kevin J; Stevens, Rick C; Kryzak, Charles J; Leininger, Brian S; Kornrumpf, William P; Forman, Glenn A; Iannotti, Joseph A; Spahn, Olga B; Cowan, William D; Dagel, Daryl J

2013-12-17

The present disclosure includes apparatus, system, and method embodiments that provide micro electo mechanical system optical switching and methods of manufacturing switches. For example, one optical switch embodiment includes at least one micro electro mechanical system type pivot mirror structure disposed along a path of an optical signal, the structure having a mirror and an actuator, and the mirror having a pivot axis along a first edge and having a second edge rotatable with respect to the pivot axis, the mirror being capable of and arranged to be actuated to pivot betweeen a position parallel to a plane of an optical signal and a position substantially normal to the plane of the optical signal.

Fundamental Scaling Laws in Nanophotonics

PubMed Central

Liu, Ke; Sun, Shuai; Majumdar, Arka; Sorger, Volker J.

2016-01-01

The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of “smaller-is-better” has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and analyze how both optical and electrical constrains influence device power consumption and operating speed. Specifically, we investigate the direct influence of scaling on the performance of four classes of photonic devices, namely laser sources, electro-optic modulators, photodetectors, and all-optical switches based on three types of optical resonators; microring, Fabry-Perot cavity, and plasmonic metal nanoparticle. Results show that while microrings and Fabry-Perot cavities can outperform plasmonic cavities at larger length-scales, they stop working when the device length drops below 100 nanometers, due to insufficient functionality such as feedback (laser), index-modulation (modulator), absorption (detector) or field density (optical switch). Our results provide a detailed understanding of the limits of nanophotonics, towards establishing an opto-electronics roadmap, akin to the International Technology Roadmap for Semiconductors. PMID:27869159

Fundamental Scaling Laws in Nanophotonics.

PubMed

Liu, Ke; Sun, Shuai; Majumdar, Arka; Sorger, Volker J

2016-11-21

The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of "smaller-is-better" has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and analyze how both optical and electrical constrains influence device power consumption and operating speed. Specifically, we investigate the direct influence of scaling on the performance of four classes of photonic devices, namely laser sources, electro-optic modulators, photodetectors, and all-optical switches based on three types of optical resonators; microring, Fabry-Perot cavity, and plasmonic metal nanoparticle. Results show that while microrings and Fabry-Perot cavities can outperform plasmonic cavities at larger length-scales, they stop working when the device length drops below 100 nanometers, due to insufficient functionality such as feedback (laser), index-modulation (modulator), absorption (detector) or field density (optical switch). Our results provide a detailed understanding of the limits of nanophotonics, towards establishing an opto-electronics roadmap, akin to the International Technology Roadmap for Semiconductors.

Fundamental Scaling Laws in Nanophotonics

NASA Astrophysics Data System (ADS)

Liu, Ke; Sun, Shuai; Majumdar, Arka; Sorger, Volker J.

2016-11-01

The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of “smaller-is-better” has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and analyze how both optical and electrical constrains influence device power consumption and operating speed. Specifically, we investigate the direct influence of scaling on the performance of four classes of photonic devices, namely laser sources, electro-optic modulators, photodetectors, and all-optical switches based on three types of optical resonators; microring, Fabry-Perot cavity, and plasmonic metal nanoparticle. Results show that while microrings and Fabry-Perot cavities can outperform plasmonic cavities at larger length-scales, they stop working when the device length drops below 100 nanometers, due to insufficient functionality such as feedback (laser), index-modulation (modulator), absorption (detector) or field density (optical switch). Our results provide a detailed understanding of the limits of nanophotonics, towards establishing an opto-electronics roadmap, akin to the International Technology Roadmap for Semiconductors.

Advances in integrated photonic circuits for packet-switched interconnection

NASA Astrophysics Data System (ADS)

Williams, Kevin A.; Stabile, Ripalta

2014-03-01

Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

All-optical switching based on optical fibre long period gratings modified bacteriorhodopsin

NASA Astrophysics Data System (ADS)

Korposh, S.; James, S.; Partridge, M.; Sichka, M.; Tatam, R.

2018-05-01

All-optical switching using an optical fibre long-period gating (LPG) modified with bacteriorhodopsin (bR) is demonstrated. The switching process is based on the photo-induced RI change of bR, which in turn changes the phase matching conditions of the mode coupling by the LPG, leading to modulation of the propagating light. The effect was studied with an LPG immersed into a bR solution and with LPGs coated with the bR films, deposited onto the LPGs using the layer-by-layer electrostatic self-assembly (LbL) method. The dependence of the all-optical switching efficiency upon the concentration of the bR solution and on the grating period of the LPG was also studied. In addition, an in-fibre Mach-Zehnder interferometer (MZI) composed of a cascaded LPG pair separated by 30 mm and modified with bR was used to enhance the wavelength range of all-optical switching. The switching wavelength is determined by the grating period of the LPG. Switching efficiencies of 16% and 35% were observed when an LPG and an MZI were immersed into bR solutions, respectively. The switching time for devices coated with bR-films was within 1 s, 10 times faster than that observed for devices immersed into bR solution.

Magnetic switching in granular FePt layers promoted by near-field laser enhancement

DOE PAGES

Granitzka, Patrick W.; Jal, Emmanuelle; Le Guyader, Loic; ...

2017-03-08

Light-matter interaction at the nanoscale in magnetic materials is a topic of intense research in view of potential applications in next-generation high-density magnetic recording. Laser-assisted switching provides a pathway for overcoming the material constraints of high-anisotropy and high-packing density media, though much about the dynamics of the switching process remains unexplored. We use ultrafast small-angle X-ray scattering at an X-ray free-electron laser to probe the magnetic switching dynamics of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse. We observe that the combination of laser excitation and applied static magnetic field, 1 order ofmore » magnitude smaller than the coercive field, can overcome the magnetic anisotropy barrier between “up” and “down” magnetization, enabling magnetization switching. This magnetic switching is found to be inhomogeneous throughout the material with some individual FePt nanoparticles neither switching nor demagnetizing. The origin of this behavior is identified as the near-field modification of the incident laser radiation around FePt nanoparticles. Furthermore, the fraction of not-switching nanoparticles is influenced by the heat flow between FePt and a heat-sink layer.« less

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.

A Mechanical Switch Using Spectral Microshifts

NASA Astrophysics Data System (ADS)

Mitchell, Gordon L.; Saaski, Elric W.; Hartl, James C.

1989-02-01

Among the simplest fiber optic sensors, are those which operate in a binary fashion; they were the first sensor types to be developed. Early experiments with fiber bundles and shutters produced demonstrations of, for example, displacement sensors. Typical applications range from position sensing for aircraft landing gear to counting objects on a production line. Because they frequently replace electrical snap action switches, binary sensors are generally called optical switches. Optical switch applications account for a much larger market than the more complex analog measurements discussed in the balance of this volume. This paper presents an optical switch concept that uses a single fiber and is tolerant of back reflections. The sensor element is a low finesse Fabry-Perot pressure sensor which replaces the electrical contact in a conventional snap action switch.

Mode selecting switch using multimode interference for on-chip optical interconnects.

PubMed

Priti, Rubana B; Pishvai Bazargani, Hamed; Xiong, Yule; Liboiron-Ladouceur, Odile

2017-10-15

A novel mode selecting switch (MSS) is experimentally demonstrated for on-chip mode-division multiplexing (MDM) optical interconnects. The MSS consists of a Mach-Zehnder interferometer with tapered multi-mode interference couplers and TiN thermo-optic phase shifters for conversion and switching between the optical data encoded on the fundamental and first-order quasi-transverse electric (TE) modes. The C-band MSS exhibits a >25  dB switching extinction ratio and < -12 dB crosstalk. We validate the dynamic switching with a 25.8 kHz gating signal measuring switching times for both TE0 and TE1 modes of <10.9  μs. All channels exhibit less than 1.7 dB power penalty at a 10 -12 bit error rate, while switching the non-return-to-zero PRBS-31 data signals at 10  Gb/s.

MEMS for optical switching: technologies, applications, and perspectives

NASA Astrophysics Data System (ADS)

Lin, Lih-Y.; Goldstein, Evan L.

1999-09-01

Micro-electro-mechanical-systems (MEMS), due to their unique ability to integrate electrical, mechanical, and optical elements on a single chip, have recently begun to exhibit great potential for realizing optical components and subsystems in compact, lowcost form. Recently, this technology has been applied to wavelength-division-multiplexed (WDM) networks, and resulted in advances in several network elements, including switches, filters, modulators, and wavelength-add/drop multiplexers. Due largely to the exploding capacity demand arising from data traffic, the transmission capacity demanded of and available from WDM networks is anticipated to increase rapidly. For managing such networks, optical switching is of particular interest due to the fact that its complexity is essentially immune to steady advances in the per-channel bit-rate. We will review various micromachined optical-switching technologies, emphasizing studies of their reliability. We then summarizing recent progress in the free-space MEMS optical switch we have demonstrated.

MEMS for optical switching: technologies, applications, and perspectives

NASA Astrophysics Data System (ADS)

Lin, Lih-Yuan; Goldstein, Evan L.

1999-09-01

Micro-electro-mechanical-systems (MEMS), due to their unique ability to integrate electrical, mechanical, and optical elements on a single chip, have recently begun to exhibit great potential for realizing optical components and subsystems in compact, low-cost form. Recently, this technology has been applied to wavelength-division-multiplexed (WDM) networks, and resulted in advances in several network elements, including switches, filters, modulators, and wavelength-add/drop multiplexers. Due largely to the exploding capacity demand arising from data traffic, the transmission capacity demanded of and available from WDM networks is anticipated to increase rapidly. For managing such networks, optical switching is of particular interest due to the fact that its complexity is essentially immune to steady advances in the per-channel bit-rate. We will review various micromachined optical-switching technologies, emphasizing studies of their reliability. We then summarizing recent progress in the free-space MEMS optical switch we have demonstrated.

On-chip quasi-digital optical switch using silicon microring resonator-coupled Mach-Zehnder interferometer.

PubMed

Song, Junfeng; Luo, Xianshu; Tu, Xiaoguang; Jia, Lianxi; Fang, Qing; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang

2013-05-20

In this work, we demonstrate thermo-optical quasi-digital optical switch (q-DOS) using silicon microring resonator-coupled Mach-Zehnder interferometer. The optical transmission spectra show box-like response with 1-dB and 3-dB bandwidths of ~1.3 nm and ~1.6 nm, respectively. Such broadband flat-top optical response improves the tolerance to the light source wavelength fluctuation of ± 6 Å and temperature variation of ± 6 °C. Dynamic characterizations show the device with switching power of ~37 mW, switching time of ~7 μs, and on/off ratio of > 30 dB. For performance comparison, we also demonstrate a carrier injection-based electro-optical q-DOS by integrating lateral P-i-N junction with the microring resonator, which significantly reduces power consumption to ~12 mW and switching time to ~0.7 ns only.

Direct measurement of photomechanical switching cross-sections of single-molecules on a surface

NASA Astrophysics Data System (ADS)

Cho, Jongweon; Comstock, Matthew J.; Levy, Niv; Berbil-Bautista, Luis; Lauterwasser, Frank; Frechet, Jean M. J.; Crommie, Michael F.

2008-03-01

The photomechanical switching of photoactive molecules in solution strongly depends on the wavelength of light. This dependence is crucial to reliably control the photomechanical state of target molecules. Recently, reversible photomechanical switching of individual azobenzene molecular derivatives on the Au(111) surface has been reported for one particular wavelength of UV illumination [1]. To further understand this process and its possible applications in future nanotechnologies, we have investigated photomechanical switching rates and saturation behavior for azobenzene molecular derivatives at a surface under optical stimulation at different wavelengths. Using single-molecule-resolved scanning tunneling microscopy, we have determined both the forward and reverse photomechanical molecular switching cross-sections at different wavelengths. In a dramatic departure from solution-based environments, visible light does not efficiently reverse the photoreaction. [1] Matthew J. Comstock, Niv Levy, Armen Kirakosian, Jongweon Cho, Frank Lauterwasser, Jessica H. Harvey, David A. Strubbe, Jean M. J. Fr'echet, Dirk Trauner, Steven G. Louie, and Michael F. Crommie, Phys. Rev. Lett. 99, 038301 (2007)

Ultralow-energy and high-contrast all-optical switch involving Fano resonance based on coupled photonic crystal nanocavities.

PubMed

Nozaki, Kengo; Shinya, Akihiko; Matsuo, Shinji; Sato, Tomonari; Kuramochi, Eiichi; Notomi, Masaya

2013-05-20

We experimentally and theoretically clarified that a Fano resonant system based on a coupled optical cavity has better performance when used as an all-optical switch than a single cavity in terms of switching energy, contrast, and operation bandwidth. We successfully fabricated a Fano system consisting of doubly coupled photonic-crystal (PhC) nanocavities, and demonstrated all-optical switching for the first time. A steep asymmetric transmission spectrum was clearly observed, thereby enabling a low-energy and high-contrast switching operation. We achieved the switching with a pump energy of a few fJ, a contrast of more than 10 dB, and an 18 ps switching time window. These levels of performance are actually better than those for Lorentzian resonance in a single cavity. We also theoretically investigated the achievable performance in a well-designed Fano system, which suggested a high contrast for the switching of more than 20 dB in a fJ energy regime.

A tunable optical Kerr switch based on a nanomechanical resonator coupled to a quantum dot.

PubMed

Li, Jin-Jin; Zhu, Ka-Di

2010-05-21

We have theoretically demonstrated the large enhancement of the optical Kerr effect in a scheme of a nanomechanical resonator coupled to a quantum dot and shown that this phenomenon can be used to realize a fast optical Kerr switch by turning the control field on or off. Due to the vibration of the nanoresonator, as we pump on the strong control beam, the optical spectrum shows that the magnitude of this optical Kerr effect is proportional to the intensity of the control field. In this case, a fast and tunable optical Kerr switch can be implemented easily by an intensity-adjustable laser. Based on this tunable optical Kerr switch, we also provide a detection method to measure the frequency of the nanomechanical resonator in this coupled system.

Optical backplane interconnect switch for data processors and computers

NASA Technical Reports Server (NTRS)

Hendricks, Herbert D.; Benz, Harry F.; Hammer, Jacob M.

1989-01-01

An optoelectronic integrated device design is reported which can be used to implement an all-optical backplane interconnect switch. The switch is sized to accommodate an array of processors and memories suitable for direct replacement into the basic avionic multiprocessor backplane. The optical backplane interconnect switch is also suitable for direct replacement of the PI bus traffic switch and at the same time, suitable for supporting pipelining of the processor and memory. The 32 bidirectional switchable interconnects are configured with broadcast capability for controls, reconfiguration, and messages. The approach described here can handle a serial interconnection of data processors or a line-to-link interconnection of data processors. An optical fiber demonstration of this approach is presented.

Liquid Nitrogen as Fast High Voltage Switching Medium

NASA Astrophysics Data System (ADS)

Dickens, J.; Neuber, A.; Haustein, M.; Krile, J.; Krompholz, H.

2002-12-01

Compact pulsed power systems require new switching technologies. For high voltages, liquid nitrogen seems to be a suitable switching medium, with high hold-off voltage, low dielectric constant, and no need for pressurized systems as in high pressure gas switches. The discharge behavior in liquid nitrogen, such as breakdown voltages, formative times, current rise as function of voltage, recovery, etc. are virtually unknown, however. The phenomenology of breakdown in liquid nitrogen is investigated with high speed (temporal resolution < 1 ns) electrical and optical diagnostics, in a coaxial system with 50-Ohm impedance. Discharge current and voltage are determined with transmission line type current sensors and capacitive voltage dividers. The discharge luminosity is measured with photomultiplier tubes. Preliminary results of self-breakdown investigations (gap 1 mm, breakdown voltage 44 kV, non-boiling supercooled nitrogen) show a fast (2 ns) transition from an unknown current level to several mA, a long-duration (100 ns) phase with constant current superimposed by ns-spikes, and a final fast transition to the impedance limited current during several nanoseconds. The optical measurements will be expanded toward spectroscopy and high speed photography with the aim of clarifying the overall breakdown mechanisms, including electronic initiation, bubble formation, bubble dynamics, and their role in breakdown, for different electrode geometries (different macroscopic field enhancements).

Compact and efficient 2μm Tm:YAP lasers with mechanical or passive Q-switching

NASA Astrophysics Data System (ADS)

Cole, Brian; Goldberg, Lew

2017-02-01

We describe compact and efficient Q-switched diode-pumped, Tm:YAP lasers operating at 1.94μm. Laser CW and Q-switched performance is compared, using both compact mechanical as well as passive Q-switching. For passive Q-switching using a Cr:ZnS saturable absorber (unsaturated transmission of 95%), the laser produced 0.5mJ pulses with an average power of 4.4W and 6.5kW peak power, and had an optical efficiency of 30%. A resonant mirror mechanical Q-switch resulted in a 4 kHz PRF pulse train, with an optical slope efficiency of 52% and an optical-to-optical conversion efficiency of 41%. The laser generated 1.5 mJ, 45 ns FWHM, 33kW peak power pulses, and 6.2W of average output. A second mechanically Q-switched laser operating at 10 kHz PRF produced 1mJ, 35kW peak power pulses, generating 11W average power with an optical efficiency of 46%, and a beam quality of 1.4x diffraction limit.

32 × 32 silicon electro-optic switch with built-in monitors and balanced-status units.

PubMed

Qiao, Lei; Tang, Weijie; Chu, Tao

2017-02-09

To construct large-scale silicon electro-optical switches for optical interconnections, we developed a method using a limited number of power monitors inserted at certain positions to detect and determine the optimum operating points of all switch units to eliminate non-uniform effects arising from fabrication errors. We also introduced an optical phase bias to one phase-shifter arm of a Mach-Zehnder interferometer (MZI)-type switch unit to balance the two operation statuses of a silicon electro-optical switch during push-pull operation. With these methods, a 32 × 32 MZI-based silicon electro-optical switch was successfully fabricated with 180-nm complementary metal-oxide-semiconductor (CMOS) process technology, which is the largest scale silicon electro-optical switch to the best of our knowledge. At a wavelength of 1520 nm, the on-chip insertion losses were 12.9 to 16.5 dB, and the crosstalk ranged from -17.9 to -24.8 dB when all units were set to the 'Cross' status. The losses were 14.4 to 18.5 dB, and the crosstalk ranged from -15.1 to -19.0 dB when all units were in the 'Bar' status. The total power consumptions of the 32 × 32 switch were 247.4 and 542.3 mW when all units were set to the 'Cross' and 'Bar' statuses, respectively.

32 × 32 silicon electro-optic switch with built-in monitors and balanced-status units

PubMed Central

Qiao, Lei; Tang, Weijie; Chu, Tao

2017-01-01

To construct large-scale silicon electro-optical switches for optical interconnections, we developed a method using a limited number of power monitors inserted at certain positions to detect and determine the optimum operating points of all switch units to eliminate non-uniform effects arising from fabrication errors. We also introduced an optical phase bias to one phase-shifter arm of a Mach–Zehnder interferometer (MZI)-type switch unit to balance the two operation statuses of a silicon electro-optical switch during push–pull operation. With these methods, a 32 × 32 MZI-based silicon electro-optical switch was successfully fabricated with 180-nm complementary metal–oxide–semiconductor (CMOS) process technology, which is the largest scale silicon electro-optical switch to the best of our knowledge. At a wavelength of 1520 nm, the on-chip insertion losses were 12.9 to 16.5 dB, and the crosstalk ranged from −17.9 to −24.8 dB when all units were set to the ‘Cross’ status. The losses were 14.4 to 18.5 dB, and the crosstalk ranged from −15.1 to −19.0 dB when all units were in the ‘Bar’ status. The total power consumptions of the 32 × 32 switch were 247.4 and 542.3 mW when all units were set to the ‘Cross’ and ‘Bar’ statuses, respectively. PMID:28181557

Reconfigurable electro-optical directed-logic circuit using carrier-depletion micro-ring resonators.

PubMed

Qiu, Ciyuan; Gao, Weilu; Soref, Richard; Robinson, Jacob T; Xu, Qianfan

2014-12-15

Here we demonstrate a reconfigurable electro-optical directed-logic circuit based on a regular array of integrated optical switches. Each 1×1 optical switch consists of a micro-ring resonator with an embedded lateral p-n junction and a micro-heater. We achieve high-speed on-off switching by applying electrical logic signals to the p-n junction. We can configure the operation mode of each switch by thermal tuning the resonance wavelength. The result is an integrated optical circuit that can be reconfigured to perform any combinational logic operation. As a proof-of-principle, we fabricated a multi-spectral directed-logic circuit based on a fourfold array of switches and showed that this circuit can be reconfigured to perform arbitrary two-input logic functions with speeds up to 3  GB/s.

Compact and low power operation optical switch using silicon-germanium/silicon hetero-structure waveguide.

PubMed

Sekiguchi, Shigeaki; Kurahashi, Teruo; Zhu, Lei; Kawaguchi, Kenichi; Morito, Ken

2012-04-09

We proposed a silicon-based optical switch with a carrier-plasma-induced phase shifter which employs a silicon-germanium (SiGe) / silicon (Si) hetero-structure in the waveguide core. A type-I hetero-interface formed by SiGe and Si is expected to confine carriers effectively in the SiGe waveguide core. The fabricated Mach-Zehnder optical switch shows a low switching power of only 1.53 mW with a compact phase shifter length of 250 μm. The switching time of the optical switch is less than 4.6 ns for the case of a square waveform driving condition, and 1 ns for the case of a pre-emphasis electric driving condition. These results show that our proposed SiGe/Si waveguide structure holds promise for active devices with compact size and low operation power.

Fast and low power Michelson interferometer thermo-optical switch on SOI.

PubMed

Song, Junfeng; Fang, Q; Tao, S H; Liow, T Y; Yu, M B; Lo, G Q; Kwong, D L

2008-09-29

We designed and fabricated silicon-on-insulator based Michelson interferometer (MI) thermo-optical switches with deep etched trenches for heat-isolation. Switch power was reduced approximately 20% for the switch with deep etched trenches, and the MI saved approximately 50% power than that of the Mach-Zehnder interferometer. 10.6 mW switch power, approximately 42 micros switch time for the MI with deep trenches, 13.14 mW switch power and approximately 34 micros switch time for the MI without deep trenches were achieved.

Correlation and squeezing for optical transistor and intensity router applications in diamond NV center.

PubMed

Ahmed, Noor; Khan, Ghulam Abbas; Wang, Ruimin; Hou, Jingru; Gong, Rui; Yang, Lingmeng; Zhang, Yanpeng

2017-05-01

We study an optical transistor (switch and amplifier) and router by spontaneous parametric four-wave mixing and fluorescence in diamond nitrogen-vacancy (NV) center. The routing results from three peaks of fluorescence signal in the time domain, while the switching and amplification are realized by correlation and squeezing. The intensity switching speed is about 17 ns. The optical transistor and router are controlled by the power of incident beams. Our experimental results provide that the advance technique of peak division and channel equalization ratio of about 90% are applicable to all optical switching and routing.

Design and analysis of photonic optical switches with improved wavelength selectivity

NASA Astrophysics Data System (ADS)

Wielichowski, Marcin; Patela, Sergiusz

2005-09-01

Efficient optical modulators and switches are the key elements of the future all-optical fiber networks. Aside from numerous advantages, the integrated optical devices suffer from excessive longitudinal dimensions. The dimensions may be significantly reduced with help of periodic structures, such as Bragg gratings, arrayed waveguides or multilayer structures. In this paper we describe methods of analysis and example of analytical results of a photonic switch with properties modified by the application of periodic change of effective refractive index. The switch is composed of a strip-waveguide directional coupler and a transversal Bragg grating.

Toggle switch from optical bistability to multistability via an elliptically polarized field

NASA Astrophysics Data System (ADS)

Yan, Xiang-An; Ren, Bo-Quan; Wang, Li-Qiang; Liu, Yao-Wu; Yu, Hua-Wa

2017-06-01

In this paper, we propose a scheme for manipulating the behavior of optical bistability (OB) and optical multistability (OM) in an N-type four-level atomic system. In the scheme, quantum interference is optimized by the left-handed and the right-handed fields of an elliptically polarized field (EPF). The threshold and the hysteresis cycle shape of OB and OM can be controlled by modulating the intensity of the EPF. Especially, the transition from OB to OM or vice versa can also be easily realized by proper tuning the phase difference between the left-handed and right-handed polarized fields under the optimal intensity of the EPF.

Evaluation of the optical switching characteristics of erbium-doped fibres for the development of a fibre Bragg grating sensor interrogator

NASA Astrophysics Data System (ADS)

Rigas, Evangelos; Correia, R.; Stathopoulos, N. A.; Savaidis, S. P.; James, S. W.; Bhattacharyya, D.; Kirby, P. B.; Tatam, R. P.

2014-05-01

A polling topology that employs optical switching based on the properties of erbium-doped fibres (EDFs) is used to interrogate an array of FBGs. The properties of the EDF are investigated in its pumped and un-pumped states and the EDFs' switching properties are evaluated by comparing them with a high performance electronically controlled MEM optical switch. Potential advantages of the proposed technique are discussed.

InGaAsP/InP optical waveguide switch operated by a carrier-induced change in the refractive index

NASA Astrophysics Data System (ADS)

Mikami, O.; Nakagome, H.

1985-11-01

Waveguided semiconductor optical switches operated by a carrier-induced change in the refractive-index associated with the plasma dispersion are proposed. InGaAsP/InP four-port switches having two intersecting single-mode channel waveguides are fabricated by selective liquid-phase epitaxy and investigated at 1.5 microns wavelength. Optical switching is observed as a result of mode interference in the waveguide intersection region.

A Fully Implemented 12 × 12 Data Vortex Optical Packet Switching Interconnection Network

NASA Astrophysics Data System (ADS)

Shacham, Assaf; Small, Benjamin A.; Liboiron-Ladouceur, Odile; Bergman, Keren

2005-10-01

A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10-12 or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain.

Photonic Switching Devices Using Light Bullets

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor)

1999-01-01

A unique ultra-fast, all-optical switching device or switch is made with readily available, relatively inexpensive, highly nonlinear optical materials. which includes highly nonlinear optical glasses, semiconductor crystals and/or multiple quantum well semiconductor materials. At the specified wavelengths. these optical materials have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counter-propagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide. and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. An advantage of the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another advantage of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in nonlinear optical materials. including highly nonlinear optical glasses and semiconductor materials such as semiconductor crystals and/or multiple quantum well semiconductor materials.

Cost-effective method of manufacturing a 3D MEMS optical switch

NASA Astrophysics Data System (ADS)

Carr, Emily; Zhang, Ping; Keebaugh, Doug; Chau, Kelvin

2009-02-01

growth of data and video transport networks. All-optical switching eliminates the need for optical-electrical conversion offering the ability to switch optical signals transparently: independent of data rates, formats and wavelength. It also provides network operators much needed automation capabilities to create, monitor and protect optical light paths. To further accelerate the market penetration, it is necessary to identify a path to reduce the manufacturing cost significantly as well as enhance the overall system performance, uniformity and reliability. Currently, most MEMS optical switches are assembled through die level flip-chip bonding with either epoxies or solder bumps. This is due to the alignment accuracy requirements of the switch assembly, defect matching of individual die, and cost of the individual components. In this paper, a wafer level assembly approach is reported based on silicon fusion bonding which aims to reduce the packaging time, defect count and cost through volume production. This approach is successfully demonstrated by the integration of two 6-inch wafers: a mirror array wafer and a "snap-guard" wafer, which provides a mechanical structure on top of the micromirror to prevent electrostatic snap-down. The direct silicon-to-silicon bond eliminates the CTEmismatch and stress issues caused by non-silicon bonding agents. Results from a completed integrated switch assembly will be presented, which demonstrates the reliability and uniformity of some key parameters of this MEMS optical switch.

Using a Semiconductor-to-Metal Transition to Control Optical Transmission through Subwavelength Hole Arrays

DOE PAGES

Donev, E. U.; Suh, J. Y.; Lopez, R.; ...

2008-01-01

We describe a simple configuration in which the extraordinary optical transmission effect through subwavelength hole arrays in noble-metal films can be switched by the semiconductor-to-metal transition in an underlying thin film of vanadium dioxide. In these experiments, the transition is brought about by thermal heating of the bilayer film. The surprising reverse hysteretic behavior of the transmission through the subwavelength holes in the vanadium oxide suggest that this modulation is accomplished by a dielectric-matching condition rather than plasmon coupling through the bilayer film. The results of this switching, including the wavelength dependence, are qualitatively reproduced by a transfer matrix model.more » The prospects for effecting a similar modulation on a much faster time scale by using ultrafast laser pulses to trigger the semiconductor-to-metal transition are also discussed.« less

Low Power Switching for Antenna Reconfiguration

NASA Technical Reports Server (NTRS)

Bauhahn, Paul E. (Inventor); Becker, Robert C. (Inventor); Meyers, David W. (Inventor); Muldoon, Kelly P. (Inventor)

2008-01-01

Methods and systems for low power switching are provided. In one embodiment, an optical switching system is provided. The system comprises at least one optically controlled switch adapted to maintain one of an open state and a closed state based on an associated light signal; and at least one light source adapted to output the associated light signal to the at least one switch, wherein the at least one light source cycles the light signal on and off, wherein the at least one light source is cycled on for a sufficient duration of time and with a sufficient periodicity to maintain the optically controlled switch in one of an open state and a closed state.

Optimal wavelength-space crossbar switches for supercomputer optical interconnects.

PubMed

Roudas, Ioannis; Hemenway, B Roe; Grzybowski, Richard R; Karinou, Fotini

2012-08-27

We propose a most economical design of the Optical Shared MemOry Supercomputer Interconnect System (OSMOSIS) all-optical, wavelength-space crossbar switch fabric. It is shown, by analysis and simulation, that the total number of on-off gates required for the proposed N × N switch fabric can scale asymptotically as N ln N if the number of input/output ports N can be factored into a product of small primes. This is of the same order of magnitude as Shannon's lower bound for switch complexity, according to which the minimum number of two-state switches required for the construction of a N × N permutation switch is log2 (N!).

Compact self-contained electrical-to-optical converter/transmitter

DOEpatents

Seligmann, Daniel A.; Moss, William C.; Valk, Theodore C.; Conder, Alan D.

1995-01-01

A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch.

Digital optical signal processing with polarization-bistable semiconductor lasers

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

Jai-Ming Liu,; Ying-Chin Chen,

1985-04-01

The operations of a complete set of optical AND, NAND, OR, and NOR gates and clocked optical S-R, D, J-K, and T flip-flops are demonstrated, based on direct polarization switching and polarization bistability, which we have recently observed in InGaAsP/InP semiconductor lasers. By operating the laser in the direct-polarizationswitchable mode, the output of the laser can be directly switched between the TM00 and TE00 modes with high extinction ratios by changing the injection-current level, and optical logic gates are constructed with two optoelectronic switches or photodetectors. In the polarization-bistable mode, the laser exhibits controllable hysteresis loops in the polarization-resolved powermore » versus current characteristics. When the laser is biased in the middle of the hysteresis loop, the light output can be switched between the two polarization states by injection of short electrical or optical pulses, and clocked optical flip-flops are constructed with a few optoelectronic switches and/or photodetectors. The 1 and 0 states of these devices are defined through polarization changes of the laser and direct complement functions are obtainable from the TE and TM output signals from the same laser. Switching of the polarization-bistable lasers with fast-rising current pulses has an instrument-limited mode-switching time on the order of 1 ns. With fast optoelectronic switches and/or fast photodetectors, the overall switching speed of the logic gates and flip-flops is limited by the polarizationbistable laser to <1 ns. We have demonstrated the operations of these devices using optical signals generated by semiconductor lasers. The proposed schemes of our devices are compatible with monolithic integration based on current fabrication technology and are applicable to other types of bistable semiconductor lasers.« less

Investigation of vertical cavity surface emitting laser dynamics for neuromorphic photonic systems

NASA Astrophysics Data System (ADS)

Hurtado, A.; Schires, K.; Henning, I. D.; Adams, M. J.

2012-03-01

We report an approach based upon vertical cavity surface emitting lasers (VCSELs) to reproduce optically different behaviors exhibited by biological neurons but on a much faster timescale. The technique proposed is based on the polarization switching and nonlinear dynamics induced in a single VCSEL under polarized optical injection. The particular attributes of VCSELs and the simple experimental configuration used in this work offer prospects of fast, reconfigurable processing elements with excellent fan-out and scaling potentials for use in future computational paradigms and artificial neural networks.

Gain and losses in THz quantum cascade laser with metal-metal waveguide.

PubMed

Martl, Michael; Darmo, Juraj; Deutsch, Christoph; Brandstetter, Martin; Andrews, Aaron Maxwell; Klang, Pavel; Strasser, Gottfried; Unterrainer, Karl

2011-01-17

Coupling of broadband terahertz pulses into metal-metal terahertz quantum cascade lasers is presented. Mode matched terahertz transients are generated on the quantum cascade laser facet of subwavelength dimension. This method provides a full overlap of optical mode and active laser medium. A longitudinal optical-phonon depletion based active region design is investigated in a coupled cavity configuration. Modulation experiments reveal spectral gain and (broadband) losses. The observed gain shows high dynamic behavior when switching from loss to gain around threshold and is clamped at total laser losses.

A molecular-sized optical logic circuit for digital modulation of a fluorescence signal

NASA Astrophysics Data System (ADS)

Nishimura, Takahiro; Tsuchida, Karin; Ogura, Yusuke; Tanida, Jun

2018-03-01

Fluorescence measurement allows simultaneous detection of multiple molecular species by using spectrally distinct fluorescence probes. However, due to the broad spectra of fluorescence emission, the multiplicity of fluorescence measurement is generally limited. To overcome this limitation, we propose a method to digitally modulate fluorescence output signals with a molecular-sized optical logic circuit by using optical control of fluorescence resonance energy transfer (FRET). The circuit receives a set of optical inputs represented with different light wavelengths, and then it switches high and low fluorescence intensity from a reporting molecule according to the result of the logic operation. By using combinational optical inputs in readout of fluorescence signals, the number of biomolecular species that can be identified is increased. To implement the FRET-based circuits, we designed two types of basic elements, YES and NOT switches. An YES switch produces a high-level output intensity when receiving a designated light wavelength input and a low-level intensity without the light irradiation. A NOT switch operates inversely to the YES switch. In experiments, we investigated the operation of the YES and NOT switches that receive a 532-nm light input and modulate the fluorescence intensity of Alexa Fluor 488. The experimental result demonstrates that the switches can modulate fluorescence signals according to the optical input.

Scalable, high-capacity optical switches for Internet routers and moving platforms

NASA Astrophysics Data System (ADS)

Joe, In-Sung

Internet traffic nearly doubles every year, and we need faster routers with higher ports count, yet lower electrical power consumption. Current internet routers use electrical switches that consume large amounts of electrical power to operate at high data rates. These internet routers dissipate ˜ 10kW per rack, and their capacity is limited by cooling constraints. The power consumption is also critical for moving platforms. As avionics advance, the demand for larger capacity networks increases. Optical fibers are already chosen for high speed data transmission in advanced aircraft. In optical communication systems, integrated passive optical components, such as Array Waveguide Gratings (AWGs), have provided larger capacity with lower power consumption, because minimal electrical power is required for their operation. In addition, compact, wavelength-tunable semiconductor lasers with wide tuning ranges that can switch their wavelengths in tens of nanoseconds have been demonstrated. Here we present a wavelength-selective optical packet switch based on Waveguide Grating Routers (WGRs), passive splitters, and combiners. Tunable lasers on the transmitter side are the only active switching elements. The WGR is operated on multiple Free Spectral Ranges (FSRs) to achieve increased port count and switching capacity while maintaining strict-sense, non-blocking operation. Switching times of less than 24ns between two wavelengths covering three FSRs is demonstrated experimentally. The electrical power consumption, size, weight, and cost of our optical switch is compared with those of conventional electrical switches, showing substantial improvements at large throughputs (˜2 Tb/s full duplex). A revised switch design that does not suffer optical loss from star couplers is proposed. This switch design uses only WGRs, and it is suitable for networks with stringent power budgets. The burst nature of the optical packet transmission requires clock recovery for every incoming packet, and conventional continuous-mode receivers are not suitable for this application. An Embedded Clock Transport (ECT) technique is adopted here. The ECT combines a clock tone with the data payload before the transmission. Simple band pass filtering can extract the transmitted clock tone, and low pass filtering can recover the data. Error-free transmissions at 2.488 Gb/s with ˜16 ns clock recovery time were demonstrated.

All-optical 4-bit binary to binary coded decimal converter with the help of semiconductor optical amplifier-assisted Sagnac switch

NASA Astrophysics Data System (ADS)

Bhattachryya, Arunava; Kumar Gayen, Dilip; Chattopadhyay, Tanay

2013-04-01

All-optical 4-bit binary to binary coded decimal (BCD) converter has been proposed and described, with the help of semiconductor optical amplifier (SOA)-assisted Sagnac interferometric switches in this manuscript. The paper describes all-optical conversion scheme using a set of all-optical switches. BCD is common in computer systems that display numeric values, especially in those consisting solely of digital logic with no microprocessor. In many personal computers, the basic input/output system (BIOS) keep the date and time in BCD format. The operations of the circuit are studied theoretically and analyzed through numerical simulations. The model accounts for the SOA small signal gain, line-width enhancement factor and carrier lifetime, the switching pulse energy and width, and the Sagnac loop asymmetry. By undertaking a detailed numerical simulation the influence of these key parameters on the metrics that determine the quality of switching is thoroughly investigated.

Methods and apparatus for optical switching using electrically movable optical fibers

DOEpatents

Peterson, Kenneth A [Albuquerque, NM

2007-03-13

Methods and apparatuses for electrically controlled optical switches are presented. An electrically controlled optical switch includes a fixture formed using a laminated dielectric material, a first optical fiber having a fixed segment supported by the fixture and a movable segment extending into a cavity, a second optical fiber having a fixed segment supported by the fixture and an extended segment where an optical interconnect may be established between the first optical fiber and the second optical fiber, and a first electrical actuator functionally coupled to the fixture and the first fiber which alters a position of the moveable segment, based upon a control signal, for changing a state of the optical interconnect between one of two states.

Electro-optically Q-switched dual-wavelength Nd:YLF laser emitting at 1047 nm and 1053 nm

NASA Astrophysics Data System (ADS)

Men, Shaojie; Liu, Zhaojun; Cong, Zhenhua; Li, Yongfu; Zhang, Xingyu

2015-05-01

A flash-lamp pumped electro-optically Q-switched dual-wavelength Nd:YLF laser is demonstrated. Two Nd:YLF crystals placed in two cavities are employed to generate orthogonally polarized 1047 nm and 1053 nm radiations, respectively. The two cavities are jointed together by a polarizer and share the same electro-optical Q-switch. Two narrow-band pass filters are used to block unexpected oscillations at the hold-off state of the electro-optical Q-switch. In this case, electro-optical Q-switching is able to operate successfully. With pulse synchronization realized, the maximum output energy of 66.2 mJ and 83.9 mJ are obtained for 1047 nm and 1053 nm lasers, respectively. Correspondingly, the minimum pulse width is both 17 ns for 1047 nm and 1053 nm lasers. Sum frequency generation is realized. This demonstrates the potential of this laser in difference-frequency generations to obtain terahertz wave.

An electromagnetically actuated fiber optic switch using magnetized ferromagnetic materials

NASA Astrophysics Data System (ADS)

Pandojirao-S, Praveen; Dhaubanjar, Naresh; Phuyal, Pratibha C.; Chiao, Mu; Chiao, J.-C.

2008-03-01

This paper presents the design, fabrication and testing of a fiber optic switch actuated electromagnetically. The ferromagnetic gel coated optical fiber is actuated using external electromagnetic fields. The ferromagnetic gel consists of ferromagnetic powders dispersed in epoxy. The fabrication utilizes a simple cost-effective coating setup. A direct fiberto-fiber alignment eliminates the need for complementary optical parts and the displacement of fiber switches the laser coupling. The magnetic characteristics of magnetized ferromagnetic materials are performed using alternating gradient magnetometer and the magnetic hysteresis curves are measured for different ferromagnetic materials including iron, cobalt, and nickel. Optical fiber switches with various fiber lengths are actuated and their static and dynamic responses for the same volume of ferromagnetic gel are summarized. The highest displacement is 1.345 mm with an input current of 260mA. In this paper, the performance of fiber switches with various coating materials is presented.

Design and implementation of optical switches based on nonlinear plasmonic ring resonators: Circular, square and octagon

NASA Astrophysics Data System (ADS)

Ghadrdan, Majid; Mansouri-Birjandi, Mohammad Ali

2018-05-01

In this paper, all-optical plasmonic switches (AOPS) based on various configurations of circular, square and octagon nonlinear plasmonic ring resonators (NPRR) were proposed and numerically investigated. Each of these configurations consisted of two metal-insulator-metal (MIM) waveguides coupled to each other by a ring resonator (RR). Nonlinear Kerr effect was used to show switching performance of the proposed NPRR. The result showed that the octagon switch structure had lower threshold power and higher transmission ratio than square and circular switch structures. The octagon switch structure had a low threshold power equal to 7.77 MW/cm2 and the high transmission ratio of approximately 0.6. Therefore, the octagon switch structure was an appropriate candidate to be applied in optical integration circuits as an AOPS.

Dynamically reconfigurable optical packet switch (DROPS)

NASA Astrophysics Data System (ADS)

Huang, Chi-Heng; Chou, Hsu-Feng; Bowers, John E.; Toudeh-Fallah, Farzam; Gyurek, Russ

2006-12-01

A novel Dynamically Reconfigurable Optical Packet Switch (DROPS) that combines both spectral and spatial switching capabilities is proposed and experimentally demonstrated for the first time. Compared with an Arrayed Waveguide Grating Router (AWGR), the added spatial switching capability provided by the microelectromechanical systems (MEMS) enables dynamically reconfigurable routing that is not possible with an AWGR alone. This methodology has several advantages over an AWGR including scalability, additional degrees of freedom in routing a packet from an ingress port to an egress port and more flexibility in path or line card recovery. The experimental demonstration implemented with 10-Gb/s packets shows that the added spatial switching does not degrade the bit-error-rate performance, indicating the promising potential of DROPS as a versatile and ultra-high capacity switch for optical packet-switched networks.

Optical implementation of a parallel out-of-band controller for large broadband ATM switch applications

NASA Astrophysics Data System (ADS)

Cloonan, Thomas J.; Richards, Gaylord W.; Lentine, Anthony L.

1996-03-01

Asynchronous transfer mode (ATM) is rapidly becoming the transport mechanism of choice for the information superhighway, because it promises the bandwidth and flexibility needed for many voice, video and data service offerings. Some industry experts project that the required sizes for ATM switching equipment in the public-switched environment will reach the Tbps range by the beginning of the next decade. This paper analyzes the problems associated with controlling the flow of packets within a broadband ATM switch of this size. The analysis is based on the requirements of the growable packet switch architecture. The paper proposes a novel solution to the problem of hunting paths within an ATM packet switch network. The resulting control scheme is unconventional in two ways. First, it uses an out-of-band control algorithm instead of the more common self-routing approach. In particular, we explore the benefits of using a parallel processor as an out-of-band controller for a growable packet switch distribution network. The processor permits additional levels of parallelism to be added to the out-of-band control function so that path hunts can be performed for all N of the input ports within a single cell interval. The proposed approach is also unconventional because it uses free-space digital optics to guide signals between successive stages of the controller. The paper describes the underlying motivations for implementing an optical out-of-band controller for an ATM switch, and it also describes the logic within a controller node that has been fabricated using a hybrid Si CMOS/GaAs SEED technology. The node uses optical detectors (in GaAs), amplifiers and digital control logic (in Si), and optical modulators (in GaAs). Free-space optical connections between successive device arrays can be provided using either bulk optical elements or micro-optics, but the optical interconnects must provide massive fanout capability. An architectural analysis studying the feasibility of applying free-space optics in this proposed ATM switch controller also is presented.

All-optical phase shifter and switch near 1550nm using tungsten disulfide (WS2) deposited tapered fiber.

PubMed

Wu, Kan; Guo, Chaoshi; Wang, Hao; Zhang, Xiaoyan; Wang, Jun; Chen, Jianping

2017-07-24

All-optical phase shifters and switches play an important role for various all-optical applications including all-optical signal processing, sensing and communication. In this paper, we demonstrate a fiber all-optical phase shifter using few-layer 2D material tungsten disulfide (WS 2 ) deposited on a tapered fiber. WS 2 absorbs injected 980 nm pump (control light) and generates heat, which changes the refractive index of both WS 2 and tapered fiber due to thermo-optic effect and achieves a maximum phase shift of 6.1π near 1550 nm. The device has a loss of 3.7 dB. By constructing a Mach-Zehnder interferometer with WS 2 based phase shifter in one arm, an all-optical switch is also obtained with an extinction ratio of 15 dB and a rise time of 7.3 ms. This all fiber low-cost and compact optical phase shifter and switch demonstrates the potential of 2D transition metal dichalcogenides for all-optical signal processing devices.

The use of 2D and 3D WA-BPM models to analyze total-internal-reflection-based integrated optical switches

NASA Astrophysics Data System (ADS)

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

2011-08-01

The well known beam propagation method (BPM) has become one of the most useful, robust and effective numerical simulation tools for the investigation of guided-wave optics, for example integrated optical waveguides and fiber optic devices. In this paper we examine the use of the 2D and 3D wide angle-beam propagation method (WA-BPM) combined with the well known perfectly matched layer (PML) boundary conditions as a tool to analyze TIR based optical switches, in particular the relationship between light propagation and the geometrical parameters of a TIR based optical switch. To analyze the influence of the length and the width of the region in which the refractive index can be externally controlled, the 3D structure of a 2x2 TIR optical switch is firstly considered in 2D using the effective index method (EIM). Then the influence of the etching depth and the tilt angle of the reflection facet on the switch performance are investigated with a 3D model.

A Novel QKD-based Secure Edge Router Architecture Design for Burst Confidentiality in Optical Burst Switched Networks

NASA Astrophysics Data System (ADS)

Balamurugan, A. M.; Sivasubramanian, A.

2014-06-01

The Optical Burst Switching (OBS) is an emergent result to the technology issue that could achieve a viable network in future. They have the ability to meet the bandwidth requisite of those applications that call for intensive bandwidth. The field of optical transmission has undergone numerous advancements and is still being researched mainly due to the fact that optical data transmission can be done at enormous speeds. The concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution and quality of service (QoS). This paper proposes a framework based on QKD based secure edge router architecture design to provide burst confidentiality. The QKD protocol offers high level of confidentiality as it is indestructible. The design architecture was implemented in FPGA using diverse models and the results were taken. The results show that the proposed model is suitable for real time secure routing applications of the Optical burst switched networks.

Optical response of two coupled optomechanical systems in the presence of nonlinear mediums

NASA Astrophysics Data System (ADS)

Asghari Nejad, A.; Askari, H. R.; Baghshahi, H. R.

2018-01-01

In this paper, we investigate response of a hybrid optomechanical system in different situations. This system is composed of two coupled optomechanical cavities, which one of them is filled with an optical parametric amplifier (OPA) and the other one encompasses a nonlinear Kerr medium. The Hamiltonian of the system is written in a rotating frame. The dynamics of the system is obtained by the quantum Langevin equations of motion in a steady state regime. The results show that the presence of OPA and the Kerr medium in the system can considerably change the behavior of both cavities. For this reason, we show that by choosing different values for the optical parameters of the system, one can switches the behaviors of the cavities between mono-, bi- and tristability. Also, we show that by changing the detunings of the cavities, one can obtain uncommon responses from the system. Furthermore, we show that it is possible to create proper optical multistability regions for both cavities.

Co-dispersion of plasmonic nanorods in thermotropic nematic liquid crystals

NASA Astrophysics Data System (ADS)

Sheetah, Ghadah; Liu, Qinkun; Smalukh, Ivan

Colloidal dispersions of plasmonic metal nanoparticles in liquid crystals promise the capability of pre-engineering tunable optical properties of mesostructured metal-dielectric composites. Recently, concentrated dispersions of anisotropic gold, silver, and metal alloy nanoparticles in nematic hosts have been achieved and successfully controlled by low-voltage fields. However, to enable versatile designs of material behavior of the composites, simultaneous co-dispersion of anisotropic particles with different shapes, alignment properties, and compositions are often needed. We achieve such co-dispersions and explore their switching characteristics in response to external stimuli like light and electric fields. We demonstrated that spectral characteristics of co-dispersions of multiple types of anisotropic nanoparticles in a common nematic host provides unprecedented variety of electrically- and optically-tunable material behavior, with a host of potential practical applications in electro-optic devices and displays Ghadah acknowledges support from the King Faisal University (KFU) graduate fellowship.

Preparation, Characterization and Application of Optical Switch Probes.

PubMed

Petchprayoon, Chutima; Marriott, Gerard

2010-08-01

Optical switches represent a new class of molecular probe with applications in high contrast imaging and optical manipulation of protein interactions. Small molecule, organic optical switches based on nitrospirobenzopyran (NitroBIPS) and their reactive derivatives and conjugates undergo efficient, rapid and reversible, orthogonal optically-driven transitions between a colorless spiro (SP) state and a colored merocyanine (MC) state. The excited MC-state also emits fluorescence, which serves as readout of the state of the switch. Defined optical perturbations of SP and MC generate a defined waveform of MC-fluorescence that can be isolated against unmodulated background signals by using a digital optical lock-in detection approach or to control specific dipolar interactions on proteins. The protocols describe general procedures for the synthesis and spectroscopic characterization of NitroBIPS and specifically labeled conjugates along with methods for the manipulation of dipolar interactions on proteins and imaging of the MC-state of NitroBIPS within living cells.

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Measurements

PubMed Central

Pérez-Prieto, Sandra; López-Cardona, Juan D.; Blanco, Enrique; Moreno-López, Jorge

2018-01-01

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 °C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 °C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point. PMID:29415477

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Measurements.

PubMed

Vázquez, Carmen; Pérez-Prieto, Sandra; López-Cardona, Juan D; Tapetado, Alberto; Blanco, Enrique; Moreno-López, Jorge; Montero, David S; Lallana, Pedro C

2018-02-06

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 °C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 °C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point.

Electrically controlled optical latch and switch requires less current

NASA Technical Reports Server (NTRS)

Pieczonka, W. A.; Roy, M. M.; Yeh, T. H.

1966-01-01

Electrically controlled optical latch consists of a sensitive phototransistor and a solid-state light source. This design requires less current to activate an optically activated switch than in prior art.

Burst switching without guard interval in all-optical software-define star intra-data center network

NASA Astrophysics Data System (ADS)

Ji, Philip N.; Wang, Ting

2014-02-01

Optical switching has been introduced in intra-data center networks (DCNs) to increase capacity and to reduce power consumption. Recently we proposed a star MIMO OFDM-based all-optical DCN with burst switching and software-defined networking. Here, we introduce the control procedure for the star DCN in detail for the first time. The timing, signaling, and operation are described for each step to achieve efficient bandwidth resource utilization. Furthermore, the guidelines for the burst assembling period selection that allows burst switching without guard interval are discussed. The star all-optical DCN offers flexible and efficient control for next-generation data center application.

Compact low crosstalk 1x2 wavelength selective switch architectures

NASA Astrophysics Data System (ADS)

Sumriddetchkajorn, Sarun; Chaitavon, Khunat

2005-02-01

Thin film filter (TF)-based 1x2 wavelength selective switch (WSS) architectures are introduced. Our key idea is to locate a movable mirror orientated at a desired angle close to the TF to switch the desired wavelength optical beams to the wanted switch ports. Our first proposed WSS is in the transmissive mode where the surfaces of the TF and the movable mirror are parallel to each other and it provides a moderate optical isolation. Another WSS structure is in reflective configuration in which the movable mirror is tilted with respect to the surface of the TF and when combined with the optical circulator leads to a very low optical coherent crosstalk. Our experiment using a commercially available TF and a movable mirror shows that our transmissive-mode WSS provides a -18.87 dB optical coherent crosstalk while a much improved < -53 dB optical coherent crosstalk can be obtained between the two switching ports in our reflective-mode WSS structure. Our reflective 1x2 WSS also gives a higher optical loss due to the use of an optical circulator. Low polarization dependent loss of < 0.1 dB is determined for both WSS structures.

Novel polarization diversity without switch duplication of a Si-wire PILOSS optical switch.

PubMed

Tanizawa, Ken; Suzuki, Keijiro; Ikeda, Kazuhiro; Namiki, Shu; Kawashima, Hitoshi

2016-04-04

We demonstrate the compact polarization diversity based on the bidirectional full-port use of a path-independent-insertion-loss (PILOSS) optical switch. A polarization-diversity 4 × 4 strictly non-blocking optical switch is developed using a single thermooptic PILOSS Si-wire switch and fiber-based polarization beam splitters (PBSs) and combiners (PBCs). We measure characteristics of the switch and confirm that the proposed configuration demonstrates the performance in the insertion loss, polarization-dependent loss (PDL), and differential group delay (DGD) comparable with that of a conventional polarization-diversity 4 × 4 PILOSS switch using double switch elements. On the other hand, higher crosstalk is observed. The crosstalk increase is associated with the backward crosstalk at a waveguide intersection based on a directional coupler. The effect of the backward crosstalk on the total crosstalk is estimated, and future prospects are discussed.

Low-threshold ultrafast all-optical switch implemented with metallic nanoshells in the photonic crystal ring resonator

NASA Astrophysics Data System (ADS)

Ghadrdan, Majid; Mansouri-Birjandi, Mohammad Ali

2017-11-01

An all-optical switch based on nonlinear photonic crystal ring resonator embedded with silica dielectric surrounded by silver nanoshell (NS) inside the ring resonator has been introduced and analyzed in this article. We considered silica with radius of 10 nm and silver with radius of 16 nm as core and shell, respectively. By placing NSs inside the photonic crystal ring resonator, we succeeded in reducing the threshold power to 12.8 mW/μm2 and the switching time to about 0.4 ps. The results of this research suggest a new technique for reducing switching light intensity. With small size, ultra-fast switching time, and low-threshold power, the structure has the potential to be applied in optical integration circuits and nanoscale optical chips.

Fiber-optical switch controlled by a single atom.

PubMed

O'Shea, Danny; Junge, Christian; Volz, Jürgen; Rauschenbeutel, Arno

2013-11-08

We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection. Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.

Nonlinear optical characterization of graphite oxide thin film by open aperture Z-scan technique

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

Sreeja, V. G.; Reshmi, R.; Devasia, Sebin

In this paper we explore the structural characterization of graphite oxide powder prepared from graphite powder by oxidation via modified Hummers method. The nonlinear optical properties of the spin coated graphite oxide thin film is also explored by open aperture Z-Scan technique. Structural and physiochemical properties of the samples were investigated with the help of Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy (Raman).The results of FT-IR and Raman spectroscopy showed that the graphite is oxidized by strong oxidants and the oxygen atoms are introduced into the graphite layers forming C=C, O-H and –C-H groups. The synthesized sample has goodmore » crystalline nature with lesser defects. The nonlinear optical property of GO thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532 nm. The Z-scan plot showed that the investigated GO thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated to explore its applications in Q switched mode locking laser systems.« less

Direct investigation of collective phenomena in patterned Ising-like arrays using high-resolution Kerr microscopy

NASA Astrophysics Data System (ADS)

Fraleigh, Robert Douglas

Magnetic systems with interacting ferromagnetic single-domain elements are a useful landscape to explore a wide range of fundamental and technological phenomena. In this dissertation, we consider a system of interacting ferromagnetic islands with perpendicular anisotropy. Islands are lithographically-defined to be single-domain and are arranged into large arrays with geometries that are geometrically frustrated and unfrustrated. We explore field-driven local and global magnetic switching behavior using a home-built diffraction-limited magneto-optical Kerr microscope wherein individual islands in each array are isolated, indexed, and tracked in the presence of an applied external field. Global and local switching behavior is directly accessed through analysis island switching fields in the presence of magnetic hysteresis loops. We first explore the considerations regarding lithographic definition of disconnected islands and deposition of Co/Pt multilayers with strong perpendicular anisotropy. The thickness and number of stacked Co/Pt bilayers as well as deposition method significantly affect the strength of perpendicular anisotropy. We find sputter deposition of a 8-stack bilayer of Co0.3 nm=Pt 1 nm optimizes strong perpendicular anisotropy with square hysteresis loops. Our experimental sample contains several sets of ordered arrays with varying geometry and inter-island spacing. Each island is single-domain with length scales amenable to Kerr imaging such that magnetic degrees of freedom are optically accessible. We next discuss the development, calibration, and operation of a home-built magneto-optical Kerr microscope. The Kerr microscope uses a xenon stabilized white light source, Glan-Thompson polarizers, and a 100x oil objective lens to illuminate a sample with linear polarized light. A cooled CCD camera receives the re ected light and transmits it to the computer in a sequence timed with the application of an external magnetic field. We use LabVIEW software to isolate, index, track, and extract intensity information and corresponding switching fields associated with individual islands in each array as a function of a magnetic field. We find the switching field distribution width is well-fit by a simple model comprising the sum of an array-independent contribution (interpreted as disorder-induced), and a term proportional to the maximum field the entire rest of the array could exert on a single island, i.e., in a fully polarized state. This supports the claim that disorder in these arrays is primarily a single-island property.

Reconfigurable visible nanophotonic switch for optogenetic applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Mohanty, Aseema; Li, Qian; Tadayon, Mohammad Amin; Bhatt, Gaurang R.; Cardenas, Jaime; Miller, Steven A.; Kepecs, Adam; Lipson, Michal

2017-02-01

High spatiotemporal resolution deep-brain optical excitation for optogenetics would enable activation of specific neural populations and in-depth study of neural circuits. Conventionally, a single fiber is used to flood light into a large area of the brain with limited resolution. The scalability of silicon photonics could enable neural excitation over large areas with single-cell resolution similar to electrical probes. However, active control of these optical circuits has yet to be demonstrated for optogenetics. Here we demonstrate the first active integrated optical switch for neural excitation at 473 nm, enabling control of multiple beams for deep-brain neural stimulation. Using a silicon nitride waveguide platform, we develop a cascaded Mach-Zehnder interferometer (MZI) network located outside the brain to direct light to 8 different grating emitters located at the tip of the neural probe. We use integrated platinum microheaters to induce a local thermo-optic phase shift in the MZI to control the switch output. We measure an ON/OFF extinction ratio of >8dB for a single switch and a switching speed of 20 microseconds. We characterize the optical output of the switch by imaging its excitation of fluorescent dye. Finally, we demonstrate in vivo single-neuron optical activation from different grating emitters using a fully packaged device inserted into a mouse brain. Directly activated neurons showed robust spike firing activities with low first-spike latency and small jitter. Active switching on a nanophotonic platform is necessary for eventually controlling highly-multiplexed reconfigurable optical circuits, enabling high-resolution optical stimulation in deep-brain regions.

Compact self-contained electrical-to-optical converter/transmitter

DOEpatents

Seligmann, D.A.; Moss, W.C.; Valk, T.C.; Conder, A.D.

1995-11-21

A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch. 13 figs.

Controlling nonlinear optical response in an open four-level molecular system using quantum control of spin-orbit interaction

NASA Astrophysics Data System (ADS)

Jamshidi-Ghaleh, Kazem; Ebrahimi-hamed, Zahra; Sahrai, Mostafa

2017-10-01

This paper investigates the behavior of linear and nonlinear optical susceptibility of an open four-level molecular system, under two-step excitation based on electromagnetically induced transparency (EIT). The system was irradiated with a weak probe field and strong coupling field. It is shown that the use of a strong coupling field in the triplet states of an alkali-metal dimer can change the spin-orbit interaction (SOI). The optical response of the system can then be modified in a controllable way. The electromagnetically induced transparency transforms into electromagnetically induced absorption (EIA) in the presence of a coupling field. Changing the sign of the dispersion, this region is associated with switching subluminal and superluminal propagation. Furthermore, for the proper value of the coupling field, the controllable parameters, enhanced Kerr nonlinearity with reduced linear absorption, can be obtained under a weak probe field. With this approach, SOI can be controlled by changing only one of the controllable parameters, using triplet-triplet strong coupling with different spin state. Therefore, the desired region of the spectra can be obtained, in contrast to the other four-level system, in which at least two strong fields are used to change optical properties. This mechanism can be suitable in molecular systems or semiconductors to be used in optical bistability and fast all-optical switching devices.

All-optical switching of silicon disk resonator based on photothermal effect in metal-insulator-metal absorber.

PubMed

Shi, Yuechun; Chen, Xi; Lou, Fei; Chen, Yiting; Yan, Min; Wosinski, Lech; Qiu, Min

2014-08-01

Efficient narrowband light absorption by a metal-insulator-metal (MIM) structure can lead to high-speed light-to-heat conversion at a micro- or nanoscale. Such a MIM structure can serve as a heater for achieving all-optical light control based on the thermo-optical (TO) effect. Here we experimentally fabricated and characterized a novel all-optical switch based on a silicon microdisk integrated with a MIM light absorber. Direct integration of the absorber on top of the microdisk reduces the thermal capacity of the whole device, leading to high-speed TO switching of the microdisk resonance. The measurement result exhibits a rise time of 2.0 μs and a fall time of 2.6 μs with switching power as low as 0.5 mW; the product of switching power and response time is only about 1.3  mW·μs. Since no auxiliary elements are required for the heater, the switch is structurally compact, and its fabrication is rather easy. The device potentially can be deployed for new kinds of all-optical applications.

Effects of gold nanoparticles on the electro-optical properties of a polymer dispersed liquid crystal

NASA Astrophysics Data System (ADS)

Hinojosa, A.; Shive, C.; Sharma, Suresh

2010-03-01

We have studied the electro-optical properties of a polymer-dispersed liquid crystal (PDLC) as functions of relative concentrations of gold nanoparticles. PDLC samples were synthesized between indium-tin-oxide (ITO) coated glass slides, separated by SiO2 spacers, by using liquid crystal E44, a monofunctional acrylic oligomer (CN135), and a tetrafunctional crosslinker (SR295). A UV photoinitiator (SR1124) was used to facilitate the curing of the monomer exposed to UV radiation from a Hg spectral lamp. A He-Ne laser was used to measure optical transmission through the PDLC as a function of applied ac electric field (1 kHz). The PDLC without gold nanoparticles shows the expected behavior; transmission through the PDLC increases from a minimum (opaque) to a maximum (transparent) with increasing electric field. The electro-optical behavior of the PDLC is altered significantly (e. g., relatively low switching field) upon addition of relatively low concentrations of gold nanoparticles into the starting PDLC syrup. We present electro-optical data as functions of gold nanoparticle concentration and discuss possible mechanism to understand our results.

Multigranular integrated services optical network

NASA Astrophysics Data System (ADS)

Yu, Oliver; Yin, Leping; Xu, Huan; Liao, Ming

2006-12-01

Based on all-optical switches without requiring fiber delay lines and optical-electrical-optical interfaces, the multigranular optical switching (MGOS) network integrates three transport services via unified core control to efficiently support bursty and stream traffic of subwavelength to multiwavelength bandwidth. Adaptive robust optical burst switching (AR-OBS) aggregates subwavelength burst traffic into asynchronous light-rate bursts, transported via slotted-time light paths established by fast two-way reservation with robust blocking recovery control. Multiwavelength optical switching (MW-OS) decomposes multiwavelength stream traffic into a group of timing-related light-rate streams, transported via a light-path group to meet end-to-end delay-variation requirements. Optical circuit switching (OCS) simply converts wavelength stream traffic from an electrical-rate into a light-rate stream. The MGOS network employs decoupled routing, wavelength, and time-slot assignment (RWTA) and novel group routing and wavelength assignment (GRWA) to select slotted-time light paths and light-path groups, respectively. The selected resources are reserved by the unified multigranular robust fast optical reservation protocol (MG-RFORP). Simulation results show that elastic traffic is efficiently supported via AR-OBS in terms of loss rate and wavelength utilization, while connection-oriented wavelength traffic is efficiently supported via wavelength-routed OCS in terms of connection blocking and wavelength utilization. The GRWA-tuning result for MW-OS is also shown.

Design Sketches For Optical Crossbar Switches Intended For Large-Scale Parallel Processing Applications

NASA Astrophysics Data System (ADS)

Hartmann, Alfred; Redfield, Steve

1989-04-01

This paper discusses design of large-scale (1000x 1000) optical crossbar switching networks for use in parallel processing supercom-puters. Alternative design sketches for an optical crossbar switching network are presented using free-space optical transmission with either a beam spreading/masking model or a beam steering model for internodal communications. The performances of alternative multiple access channel communications protocol-unslotted and slotted ALOHA and carrier sense multiple access (CSMA)-are compared with the performance of the classic arbitrated bus crossbar of conventional electronic parallel computing. These comparisons indicate an almost inverse relationship between ease of implementation and speed of operation. Practical issues of optical system design are addressed, and an optically addressed, composite spatial light modulator design is presented for fabrication to arbitrarily large scale. The wide range of switch architecture, communications protocol, optical systems design, device fabrication, and system performance problems presented by these design sketches poses a serious challenge to practical exploitation of highly parallel optical interconnects in advanced computer designs.

Crossbar Switches For Optical Data-Communication Networks

NASA Technical Reports Server (NTRS)

Monacos, Steve P.

1994-01-01

Optoelectronic and electro-optical crossbar switches called "permutation engines" (PE's) developed to route packets of data through fiber-optic communication networks. Basic network concept described in "High-Speed Optical Wide-Area Data-Communication Network" (NPO-18983). Nonblocking operation achieved by decentralized switching and control scheme. Each packet routed up or down in each column of this 5-input/5-output permutation engine. Routing algorithm ensures each packet arrives at its designated output port without blocking any other packet that does not contend for same output port.

Coupling and Switching in Optically Resonant Periodic Electrode Structures

NASA Astrophysics Data System (ADS)

Bieber, Amy Erica

This thesis describes coupling and switching of optical radiation using metal-semiconductor-metal (MSM) structures, specifically in a metal-on-silicon waveguide configuration. The structures which are the subject of this research have the special advantage of being VLSI -compatible; this is very important for the ultimate acceptance of any integrated optoelectronics technology by the mainstream semiconductor community. To date, research efforts in VLSI electronics, MSM detectors, metal devices, and optical switching have existed as separate entities with decidedly different goals. This work attempts to unite these specialties; an interdigitated array of metal fingers on a silicon waveguide allows for (1) fabrication processes which are well-understood and compatible with current or next-generation semiconductor manufacturing standards, (2) electrical bias capability which can potentially provide modulation, tuning, and enhanced speed, and (3) potentially efficient waveguide coupling which takes advantage of TM coupling. The latter two items are made possible by the use of metallic gratings, which sets this work apart from previous optical switching results. This MSM structure represents an important step in uniting four vital technologies which, taken together, can lead to switching performance and operational flexibility which could substantially advance the capabilities of current optoelectronic devices. Three different designs were successfully used to examine modulation and optical switching based upon nonlinear interactions in the silicon waveguide. First, a traditional Bragg reflector design with input and output couplers on either side was used to observe switching of nanosecond-regime Nd:YAG pulses. This structure was thermally tuned to obtain a variety of switching dynamics. Next, a phase-shift was incorporated into the Bragg reflector, and again thermally-tunable switching dynamics were observed, but with the added advantage of a reduction in the energy requirements for optical switching. Finally, the roles of the coupler and Bragg reflector were combined in a normal -incidence structure which exhibited nonlinear reflectivity modulation. This has not only been the first experimental demonstration of optical switching in a metal-semiconductor waveguide structure, but, to our knowledge, one of the first such demonstrations using a nonlinear phase-shifted or normal incidence grating of any kind.

Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

DOEpatents

Woodruff, Steven D.; Mcintyre, Dustin L.

2016-03-29

A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

Experimental study of electro-optical Q-switched pulsed Nd:YAG laser

NASA Astrophysics Data System (ADS)

A, Maleki; M Kavosh, Tehrani; H, Saghafifar; M, H. Moghtader Dindarlu

2016-03-01

We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd:YAG laser. We experimentally study and compare the performance of the pulsed Nd:YAG laser in the free-running and Q-switched modes at different pulse repetition rates from 1 Hz to 100 Hz. The laser output energy is stabilized by using a special configuration of the optical resonator. In this laser, an unsymmetrical concave-concave resonator is used and this structure helps the mode volume to be nearly fixed when the pulse repetition rate is increased. According to the experimental results in the Q-switched operation, the laser output energy is nearly constant around 70 mJ with an FWHM pulse width of 7 ns at 100 Hz. The optical-to-optical conversion efficiency in the Q-switched regime is 17.5%.

New Remote Gas Sensor Using Rapid Electro-Optical Path Switching

NASA Technical Reports Server (NTRS)

Sachse, G. W.; Lebel, P. J.; Wallio, H. A.; Vay, S. A.; Wang, L. G.

1994-01-01

Innovative gas filter correlation radiometer (GFCR) features nonmechanical switching of internal optical paths. Incoming radiation switched electro-optically, by means of polarization, between two optical paths, one of which contains correlation gas cell while other does not. Advantages include switching speed, 2 to 3 orders of magnitude faster than mechanical techniques, and high reliability. Applications include regional studies of atmospheric chemistry from either manned or unmanned aircraft as well as satellite studies of global distributions, sources and sink mechanisms for key species involved in chemistry of troposphere. Commercial applications: ability to survey many miles of natural gas pipelines rapidly from aircraft, pinpointing gas leaks by measuring methane at 2.3 micrometers.

CW all optical self switching in nonlinear chalcogenide nano plasmonic directional coupler

NASA Astrophysics Data System (ADS)

Motamed-Jahromi, Leila; Hatami, Mohsen

2018-04-01

In this paper we obtain the coupling coefficient of plasmonic directional coupler (PDC) made up of two parallel monolayer waveguides filled with high nonlinear chalcogenide material for TM mode in continues wave (CW) regime. In addition, we assume each waveguides acts as a perturbation to other waveguide. Four nonlinear-coupled equations are derived. Transfer distances are numerically calculated and used for deriving length of all optical switch. The length of designed switch is in the range of 10-1000 μm, and the switching power is in the range of 1-100 W/m. Obtained values are suitable for designing all optical elements in the integrated optical circuits.

All-optical diffractive/transmissive switch based on coupled cycloidal diffractive waveplates.

PubMed

Serak, Svetlana V; Hakobyan, Rafael S; Nersisyan, Sarik R; Tabiryan, Nelson V; White, Timothy J; Bunning, Timothy J; Steeves, Diane M; Kimball, Brian R

2012-02-27

Pairs of cycloidal diffractive waveplates can be used to doubly diffract or collinearly propagate laser radiation of the appropriate wavelength. The use of a dynamic phase retarder placed in between the pair can be utilized to switch between the two optical states. We present results from the implementation of an azo-based retarder whose optical properties can be modulated using light itself. We show fast and efficient switching between the two states for both CW and single nanosecond laser pulses of green radiation. Contrasts greater than 100:1 were achieved. The temporal response as a function of light intensity is presented and the optical switching is shown to be polarization independent.

Novel flat datacenter network architecture based on scalable and flow-controlled optical switch system.

PubMed

Miao, Wang; Luo, Jun; Di Lucente, Stefano; Dorren, Harm; Calabretta, Nicola

2014-02-10

We propose and demonstrate an optical flat datacenter network based on scalable optical switch system with optical flow control. Modular structure with distributed control results in port-count independent optical switch reconfiguration time. RF tone in-band labeling technique allowing parallel processing of the label bits ensures the low latency operation regardless of the switch port-count. Hardware flow control is conducted at optical level by re-using the label wavelength without occupying extra bandwidth, space, and network resources which further improves the performance of latency within a simple structure. Dynamic switching including multicasting operation is validated for a 4 x 4 system. Error free operation of 40 Gb/s data packets has been achieved with only 1 dB penalty. The system could handle an input load up to 0.5 providing a packet loss lower that 10(-5) and an average latency less that 500 ns when a buffer size of 16 packets is employed. Investigation on scalability also indicates that the proposed system could potentially scale up to large port count with limited power penalty.

A hybrid optical switch architecture to integrate IP into optical networks to provide flexible and intelligent bandwidth on demand for cloud computing

NASA Astrophysics Data System (ADS)

Yang, Wei; Hall, Trevor J.

2013-12-01

The Internet is entering an era of cloud computing to provide more cost effective, eco-friendly and reliable services to consumer and business users. As a consequence, the nature of the Internet traffic has been fundamentally transformed from a pure packet-based pattern to today's predominantly flow-based pattern. Cloud computing has also brought about an unprecedented growth in the Internet traffic. In this paper, a hybrid optical switch architecture is presented to deal with the flow-based Internet traffic, aiming to offer flexible and intelligent bandwidth on demand to improve fiber capacity utilization. The hybrid optical switch is capable of integrating IP into optical networks for cloud-based traffic with predictable performance, for which the delay performance of the electronic module in the hybrid optical switch architecture is evaluated through simulation.

Moving the boundary between wavelength resources in optical packet and circuit integrated ring network.

PubMed

Furukawa, Hideaki; Miyazawa, Takaya; Wada, Naoya; Harai, Hiroaki

2014-01-13

Optical packet and circuit integrated (OPCI) networks provide both optical packet switching (OPS) and optical circuit switching (OCS) links on the same physical infrastructure using a wavelength multiplexing technique in order to deal with best-effort services and quality-guaranteed services. To immediately respond to changes in user demand for OPS and OCS links, OPCI networks should dynamically adjust the amount of wavelength resources for each link. We propose a resource-adjustable hybrid optical packet/circuit switch and transponder. We also verify that distributed control of resource adjustments can be applied to the OPCI ring network testbed we developed. In cooperation with the resource adjustment mechanism and the hybrid switch and transponder, we demonstrate that automatically allocating a shared resource and moving the wavelength resource boundary between OPS and OCS links can be successfully executed, depending on the number of optical paths in use.

Intelligent optical networking with photonic cross connections

NASA Astrophysics Data System (ADS)

Ceuppens, L.; Jerphagnon, Olivier L.; Lang, Jonathan; Banerjee, Ayan; Blumenthal, Daniel J.

2002-09-01

Optical amplification and dense wavelength division multiplexing (DWDM) have fundamentally changed optical transport networks. Now that these technologies are widely adopted, the bottleneck has moved from the outside line plant to nodal central offices, where electrical switching equipment has not kept pace. While OEO technology was (and still is) necessary for grooming and traffic aggregation, the transport network has dramatically changed, requiring a dramatic rethinking of how networks need to be designed and operated. While todays transport networks carry remarkable amounts of bandwidth, their optical layer is fundamentally static and provides for only simple point-to-point transport. Efficiently managing the growing number of wavelengths can only be achieved through a new breed of networking element. Photonic switching systems (PSS) can efficiently execute these functions because they are bit rate, wavelength, and protocol transparent. With their all-optical switch cores and interfaces, PSS can switch optical signals at various levels of granularity wavelength, sub band, and composite DWDM fiber levels. Though cross-connect systems with electrical switch cores are available, they perform these functions at very high capital costs and operational inefficiencies. This paper examines enabling technologies for deployment of intelligent optical transport networks (OTN), and takes a practical perspective on survivability architecture migration and implementation issues.

Improved silica-PLC Mach-Zehnder interferometer type optical switches with error dependence compensation of directional coupler

NASA Astrophysics Data System (ADS)

Wang, Jun; Yi, Jia; Guo, Lijun; Liu, Peng; Hall, Trevor J.; Sun, DeGui

2017-03-01

For the most popular structure of planer lightwave circuit (PLC) 2×2 thermo-optic switches, Mach-Zehnder interferometer (MZI), a full range of splitting ratio errors of directional coupler (DC) are investigated. All the parameters determining the splitting ratio are the dimensions and the refractive indices of the waveguide core and cladding layers. In this work, the coherent relationships between the waveguide size and the refractive indices are analyzed and then the error compensation between the width and the refractive index of waveguide core, and the controllable effect of over clad layer refractive index error upon the MZI-type optical switch are all discovered with numerical calculation and BPM simulations. Then, an MZI-type 2×2 thermo-optic switch having a higher error tolerance is established with the efficient optimizations of all the 3 dB-DC parameters. As a result, for the symmetric MZI switch, an insertion loss of 1.5 dB and optical extinction ratio of over 20 dB are realized for the average tolerance of±5.0%. An asymmetric arm optical phase and unequal arm lengths is also employed to improve the uniformities of insertion loss. The agreements between the designs and the experiments are recognized, leading to a wide adoption of practical silica-PLC optical switch products.

Switching Matrix For Optical Signals

NASA Technical Reports Server (NTRS)

Grove, Charles H.

1990-01-01

Proposed matrix of electronically controlled shutters switches signals in optical fibers between multiple input and output channels. Size, weight, and power consumption reduced. Device serves as building block for small, low-power, broad-band television- and data-signal-switching systems providing high isolation between nominally disconnected channels.

Magnetization switching behavior with competing anisotropies in epitaxial Co3FeN /MnN exchange-coupled bilayers

NASA Astrophysics Data System (ADS)

Hajiri, T.; Yoshida, T.; Jaiswal, S.; Filianina, M.; Borie, B.; Ando, H.; Asano, H.; Zabel, H.; Kläui, M.

2016-11-01

We report unusual magnetization switching processes and angular-dependent exchange bias effects in fully epitaxial Co3FeN /MnN bilayers, where magnetocrystalline anisotropy and exchange coupling compete, probed by longitudinal and transverse magneto-optic Kerr effect (MOKE) magnetometry. The MOKE loops show multistep jumps corresponding to the nucleation and propagation of 90∘ domain walls in as-grown bilayers. By inducing exchange coupling, we confirm changes of the magnetization switching process due to the unidirectional anisotropy field of the exchange coupling. Taking into account the experimentally obtained values of the fourfold magnetocrystalline anisotropy, the unidirectional anisotropy field, the exchange-coupling constant, and the uniaxial anisotropy including its direction, the calculated angular-dependent exchange bias reproduces the experimental results. These results demonstrate the essential role of the competition between magnetocrystalline anisotropy and exchange coupling for understanding and tailoring exchange-coupling phenomena usable for engineering switching in fully epitaxial bilayers made of tailored materials.

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

Field-programmable logic devices with optical input-output.

PubMed

Szymanski, T H; Saint-Laurent, M; Tyan, V; Au, A; Supmonchai, B

2000-02-10

A field-programmable logic device (FPLD) with optical I/O is described. FPLD's with optical I/O can have their functionality specified in the field by means of downloading a control-bit stream and can be used in a wide range of applications, such as optical signal processing, optical image processing, and optical interconnects. Our device implements six state-of-the-art dynamically programmable logic arrays (PLA's) on a 2 mm x 2 mm die. The devices were fabricated through the Lucent Technologies-Advanced Research Projects Agency-Consortium for Optical and Optoelectronic Technologies in Computing (Lucent/ARPA/COOP) workshop by use of 0.5-microm complementary metal-oxide semiconductor-self-electro-optic device technology and were delivered in 1998. All devices are fully functional: The electronic data paths have been verified at 200 MHz, and optical tests are pending. The device has been programmed to implement a two-stage optical switching network with six 4 x 4 crossbar switches, which can realize more than 190 x 10(6) unique programmable input-output permutations. The same device scaled to a 2 cm x 2 cm substrate could support as many as 4000 optical I/O and 1 Tbit/s of optical I/O bandwidth and offer fully programmable digital functionality with approximately 110,000 programmable logic gates. The proposed optoelectronic FPLD is also ideally suited to realizing dense, statically reconfigurable crossbar switches. We describe an attractive application area for such devices: a rearrangeable three-stage optical switch for a wide-area-network backbone, switching 1000 traffic streams at the OC-48 data rate and supporting several terabits of traffic.

Optical implementation of polarization-independent, bidirectional, nonblocking Clos network using polarization control technique in free space

NASA Astrophysics Data System (ADS)

Yang, Junbo; Yang, Jiankun; Li, Xiujian; Chang, Shengli; Su, Xianyu; Ping, Xu

2011-04-01

The clos network is one of the earliest multistage interconnection networks. Recently, it has been widely studied in parallel optical information processing systems, and there have been many efforts to develop this network. In this paper, a smart and compact Clos network, including Clos(2,3,2) and Clos(2,4,2), is proposed by using polarizing beam-splitters (PBS), phase spatial light modulators (PSLM), and mirrors. PBS features that are s-component (perpendicular to the incident plane) of the incident light beam is reflected, and the p-component (parallel to the incident plane) passes through it. According to switching logic, under control of external electrical signals, PSLM functions to control routing paths of the signal beams, i.e., the polarization of each optical signal is rotated or not rotated 90° by a programmable PSLM. This new type of configuration grants the features of less optical components, compact in structure, efficient in performance, and insensitive to polarization of signal beam. In addition, the straight, the exchange, and the broadcast functions of the basic switch element are implemented bidirectionally in free-space. Furthermore, the new optical experimental module of 2×3 and 2×4 optical switch is also presented by a cascading polarization-independent bidirectional 2×2 optical switch. Simultaneously, the routing state-table of 2×3 and 2×4 optical switch to perform all permutation output and nonblocking switch for the input signal beam, is achieved. Since the proposed optical setup consists of only optical polarization elements, it is compact in structure, and possesses a low energy loss, a high signal-to-ratio, and an available large number of optical channels. Finally, the discussions and the experimental results show that the Clos network proposed here should be helpful in the design of large-scale network matrix, and may be used in optical communication and optical information processing.

Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

NASA Astrophysics Data System (ADS)

G, Sreeja V.; V, Sabitha P.; Anila, E. I.; R, Reshmi; John, Manu Punnan; Radhakrishnan, P.

2014-10-01

ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

Fabrication and demonstration of 1 × 8 silicon-silica multi-chip switch based on optical phased array

NASA Astrophysics Data System (ADS)

Katayose, Satomi; Hashizume, Yasuaki; Itoh, Mikitaka

2016-08-01

We experimentally demonstrated a 1 × 8 silicon-silica hybrid thermo-optic switch based on an optical phased array using a multi-chip integration technique. The switch consists of a silicon chip with optical phase shifters and two silica-based planar lightwave circuit (PLC) chips composed of optical couplers and fiber connections. We adopted a rib waveguide as the silicon waveguide to reduce the coupling loss and increase the alignment tolerance for coupling between silicon and silica waveguides. As a result, we achieved a fast switching response of 81 µs, a high extinction ratio of over 18 dB and a low insertion loss of 4.9-8.1 dB including a silicon-silica coupling loss of 0.5 ± 0.3 dB at a wavelength of 1.55 µm.

Low-photon-number optical switch and AND/OR logic gates based on quantum dot-bimodal cavity coupling system.

PubMed

Ma, Shen; Ye, Han; Yu, Zhong-Yuan; Zhang, Wen; Peng, Yi-Wei; Cheng, Xiang; Liu, Yu-Min

2016-01-11

We propose a new scheme based on quantum dot-bimodal cavity coupling system to realize all-optical switch and logic gates in low-photon-number regime. Suppression of mode transmission due to the destructive interference effect is theoretically demonstrated by driving the cavity with two orthogonally polarized pulsed lasers at certain pulse delay. The transmitted mode can be selected by designing laser pulse sequence. The optical switch with high on-off ratio emerges when considering one driving laser as the control. Moreover, the AND/OR logic gates based on photon polarization are achieved by cascading the coupling system. Both proposed optical switch and logic gates work well in ultra-low energy magnitude. Our work may enable various applications of all-optical computing and quantum information processing.

Low-photon-number optical switch and AND/OR logic gates based on quantum dot-bimodal cavity coupling system

PubMed Central

Ma, Shen; Ye, Han; Yu, Zhong-Yuan; Zhang, Wen; Peng, Yi-Wei; Cheng, Xiang; Liu, Yu-Min

2016-01-01

We propose a new scheme based on quantum dot-bimodal cavity coupling system to realize all-optical switch and logic gates in low-photon-number regime. Suppression of mode transmission due to the destructive interference effect is theoretically demonstrated by driving the cavity with two orthogonally polarized pulsed lasers at certain pulse delay. The transmitted mode can be selected by designing laser pulse sequence. The optical switch with high on-off ratio emerges when considering one driving laser as the control. Moreover, the AND/OR logic gates based on photon polarization are achieved by cascading the coupling system. Both proposed optical switch and logic gates work well in ultra-low energy magnitude. Our work may enable various applications of all-optical computing and quantum information processing. PMID:26750557

Transparent selective illumination means suitable for use in optically activated electrical switches and optically activated electrical switches constructed using same

DOEpatents

Wilcox, R.B.

1991-09-10

A planar transparent light conducting means and an improved optically activated electrical switch made using the novel light conducting means are disclosed. The light conducting means further comprise light scattering means on one or more opposite planar surfaces thereof to transmit light from the light conducting means into adjacent media and reflective means on other surfaces of the light conducting means not containing the light scattering means. The optically activated electrical switch comprises at least two stacked photoconductive wafers, each having electrodes formed on both surfaces thereof, and separated by the planar transparent light conducting means. The light scattering means on the light conducting means face surfaces of the wafers not covered by the electrodes to transmit light from the light conducting means into the photoconductive wafers to uniformly illuminate and activate the switch. 11 figures.

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

Allen, James J.

A microelectromechanical (MEM) optical switching apparatus is disclosed that is based on an erectable mirror which is formed on a rotatable stage using surface micromachining. An electrostatic actuator is also formed on the substrate to rotate the stage and mirror with a high angular precision. The mirror can be erected manually after fabrication of the device and used to redirect an incident light beam at an arbitrary angel and to maintain this state in the absence of any applied electrical power. A 1.times.N optical switch can be formed using a single rotatable mirror. In some embodiments of the present invention,more » a plurality of rotatable mirrors can be configured so that the stages and mirrors rotate in unison when driven by a single micromotor thereby forming a 2.times.2 optical switch which can be used to switch a pair of incident light beams, or as a building block to form a higher-order optical switch.« less

Transparent selective illumination means suitable for use in optically activated electrical switches and optically activated electrical switches constructed using same

DOEpatents

Wilcox, Russell B.

1991-01-01

A planar transparent light conducting means and an improved optically activated electrical switch made using the novel light conducting means are disclosed. The light conducting means further comprise light scattering means on one or more opposite planar surfaces thereof to transmit light from the light conducting means into adjacent media and reflective means on other surfaces of the light conducting means not containing the light scattering means. The optically activated electrical switch comprises at least two stacked photoconductive wafers, each having electrodes formed on both surfaces thereof, and separated by the planar transparent light conducting means. The light scattering means on the light conducting means face surfaces of the wafers not covered by the electrodes to transmit light from the light conducting means into the photoconductive wafers to uniformly illuminate and activate the switch.

16 × 16 non-blocking silicon optical switch based on electro-optic Mach-Zehnder interferometers.

PubMed

Lu, Liangjun; Zhao, Shuoyi; Zhou, Linjie; Li, Dong; Li, Zuxiang; Wang, Minjuan; Li, Xinwan; Chen, Jianping

2016-05-02

We experimentally demonstrate a 16 × 16 non-blocking optical switch fabric with a footprint of 10.7 × 4.4 mm². The switch fabric is composed of 56 2 × 2 silicon Mach-Zehnder interferometers (MZIs), with each integrated with a pair of TiN resistive micro-heaters and a p-i-n diode. The average on-chip insertion loss at 1560 nm wavelength is ~6.7 dB and ~14 dB for the "all-cross" and "all-bar" states, respectively, with a loss variation of ± 1 dB over all routing paths. The measured rise/fall time of the switch upon electrical tuning is 3.2/2.5 ns. The switching functionality is verified by transmission of 20 Gb/s on-off keying (OOK) and 50 Gb/s quadrature phase-shift keying (QPSK) optical signals.

Ultrafast Coherent Dynamics of a Photonic Crystal All-Optical Switch.

PubMed

Colman, Pierre; Lunnemann, Per; Yu, Yi; Mørk, Jesper

2016-12-02

We present pump-probe measurements of an all-optical photonic crystal switch based on a nanocavity, resolving fast coherent temporal dynamics. The measurements demonstrate the importance of coherent effects typically neglected when considering nanocavity dynamics. In particular, we report the observation of an idler pulse and more than 10 dB parametric gain. The measurements are in good agreement with a theoretical model that ascribes the observation to oscillations of the free-carrier population in the nanocavity. The effect opens perspectives for the realization of new all-optical photonic crystal switches with unprecedented switching contrast.

Investigation of Optically Induced Avalanching in GaAs

DTIC Science & Technology

1989-06-01

by Bovino , et al 4 to increase the hold off voltage. The button switch design of Fig. 4c has been used by several researchers5 ’ 7 to obtain the...ul Long flashover palh Figure 3b. 434 Optical Jlatlern a. Mourou Switch b. Bovino Switch c. Button Switch Figure 4. Photoconductive Switches...Technology and Devices Laboratory, ERADCOM (by L. Bovino , et. all) 4 • The deposition recipe for the contacts is 1) 50 ANi (provides contact to GaAs

A novel micro/nano 1 × 4 mechanical optical switch

NASA Astrophysics Data System (ADS)

Lin, Wu-Lang; Fan, Kuang-Chao; Chiang, Li-Hung; Yang, Yao-Joe; Kuo, Wen-Cheng; Chung, Tien-Tung

2006-07-01

This paper presents the design, fabrication and testing of a novel 1 × 4 mechanical optical switch, whose components are fabricated by precision machining and MEMS technologies. The switch uses two relays as the two actuators whose switching direction is perpendicular to each other by an orthogonal arrangement. We adopt a direct fiber-to-fiber principle that aligns the input fiber directly to four output fibers. This configuration eliminates the use of traditional parts such as collimators, turning mirrors or prisms. In addition, due to the use of a fiber holder, the fiber position errors could be reduced to less than 0.27 µm using the two-stage geometry error reduction principle. We have successfully developed a simple and low-cost switch, which performs like most of the 1 × 4 mechanical optical switches that dominate the optics communications market. The advantages of our switch are a small size (20 × 20 × 25 mm3), low cost, high reliability, and the latching function does not need external force for maintaining the state. The experimental results showed that the insertion losses of the four channels are ch1: 0.68 dB, ch2: 1.49 dB, ch3: 0.71 dB and ch4: 0.97 dB. The switching time is 5 ms, the crosstalk <=80 dB. The reliability tests of the insertion loss after 10 000 cycles in four channels yield ch1: 1.67 dB, ch2: 1.63 dB, ch3: 0.75 dB and ch4: 0.98 dB. The size and the cost of our 1 × 4 mechanical optical switch are only about 1/5-1/10 and 1/10 of the series-connect-type and prism-type switches, respectively.

High-performance and power-efficient 2×2 optical switch on Silicon-on-Insulator.

PubMed

Han, Zheng; Moille, Grégory; Checoury, Xavier; Bourderionnet, Jérôme; Boucaud, Philippe; De Rossi, Alfredo; Combrié, Sylvain

2015-09-21

A compact (15µm × 15µm) and highly-optimized 2×2 optical switch is demonstrated on a CMOS-compatible photonic crystal technology. On-chip insertion loss are below 1 dB, static and dynamic contrast are 40 dB and >20 dB respectively. Owing to efficient thermo-optic design, the power consumption is below 3 mW while the switching time is 1 µs.

MPNACK: an optical switching scheme enabling the buffer-less reliable transmission

NASA Astrophysics Data System (ADS)

Yu, Xiaoshan; Gu, Huaxi; Wang, Kun; Xu, Meng; Guo, Yantao

2016-01-01

Optical data center networks are becoming an increasingly promising solution to solve the bottlenecks faced by electrical networks, such as low transmission bandwidth, high wiring complexity, and unaffordable power consumption. However, the optical circuit switching (OCS) network is not flexible enough to carry the traffic burst while the optical packet switching (OPS) network cannot solve the packet contention in an efficient way. To this end, an improved switching strategy named OPS with multi-hop Negative Acknowledgement (MPNACK) is proposed. This scheme uses a feedback mechanism, rather than the buffering structure, to handle the optical packet contention. The collided packet is treated as a NACK packet and sent back to the source server. When the sender receives this NACK packet, it knows a collision happens in the transmission path and a retransmission procedure is triggered. Overall, the OPS-NACK scheme enables a reliable transmission in the buffer-less optical network. Furthermore, with this scheme, the expensive and energy-hungry elements, optical or electrical buffers, can be removed from the optical interconnects, thus a more scalable and cost-efficient network can be constructed for cloud computing data centers.

Reversible optical switching memristors with tunable STDP synaptic plasticity: a route to hierarchical control in artificial intelligent systems.

PubMed

Jaafar, Ayoub H; Gray, Robert J; Verrelli, Emanuele; O'Neill, Mary; Kelly, Stephen M; Kemp, Neil T

2017-11-09

Optical control of memristors opens the route to new applications in optoelectronic switching and neuromorphic computing. Motivated by the need for reversible and latched optical switching we report on the development of a memristor with electronic properties tunable and switchable by wavelength and polarization specific light. The device consists of an optically active azobenzene polymer, poly(disperse red 1 acrylate), overlaying a forest of vertically aligned ZnO nanorods. Illumination induces trans-cis isomerization of the azobenzene molecules, which expands or contracts the polymer layer and alters the resistance of the off/on states, their ratio and retention time. The reversible optical effect enables dynamic control of a memristor's learning properties including control of synaptic potentiation and depression, optical switching between short-term and long-term memory and optical modulation of the synaptic efficacy via spike timing dependent plasticity. The work opens the route to the dynamic patterning of memristor networks both spatially and temporally by light, thus allowing the development of new optically reconfigurable neural networks and adaptive electronic circuits.

All-optical OXC transition strategy from WDM optical network to elastic optical network.

PubMed

Chen, Xin; Li, Juhao; Guo, Bingli; Zhu, Paikun; Tang, Ruizhi; Chen, Zhangyuan; He, Yongqi

2016-02-22

Elastic optical network (EON) has been proposed recently as a spectrum-efficient optical layer to adapt to rapidly-increasing traffic demands instead of current deployed wavelength-division-multiplexing (WDM) optical network. In contrast with conventional WDM optical cross-connect (OXCs) based on wavelength selective switches (WSSs), the EON OXCs are based on spectrum selective switches (SSSs) which are much more expensive than WSSs, especially for large-scale switching architectures. So the transition cost from WDM OXCs to EON OXCs is a major obstacle to realizing EON. In this paper, we propose and experimentally demonstrate a transition OXC (TOXC) structure based on 2-stage cascading switching architectures, which make full use of available WSSs in current deployed WDM OXCs to reduce number and port count of required SSSs. Moreover, we propose a contention-aware spectrum allocation (CASA) scheme for EON built with the proposed TOXCs. We show by simulation that the TOXCs reduce the network capital expenditure transiting from WDM optical network to EON about 50%, with a minor traffic blocking performance degradation and about 10% accommodated traffic number detriment compared with all-SSS EON OXC architectures.

Fast optical switch having reduced light loss

NASA Technical Reports Server (NTRS)

Nelson, Bruce N. (Inventor); Cooper, Ronald F. (Inventor)

1992-01-01

An electrically controlled optical switch uses an electro-optic crystal of the type having at least one set of fast and slow optical axes. The crystal exhibits electric field induced birefringence such that a plane of polarization oriented along a first direction of a light beam passing through the crystal may be switched to a plane of polarization oriented along a second direction. A beam splitting polarizer means is disposed at one end of the crystal and directs a light beam passing through the crystal whose plane of polarization is oriented along the first direction differently from a light beam having a plane of polarization oriented along the second direction. The electro-optic crystal may be chosen from the crystal classes 43m, 42m, and 23. In a preferred embodiment, the electro-optic crystal is a bismuth germanium oxide crystal or a bismuth silicon oxide crystal. In another embodiment of the invention, polarization control optics are provided which transmit substantially all of the incident light to the electro-optic crystal, substantially reducing the insertion loss of the switch.

The other fiber, the other fabric, the other way

NASA Astrophysics Data System (ADS)

Stephens, Gary R.

1993-02-01

Coaxial cable and distributed switches provide a way to configure high-speed Fiber Channel fabrics. This type of fabric provides a cost-effective alternative to a fabric of optical fibers and centralized cross-point switches. The fabric topology is a simple tree. Products using parallel busses require a significant change to migrate to a serial bus. Coaxial cables and distributed switches require a smaller technology shift for these device manufacturers. Each distributed switch permits both medium type and speed changes. The fabric can grow and bridge to optical fibers as the needs expand. A distributed fabric permits earlier entry into high-speed serial operations. For very low-cost fabrics, a distributed switch may permit a link configured as a loop. The loop eliminates half of the ports when compared to a switched point-to-point fabric. A fabric of distributed switches can interface to a cross-point switch fabric. The expected sequence of migration is: closed loops, small closed fabrics, and, finally, bridges, to connect optical cross-point switch fabrics. This paper presents the concept of distributed fabrics, including address assignment, frame routing, and general operation.

Tutorial: Integrated-photonic switching structures

NASA Astrophysics Data System (ADS)

Soref, Richard

2018-02-01

Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

Optical network scaling: roles of spectral and spatial aggregation.

PubMed

Arık, Sercan Ö; Ho, Keang-Po; Kahn, Joseph M

2014-12-01

As the bit rates of routed data streams exceed the throughput of single wavelength-division multiplexing channels, spectral and spatial traffic aggregation become essential for optical network scaling. These aggregation techniques reduce network routing complexity by increasing spectral efficiency to decrease the number of fibers, and by increasing switching granularity to decrease the number of switching components. Spectral aggregation yields a modest decrease in the number of fibers but a substantial decrease in the number of switching components. Spatial aggregation yields a substantial decrease in both the number of fibers and the number of switching components. To quantify routing complexity reduction, we analyze the number of multi-cast and wavelength-selective switches required in a colorless, directionless and contentionless reconfigurable optical add-drop multiplexer architecture. Traffic aggregation has two potential drawbacks: reduced routing power and increased switching component size.

Correlation and squeezing for optical transistor and intensity for router applications in Pr3+:YSO.

PubMed

Khan, Ghulam Abbas; Li, Changbiao; Raza, Faizan; Ahmed, Noor; Mahesar, Abdul Rasheed; Ahmed, Irfan; Zhang, Yanpeng

2017-06-14

We realized an optical transistor and router utilizing multi-order fluorescence and spontaneous parametric four-wave mixing. Specifically, the optical routing action was derived from the results of splitting in the intensity signal due to a dressing effect, whereas the transistor as a switch and amplifier was realized by a switching correlation and squeezing via a nonlinear phase. A substantial enhancement of the optical contrast was observed for switching applications using correlation and squeezing contrary to the intensity signal. Moreover, the controlling parameters were also configured to devise a control mechanism for the optical transistor and router.

A multi-ring optical packet and circuit integrated network with optical buffering.

PubMed

Furukawa, Hideaki; Shinada, Satoshi; Miyazawa, Takaya; Harai, Hiroaki; Kawasaki, Wataru; Saito, Tatsuhiko; Matsunaga, Koji; Toyozumi, Tatuya; Wada, Naoya

2012-12-17

We newly developed a 3 × 3 integrated optical packet and circuit switch-node. Optical buffers and burst-mode erbium-doped fiber amplifiers with the gain flatness are installed in the 3 × 3 switch-node. The optical buffer can prevent packet collisions and decrease packet loss. We constructed a multi-ring optical packet and circuit integrated network testbed connecting two single-ring networks and a client network by the 3 × 3 switch-node. For the first time, we demonstrated 244 km fiber transmission and 5-node hopping of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10 Gigabit Ethernet frames on the testbed. Error-free (frame error rate < 1 × 10(-4)) operation was achieved with optical packets of various packet lengths. In addition, successful avoidance of packet collisions by optical buffers was confirmed.

A 10Gbps optical burst switching network incorporating ultra-fast (5ns) wavelength switched tunable laser sources

NASA Astrophysics Data System (ADS)

Ryan, Neil; Todd, Michael; Farrell, Tom; Lavin, Adrian; Rigole, Pierre-Jean; Corbett, Brian; Roycroft, Brendan; Engelstaedter, Jan-Peter

2017-11-01

This paper outlines the development of a prototype optical burst mode switching network based upon a star topology, the ultimate application of which could be as a transparent payload processor onboard satellite repeaters. The network architecture incorporates multiple tunable laser sources, burst mode receivers and a passive optical router (Arrayed Waveguide Grating). Each tunable optical signal should carry >=10Gbps and be capable of wavelength switching in c. 5ns timescales. Two monolithic tunable laser types, based upon different technologies, will be utilised: a Slotted Fabry Perot laser (a Fabry Perot laser with slots added in order to introduce controlled cavity perturbations); and a Modulated Grating Y-Branch Laser (MGY: a widely tunable, multi-section device similar to the DBR laser). While the Slotted Fabry Perot laser is expected to achieve the required switching times, it is an immature technology not yet capable of achieving tunability over 80 ITU channels from a single chip. The MGY device is a more mature technology and has full C-band ITU channel coverage, but is not capable of the required short switching times. Hence, in order to facilitate the integration of this more mature technology into the prototype breadboard with the requisite switching time capabilities, a system of `dual laser' transmitters is being developed to enable data transmission from one MGY laser while the other switches and vice-versa. This work is being performed under ESA contract AO 1-5025/06/NL/PM, Optical Technologies for Ultra - fast Processing.

Supra-dendron Gelator Based on Azobenzene-Cyclodextrin Host-Guest Interactions: Photoswitched Optical and Chiroptical Reversibility.

PubMed

Xie, Fan; Ouyang, Guanghui; Qin, Long; Liu, Minghua

2016-12-12

A novel amphiphilic dendron (AZOC 8 GAc) with three l-glutamic acid units and an azobenzene moiety covalently linked by an alkyl spacer has been designed. The compound formed hydrogels with water at very low concentration and self-assembled into chiral-twist structures. The gel showed a reversible macroscopic volume phase transition in response to pH variations and photo-irradiation. During the photo-triggered changes, although the gel showed complete reversibility in its optical absorptions, only an incomplete chiroptical property change was achieved. On the other hand, the dendron could form a 1:1 inclusion complex through a host-guest interaction with α-cyclodextrin (α-CD), designated as supra-dendron gelator AZOC 8 GAc/α-CD. The supra-dendron showed similar gelation behavior to that of AZOC 8 GAc, but with enhanced photoisomerization-transition efficiency and chiroptical switching capacity, which was completely reversible in terms of both optical and chiroptical performances. The self-assembly of the supra-dendron is a hierarchical or multi-supramolecular self-assembling process. This work has clearly illustrated that the hierarchical and multi-supramolecular self-assembling system endows the supramolecular nanostructures or materials with superior reversible optical and chiroptical switching. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing the liquid crystal alignment interface and switching dynamics in a slab waveguide architecture

NASA Astrophysics Data System (ADS)

Gotjen, Henry G.; Kolacz, Jakub; Myers, Jason D.; Frantz, Jesse A.; Bekele, Robel Y.; Naciri, Jawad; Spillmann, Christopher M.

2018-02-01

A non-mechanical refractive laser beam steering device has been developed to provide continuous, two-dimensional steering of infrared beams. The technology implements a dielectric slab waveguide architecture with a liquid crystal (LC) cladding. With voltage control, the birefringence of the LC can be leveraged to tune the effective index of the waveguide under an electrode. With a clever prism electrode design a beam coupled into the waveguide can be deflected continuously in two dimensions as it is coupled out into free space. The optical interaction with LC in this beamsteerer is unique from typical LC applications: only the thin layer of LC (100s of nm) near the alignment interface interacts with the beam's evanescent field. Whereas most LC interactions take place over short path lengths (microns) in the bulk of the material, here we can interrogate the behavior of LC near the alignment interface over long path lengths (centimeters). In this work the beamsteerer is leveraged as a tool to study the behavior of LC near the alignment layer in contrast to the bulk material. We find that scattering is substantially decreased near the alignment interface due to the influence of the surface anchoring energy to suppress thermal fluctuations. By tracking the position of the deflected beam with a high speed camera, we measure response times of the LC near the interface in off-to-on switching ( ms) and on-to-off switching ( 100ms). Combined, this work will provide a path for improved alignment techniques, greater optical throughput, and faster response times in this unique approach to non-mechanical beamsteering.

A low-latency high-port count optical switch with optical delay line buffering for disaggregated data centers

NASA Astrophysics Data System (ADS)

Moralis-Pegios, M.; Terzenidis, N.; Mourgias-Alexandris, G.; Vyrsokinos, K.; Pleros, N.

2018-02-01

Disaggregated Data Centers (DCs) have emerged as a powerful architectural framework towards increasing resource utilization and system power efficiency, requiring, however, a networking infrastructure that can ensure low-latency and high-bandwidth connectivity between a high-number of interconnected nodes. This reality has been the driving force towards high-port count and low-latency optical switching platforms, with recent efforts concluding that the use of distributed control architectures as offered by Broadcast-and-Select (BS) layouts can lead to sub-μsec latencies. However, almost all high-port count optical switch designs proposed so far rely either on electronic buffering and associated SerDes circuitry for resolving contention or on buffer-less designs with packet drop and re-transmit procedures, unavoidably increasing latency or limiting throughput. In this article, we demonstrate a 256x256 optical switch architecture for disaggregated DCs that employs small-size optical delay line buffering in a distributed control scheme, exploiting FPGA-based header processing over a hybrid BS/Wavelength routing topology that is implemented by a 16x16 BS design and a 16x16 AWGR. Simulation-based performance analysis reveals that even the use of a 2- packet optical buffer can yield <620nsec latency with >85% throughput for up to 100% loads. The switch has been experimentally validated with 10Gb/s optical data packets using 1:16 optical splitting and a SOA-MZI wavelength converter (WC) along with fiber delay lines for the 2-packet buffer implementation at every BS outgoing port, followed by an additional SOA-MZI tunable WC and the 16x16 AWGR. Error-free performance in all different switch input/output combinations has been obtained with a power penalty of <2.5dB.

Large optical 3D MEMS switches in access networks

NASA Astrophysics Data System (ADS)

Madamopoulos, Nicholas; Kaman, Volkan; Yuan, Shifu; Jerphagnon, Olivier; Helkey, Roger; Bowers, John E.

2007-09-01

Interest is high among residential customers and businesses for advanced, broadband services such as fast Internet access, electronic commerce, video-on-demand, digital broadcasting, teleconferencing and telemedicine. In order to satisfy such growing demand of end-customers, access technologies such as fiber-to-the-home/building (FTTH/B) are increasingly being deployed. Carriers can reduce maintenance costs, minimize technology obsolescence and introduce new services easily by reducing active elements in the fiber access network. However, having a passive optical network (PON) also introduces operational and maintenance challenges. Increased diagnostic monitoring capability of the network becomes a necessity as more and more fibers are provisioned to deliver services to the end-customers. This paper demonstrates the clear advantages that large 3D optical MEMS switches offer in solving these access network problems. The advantages in preventative maintenance, remote monitoring, test and diagnostic capability are highlighted. The low optical insertion loss for all switch optical connections of the switch enables the monitoring, grooming and serving of a large number of PON lines and customers. Furthermore, the 3D MEMS switch is transparent to optical wavelengths and data formats, thus making it easy to incorporate future upgrades, such higher bit rates or DWDM overlay to a PON.

WDM Network and Multicasting Protocol Strategies

PubMed Central

Zaim, Abdul Halim

2014-01-01

Optical technology gains extensive attention and ever increasing improvement because of the huge amount of network traffic caused by the growing number of internet users and their rising demands. However, with wavelength division multiplexing (WDM), it is easier to take the advantage of optical networks and optical burst switching (OBS) and to construct WDM networks with low delay rates and better data transparency these technologies are the best choices. Furthermore, multicasting in WDM is an urgent solution for bandwidth-intensive applications. In the paper, a new multicasting protocol with OBS is proposed. The protocol depends on a leaf initiated structure. The network is composed of source, ingress switches, intermediate switches, edge switches, and client nodes. The performance of the protocol is examined with Just Enough Time (JET) and Just In Time (JIT) reservation protocols. Also, the paper involves most of the recent advances about WDM multicasting in optical networks. WDM multicasting in optical networks is given as three common subtitles: Broadcast and-select networks, wavelength-routed networks, and OBS networks. Also, in the paper, multicast routing protocols are briefly summarized and optical burst switched WDM networks are investigated with the proposed multicast schemes. PMID:24744683

Research on high power intra-channel crosstalk attack in optical networks

NASA Astrophysics Data System (ADS)

Ren, Shuai; Zhang, Yinfa; Wang, Jingyu; Zhang, Jumei; Rao, Xuejun; Fang, Yuanyuan

2017-02-01

The mechanism of high power intra-channel crosstalk attack is analyzed theoretically and the conclusion that power of attack signal and crosstalk coefficient of optical switch are the main factors for which high power intra-channel have destructive effect on quality of legitimate signals is drawn. Effects of high power intra-channel crosstalk attack on quality of legitimate signals and its capability of attack propagation are investigated quantitatively by building the simulation system in VPI software. The results show that legitimate signals through the first and the second stage optical switch are affected by attack and legitimate signal through the third stage optical switch is almost unaffected by attack when power of original attack signal (OAS) is above 20dB more than that of legitimate signals and crosstalk coefficient of optical switch is -20dB at optical cross connect 1 (OXC1). High power intra-channel crosstalk attack has a certain capability of attack propagation. Attack capability of OAS can be propagated to OXC3 when power of OAS is 27dB more than that of legitimate signals and crosstalk coefficient of optical switch is -20dB. We also find that the secondary attack signal (SAS) does not have capability of attack propagation.

25-Gbit/s burst-mode optical receiver using high-speed avalanche photodiode for 100-Gbit/s optical packet switching.

PubMed

Nada, Masahiro; Nakamura, Makoto; Matsuzaki, Hideaki

2014-01-13

25-Gbit/s error-free operation of an optical receiver is successfully demonstrated against burst-mode optical input signals without preambles. The receiver, with a high-sensitivity avalanche photodiode and burst-mode transimpedance amplifier, exhibits sufficient receiver sensitivity and an extremely quick response suitable for burst-mode operation in 100-Gbit/s optical packet switching.

Transparent Electrochemical Gratings from a Patterned Bistable Silver Mirror.

PubMed

Park, Chihyun; Na, Jongbeom; Han, Minsu; Kim, Eunkyoung

2017-07-25

Silver mirror patterns were formed reversibly on a polystyrene (PS)-patterned electrode to produce gratings through the electrochemical reduction of silver ions. The electrochemical gratings exhibited high transparency (T > 95%), similar to a see-through window, by matching the refractive index of the grating pattern with the surrounding medium. The gratings switch to a diffractive state upon the formation of a mirror pattern (T < 5%) with a high diffraction efficiency up to 40%, providing reversible diffractive gratings. The diffraction state was maintained in the voltage-off state (V-off) for 40 min, which demonstrated bistable reversible electrochemical grating (BREG) behavior. By carefully combining the BREGs through period matching, dual-color switching was achieved within the full color region, which exhibited three distinct optical switching states between -2.5, 0, and +2.5 V. The wide range of light tenability using the metallic BREGs developed herein enabled IR modulation, NIR light reflection, and on-demand heat transfer.

High-speed electro-optic switch with -80 dB crosstalk

NASA Technical Reports Server (NTRS)

Pan, J. J.; Su, W. H.; Xu, J. Y.; Grove, C. H.

1992-01-01

Special device modeling, design and layout, and precision processing controls were employed to fabricate new balanced-bridge 2x2 and 4x4 switches on X-cut, Y-propagation LiNbO3 substrate using Ti indiffused optical waveguides. The best of these devices achieved extinction ratio and crosstalk isolation of better than 93 dB electrically (46.5 dB optically). The new switches demonstrate good reproducibility with electrical crosstalk less than -80 dB.

Microgravity Processing and Photonic Applications of Organic and Polymeric Materials

NASA Technical Reports Server (NTRS)

Frazier, Donald 0; Penn, Benjamin G.; Smith, David; Witherow, William K.; Paley, M. S.; Abdeldayem, Hossin A.

1998-01-01

In recent years, a great deal of interest has been directed toward the use of organic materials in the development of high-efficiency optoelectronic and photonic devices. There is a myriad of possibilities among organic which allow flexibility in the design of unique structures with a variety of functional groups. The use of nonlinear optical (NLO) organic materials such as thin-film waveguides allows full exploitation of their desirable qualities by permitting long interaction lengths and large susceptibilities allowing modest power input. There are several methods in use to prepare thin films, such as Langmuir-Blodgett (LB) and self-assembly techniques, vapor deposition, growth from sheared solution or melt, and melt growth between glass plates. Organics have many features that make Abstract: them desirable for use in optical devices such as high second- and third-order nonlinearities, flexibility of molecular design, and damage resistance to optical radiation. However, their use in devices has been hindered by processing difficulties for crystals and thin films. In this chapter, we discuss photonic and optoelectronic applications of a few organic materials and the potential role of microgravity on processing these materials. It is of interest to note how materials with second- and third-order nonlinear optical behavior may be improved in a diffusion-limited environment and ways in which convection may be detrimental to these materials. We focus our discussion on third-order materials for all-optical switching, and second-order materials for all-optical switching, and second-order materials for frequency conversion and electrooptics.

TWC and AWG based optical switching structure for OVPN in WDM-PON

NASA Astrophysics Data System (ADS)

Bai, Hui-feng; Chen, Yu-xin; Wang, Qin

2015-03-01

With the rapid development of optical elements with large capacity and high speed, the network architecture is of great importance in determing the performance of wavelength division multiplexing passive optical network (WDM-PON). This paper proposes a switching structure based on the tunable wavelength converter (TWC) and the arrayed-waveguide grating (AWG) for WDM-PON, in order to provide the function of opitcal virtual private network (OVPN). Using the tunable wavelength converter technology, this switch structure is designed and works between the optical line terminal (OLT) and optical network units (ONUs) in the WDM-PON system. Moreover, the wavelength assignment of upstream/downstream can be realized and direct communication between ONUs is also allowed by privite wavelength channel. Simulation results show that the proposed TWC and AWG based switching structure is able to achieve OVPN function and to gain better performances in terms of bite error rate (BER) and time delay.

Bidirectional optical switch based on electrowetting

NASA Astrophysics Data System (ADS)

Liu, Chao; Li, Lei; Wang, Qiong-Hua

2013-05-01

In this paper, we demonstrate a bidirectional optical switch based on electrowetting. Four rectangular polymethyl methacrylate substrates are stacked to form the device and three ITO electrodes are fabricated on the bottom substrate. A black liquid droplet is placed on the middle of the ITO electrode and surrounded by silicone oil. When we apply a voltage to one ITO electrode, the droplet stretches and moves in one direction and a light beam is covered by the stretched droplet, while the droplet yields a space to let the original blocked light pass through. Due to the shift of the droplet, our device functions as a bidirectional optical switch. Our experiment shows that the device can obtain a wide optical attenuation from ˜1 dB to 30 dB and the transmission loss is ˜0.67 dB. The response time of the device is ˜177 ms. The proposed optical switch has potential applications in variable optical attenuators, electronic displays, and light shutters.

A trident dithienylethene-perylenemonoimide dyad with super fluorescence switching speed and ratio

NASA Astrophysics Data System (ADS)

Li, Chong; Yan, Hui; Zhao, Ling-Xi; Zhang, Guo-Feng; Hu, Zhe; Huang, Zhen-Li; Zhu, Ming-Qiang

2014-12-01

Photoswitchable fluorescent diarylethenes are promising in molecular optical memory and photonic devices. However, the performance of current diarylethenes is far from satisfactory because of the scarcity of high-speed switching capability and large fluorescence on-off ratio. Here we report a trident perylenemonoimide dyad modified by triple dithienylethenes whose photochromic fluorescence quenching ratio at the photostationary state exceeds 10,000 and the fluorescence quenching efficiency is close to 100% within seconds of ultraviolet irradiation. The highly sensitive fluorescence on/off switching of the trident dyad enables recyclable fluorescence patterning and all-optical transistors. The prototype optical device based on the trident dyad enables the optical switching of incident light and conversion from incident light wavelength to transmitted light wavelength, which is all-optically controlled, reversible and wavelength-convertible. In addition, the trident dyad-staining block copolymer vesicles are observed via optical nanoimaging with a sub-100 nm resolution, portending a potential prospect of the dithienylethene dyad in super-resolution imaging.

A trident dithienylethene-perylenemonoimide dyad with super fluorescence switching speed and ratio.

PubMed

Li, Chong; Yan, Hui; Zhao, Ling-Xi; Zhang, Guo-Feng; Hu, Zhe; Huang, Zhen-Li; Zhu, Ming-Qiang

2014-12-12

Photoswitchable fluorescent diarylethenes are promising in molecular optical memory and photonic devices. However, the performance of current diarylethenes is far from satisfactory because of the scarcity of high-speed switching capability and large fluorescence on-off ratio. Here we report a trident perylenemonoimide dyad modified by triple dithienylethenes whose photochromic fluorescence quenching ratio at the photostationary state exceeds 10,000 and the fluorescence quenching efficiency is close to 100% within seconds of ultraviolet irradiation. The highly sensitive fluorescence on/off switching of the trident dyad enables recyclable fluorescence patterning and all-optical transistors. The prototype optical device based on the trident dyad enables the optical switching of incident light and conversion from incident light wavelength to transmitted light wavelength, which is all-optically controlled, reversible and wavelength-convertible. In addition, the trident dyad-staining block copolymer vesicles are observed via optical nanoimaging with a sub-100 nm resolution, portending a potential prospect of the dithienylethene dyad in super-resolution imaging.

Thermo-optic characteristics and switching power limit of slow-light photonic crystal structures on a silicon-on-insulator platform.

PubMed

Chahal, Manjit; Celler, George K; Jaluria, Yogesh; Jiang, Wei

2012-02-13

Employing a semi-analytic approach, we study the influence of key structural and optical parameters on the thermo-optic characteristics of photonic crystal waveguide (PCW) structures on a silicon-on-insulator (SOI) platform. The power consumption and spatial temperature profile of such structures are given as explicit functions of various structural, thermal and optical parameters, offering physical insight not available in finite-element simulations. Agreement with finite-element simulations and experiments is demonstrated. Thermal enhancement of the air-bridge structure is analyzed. The practical limit of thermo-optic switching power in slow light PCWs is discussed, and the scaling with key parameters is analyzed. Optical switching with sub-milliwatt power is shown viable.

Organic solid state optical switches and method for producing organic solid state optical switches

DOEpatents

Wasielewski, M.R.; Gaines, G.L.; Niemczyk, M.P.; Johnson, D.G.; Gosztola, D.J.; O`Neil, M.P.

1993-01-01

This invention consists of a light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, and a method for making said compound.

High speed all optical networks

NASA Technical Reports Server (NTRS)

Chlamtac, Imrich; Ganz, Aura

1990-01-01

An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. The first solution to wavelength division multiplexing (WDM) based WAN networks that overcomes this limitation is presented. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs. The principle of the Lightnet architecture is the construction and use of virtual topology networks, embedded in the original network in the wavelength domain. For this construction Lightnets utilize the new concept of lightpaths which constitute the links of the virtual topology. Lightpaths are all-optical, multihop, paths in the network that allow data to be switched through intermediate nodes using high throughput passive optical switches. The use of the virtual topologies and the associated switching design introduce a number of new ideas, which are discussed in detail.

Fiber-optical switch using cam-micromotor driven by scratch drive actuators

NASA Astrophysics Data System (ADS)

Kanamori, Y.; Aoki, Y.; Sasaki, M.; Hosoya, H.; Wada, A.; Hane, K.

2005-01-01

We fabricated a 1 × 1 fiber-optic switch using a cam-micromotor driven by scratch drive actuators (SDAs). Using the cam-micromotor, mechanical translation and precise positioning of an optical fiber were performed. An optical fiber of diameter 50 µm was bent and pushed out with a cam-mechanism driven by the SDAs fabricated by surface micromachining. The maximum rotation speed of the cam-micromotor was 7.5 rpm at a driving frequency of 1.5 kHz. The transient time of the switch to attenuate coupling efficiency less than -40 dB was around 10 ms.

Polarization and resistive switching behavior of ferroelectric tunnel junctions with transition metal dichalcogenides

NASA Astrophysics Data System (ADS)

Li, Tao; Lipatov, Alexey; Sharma, Pankaj; Lee, Hyungwoo; Eom, Chang-Beom; Sinitskii, Alexander; Gruverman, Alexei; Alexei Gruverman Team; Alexander Sinitskii Team; Chang-Beom Eom Team

Transition metal dichalcogenides (TMDs) are emerging 2-dimensional (2D) materials of the MX2 type, where M is a transition metal atom (Mo, W, Ti, Sn, Zr, etc.) and X is a chalcogen atom (S, Se, or Te.). Comparing to graphene, TMDs have a sizable band gap and can be metal, half-metal, semiconductor or superconductor. Their band structures can be tuned by external bias voltage, mechanical force, or light illumination. Their rich physical properties make TMDs potential candidates for a variety of applications in nanoelectronics and optoelectronics. Ferroelectric tunnel junctions (FTJs) are actively studied as a next-generation of non-volatile memory elements. An FTJ comprises a ferroelectric tunnel barrier sandwiched between two electrodes. In this work, we investigate the resistive switching behavior of MoS2/BaTiO3-based FTJs. The ON/OFF ratio can be modulated via electric or mechanical control of the switched polarization fraction opening a possibility of tunable electroresistance effect. Effect of optical illumination on the polarization reversal dynamics has been observed and analyzed based on the polarization-induced modulation of the MoS2 layered electronic properties.

Precise measurement of single-mode fiber lengths using a gain-switched distributed feedback laser with delayed optical feedback.

PubMed

Wada, Kenji; Matsukura, Satoru; Tanaka, Amaka; Matsuyama, Tetsuya; Horinaka, Hiromichi

2015-09-07

A simple method to measure single-mode optical fiber lengths is proposed and demonstrated using a gain-switched 1.55-μm distributed feedback laser without a fast photodetector or an optical interferometer. From the variation in the amplified spontaneous emission noise intensity with respect to the modulation frequency of the gain switching, the optical length of a 1-km single-mode fiber immersed in water is found to be 1471.043915 m ± 33 μm, corresponding to a relative standard deviation of 2.2 × 10(-8). This optical length is an average value over a measurement time of one minute under ordinary laboratory conditions.

Wavelength selective switch array employing silica-based waveguide frontend with integrated polarization diversity optics.

PubMed

Sakamaki, Yohei; Shikama, Kota; Ikuma, Yuichiro; Suzuki, Kenya

2017-08-21

We propose a waveguide frontend with integrated polarization diversity optics for a wavelength selective switch (WSS) array with a liquid crystal on silicon switching engine to simplify the free space optics configuration and the alignment process in optical modules. The polarization diversity function is realized by the integration of a waveguide-type polarization beam splitter and a polarization rotating half-wave plate in a beam launcher using silica-based planar lightwave circuit technology. We confirmed experimentally the feasibility of using our proposed waveguide frontend in a two-in-one 1 × 20 WSS. The experimental results show that the fabricated waveguide frontend provides a polarization diversity function without any degradation in optical performance.

Optical fiber switch

DOEpatents

Early, James W.; Lester, Charles S.

2002-01-01

Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

Interfacial behavior of confined mesogens at smectic-C*-water boundary.

PubMed

Chandran, Achu; Khanna, P K; Haranath, D; Biradar, Ashok M

2018-02-01

In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-C* domain patterns at water interface owing to the reorientation of mesogens. The undulated stripe domains observed at the air interface of smectic-C* meniscus vanished as the water entered into the smectic layers and focal conical domain patterns appeared at smectic-C*-water boundary. A spatially variable electro-optical switching of LC molecules was also observed outside the electrode area of the interfacial cell. The electrode region at the interface, as well as on the water side, was damaged upon application of an electric field of magnitude more than 150 kV/m. The change in dielectric parameters of mesogens was extensively studied at interface after evaporating the water. These studies give fundamental insights into smectic-C*-water interface and also will be helpful in fabricating better LC devices for electro-optical and sensing applications.

Interfacial behavior of confined mesogens at smectic-C*-water boundary

NASA Astrophysics Data System (ADS)

Chandran, Achu; Khanna, P. K.; Haranath, D.; Biradar, Ashok M.

2018-02-01

In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-C* domain patterns at water interface owing to the reorientation of mesogens. The undulated stripe domains observed at the air interface of smectic-C* meniscus vanished as the water entered into the smectic layers and focal conical domain patterns appeared at smectic-C*-water boundary. A spatially variable electro-optical switching of LC molecules was also observed outside the electrode area of the interfacial cell. The electrode region at the interface, as well as on the water side, was damaged upon application of an electric field of magnitude more than 150 kV/m. The change in dielectric parameters of mesogens was extensively studied at interface after evaporating the water. These studies give fundamental insights into smectic-C*-water interface and also will be helpful in fabricating better LC devices for electro-optical and sensing applications.

Critical switching fluence of L10-FePt nanoparticles with practical size to ultrafast all-optical polarization switching

NASA Astrophysics Data System (ADS)

Huang, Tao; Wang, Haiwei; Cheng, Weiming; Zou, Yuhao; Xie, Changsheng

2017-06-01

The magnetic storage industry will be pushed into a new era by emerging magnetic materials and ingenious read/write techniques. Recently, L10-FePt nanoparticles with exceptionally high uniaxial anisotropy, combined with the technique of all-optical magnetic switching, have increasingly drawn the attention of researchers. Focusing on L10-FePt nanoparticles, we report the superparamagnetic size limits and three elaborate stages of magnetic orientation switching, which demonstrate that in terms of the opto-magnetic responses of L10-FePt nanoparticles with the size of 6 nm, the fluence of an ultrashort laser pulse should not be larger than the level of 40 mJ/cm2 in order to achieve the helicity-dependent all-optical switching.

Optical burst switching based satellite backbone network

NASA Astrophysics Data System (ADS)

Li, Tingting; Guo, Hongxiang; Wang, Cen; Wu, Jian

2018-02-01

We propose a novel time slot based optical burst switching (OBS) architecture for GEO/LEO based satellite backbone network. This architecture can provide high speed data transmission rate and high switching capacity . Furthermore, we design the control plane of this optical satellite backbone network. The software defined network (SDN) and network slice (NS) technologies are introduced. Under the properly designed control mechanism, this backbone network is flexible to support various services with diverse transmission requirements. Additionally, the LEO access and handoff management in this network is also discussed.

Controlled Photon Switch Assisted by Coupled Quantum Dots

PubMed Central

Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

2015-01-01

Quantum switch is a primitive element in quantum network communication. In contrast to previous switch schemes on one degree of freedom (DOF) of quantum systems, we consider controlled switches of photon system with two DOFs. These controlled photon switches are constructed by exploring the optical selection rules derived from the quantum-dot spins in one-sided optical microcavities. Several double controlled-NOT gate on different joint systems are greatly simplified with an auxiliary DOF of the controlling photon. The photon switches show that two DOFs of photons can be independently transmitted in quantum networks. This result reduces the quantum resources for quantum network communication. PMID:26095049

Atomtronics: Realizing the behavior of electronic components in ultracold atomic systems

NASA Astrophysics Data System (ADS)

Pepino, Ron

2007-06-01

Atomtronics focuses on creating an analogy of electronic devices and circuits with ultracold atoms. Such an analogy can come from the highly tunable band structure of ultracold neutral atoms trapped in optical lattices. Solely by tuning the parameters of the optical lattice, we demonstrate that conditions can be created that cause atoms in lattices to exhibit the same behavior as electrons moving through solid state media. We present our model and show how the atomtronic diode, field effect transistor, and bipolar junction transistor can all be realized. Our analogs of these fundamental components exhibit precisely-controlled atomic signal amplification, trimming, and switching (on/off) characteristics. In addition, the evolution of dynamics of the superfluid atomic currents within these systems is completely reversible. This implies a possible use of atomtronic systems in the development of quantum computational devices.

Wide Bandgap Extrinsic Photoconductive Switches

NASA Astrophysics Data System (ADS)

Sullivan, James Stephen

Wide Bandgap Extrinsic Photoconductive Switches Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6H-SiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators. The successful development of a vanadium compensated, 6H-SiC extrinsic photoconductive switch for use as a closing switch for compact accelerator applications was realized by improvements made to the vanadium, nitrogen and boron impurity densities. The changes made to the impurity densities were based on the physical intuition outlined and simple rate equation models. The final 6H-SiC impurity 'recipe' calls for vanadium, nitrogen and boron densities of 2.5 e17 cm-3, 1.25e17 cm-3 and ≤ 1e16 cm-3, respectively. This recipe was originally developed to maximize the quantum efficiency of the vanadium compensated 6H-SiC, while maintaining a thermally stable semi-insulating material. The rate equation models indicate that, besides increasing the quantum efficiency, the impurity recipe should be expected to also increase the carrier recombination time. Three generations of 6H-SiC materials were tested. The third generation vanadium compensated 6H-SiC has average impurity densities close to the recipe values. Extrinsic photoconductive switches constructed from the third generation vanadium compensated, 6H-SiC, 1 mm thick, 1 cm2, substrates have achieved high power operation at 16 kV with pulsed currents exceeding 1400 Amperes and a minimum on resistance of 1 ohm. The extrinsic photoconductive switch performance of the third generation 6H-SiC material was improved by a factor of up to 50 for excitation at the 532 nm wavelength compared to the initial 6H-SiC material. Switches based on this material have been incorporated into a prototype compact proton medical accelerator being developed by the Compact Particle Acceleration Corporation (CPAC). The vanadium compensated, 6H-SiC, extrinsic photoconductive switch operates differently when excited by 1064, or 532 nm, wavelength light. The 6H-SiC extrinsic photoconductive switch is a unipolar device when excited with 1064 nm light. The carriers are electrons excited from filled vanadium acceptor levels and other electron traps located within 1.17 eV of the conduction band. The switch is bipolar at 532 nm since the carriers consist of holes, as well as electrons. The holes are primarily generated by the excitation of valence band electrons into empty trap/acceptor levels and by two-photon absorption. Carrier generation by two-photon absorption becomes more important at high applied optical intensity at 532 nm and contributes to the supralinear behavior of switch conductance as a function of optical power. The 6H-SiC switch material is trap dominated at low nitrogen to vanadium ratios. The trap dominated vanadium compensated 6H-SiC exhibits low quantum efficiency when excited with 1064 and 532 nm light and has a carrier recombination time of ˜ 150 - 300 ps. The vanadium compensated 6H-SiC transitions to an impurity dominated material as the ratio of nitrogen to vanadium is increased to 0.5. The increased nitrogen doping produces a material with much higher quantum efficiency and carrier recombination time of 0.9 to 1.0 ns. The iron compensated 2H-GaN did not perform well as an extrinsic photoconductive switch. The density of carriers generated at 1064 nm was, low indicating that there were very few electrons trapped in the iron acceptor level located at 0.5 - 0.6 eV below the conduction band. Carrier generation at 532 nm was dominated by two photon absorption resulting in the switch conductance increasing as the square of applied optical intensity. A minimum switch resistance of 0.8 ohms was calculated for the 400 nm thick, 1.2 by 1.2 cm, 2H-GaN switch for an applied optical intensity of 41.25 MW/cm2. An optical intensity of ˜ 70 MW/cm2 at 532 nm would be required to achieve a 0.8 ohm on resistance for a 1 mm thick, 1 cm2, 2H-GaN switch.

Nonlinear optical switching and optical limiting in colloidal CdSe quantum dots investigated by nanosecond Z-scan measurement

NASA Astrophysics Data System (ADS)

Valligatla, Sreeramulu; Haldar, Krishna Kanta; Patra, Amitava; Desai, Narayana Rao

2016-10-01

The semiconductor nanocrystals are found to be promising class of third order nonlinear optical materials because of quantum confinement effects. Here, we highlight the nonlinear optical switching and optical limiting of cadmium selenide (CdSe) quantum dots (QDs) using nanosecond Z-scan measurement. The intensity dependent nonlinear absorption and nonlinear refraction of CdSe QDs were investigated by applying the Z-scan technique with 532 nm, nanosecond laser pulses. At lower intensities, the nonlinear process is dominated by saturable absorption (SA) and it is changed to reverse saturable absorption (RSA) at higher intensities. The SA behaviour is attributed to the ground state bleaching and the RSA is ascribed to free carrier absorption (FCA) of CdSe QDs. The nonlinear optical switching behaviour and reverse saturable absorption makes CdSe QDs are good candidate for all-optical device and optical limiting applications.

Photo-switchable bistable twisted nematic liquid crystal optical switch.

PubMed

Wang, Chun-Ta; Wu, Yueh-Chi; Lin, Tsung-Hsien

2013-02-25

This work demonstrates a photo-switchable bistable optical switch that is based on an azo-chiral doped liquid crystal (ACDLC). The photo-induced isomerization of the azo-chiral dopant can change the chirality of twisted nematic liquid crystal and the gap/pitch ratio of an ACDLC device, enabling switching between 0° and 180° twist states in a homogeneous aligned cell. The bistable 180° and 0° twist states of the azo-chiral doped liquid crystal between crossed polarizers correspond to the ON and OFF states of a light shutter, respectively, and they can be maintained stably for tens of hours. Rapid switching between 180° and 0° twist states can be carried out using 408 and 532 nm addressing light. Such a photo-controllable optical switch requires no specific asymmetric alignment layer or precise control of the cell gap/pitch ratio, so it is easily fabricated and has the potential for use in optical systems.

Optical burst switching for the next generation Optical Internet

NASA Astrophysics Data System (ADS)

Yoo, Myungsik

2000-11-01

In recent years, Internet Protocol (IP) over Wavelength Division Multiplexing (WDM) networks for the next generation Internet (or the so-called Optical Internet) have received enormous attention. There are two main drivers for an Optical Internet. One is the explosion of Internet traffic, which seems to keep growing exponentially. The other driver is the rapid advance in the WDM optical networking technology. In this study, key issues in the optical (WDM) layer will be investigated. As a novel switching paradigm for Optical Internet, Optical Burst Switching (OBS) is discussed. By leveraging the attractive properties of optical communications and at the same time, taking into account its limitations, OBS can combine the best of optical circuit-switching and packet/cell switching. The general concept of JET-based OBS protocol is described, including offset time and delayed reservation. In the next generation Optical Internet, one must address how to support Quality of Service (QoS) at the WDM layer since current IP provides only best effort services. The offset-time- based QoS scheme is proposed as a way of supporting QoS at the WDM layer. Unlike existing QoS schemes, offset- time-based QoS scheme does not mandate the use of buffer to differentiate services. For the bufferless WDM switch, the performance of offset- time-based QoS scheme is evaluated in term of blocking probability. In addition, the extra offset time required for class isolation is quantified and the theoretical bounds on blocking probability are analyzed. The offset-time-based scheme is applied to WDM switch with limited fiber delay line (FDL) buffer. We evaluate the effect of having a FDL buffer on the QoS performance of the offset-time-based scheme in terms of the loss probability and queuing delay of bursts. Finally, in order to dimension the network resources in Optical Internet backbone networks, the performance of the offset-time-based QoS scheme is evaluated for the multi-hop case. In particular, we consider very high performance Backbone Network Service (vBNS) backbone network. Various policies such as drop, retransmission, deflection routing and buffering are considered for performance evaluation. The performance results obtained under these policies are compared to decide the most efficient policy for the WDM backbone network.

Harnessing the polariton drag effect to design an electrically controlled optical switch.

PubMed

Berman, Oleg L; Kezerashvili, Roman Ya; Kolmakov, German V

2014-10-28

We propose a design of a Y-shaped electrically controlled optical switch based on the studies of propagation of an exciton-polariton condensate in a patterned optical microcavity with an embedded quantum well. The polaritons are driven by a time-independent force due to the microcavity wedge shape and by a time-dependent drag force owing to the interaction of excitons in a quantum well and the electric current running in a neighboring quantum well. It is demonstrated that by applying the drag force one can direct more than 90% of the polariton flow toward the desired branch of the switch with no hysteresis. By considering the transient dynamics of the polariton condensate, we estimate the response speed of the switch as 9.1 GHz. We also propose a design of the polariton switch in a flat microcavity based on the geometrically identical Y-shaped quantum wells where the polariton flow is only induced by the drag force. The latter setup enables one to design a multiway switch that can act as an electrically controlled optical transistor with on and off functions. Finally, we performed the simulations for a microcavity with an embedded gapped graphene layer and demonstrated that in this case the response speed of the switch can be increased up to 14 GHz for the same switch size. The simulations also show that the energy gap in the quasiparticle spectrum in graphene can be utilized as an additional parameter that controls the propagation of the signals in the switch.

Noise tolerance in wavelength-selective switching of optical differential quadrature-phase-shift-keying pulse train by collinear acousto-optic devices.

PubMed

Goto, Nobuo; Miyazaki, Yasumitsu

2014-06-01

Optical switching of high-bit-rate quadrature-phase-shift-keying (QPSK) pulse trains using collinear acousto-optic (AO) devices is theoretically discussed. Since the collinear AO devices have wavelength selectivity, the switched optical pulse trains suffer from distortion when the bandwidth of the pulse train is comparable to the pass bandwidth of the AO device. As the AO device, a sidelobe-suppressed device with a tapered surface-acoustic-wave (SAW) waveguide and a Butterworth-type filter device with a lossy SAW directional coupler are considered. Phase distortion of optical pulse trains at 40 to 100  Gsymbols/s in QPSK format is numerically analyzed. Bit-error-rate performance with additive Gaussian noise is also evaluated by the Monte Carlo method.

Microsecond reconfigurable NxN data-communication switch using DMD

NASA Astrophysics Data System (ADS)

Blanche, Pierre-Alexandre; Miles, Alexander; Lynn, Brittany; Wissinger, John; Carothers, Daniel; Norwood, Robert A.; Peyghambarian, Nasser

2014-03-01

We present here the use the DMD as a diffraction-based optical switch, where Fourier diffraction patterns are used to steer the incoming beams to any output configuration. We have implemented a single-mode fiber coupled N X N switch and demonstrated its ability to operate over the entire telecommunication C-band centered at 1550 nm. The all-optical switch was built primarily with off-the-shelf components and a Texas Instruments DLP7000™with an array of 1024 X 768 micromirrors. This DMD is capable of switching 100 times faster than currently available technology (3D MOEMS). The switch is robust to typical failure modes, protocol and bit-rate agnostic, and permits full reconfigurable optical add drop multiplexing (ROADM). The switch demonstrator was inserted into a networking testbed for the majority of the measurements. The testbed assembled under the Center for Integrated Access Networks (ClAN), a National Science Foundation (NSF) Engineering Research Center (ERC), provided an environment in which to simulate and test the data routing functionality of the switch. A Fujitsu Flashwave 9500 PS was used to provide the data signal, which was sent through the switch and received by a second Flashwave node. We successfully transmitted an HD video stream through a switched channel without any measurable data loss.

Integrated Model for Performance Analysis of All-Optical Multihop Packet Switches

NASA Astrophysics Data System (ADS)

Jeong, Han-You; Seo, Seung-Woo

2000-09-01

The overall performance of an all-optical packet switching system is usually determined by two criteria, i.e., switching latency and packet loss rate. In some real-time applications, however, in which packets arriving later than a timeout period are discarded as loss, the packet loss rate becomes the most dominant criterion for system performance. Here we focus on evaluating the performance of all-optical packet switches in terms of the packet loss rate, which normally arises from the insufficient hardware or the degradation of an optical signal. Considering both aspects, we propose what we believe is a new analysis model for the packet loss rate that reflects the complicated interactions between physical impairments and system-level parameters. On the basis of the estimation model for signal quality degradation in a multihop path we construct an equivalent analysis model of a switching network for evaluating an average bit error rate. With the model constructed we then propose an integrated model for estimating the packet loss rate in three architectural examples of multihop packet switches, each of which is based on a different switching concept. We also derive the bounds on the packet loss rate induced by bit errors. Finally, it is verified through simulation studies that our analysis model accurately predicts system performance.

High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes.

PubMed

Rosa, Álvaro; Gutiérrez, Ana; Brimont, Antoine; Griol, Amadeu; Sanchis, Pablo

2016-01-11

Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005 mm(2) is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 µs have also been achieved.

Extreme nonlinear terahertz electro-optics in diamond for ultrafast pulse switching

NASA Astrophysics Data System (ADS)

Shalaby, Mostafa; Vicario, Carlo; Hauri, Christoph P.

2017-03-01

Polarization switching of picosecond laser pulses is a fundamental concept in signal processing [C. Chen and G. Liu, Annu. Rev. Mater. Sci. 16, 203 (1986); V. R. Almeida et al., Nature 431, 1081 (2004); and A. A. P. Pohl et al., Photonics Sens. 3, 1 (2013)]. Conventional switching devices rely on the electro-optical Pockels effect and work at radio frequencies. The ensuing gating time of several nanoseconds is a bottleneck for faster switches which is set by the performance of state-of-the-art high-voltage electronics. Here we show that by substituting the electric field of several kV/cm provided by modern electronics by the MV/cm field of a single-cycle THz laser pulse, the electro-optical gating process can be driven orders of magnitude faster, at THz frequencies. In this context, we introduce diamond as an exceptional electro-optical material and demonstrate a pulse gating time as fast as 100 fs using sub-cycle THz-induced Kerr nonlinearity. We show that THz-induced switching in the insulator diamond is fully governed by the THz pulse shape. The presented THz-based electro-optical approach overcomes the bandwidth and switching speed limits of conventional MHz/GHz electronics and establishes the ultrafast electro-optical gating technology for the first time in the THz frequency range. We finally show that the presented THz polarization gating technique is applicable for advanced beam diagnostics. As a first example, we demonstrate tomographic reconstruction of a THz pulse in three dimensions.

Operating principles of an electrothermal vibrometer for optical switching applications

NASA Astrophysics Data System (ADS)

Pai, Min-fan; Tien, Norman C.

1999-09-01

A compact polysilicon surface-micromachined microactuator designed for optical switching applications is described. This actuator is fabricated using the foundry MUMPs process provided by Cronos Integrated Microsystems Inc. Actuated electrothermally, the microactuator allows fast switching speeds and can be operated with a low voltage square-wave signal. The design, operation mechanisms for this long-range and high frequency thermal actuation are described. A vertical micromirror integrated with this actuator can be operated with a 10.5 V, 20 kHz 15% duty-cycle pulse signal, achieving a lateral moving speed higher than 15.6 mm/sec. The optical switch has been operated to frequencies as high as 30 kHz.

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

Podoskin, A. A., E-mail: podoskin@mail.ioffe.ru; Shashkin, I. S.; Slipchenko, S. O.

A model describing the operation of a completely optical cell, based on the competition of lasing of Fabry-Perot cavity modes and the high-Q closed mode in high-power semiconductor lasers is proposed. Based on rate equations, the conditions of lasing switching between Fabry-Perot modes for ground and excited lasing levels and the closed mode are considered in the case of increasing internal optical loss under conditions of high current pump levels. The optical-cell operation conditions in the mode of a high-power laser radiation switch (reversible mode-structure switching) and in the mode of a memory cell with bistable irreversible lasing switching betweenmore » mode structures with various Q-factors are considered.« less

Monolithic InP strictly non-blocking 8×8 switch for high-speed WDM optical interconnection.

PubMed

Kwack, Myung-Joon; Tanemura, Takuo; Higo, Akio; Nakano, Yoshiaki

2012-12-17

A strictly non-blocking 8 × 8 switch for high-speed WDM optical interconnection is realized on InP by using the phased-array scheme for the first time. The matrix switch architecture consists of over 200 functional devices such as star couplers, phase-shifters and so on without any waveguide cross-section. We demonstrate ultra-broad optical bandwidth covering the entire C-band through several Input/Output ports combination with extinction ratio performance of more than 20dB. Also, nanoseconds reconfiguration time was successfully achieved by dynamic switching experiment. Error-free transmission was verified for 40-Gbps (10-Gbps × 4ch) WDM signal.

A Novel Phase Sensitive Quantum Well Nanostructure Scheme for Controlling Optical Bistability

NASA Astrophysics Data System (ADS)

Raheli, Ali

2018-04-01

A novel four-level lambda-type quantum well (QW) nanostructure is proposed based on phase sensitive optical bistability (OB) and multistability (OM) with a closed-loop configuration. The influence of controlling parameters of the system on OB and OM is investigated. In particular, it is found that the OB behavior is strongly sensitive to the relative phase of applied fields. It is also shown that under certain parametric conditions, the OB can be switched to OM or vice versa. The controllability of OB/OM in such a QW nanostructure may bring some new possibilities for technological applications in solid-state quantum information science and optoelectronics.

High-speed low-power photonic transistor devices based on optically-controlled gain or absorption to affect optical interference.

PubMed

Huang, Yingyan; Ho, Seng-Tiong

2008-10-13

We show that a photonic transistor device can be realized via the manipulation of optical interference by optically controlled gain or absorption in novel ways, resulting in efficient transistor signal gain and switching action. Exemplary devices illustrate two complementary device types with high operating speed, microm size, microW switching power, and switching gain. They can act in tandem to provide a wide variety of operations including wavelength conversion, pulse regeneration, and logical operations. These devices could have a Transistor Figure-of-Merits >10(5) times higher than current chi((3)) approaches and are highly attractive.

Theoretical and experimental study of a laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser with acoustic-optic modulator

NASA Astrophysics Data System (ADS)

Zhang, Haikun; Xia, Wei; Song, Peng; Wang, Jing; Li, Xin

2018-03-01

A laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser operating at around 1040 nm is presented for the first time with acoustic-optic modulator. The dependence of pulse width on incident pump power for different pulse repetition rates is measured. By considering the Guassian spatial distribution of the intracavity photon density and the initial population-inversion density as well as the longitudinal distribution of the photon density along the cavity axis and the turn off time of the acoustic-optic Q-switch, the coupled equations of the actively Q-switched Yb:NaY(WO4)2 laser are given. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results.

Optically controlled redshift switching effects in hybrid fishscale metamaterials

NASA Astrophysics Data System (ADS)

Wang, Yu; Zhu, Jinwei; Zhang, Hao; Zhang, Wenxing; Dong, Guohua; Ye, Peng; Lv, Tingting; Zhu, Zheng; Li, Yuxiang; Guan, Chunying; Shi, Jinhui

2018-05-01

We numerically demonstrate optically controlled THz response in a hybrid fishscale metamaterial with embedded photoconductive silicon at oblique incidence of TE wave. The oblique incidence allows excitation of Fano-type trapped mode resonance in a 2-fold rotational symmetric metamaterial. The hybrid fishscale metamaterial exhibits an optically controlled redshift switching effect in the THz range. The switching effect is dominated by the conductivity of the silicon instead of mechanically adjusting angles of incidence. The tuning frequency range is up to 0.3THz with a large modulation depth and high transmission in the "ON" state. The fishscale metamaterial-based switching has been experimentally verified by its microwave counterpart integrated by variable resistors. Our work provides an alternative route to realize tunable Fano-type response in metamaterials and is of importance to active manipulation, sensing and switching of THz waves in practical applications.

Time-gated ballistic imaging using a large aperture switching beam.

PubMed

Mathieu, Florian; Reddemann, Manuel A; Palmer, Johannes; Kneer, Reinhold

2014-03-24

Ballistic imaging commonly denotes the formation of line-of-sight shadowgraphs through turbid media by suppression of multiply scattered photons. The technique relies on a femtosecond laser acting as light source for the images and as switch for an optical Kerr gate that separates ballistic photons from multiply scattered ones. The achievable image resolution is one major limitation for the investigation of small objects. In this study, practical influences on the optical Kerr gate and image quality are discussed theoretically and experimentally applying a switching beam with large aperture (D = 19 mm). It is shown how switching pulse energy and synchronization of switching and imaging pulse in the Kerr cell influence the gate's transmission. Image quality of ballistic imaging and standard shadowgraphy is evaluated and compared, showing that the present ballistic imaging setup is advantageous for optical densities in the range of 8 < OD < 13. Owing to the spatial transmission characteristics of the optical Kerr gate, a rectangular aperture stop is formed, which leads to different resolution limits for vertical and horizontal structures in the object. Furthermore, it is reported how to convert the ballistic imaging setup into a schlieren-type system with an optical schlieren edge.

Preparation, thermo-optic property and simulation of optical switch based on azo benzothiazole polymer

NASA Astrophysics Data System (ADS)

Cao, Zhijuan; Qiu, Fengxian; Wang, Qing; Cao, Guorong; Guan, Yijun; Zhuang, Lin; Xu, Xiaolong; Wang, Jie; Chen, Qian; Yang, Dongya

2013-04-01

An azo chromophore molecule 4-[(benzothiazole-2-yl)diazenyl]phenyl-1,3-diamine (BTPD) was prepared with 2-amino benzothiazole and m-phenylenediamine by diazo-coupling reaction. Then, the chromophore molecule BTPD was polymerized with NJ-210 and isophorone diisocyanate (IPDI) to obtain novel azo benzothiazole polymer (BTPU). The structures of BTPD and BTPU were characterized using the Fourier transform infrared, UV-visible spectroscopy, DSC and TGA. The physical properties of the obtained BTPU were investigated. The refractive index ( n) of BTPU was demonstrated at different temperature and wavelength (532, 650 and 850 nm) using attenuated total reflection technique. The transmission loss and dispersion characteristic of BTPU film were investigated using the CCD digital imaging devices and Sellmeyer equation. A Y-branch and 2 × 2 Mach-Zehnder interferometer (MZI) polymeric thermo-optic switches based on the thermo-optic effect of prepared BTPU were proposed and the performance of switches was simulated. The results indicated that the power consumption of the Y-branch thermo-optic switch could be only 0.6 mW. The Y-branch and MZI switching rising and falling times obtained were 8.0 and 1.8 ms.

Instant provisioning of wavelength service using quasi-circuit optical burst switching

NASA Astrophysics Data System (ADS)

Xie, Hongyi; Li, Yanhe; Zheng, Xiaoping; Zhang, Hanyi

2006-09-01

Due to the recent outstanding advancement of optical networking technology, pervasive Grid computing will be a feasible option in the near future. As Grid infrastructure, optical networks must be able to handle different Grid traffic patterns with various traffic characteristics as well as different QoS requirements. With current optical switching technology, optical circuit switching is suitable for data-intensive Grid applications while optical burst switching is suitable to submit small Grid jobs. However, there would be high bandwidth short-lived traffic in some emerging Grid applications such as multimedia editing. This kind of traffic couldn't be well supported by both OCS and conventional OBS because of considerable path setup delay and bandwidth waste in OCS and inherent loss in OBS. Quasi-Circuit OBS (QCOBS) is proposed in this paper to address this challenge, providing one-way reserved, nearly lossless, instant provisioned wavelength service in OBS networks. Simulation results show that QCOBS achieves lossless transmission at low and moderate loads, and very low loss probability at high loads with proper guard time configuration.

Pixel switching of epitaxial Pd/YHx/CaF2 switchable mirrors

PubMed

Kerssemakers; van der Molen SJ; Koeman; Gunther; Griessen

2000-08-03

Exposure of rare-earth films to hydrogen can induce a metal-insulator transition, accompanied by pronounced optical changes. This 'switchable mirror' effect has received considerable attention from theoretical, experimental and technological points of view. Most systems use polycrystalline films, but the synthesis of yttrium-based epitaxial switchable mirrors has also been reported. The latter form an extended self-organized ridge network during initial hydrogen loading, which results in the creation of micrometre-sized triangular domains. Here we observe homogeneous and essentially independent optical switching of individual domains in epitaxial switchable mirrors during hydrogen absorption. The optical switching is accompanied by topographical changes as the domains sequentially expand and contract; the ridges block lateral hydrogen diffusion and serve as a microscopic lubricant for the domain oscillations. We observe the correlated changes in topology and optical properties using in situ atomic force and optical microscopy. Single-domain phase switching is not observed in polycrystalline films, which are optically homogeneous. The ability to generate a tunable, dense pattern of switchable pixels is of technological relevance for solid-state displays based on switchable mirrors.

New scheme for image edge detection using the switching mechanism of nonlinear optical material

NASA Astrophysics Data System (ADS)

Pahari, Nirmalya; Mukhopadhyay, Sourangshu

2006-03-01

The limitations of electronics in conducting parallel arithmetic, algebraic, and logic processing are well known. Very high-speed (terahertz) performance cannot be expected in conventional electronic mechanisms. To achieve such performance we can introduce optics instead of electronics for information processing, computing, and data handling. Nonlinear optical material (NOM) is a successful candidate in this regard to play a major role in the domain of optically controlled switching systems. The character of some NOMs is such as to reflect the probe beam in the presence of two read beams (or pump beams) exciting the material from opposite directions, using the principle of four-wave mixing. In image processing, edge extraction from an image is an important and essential task. Several optical methods of digital image processing are used for properly evaluating the image edges. We propose here a new method of image edge detection, extraction, and enhancement by use of AND-based switching operations with NOM. In this process we have used the optically inverted image of a supplied image. This can be obtained by the EXOR switching operation of the NOM.

A Quasi-Optical Transmit/Receive Switch for the Goldstone Solar System Radar

NASA Technical Reports Server (NTRS)

Bhanji, Al

1997-01-01

A novel quasi-optical transmit/receive switch design for use with a high transmit power, low receive noise planetary imaging radar system is described. Design tradeoffs and implementation are discussed.

Research on performance of three-layer MG-OXC system based on MLAG and OCDM

NASA Astrophysics Data System (ADS)

Wang, Yubao; Ren, Yanfei; Meng, Ying; Bai, Jian

2017-10-01

At present, as traffic volume which optical transport networks convey and species of traffic grooming methods increase rapidly, optical switching techniques are faced with a series of issues, such as more requests for the number of wavelengths and complicated structure management and implementation. This work introduces optical code switching based on wavelength switching, constructs the three layers multi-granularity optical cross connection (MG-OXC) system on the basis of optical code division multiplexing (OCDM) and presents a new traffic grooming algorithm. The proposed architecture can improve the flexibility of traffic grooming, reduce the amount of used wavelengths and save the number of consumed ports, hence, it can simplify routing device and enhance the performance of the system significantly. Through analyzing the network model of switching structure on multicast layered auxiliary graph (MLAG) and the establishment of traffic grooming links, and the simulation of blocking probability and throughput, this paper shows the excellent performance of this mentioned architecture.

Programming Nanoparticles in Multiscale: Optically Modulated Assembly and Phase Switching of Silicon Nanoparticle Array.

PubMed

Wang, Letian; Rho, Yoonsoo; Shou, Wan; Hong, Sukjoon; Kato, Kimihiko; Eliceiri, Matthew; Shi, Meng; Grigoropoulos, Costas P; Pan, Heng; Carraro, Carlo; Qi, Dongfeng

2018-03-27

Manipulating and tuning nanoparticles by means of optical field interactions is of key interest for nanoscience and applications in electronics and photonics. We report scalable, direct, and optically modulated writing of nanoparticle patterns (size, number, and location) of high precision using a pulsed nanosecond laser. The complex nanoparticle arrangement is modulated by the laser pulse energy and polarization with the particle size ranging from 60 to 330 nm. Furthermore, we report fast cooling-rate induced phase switching of crystalline Si nanoparticles to the amorphous state. Such phase switching has usually been observed in compound phase change materials like GeSbTe. The ensuing modification of atomic structure leads to dielectric constant switching. Based on these effects, a multiscale laser-assisted method of fabricating Mie resonator arrays is proposed. The number of Mie resonators, as well as the resonance peaks and dielectric constants of selected resonators, can be programmed. The programmable light-matter interaction serves as a mechanism to fabricate optical metasurfaces, structural color, and multidimensional optical storage devices.

A novel graphene oxide-polyimide as optical waveguide material: Synthesis and thermo-optic switch properties

NASA Astrophysics Data System (ADS)

Cao, Tianlin; Zhao, Fanyu; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong; Zhao, Zerun; Li, Jiaxin; Guo, Xiaotong

2016-10-01

In this work, a novel graphene oxide-polyimide (GOPI) as optical waveguide material was prepared. The structure, mechanical, thermal property and morphology of the GOPI was characterized by using fourier transform infrared, UV-visible spectroscopy, near-infrared spectrum, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscope and transmission electron microscopy. The thermo-optic coefficients (dn/dT) are -9.16 × 10-4 (532 nm), -7.56 × 10-4 (650 nm) and -4.82 × 10-4 (850 nm) °C-1, respectively. Based on the thermo-optic effect of prepared GOPI as waveguide material, a Y-branch with branching angle of 0.143° and Mach-Zehnder thermo-optic switches were designed. Using finite difference beam propagation method (FD-BPM) method, the simulation results such as power consumptions and response times of two different thermo-optic switches were obtained.

A fast low-power optical memory based on coupled micro-ring lasers

NASA Astrophysics Data System (ADS)

Hill, Martin T.; Dorren, Harmen J. S.; de Vries, Tjibbe; Leijtens, Xaveer J. M.; den Besten, Jan Hendrik; Smalbrugge, Barry; Oei, Yok-Siang; Binsma, Hans; Khoe, Giok-Djan; Smit, Meint K.

2004-11-01

The increasing speed of fibre-optic-based telecommunications has focused attention on high-speed optical processing of digital information. Complex optical processing requires a high-density, high-speed, low-power optical memory that can be integrated with planar semiconductor technology for buffering of decisions and telecommunication data. Recently, ring lasers with extremely small size and low operating power have been made, and we demonstrate here a memory element constructed by interconnecting these microscopic lasers. Our device occupies an area of 18 × 40µm2 on an InP/InGaAsP photonic integrated circuit, and switches within 20ps with 5.5fJ optical switching energy. Simulations show that the element has the potential for much smaller dimensions and switching times. Large numbers of such memory elements can be densely integrated and interconnected on a photonic integrated circuit: fast digital optical information processing systems employing large-scale integration should now be viable.

2.79 μm high peak power LGS electro-optically Q-switched Cr,Er:YSGG laser.

PubMed

Wang, Li; Wang, Jintao; Yang, Jingwei; Wu, Xianyou; Sun, Dunlu; Yin, Shaotang; Jiang, Haihe; Wang, Jiyang; Xu, Changqing

2013-06-15

A flash lamp pumped Cr,Er:YSGG laser utilizing a langasite (LGS) crystal as an electro-optic Q-switch is proposed and demonstrated. It is proved that a LGS crystal with relatively high damage threshold can be used as the electro-optic Q-switch at 2.79 μm, and 216 mJ pulse energy with 14.36 ns pulse width is achieved. Its corresponding peak power of pulse can reach 15 MW, to our knowledge the best result at a 2.79 μm wavelength.

Optical switch

DOEpatents

Reedy, R.P.

1985-01-18

An optical switching device is provided whereby light from a first glass fiber or a second glass fiber may be selectively transmitted into a third glass fiber. Each glass fiber is provided with a focusing and collimating lens system. In one mode of operation, light from the first glass fiber is reflected by a planar mirror into the third glass fiber. In another mode of operation, light from the second glass fiber passes directly into the third glass fiber. The planar mirror is attached to a rotatable table which is rotated to provide the optical switching.

Optical switch

DOEpatents

Reedy, R.P.

1987-11-10

An optical switching device is provided whereby light from a first glass fiber or a second glass fiber may be selectively transmitted into a third glass fiber. Each glass fiber is provided with a focusing and collimating lens system. In one mode of operation, light from the first glass fiber is reflected by a planar mirror into the third glass fiber. In another mode of operation, light from the second glass fiber passes directly into the third glass fiber. The planar mirror is attached to a rotatable table which is rotated to provide the optical switching. 3 figs.

Harmonic Bloch and dipole oscillations and their transition in elliptical optical waveguide arrays

NASA Astrophysics Data System (ADS)

Chan, Yun San; Zheng, Ming Jie; Yu, Kin Wah

2011-03-01

We have studied harmonic oscillations in an elliptical optical waveguide array in which the couplings between neighboring waveguides are varied in accord with a Kac matrix so that the propagation constant eigenvalues can take equally spaced values. As a result, the long-living optical Bloch oscillation (BO) and dipole oscillation (DO) are obtained. Moreover, when a linear gradient in the propagation constant is applied, we achieve a switching from DO to BO and vice versa by ramping up or down the gradient profile]. The various optical oscillations as well as their switching are investigated by field evolution analysis and confirmed by Hamiltonian optics. The equally spaced eigenvalues in the propagation constant allow viable applications in transmitting images, switching and routing of optical signals. Work supported by the General Research Fund of the Hong Kong SAR Government.

Improved wavelength coded optical time domain reflectometry based on the optical switch.

PubMed

Zhu, Ninghua; Tong, Youwan; Chen, Wei; Wang, Sunlong; Sun, Wenhui; Liu, Jianguo

2014-06-16

This paper presents an improved wavelength coded time-domain reflectometry based on the 2 × 1 optical switch. In this scheme, in order to improve the signal-noise-ratio (SNR) of the beat signal, the improved system used an optical switch to obtain wavelength-stable, low-noise and narrow optical pulses for probe and reference. Experiments were set up to demonstrate a spatial resolution of 2.5m within a range of 70km and obtain the beat signal with line width narrower than 15 MHz within a range of 50 km in fiber break detection. A system for wavelength-division-multiplexing passive optical network (WDM-PON) monitoring was also constructed to detect the fiber break of different channels by tuning the current applied on the gating section of the distributed Bragg reflector (DBR) laser.

Prioritized retransmission in slotted all-optical packet-switched networks

NASA Astrophysics Data System (ADS)

Ghaffar Pour Rahbar, Akbar; Yang, Oliver

2006-12-01

We consider an all-optical slotted packet-switched network interconnected by a number of bufferless all-optical switches with contention-based operation. One approach to reduce the cost of the expensive contention resolution hardware could be retransmission in which each ingress switch keeps a copy of the transmitted traffic in the electronic buffer and retransmits whenever required. The conventional retransmission technique may need a higher number of retransmissions until traffic passes through the network. This in turn may lead to a retransmission at a higher layer and reduce the network throughput. In this paper, we propose and analyze a simple but effective prioritized retransmission technique in which dropped traffic is prioritized when retransmitted from ingress switches so that the core switch can process them with a higher priority. We present the analysis of both techniques in multifiber network architecture and verify it via simulation to demonstrate that our proposed algorithm can limit the number of retransmissions significantly and can improve TCP throughput better than the conventional retransmission technique.

Asynchronous transfer mode distribution network by use of an optoelectronic VLSI switching chip.

PubMed

Lentine, A L; Reiley, D J; Novotny, R A; Morrison, R L; Sasian, J M; Beckman, M G; Buchholz, D B; Hinterlong, S J; Cloonan, T J; Richards, G W; McCormick, F B

1997-03-10

We describe a new optoelectronic switching system demonstration that implements part of the distribution fabric for a large asynchronous transfer mode (ATM) switch. The system uses a single optoelectronic VLSI modulator-based switching chip with more than 4000 optical input-outputs. The optical system images the input fibers from a two-dimensional fiber bundle onto this chip. A new optomechanical design allows the system to be mounted in a standard electronic equipment frame. A large section of the switch was operated as a 208-Mbits/s time-multiplexed space switch, which can serve as part of an ATM switch by use of an appropriate out-of-band controller. A larger section with 896 input light beams and 256 output beams was operated at 160 Mbits/s as a slowly reconfigurable space switch.

Trading off switch costs and stimulus availability benefits: An investigation of voluntary task-switching behavior in a predictable dynamic multitasking environment.

PubMed

Mittelstädt, Victor; Miller, Jeff; Kiesel, Andrea

2018-03-09

In the present study, we introduce a novel, self-organized task-switching paradigm that can be used to study more directly the determinants of switching. Instead of instructing participants to randomly switch between tasks, as in the classic voluntary task-switching paradigm (Arrington & Logan, 2004), we instructed participants to optimize their task performance in a voluntary task-switching environment in which the stimulus associated with the previously selected task appeared in each trial after a delay. Importantly, the stimulus onset asynchrony (SOA) increased further with each additional repetition of this task, whereas the stimulus needed for a task switch was always immediately available. We conducted two experiments with different SOA increments (i.e., Exp. 1a = 50 ms, Exp. 1b = 33 ms) to see whether this procedure would induce switching behavior, and we explored how people trade off switch costs against the increasing availability of the stimulus needed for a task repetition. We observed that participants adapted their behavior to the different task environments (i.e., SOA increments) and that participants switched tasks when the SOA in task switches approximately matched the switch costs. Moreover, correlational analyses indicated relations between individual switch costs and individual switch rates across participants. Together, these results demonstrate that participants were sensitive to the increased availability of switch stimuli in deciding whether to switch or to repeat, which in turn demonstrates flexible adaptive task selection behavior. We suggest that performance limitations in task switching interact with the task environment to influence switching behavior.

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.

Optical switch probes and optical lock-in detection (OLID) imaging microscopy: high-contrast fluorescence imaging within living systems.

PubMed

Yan, Yuling; Marriott, M Emma; Petchprayoon, Chutima; Marriott, Gerard

2011-02-01

Few to single molecule imaging of fluorescent probe molecules can provide information on the distribution, dynamics, interactions and activity of specific fluorescently tagged proteins during cellular processes. Unfortunately, these imaging studies are made challenging in living cells because of fluorescence signals from endogenous cofactors. Moreover, related background signals within multi-cell systems and intact tissue are even higher and reduce signal contrast even for ensemble populations of probe molecules. High-contrast optical imaging within high-background environments will therefore require new ideas on the design of fluorescence probes, and the way their fluorescence signals are generated and analysed to form an image. To this end, in the present review we describe recent studies on a new family of fluorescent probe called optical switches, with descriptions of the mechanisms that underlie their ability to undergo rapid and reversible transitions between two distinct states. Optical manipulation of the fluorescent and non-fluorescent states of an optical switch probe generates a modulated fluorescence signal that can be isolated from a larger unmodulated background by using OLID (optical lock-in detection) techniques. The present review concludes with a discussion on select applications of synthetic and genetically encoded optical switch probes and OLID microscopy for high-contrast imaging of specific proteins and membrane structures within living systems.

Fiber optic crossbar switch for automatically patching optical signals

NASA Technical Reports Server (NTRS)

Bell, C. H. (Inventor)

1983-01-01

A system for automatically optically switching fiber optic data signals between a plurality of input optical fibers and selective ones of a plurality of output fibers is described. The system includes optical detectors which are connected to each of the input fibers for converting the optic data signals appearing at the respective input fibers to an RF signal. A plurality of RF to optical signal converters are arranged in rows and columns. The output of each of the optical detectors are each applied to a respective row of optical signal converted for being converters back to an optical signal when the particular optical signal converter is selectively activated by a dc voltage.

Fiber-optic beam control systems using microelectromechanical systems

NASA Astrophysics Data System (ADS)

Sumriddetchkajorn, Sarun

This dissertation, for the first time, proposes, studies, and experimentally demonstrated novel fiber-optic beam control systems based on the use of microelectromechanical system (MEMS) technology in which the miniaturized versions of mechanical systems can be obtained. Beam control modules include optical add/drop filters, optical switches, variable photonic delay lines (VPDLs), and variable optical attenuators (VOAs). The optical add/drop filter functions as a multiwavelength optical switch that offers the ability to drop and add a certain number of desired wavelengths at an intermediate location where access to all the propagating optical channels is not required between transmission terminals. The VOA can also be used in networks where stocking and tracking of fixed attenuators is difficult. Other specific applications of the VOA are optical gain equalization and polarization dependent loss and gain compensation required in high data-rate wavelength division multiplexed (WDM) lightwave systems. A VPDL can be used to adjust timing amongst multiwavelength optical signals in order to reduce timing jitter and burst traffic in photonic packet switching and parallel signal processing systems. In this dissertation, a small tilt micromirror device is proposed for the implementation of all fiber-optic beam control modules. In particular, the macro-pixel approach where several micromirrors are used to manipulate the desired optical beam is introduced to realize high speed and fault tolerant beam control modules. To eliminate the need of careful optical alignment, an all fiber-connectorized multiwavelength optical switch structure is presented and experimentally demonstrated by using a fiber-loop mirror concept with polarization control. In addition, liquid crystal (LC) devices are studied and are used to implement a compact retro- reflective 2 x 2 fiber-optic switch. Compared to MEMS- based mirror technology, the LC technology is more sensitive to temperature, thereby inappropriate to deploy in a harsh environment. With the benefit provided by WDM systems, wavelength sensitive fiber-optic beam controllers are proposed, offering wavelength sensitive time delay and amplitude controls that can be applied in several applications ranging from optical communications to high speed parallel signal processing. (Abstract shortened by UMI.)

Mindset switching increases the use of 'want-based' over 'should-based' behaviors

PubMed Central

Zhang, Nan-Nan; Xu, Dai-Xuan

2018-01-01

This study examines the consequences of mindset switching on behavioral choices in want/should conflicts. Building on the insights of the ego depletion literature, we propose that mindset switching depletes individuals’ self-control resources and therefore prompts the choice of want behavior, which provides immediate pleasure, over should behavior, which provides long-term utility. Four laboratory experiments with university students that stimulated individuals to switch mindsets were conducted to test our hypotheses. Experiment 1 demonstrated that switching between individualist and collectivist mindsets increased the subjects’ tendency to prefer popular magazines over scientific journals. Experiment 2 replicated the results by testing the relationship between an abstract/concrete mindset-switching task and want/should online behavioral choices. The mediating effect of ego depletion was also supported. Experiment 3 retested the main effect of language-switching on reading choices, and the mediating effect of ego-depletion. Experiment 3 also tested the moderating effect of the Need for Cognition, and eliminated the alternative explanation of cognitive fatigue. In Experiment 4, actual food choices were used as the direct measure of want/should behaviors to test the robustness of our findings. The results consistently supported our hypotheses that mindset switching has significant effects on behavioral choices in terms of overindulgence, such as increasing want behavior and thus foregoing should behavior. PMID:29709003

Q-switched Nd:YAG optical vortex lasers.

PubMed

Kim, D J; Kim, J W; Clarkson, W A

2013-12-02

Q-switched operation of a high-quality Nd:YAG optical vortex laser with the first order Laguerre-Gaussian mode and well-determined helical wavefronts using a fiber-based pump beam conditioning scheme is reported. A simple two-mirror resonator incorporating an acousto-optic Q-switch was employed, along with an etalon and a Brewster plate to enforce the particular helicity of the output. The laser yielded Q-switched pulses with ~250 μJ pulse energy and ~33 ns pulse duration (FWHM) at a 0.1 kHz repetition rate for 5.1 W of absorbed pump power. The handedness of the helical wavefronts was preserved regardless of the repetition rates. The prospects of further power scaling and improved laser performance are discussed.

Broadband nonvolatile photonic switching based on optical phase change materials: beyond the classical figure-of-merit.

PubMed

Zhang, Qihang; Zhang, Yifei; Li, Junying; Soref, Richard; Gu, Tian; Hu, Juejun

2018-01-01

In this Letter, we propose a broadband, nonvolatile on-chip switch design in the telecommunication C-band with record low loss and crosstalk. The unprecedented device performance builds on: 1) a new optical phase change material (O-PCM) Ge 2 Sb 2 Se 4 Te 1 (GSST), which exhibits significantly reduced optical attenuation compared to traditional O-PCMs, and 2) a nonperturbative design that enables low-loss device operation beyond the classical figure-of-merit (FOM) limit. We further demonstrate that the 1-by-2 and 2-by-2 switches can serve as basic building blocks to construct nonblocking and nonvolatile on-chip switching fabric supporting arbitrary numbers of input and output ports.

Reconfigurable optofluidic switch for generation of optical pulse width modulation based on tunable reflective interface.

PubMed

Mansuori, M; Zareei, G H; Hashemi, H

2015-10-01

We present a numerical method for generation of optical pulse width modulation (PWM) based on tunable reflective interface by using a microfluidic droplet. We demonstrate a single layer, planar, optofluidic PWM switch that is driven by excited alternating microbubbles. The main parameters of generation of this PWM such as frequency and speed of switching can be controlled by the mass flow rates of input fluids, and the shape of plug or droplet. Advantages of this design are the reconfigurability in design and the easy control of the switching parameters. The validation of the proposed design is carried out by employing the finite element method (FEM) for the mechanical simulation and the finite-difference time-domain (FDTD) for the optical simulation.

Investigation of Surface Breakdown on Semiconductor Devices Using Optical Probing Techniques.

DTIC Science & Technology

1990-01-01

18] L. Bovino , T. Burke, R. Youmans, M. Weiner, and J. Car, r, "Recent Advances in Optically C’ntrolled Bulk Semiconductor Switches," Digest of...Comp. Simul. 5 (3), 175 (1988). [321 M. Weiner, L. Bovino , R. Youmans, and T. Burke, "Modeling of the Optically Conrolled Semiconductor Switch," J

Topological photonic orbital-angular-momentum switch

NASA Astrophysics Data System (ADS)

Luo, Xi-Wang; Zhang, Chuanwei; Guo, Guang-Can; Zhou, Zheng-Wei

2018-04-01

The large number of available orbital-angular-momentum (OAM) states of photons provides a unique resource for many important applications in quantum information and optical communications. However, conventional OAM switching devices usually rely on precise parameter control and are limited by slow switching rate and low efficiency. Here we propose a robust, fast, and efficient photonic OAM switch device based on a topological process, where photons are adiabatically pumped to a target OAM state on demand. Such topological OAM pumping can be realized through manipulating photons in a few degenerate main cavities and involves only a limited number of optical elements. A large change of OAM at ˜10q can be realized with only q degenerate main cavities and at most 5 q pumping cycles. The topological photonic OAM switch may become a powerful device for broad applications in many different fields and motivate a topological design of conventional optical devices.

Microwave-mediated magneto-optical trap for polar molecules

NASA Astrophysics Data System (ADS)

Dizhou, Xie; Wenhao, Bu; Bo, Yan

2016-05-01

Realizing a molecular magneto-optical trap has been a dream for cold molecular physicists for a long time. However, due to the complex energy levels and the small effective Lande g-factor of the excited states, the traditional magneto-optical trap (MOT) scheme does not work very well for polar molecules. One way to overcome this problem is the switching MOT, which requires very fast switching of both the magnetic field and the laser polarizations. Switching laser polarizations is relatively easy, but fast switching of the magnetic field is experimentally challenging. Here we propose an alternative approach, the microwave-mediated MOT, which requires a slight change of the current experimental setup to solve the problem. We calculate the MOT force and compare it with the traditional MOT and the switching MOT scheme. The results show that we can operate a good MOT with this simple setup. Project supported by the Fundamental Research Funds for the Central Universities of China.

A scalable silicon photonic chip-scale optical switch for high performance computing systems.

PubMed

Yu, Runxiang; Cheung, Stanley; Li, Yuliang; Okamoto, Katsunari; Proietti, Roberto; Yin, Yawei; Yoo, S J B

2013-12-30

This paper discusses the architecture and provides performance studies of a silicon photonic chip-scale optical switch for scalable interconnect network in high performance computing systems. The proposed switch exploits optical wavelength parallelism and wavelength routing characteristics of an Arrayed Waveguide Grating Router (AWGR) to allow contention resolution in the wavelength domain. Simulation results from a cycle-accurate network simulator indicate that, even with only two transmitter/receiver pairs per node, the switch exhibits lower end-to-end latency and higher throughput at high (>90%) input loads compared with electronic switches. On the device integration level, we propose to integrate all the components (ring modulators, photodetectors and AWGR) on a CMOS-compatible silicon photonic platform to ensure a compact, energy efficient and cost-effective device. We successfully demonstrate proof-of-concept routing functions on an 8 × 8 prototype fabricated using foundry services provided by OpSIS-IME.

Broadband optical switch based on liquid crystal dynamic scattering.

PubMed

Geis, M W; Bos, P J; Liberman, V; Rothschild, M

2016-06-27

This work demonstrates a novel broadband optical switch, based on dynamic-scattering effect in liquid crystals (LCs). Dynamic-scattering-mode technology was developed for display applications over four decades ago, but was displaced in favor of the twisted-nematic LCs. However, with the recent development of more stable LCs, dynamic scattering provides advantages over other technologies for optical switching. We demonstrate broadband polarization-insensitive attenuation of light directly passing thought the cell by 4 to 5 orders of magnitude at 633 nm. The attenuation is accomplished by light scattering to higher angles. Switching times of 150 μs to 10% transmission have been demonstrated. No degradation of devices is found after hundreds of switching cycles. The light-rejection mechanism is due to scattering, induced by disruption of LC director orientation with dopant ion motion with an applied electric field. Angular dependence of scattering is characterized as a function of bias voltage.

Optical switch based on electrowetting liquid lens

NASA Astrophysics Data System (ADS)

Li, Lei; Liu, Chao; Peng, Hua-Rong; Wang, Qiong-Hua

2012-05-01

In this paper, we propose an optical switch based on an electrowetting liquid lens. The device consists of an electrowetting liquid lens and a non-transparent cap with a pin hole. When the lens is actuated to be positive, the incident light can be converged on the pin hole and pass through the hole with less attenuation. When the lens is deformed to be negative, the incident light is diverged and most of light is blocked by the cap. Our results show that the system can provide high contrast ratio (˜800:1) and reasonable response time (˜88 ms). The proposed optical switch has potential application in light shutters, variable optical attenuators, and adaptive irises.

Innovative architecture of switching device for expanding the applications in fiber to the home (FTTH)

NASA Astrophysics Data System (ADS)

Mahmoud, Mohamed; Fayed, Heba A.; Aly, Moustafa H.; Aboul Seoud, A. K.

2011-08-01

A new device, optical cross add drop multiplexer (OXADM), is proposed and analyzed. It uses the combination concept of optical add drop multiplexer (OADM) and optical cross connect (OXC). It enables a wavelength switch while implementing add and drop functions simultaneously. So, it expands the applications in fiber to the home (FTTH) and optical core networks. A very high isolation crosstalk level (~ 60 dB) is achieved. Also, a bidirectional OXADM and N×N OXADM are proposed. Finally, a multistage OXADM is presented making some sort of wavelength buffering. To make these devices operate more efficient, tunable fiber Bragg gratings (TFBGs) switches are used to control the operation mechanism.

High-port low-latency optical switch architecture with optical feed-forward buffering for 256-node disaggregated data centers.

PubMed

Terzenidis, Nikos; Moralis-Pegios, Miltiadis; Mourgias-Alexandris, George; Vyrsokinos, Konstantinos; Pleros, Nikos

2018-04-02

Departing from traditional server-centric data center architectures towards disaggregated systems that can offer increased resource utilization at reduced cost and energy envelopes, the use of high-port switching with highly stringent latency and bandwidth requirements becomes a necessity. We present an optical switch architecture exploiting a hybrid broadcast-and-select/wavelength routing scheme with small-scale optical feedforward buffering. The architecture is experimentally demonstrated at 10Gb/s, reporting error-free performance with a power penalty of <2.5dB. Moreover, network simulations for a 256-node system, revealed low-latency values of only 605nsec, at throughput values reaching 80% when employing 2-packet-size optical buffers, while multi-rack network performance was also investigated.

Ultrafast Nyquist OTDM demultiplexing using optical Nyquist pulse sampling in an all-optical nonlinear switch.

PubMed

Hirooka, Toshihiko; Seya, Daiki; Harako, Koudai; Suzuki, Daiki; Nakazawa, Masataka

2015-08-10

We propose the ultrahigh-speed demultiplexing of Nyquist OTDM signals using an optical Nyquist pulse as both a signal and a sampling pulse in an all-optical nonlinear switch. The narrow spectral width of the Nyquist pulses means that the spectral overlap between data and control pulses is greatly reduced, and the control pulse itself can be made more tolerant to dispersion and nonlinear distortions inside the nonlinear switch. We apply the Nyquist control pulse to the 640 to 40 Gbaud demultiplexing of DPSK and DQPSK signals using a nonlinear optical loop mirror (NOLM), and demonstrate a large performance improvement compared with conventional Gaussian control pulses. We also show that the optimum spectral profile of the Nyquist control pulse depends on the walk-off property of the NOLM.

All-optical controlled switching of solitons

NASA Astrophysics Data System (ADS)

Man, Wai Sing

1999-11-01

In this dissertation, we have numerically investigated various method of switching solitons using two different nonlinear optical switching devices, namely the twin core nonlinear directional coupler (TCNLDC) and the nonlinear optical loop mirror (NOLM). In the case of TCNLDC, four different schemes were explored where the polarization of the controlling pulse is either parallel or orthogonal to that of the signal soliton, or the controlling pulse may be launched into either of the input ports or it may have a wavelength different from that of the signal. It has been shown that high switching efficiency and distortionless propagation of the signal pulse through the coupler can only be achieved for the case in which the control pulse is launched into the adjacent port of the directional coupler and that its dispersion has equal magnitude but opposite sign as that of the signal. The effect of varying pulse width, walk-off and timing jitter were also investigated for this particular scheme for signal pulse width of 1 ps wide. In the case of NOLM, a control pulse having central wavelength located at the normal dispersion region is used to switch the soliton. The control pulse width and the NOLM's loop length were varied to obtain the switched soliton with minimum distortion and high switching efficiency. In this analysis, Raman effect is included because the control pulse transfers part of its energy to the co-propagating signal pulse in the optical loop. A compact soliton laser has also been developed for this project and its performance was analyzed experimentally and numerically. In our analysis of this soliton laser, we found that the wavelength of the mode-locked pulse can be tuned by varying the polarization elements in the laser and this is entirely due to the birefringence in the laser cavity. In summary, our works have shown that optical solitons can be switched effectively by TCNLDC and NOLM in the high bit-rate and low switching energy regime. (Abstract shortened by UMI.)

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.

Photo-induced micro-mechanical optical switch

DOEpatents

Rajic, Slobodan; Datskos, Panagiotis George; Egert, Charles M.

2002-01-01

An optical switch is formed by introducing light lengthwise to a microcantilever waveguide directed toward a second waveguide. The microcantilever is caused to bend by light emitted from a laser diode orthogonal to the microcantilever and at an energy above the band gap, which induces stress as a result of the generation of free carriers. The bending of the waveguide directs the carrier frequency light to a second receptor waveguide or to a non-responsive surface. The switch may be combined in an array to perform multiple switching functions rapidly and at low energy losses.

Chirp and error rate analyses of an optical-injection gain-switching VCSEL based all-optical NRZ-to-PRZ converter.

PubMed

Lin, Chia-Chi; Kuo, Hao-Chung; Peng, Peng-Chun; Lin, Gong-Ru

2008-03-31

Optically injection-locked single-wavelength gain-switching VCSEL based all-optical converter is demonstrated to generate RZ data at 2.5 Gbit/s with bit-error-rate of 10(-9) under receiving power of -29.3 dBm. A modified rate equation model is established to elucidate the optical injection induced gain-switching and NRZ-to-RZ data conversion in the VCSEL. The peak-to-peak frequency chirp of the VCSEL based NRZ-to-RZ is 4.5 GHz associated with a reduced frequency chirp rate of 178 MHz/ps at input optical NRZ power of -21 dBm, which is almost decreasing by a factor of 1/3 comparing with chirp on the SOA based NRZ-to-RZ converter reported previously. The power penalty of the BER measured back-to-back is about 2 dB from 1 Gbit/s to 2.5 Gbit/s.

High-speed spectral domain polarization- sensitive optical coherence tomography using a single camera and an optical switch at 1.3 microm.

PubMed

Lee, Sang-Won; Jeong, Hyun-Woo; Kim, Beop-Min

2010-01-01

We propose high-speed spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) using a single camera and a 1x2 optical switch at the 1.3-microm region. The PS-low coherence interferometer used in the system is constructed using free-space optics. The reflected horizontal and vertical polarization light rays are delivered via an optical switch to a single spectrometer by turns. Therefore, our system costs less to build than those that use dual spectrometers, and the processes of timing and triggering are simpler from the viewpoints of both hardware and software. Our SD-PS-OCT has a sensitivity of 101.5 dB, an axial resolution of 8.2 microm, and an acquisition speed of 23,496 A-scans per second. We obtain the intensity, phase retardation, and fast axis orientation images of a rat tail tendon ex vivo.

PHz current switching in calcium fluoride single crystal

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

Kwon, Ojoon; Kim, D., E-mail: kimd@postech.ac.kr; Max Planck Center for Attosecond Science, Max Planck POSTECH/Korea Res. Init., Pohang 37673

2016-05-09

We demonstrate that a current can be induced and switched in a sub-femtosecond time-scale in an insulating calcium fluoride single crystal by an intense optical field. This measurement indicates that a sizable current can be generated and also controlled by an optical field in a dielectric medium, implying the capability of rapid current switching at a rate of optical frequency, PHz (10{sup 15} Hz), which is a couple of orders of magnitude higher than that of contemporary electronic signal processing. This demonstration may serve to facilitate the development of ultrafast devices in PHz frequency.

Ultrafast optical transistor and router of multi-order fluorescence and spontaneous parametric four-wave mixing in Pr³⁺:YSO.

PubMed

Wen, Feng; Ali, Imran; Hasan, Abdulkhaleq; Li, Changbiao; Tang, Haijun; Zhang, Yufei; Zhang, Yanpeng

2015-10-15

We study the realization of an optical transistor (switch and amplifier) and router in multi-order fluorescence (FL) and spontaneous parametric four-wave mixing (SP-FWM). We estimate that the switching speed is about 15 ns. The router action results from the Autler-Townes splitting in spectral or time domain. The switch and amplifier are realized by dressing suppression and enhancement in FL and SP-FWM. The optical transistor and router can be controlled by multi-parameters (i.e., power, detuning, or polarization).

Multiwavelength Optical Switch Based on Controlling the Fermi Energy of Graphene

NASA Astrophysics Data System (ADS)

Jiang, Xiangqian; Bao, Jinlin; Sun, Xiudong

2018-04-01

We propose a graphene-dielectric-graphene corrugated structure to achieve a multiwavelength optical switch. The transmission and reflection properties of the structure are discussed, and multiultranarrow resonant peaks in the transmission and reflection spectra are found. By adjusting the Fermi energy of graphene, the resonant peaks will shift obviously. Based on this shifting property we present an active multiwavelength optical switch and achieve the on-off of four different wavelengths simultaneously. We also discuss the modulation depths of transmission and reflection. For the transmission of all four wavelengths we can get a very high modulation depth close to 100%.

On the size-dependent magnetism and all-optical magnetization switching of transition-metal silicide nanostructures

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

Glushkov, G. I.; Tuchin, A. V.; Popov, S. V.

Theoretical investigations of the electronic structure, synthesis, and all-optical magnetization switching of transition-metal silicide nanostructures are reported. The magnetic moment of the nanostructures is studied as a function of the silicide cluster size and configuration. The experimentally demonstrated magnetization switching of nanostructured nickel silicide by circularly polarized light makes it possible to create high-speed storage devices with high density data recording.

High-power electro-optic switch technology based on novel transparent ceramic

NASA Astrophysics Data System (ADS)

Xue-Jiao, Zhang; Qing, Ye; Rong-Hui, Qu; Hai-wen, Cai

2016-03-01

A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structure Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally. The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their polarization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method. An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a non-polarizing cube beam splitter (NPBS) replaces the beam splitter (BS) to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 dB. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed. It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide, especially for ultrafast high-power laser systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 61137004, 61405218, and 61535014).

Power requirements reducing of FBG based all-optical switching

NASA Astrophysics Data System (ADS)

Scholtz, Ľubomír.; Solanská, Michaela; Ladányi, Libor; Müllerová, Jarmila

2017-12-01

Although Fiber Bragg gratings (FBGs) are well known devices, their using as all-optical switching elements has been still examined. Current research is focused on optimization of their properties for their using in future all-optical networks. The main problem are high switching intensities needed for achieving the changes of the transmission state. Over several years switching intensities have been reduced from hundreds of GW/cm2 to tens of MW/cm2 by selecting appropriate gratings and signal parameters or using suitable materials. Two principal nonlinear effects with similar power requirements can result in the bistable transmission/reflection of an input optical pulse. In the self-phase modulation (SPM) regime switching is achieved by the intense probe pulse itself. Using cross-phase modulation (XPM) a strong pump alters the FBG refractive index experienced by a weak probe pulse. As a result of this the detuning of the probe pulse from the center of the photonic band gap occurs. Using of XPM the effect of modulation instability is reduced. Modulation instability which is the main SPM degradation mechanism. We focused on nonlinear FBGs based on chalcogenide glasses which are very often used in various applications. Thanks to high nonlinear parameters chalcogenide glasses are suitable candidates for reducing switching intensities of nonlinear FBGs.

Phase change material based tunable reflectarray for free-space optical inter/intra chip interconnects.

PubMed

Zou, Longfang; Cryan, Martin; Klemm, Maciej

2014-10-06

The concept of phase change material (PCM) based optical antennas and antenna arrays is proposed for dynamic beam shaping and steering utilized in free-space optical inter/intra chip interconnects. The essence of this concept lies in the fact that the behaviour of PCM based optical antennas will change due to the different optical properties of the amorphous and crystalline state of the PCM. By engineering optical antennas or antenna arrays, it is feasible to design dynamic optical links in a desired manner. In order to illustrate this concept, a PCM based tunable reflectarray is proposed for a scenario of a dynamic optical link between a source and two receivers. The designed reflectarray is able to switch the optical link between two receivers by switching the two states of the PCM. Two types of antennas are employed in the proposed tunable reflectarray to achieve full control of the wavefront of the reflected beam. Numerical studies show the expected binary beam steering at the optical communication wavelength of 1.55 μm. This study suggests a new research area of PCM based optical antennas and antenna arrays for dynamic optical switching and routing.

Spin state switching in iron coordination compounds

PubMed Central

Gaspar, Ana B; Garcia, Yann

2013-01-01

Summary The article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices. The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property. PMID:23504535

Optical multicast system for data center networks.

PubMed

Samadi, Payman; Gupta, Varun; Xu, Junjie; Wang, Howard; Zussman, Gil; Bergman, Keren

2015-08-24

We present the design and experimental evaluation of an Optical Multicast System for Data Center Networks, a hardware-software system architecture that uniquely integrates passive optical splitters in a hybrid network architecture for faster and simpler delivery of multicast traffic flows. An application-driven control plane manages the integrated optical and electronic switched traffic routing in the data plane layer. The control plane includes a resource allocation algorithm to optimally assign optical splitters to the flows. The hardware architecture is built on a hybrid network with both Electronic Packet Switching (EPS) and Optical Circuit Switching (OCS) networks to aggregate Top-of-Rack switches. The OCS is also the connectivity substrate of splitters to the optical network. The optical multicast system implementation requires only commodity optical components. We built a prototype and developed a simulation environment to evaluate the performance of the system for bulk multicasting. Experimental and numerical results show simultaneous delivery of multicast flows to all receivers with steady throughput. Compared to IP multicast that is the electronic counterpart, optical multicast performs with less protocol complexity and reduced energy consumption. Compared to peer-to-peer multicast methods, it achieves at minimum an order of magnitude higher throughput for flows under 250 MB with significantly less connection overheads. Furthermore, for delivering 20 TB of data containing only 15% multicast flows, it reduces the total delivery energy consumption by 50% and improves latency by 55% compared to a data center with a sole non-blocking EPS network.

Short-pulse controlled optical switch using external cavity based single mode Fabry-Pérot laser diode.

PubMed

Nakarmi, Bikash; Hoai, Tran Quoc; Won, Yong-Hyub; Zhang, Xuping

2014-06-30

We propose and demonstrate a novel scheme for short pulse controlled all-optical switch using external cavity based single mode Fabry- Pérot laser diode (SMFP-LD). The proposed scheme consists of control unit and switching unit as two essential blocks. The basic principle of the proposed scheme is the optical bistability property of SMFP-LD for the control unit and the suppression of the dominant beam of SMFP-LD with injection locking for the switching unit. We also present the analysis of hysteresis width and rising/falling time with change in wavelength detuning which helps to find the optimum wavelength detuning value and power of light beams at different stages of the proposed scheme that gives wide input dynamic power range, high ON/OFF contrast ratio, and low rising/falling time. Input data of 10 Gb/s Non Return to Zero (NRZ) signal is switched at output ports depending upon the control signal generated by the control unit, which comprises of optical SR latch. Output waveforms, clear eye diagrams with extinction ratio of about 11 dB, rising/falling time of about 30 ps and 40 ps, and bit error rate (BER) are measured to validate proposed scheme. No noise floor is observed at output ports up to BER of 10-(12) and the maximum power penalty recorded is about 1.7 dB at a BER of 10-(9) which shows good performance of the proposed short pulse controlled optical switch using SMFP-LDs.

Integrated optical maze

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

Roos, E.V.; Hendrix, J.L.

1994-06-01

Improvements to Nuclear Weapons Surety through the development of new detonation control techniques incorporating electro-optic technology are reviewed and proposed in this report. The results of the Kansas City Division`s (KCD`s) literature and vendor search, potential system architecture synthesis, and device test results are the basis of this report. This study has revealed several potential reconfigureable optical interconnect architectures that meet Los Alamos National Laboratory`s preliminary performance specifications. Several planer and global architectures have the potential for meeting the Department of Energy`s applications. Preliminary conclusions on the proposed architectures are discussed. The planer approach of monolithic GaAs amplifier switch arraysmore » is the leading candidate because it meets most of the specifications now. LiNbO{sub 3} and LiTaO{sub 3} planer tree switch arrays are the second choice because they meet all the specifications except for laser power transmission. Although not atop choice, acousto-optical free space switch arrays have been considered and meet most of the specifications. Symmetric-Self Electro-Optic Effect Devices (S-SEED) free space switch arrays are being considered and have excellent potential for smart reconfigureable optical interconnects in the future.« less

MEMS micromirrors for optical switching in multichannel spectrophotometers

NASA Astrophysics Data System (ADS)

Tuantranont, Adisorn; Lomas, Tanom; Bright, Victor M.

2004-04-01

This paper reports for the first time that a novel MEMS-based micromirror switch has successfully demonstrated for optical switching in a multi-channel fiber optics spectrophotometer system. The conventional optomechanical fiber optic switches for multi-channel spectrophotometers available in market are bulky, slow, low numbers of channels and expensive. Our foundry MEMS-based micromirror switch designed for integrating with commercially available spectrophotometers offers more compact devices, increased number of probing channels, higher performance and cheaper. Our MEMS-based micromirror switch is a surface micromachined mirror fabricated through MUMPs foundry. The 280 μm x 280 μm gold coated mirror is suspended by the double-gimbal structure for X and Y axis scanning. Self-assembly by solders is used to elevate the torsion mirror 30 μm over the substrate to achieve large scan angle. The solder self-assembly approach dramatically reduces the time to assembly the switch. The scan mirror is electrostatically controlled by applying voltages. The individual probing signal from each probing head is guided by fibers with collimated lenses and incidents on the center of the mirror. The operating scan angle is in the range of 3.5 degrees with driving voltage of 0-100 V. The fastest switching time of 4 millisecond (1 ms rise time and 3 ms fall time) is measured corresponding to the maximum speed of the mirror of 0.25 kHz when the mirror is scanning at +/- 1.5 degrees. The micromirror switch is packaged with a multi-mode fiber bundle using active alignment technique. A centered fiber is the output fiber that is connected to spectrophotometer. Maximum insertion loss of 5 dB has been obtained. The accuracy of measured spectral data is equivalent to the single channel spectrophotometer with a small degradation on probing signal due to fiber coupling.

Sub-20-ps pulses from a passively Q-switched microchip laser at 1  MHz repetition rate.

PubMed

Mehner, Eva; Bernard, Benjamin; Giessen, Harald; Kopf, Daniel; Braun, Bernd

2014-05-15

We present a 50 μm Nd3+:YVO4 microchip laser that is passively Q-switched by a semiconductor saturable absorber mirror. To reduce handling problems caused by the small crystal dimensions, the 50 μm Nd3+:YVO4 crystal is optically bonded to an undoped YVO4 crystal of a length of about 500 μm. By using a saturable absorber mirror with an effective modulation depth of >10% the system is able to deliver 16 ps pulses at a repetition rate of up to 1.0 MHz. The average laser power is 16 mW at 1064 nm. To our knowledge these are the shortest Q-switched pulses ever reported from a solid-state laser. The limits in terms of pulse width, repetition rate, output power, and system stability are discussed. Additionally, continuous-wave behavior is analyzed. Experimental data is compared with the simulation results of the coupled rate equations.

Pattern Formations for Optical Switching Using Cold Atoms as a Nonlinear Medium

NASA Astrophysics Data System (ADS)

Schmittberger, Bonnie; Greenberg, Joel; Gauthier, Daniel

2011-05-01

The study of spatio-temporal pattern formation in nonlinear optical systems has both led to an increased understanding of nonlinear dynamics as well as given rise to sensitive new methods for all-optical switching. Whereas the majority of past experiments utilized warm atomic vapors as nonlinear media, we report the first observation of an optical instability leading to pattern formation in a cloud of cold Rubidium atoms. When we shine a pair of counterpropagating pump laser beams along the pencil-shaped cloud's long axis, new beams of light are generated along cones centered on the trap. This generated light produces petal-like patterns in the plane orthogonal to the pump beams that can be used for optical switching. We gratefully acknowledge the financial support of the NSF through Grant #PHY-0855399 and the DARPA Slow Light Program.

Sequential double second-order nonlinear optical switch by an acido-triggered photochromic cyclometallated platinum(II) complex.

PubMed

Boixel, Julien; Guerchais, Véronique; Le Bozec, Hubert; Chantzis, Agisilaos; Jacquemin, Denis; Colombo, Alessia; Dragonetti, Claudia; Marinotto, Daniele; Roberto, Dominique

2015-05-07

An unprecedented DTE-based Pt(II) complex, 2(o), which stands as the first example of a sequential double nonlinear optical switch, induced first by protonation and next upon irradiation with UV light is presented.

Wavelength-tunable filter utilizing non-cyclic arrayed waveguide grating to create colorless, directionless, contentionless ROADMs

NASA Astrophysics Data System (ADS)

Niwa, Masaki; Takashina, Shoichi; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi; Watanabe, Toshio

2015-01-01

With the continuous increase in Internet traffic, reconfigurable optical add-drop multiplexers (ROADMs) have been widely adopted in the core and metro core networks. Current ROADMs, however, allow only static operation. To realize future dynamic optical-network services, and to minimize any human intervention in network operation, the optical signal add/drop part should have colorless/directionless/contentionless (C/D/C) capabilities. This is possible with matrix switches or a combination of splitter-switches and optical tunable filters. The scale of the matrix switch increases with the square of the number of supported channels, and hence, the matrix-switch-based architecture is not suitable for creating future large-scale ROADMs. In contrast, the numbers of splitter ports, switches, and tunable filters increase linearly with the number of supported channels, and hence the tunable-filter-based architecture will support all future traffic. So far, we have succeeded in fabricating a compact tunable filter that consists of multi-stage cyclic arrayed-waveguide gratings (AWGs) and switches by using planar-lightwave-circuit (PLC) technologies. However, this multistage configuration suffers from large insertion loss and filter narrowing. Moreover, power-consuming temperature control is necessary since it is difficult to make cyclic AWGs athermal. We propose here novel tunable-filter architecture that sandwiches a single-stage non-cyclic athermal AWG having flatter-topped passbands between small-scale switches. With this configuration, the optical tunable filter attains low insertion loss, large passband bandwidths, low power consumption, compactness, and high cost-effectiveness. A prototype is monolithically fabricated with PLC technologies and its excellent performance is experimentally confirmed utilizing 80-channel 30-GBaud dual-polarization quadrature phase-shift-keying (QPSK) signals.

Design of a Multicast Optical Packet Switch Based on Fiber Bragg Grating Technology for Future Networks

NASA Astrophysics Data System (ADS)

Cheng, Yuh-Jiuh; Yeh, Tzuoh-Chyau; Cheng, Shyr-Yuan

2011-09-01

In this paper, a non-blocking multicast optical packet switch based on fiber Bragg grating technology with optical output buffers is proposed. Only the header of optical packets is converted to electronic signals to control the fiber Bragg grating array of input ports and the packet payloads should be transparently destined to their output ports so that the proposed switch can reduce electronic interfaces as well as the bit rate. The modulation and the format of packet payloads may be non-standard where packet payloads could also include different wavelengths for increasing the volume of traffic. The advantage is obvious: the proposed switch could transport various types of traffic. An easily implemented architecture which can provide multicast services is also presented. An optical output buffer is designed to queue the packets if more than one incoming packet should reach to the same destination output port or including any waiting packets in optical output buffer that will be sent to the output port at a time slot. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The fiber Bragg grating arrays for both input ports and output ports are designed for routing incoming packets using optical code division multiple access technology.

Reversible optical control of cyanine fluorescence in fixed and living cells: optical lock-in detection immunofluorescence imaging microscopy

PubMed Central

Yan, Yuling; Petchprayoon, Chutima; Mao, Shu; Marriott, Gerard

2013-01-01

Optical switch probes undergo rapid and reversible transitions between two distinct states, one of which may fluoresce. This class of probe is used in various super-resolution imaging techniques and in the high-contrast imaging technique of optical lock-in detection (OLID) microscopy. Here, we introduce optimized optical switches for studies in living cells under standard conditions of cell culture. In particular, a highly fluorescent cyanine probe (Cy or Cy3) is directly or indirectly linked to naphthoxazine (NISO), a highly efficient optical switch that undergoes robust, 405/532 nm-driven transitions between a colourless spiro (SP) state and a colourful merocyanine (MC) state. The intensity of Cy fluorescence in these Cy/Cy3-NISO probes is reversibly modulated between a low and high value in SP and MC states, respectively, as a result of Förster resonance energy transfer. Cy/Cy3-NISO probes are targeted to specific proteins in living cells where defined waveforms of Cy3 fluorescence are generated by optical switching of the SP and MC states. Finally, we introduce a new imaging technique (called OLID-immunofluorescence microscopy) that combines optical modulation of Cy3 fluorescence from Cy3/NISO co-labelled antibodies within fixed cells and OLID analysis to significantly improve image contrast in samples having high background or rare antigens. PMID:23267183

Design of frequency-encoded data-based optical master-slave-JK flip-flop using polarization switch

NASA Astrophysics Data System (ADS)

Mandal, Sumana; Mandal, Dhoumendra; Mandal, Mrinal Kanti; Garai, Sisir Kumar

2017-06-01

An optical data processing and communication system provides enormous potential bandwidth and a very high processing speed, and it can fulfill the demands of the present generation. For an optical computing system, several data processing units that work in the optical domain are essential. Memory elements are undoubtedly essential to storing any information. Optical flip-flops can store one bit of optical information. From these flip-flop registers, counters can be developed. Here, the authors proposed an optical master-slave (MS)-JK flip-flop with the help of two-input and three-input optical NAND gates. Optical NAND gates have been developed using semiconductor optical amplifiers (SOAs). The nonlinear polarization switching property of an SOA has been exploited here, and it acts as a polarization switch in the proposed scheme. A frequency encoding technique is adopted for representing data. A specific frequency of an optical signal represents a binary data bit. This technique of data representation is helpful because frequency is the fundamental property of a signal, and it remains unaltered during reflection, refraction, absorption, etc. throughout the data propagation. The simulated results enhance the admissibility of the scheme.

Mathematical modeling and design of a novel 2-DOF micro attraction actuator for a micro optical switch

NASA Astrophysics Data System (ADS)

Kamiya, Daiki; Bagheri, Saeed; Horie, Mikio

2004-08-01

Many studies on optical switches have been performed in an attempt to develop optical information networks to speed information technology. In reality, however, mirror manipulators cannot be applied to multiple input and output systems due to both insufficient output displacements by the mirror parts inside the manipulator, and the difficulty of designing structures and mechanisms suitable for multi-dimensional manipulation. The principal reasons for insufficient displacement are the high rigidity of the elastic parts compared to the available driving forces and the pull-in effect. Therefore, in order to develop optical switches capable of multiple input and output switching, we suggest a novel 2-DOF(degree of freedom) electrostatic microactuator. The actuator is composed of one mirror with four beams laid about it in a corkscrew pattern, with four corkscrew electrodes on the substrate below and one mirror support pyramid situated under the mirror. Using electrostatic force, one or more of the beams are attracted from their outer ends toward the substrate. The mirror is then tilted by an angle proportional to the attracted length along the beam. The inclination and direction of the mirror are determined by the combined attracted length of the four beams. In this work we derive the mathematical model for the corkscrew beam microactuator for optical switches and show that this mathematical model accurately simulates the device by comparison with finite element analysis results. We use this mathematical model for design of the microactuator. Further we show that the designed optical switch microactuator is capable of rotating the mirror from +32 to -32 degrees about two axes with a maximum operating voltage of 163 volts. Finally, stress analysis of the actuator shows that the generated stress in the structure is at most 369 MPa.

Future optical communication networks beyond 160 Gbit/s based on OTDM

NASA Astrophysics Data System (ADS)

Prati, Giancarlo; Bogoni, Antonella; Poti, Luca

2005-01-01

The virtually unlimited bandwidth of optical fibers has caused a great increase in data transmission speed over the past decade and, hence, stimulated high-demand multimedia services such as distance learning, video-conferencing and peer to peer applications. For this reason data traffic is exceeding telephony traffic, and this trend is driving the convergence of telecommunications and computer communications. In this scenario Internet Protocol (IP) is becoming the dominant protocol for any traffic, shifting the attention of the network designers from a circuit switching approach to a packet switching approach. A role of paramount importance in packet switching networks is played by the router that must implement the functionalities to set up and maintain the inter-nodal communications. The main functionalities a router must implement are routing, forwarding, switching, synchronization, contention resolution, and buffering. Nowadays, opto-electronic conversion is still required at each network node to process the incoming signal before routing that to the right output port. However, when the single channel bit rate increases beyond electronic speed limit, Optical Time Division Multiplexing (OTDM) becomes a forced choice, and all-optical processing must be performed to extract the information from the incoming packet. In this paper enabling techniques for ultra-fast all-optical network will be addressed. First a 160 Gbit/s complete transmission system will be considered. As enabling technique, an overview for all-optical logics will be discussed and experimental results will be presented using a particular reconfigurable NOLM based on Self-Phase-Modulation (SPM) or Cross-Phase-Modulation (XPM). Finally, a rough experiment on label extraction, all-optical switching and packet forwarding is shown.

Optical zero-differential pressure switch and its evaluation in a multiple pressure measuring system

NASA Technical Reports Server (NTRS)

Powell, J. A.

1977-01-01

The design of a clamped-diaphragm pressure switch is described in which diaphragm motion is detected by a simple fiber-optic displacement sensor. The switch was evaluated in a pressure measurement system where it detected the zero crossing of the differential pressure between a static test pressure and a tank pressure that was periodically ramped from near zero to fullscale gage pressure. With a ramping frequency of 1 hertz and a full-scale tank pressure of 69 N/sq cm gage (100 psig), the switch delay was as long as 2 milliseconds. Pressure measurement accuracies were 0.25 to 0.75 percent of full scale. Factors affecting switch performance are also discussed.

Complexity-Enabled Sensor Networks and Photonic Switching Devices

DTIC Science & Technology

2008-12-20

slow diffusion of atoms out of the pump laser beams. The Doppler -broadened linewidth of the transition at this temperature was ~550 MHz. To prevent...Transverse Patterns for All-Optical Switching,’ Quantum Electronics and Laser Science 2008, San Jose, CA, May 5, 2008. Z. Gao and D.J. Gauthier...2007. A. M. C. Dawes and D. J. Gauthier, `Using Transverse Patterns for All-Optical Switching,’ Ninth Rochester Conference on Coherence & Quantum

Integration of GaN/AlN all-optical switch with SiN/AlN waveguide utilizing spot-size conversion.

PubMed

Iizuka, Norio; Yoshida, Haruhiko; Managaki, Nobuto; Shimizu, Toshimasa; Hassanet, Sodabanlu; Cumtornkittikul, Chiyasit; Sugiyama, Masakazu; Nakano, Yoshiaki

2009-12-07

Spot-size converters for an all-optical switch utilizing the intersubband transition in GaN/AlN multiple quantum wells are studied with the purpose of reducing operation power by improving the coupling efficiency between the input fiber and the switch. With a stair-like spot-size converter, the absorption saturation of 5 dB is achieved with a pulse energy of 25 pJ. The switch is integrated with a SiN/AlN waveguide and spot-size converters, and the structure provides the possibility of an integration of the switch with other functional devices. To further improve the coupling loss between the waveguide and the switch, triangular-shaped converters are investigated, demonstrating losses as low as 2 dB/facet.

Fiber-optic interconnection networks for spacecraft

NASA Technical Reports Server (NTRS)

Powers, Robert S.

1992-01-01

The overall goal of this effort was to perform the detailed design, development, and construction of a prototype 8x8 all-optical fiber optic crossbar switch using low power liquid crystal shutters capable of operation in a network with suitable fiber optic transmitters and receivers at a data rate of 1 Gb/s. During the earlier Phase 1 feasibility study, it was determined that the all-optical crossbar system had significant advantages compared to electronic crossbars in terms of power consumption, weight, size, and reliability. The result is primarily due to the fact that no optical transmitters and receivers are required for electro-optic conversion within the crossbar switch itself.

Engineered Multifunctional Nanophotonic Materials for Ultrafast Optical Switching

DTIC Science & Technology

2012-11-02

and Co3 + placed at tetrahedral and octahedral sites, respectively. Single -layer thin films of Co3O4 nanoparticles have large optical nonlinearity and...the first two methodologies in systems having weakly resonant structures, including 3-D and/or 1-D photonic crystal structures (i.e. nonlinear Bragg...Nonlinear optical transmission of lead phthalocyanine-doped nematic liquid crystal composites for multiscale nonlinear switching from nanosecond to

Silicon waveguide optical switch with embedded phase change material.

PubMed

Miller, Kevin J; Hallman, Kent A; Haglund, Richard F; Weiss, Sharon M

2017-10-30

Phase-change materials (PCMs) have emerged as promising active elements in silicon (Si) photonic systems. In this work, we design, fabricate, and characterize a hybrid Si-PCM optical switch. By integrating vanadium dioxide (a PCM) within a Si photonic waveguide, in a non-resonant geometry, we achieve ~10 dB broadband optical contrast with a PCM length of 500 nm using thermal actuation.

40-Gbit/s all-optical circulating shift register with an inverter.

PubMed

Hall, K L; Donnelly, J P; Groves, S H; Fennelly, C I; Bailey, R J; Napoleone, A

1997-10-01

We report what is believed to be the first demonstration of an all-optical circulating shift register using an ultrafast nonlinear interferometer with a polarization-insensitive semiconductor optical amplifier as the nonlinear switching element. The device operates at 40 Gbits/s, to our knowledge the highest speed demonstrated to date. Also, the demonstration proves the cascadability of the ultrafast nonlinear interferometric switch.

A 2D Rods-in-Air Square-Lattice Photonic Crystal Optical Switch

DTIC Science & Technology

2009-03-01

4] Tao Chu, Hirohito Yamada, Satomi Ishida, Yasuhiko Arakawa, Thermooptic switch based on photonic-crystal line-defect waveguides, IEEE Photon...Ishida, Yasuhiko Arakawa, Hiroyuki Fujita, Hiroshi Toshiyoshi, Design and fabrication on MEMS optical mod- ulators integrated with Phc waveguide, in

A sub-femtojoule electrical spin-switch based on optically trapped polariton condensates.

PubMed

Dreismann, Alexander; Ohadi, Hamid; Del Valle-Inclan Redondo, Yago; Balili, Ryan; Rubo, Yuri G; Tsintzos, Simeon I; Deligeorgis, George; Hatzopoulos, Zacharias; Savvidis, Pavlos G; Baumberg, Jeremy J

2016-10-01

Practical challenges to extrapolating Moore's law favour alternatives to electrons as information carriers. Two promising candidates are spin-based and all-optical architectures, the former offering lower energy consumption, the latter superior signal transfer down to the level of chip-interconnects. Polaritons-spinor quasi-particles composed of semiconductor excitons and microcavity photons-directly couple exciton spins and photon polarizations, combining the advantages of both approaches. However, their implementation for spintronics has been hindered because polariton spins can be manipulated only optically or by strong magnetic fields. Here we use an external electric field to directly control the spin of a polariton condensate, bias-tuning the emission polarization. The nonlinear spin dynamics offers an alternative route to switching, allowing us to realize an electrical spin-switch exhibiting ultralow switching energies below 0.5 fJ. Our results lay the foundation for development of devices based on the electro-optical control of coherent spin ensembles on a chip.

Electro-optical full-adder/full-subtractor based on graphene-silicon switches

NASA Astrophysics Data System (ADS)

Zivarian, Hossein; Zarifkar, Abbas; Miri, Mehdi

2018-01-01

A compact footprint, low-power consumption, and high-speed operation electro-optical full-adder/full-subtractor based on graphene-silicon electro-optical switches is demonstrated. Each switch consists of a Mach-Zehnder interferometer in which few-layer graphene is embedded in a silicon slot waveguide to construct phase shifters. The presented structure can be used as full-adder and full-subtractor simultaneously. The analysis of various factors such as extinction ratio, power consumption, and operation speed has been presented. As will be shown, the proposed electro-optical switch has a minimum extinction ratio of 36.21 dB, maximum insertion loss about 0.18 dB, high operation speed of 180 GHz, and is able to work with a low applied voltage about 1.4 V. Also, the extinction ratio and insertion loss of the full-adder/full-subtractor are about 30 and 1.5 dB, respectively, for transfer electric modes at telecommunication wavelength of 1.55 μm.

[Intracranial pressure monitoring apparatus for clinical use balanced pressure sensors].

PubMed

Numoto, M

1976-04-01

Three types of pressure sensors, (1) electric pressure switch, (2) fiber optic pressure switch and (3) pressure indicating bag for intracranial pressure monitoring which were developed by the author are described. Advantages and disadvantages between them are also discussed. The electric pressure switch is relatively simple in construction but has a possibility of producing micro-shock hazard in case of accidental electric leakage. The fiber optic pressure switch is the safest for the micro shock but its structure is rather complicated and fragile. The pressure indicating bag is simple to make and durable to use. However, it has a hydrostatic effect.

In-ground optical fibre Bragg grating pressure switch for security applications

NASA Astrophysics Data System (ADS)

Allwood, Gary; Wild, Graham; Hinckley, Steven

2012-02-01

In this study, a fibre Bragg grating (FBG) was embedded beneath three common flooring materials acting as a pressure switch for in-ground intrusion detection. This is achieved using an intensiometric detection system, where a laser diode and FBG were optically mismatched so that there was a static dc offset from the transmitted and reflected optical power signals. As pressure was applied, in the form of a footstep, a strain induced wavelength shift occurred that could then be detected by converting the wavelength shift into an intensity change. The change in intensity caused a significant change in the DC offset which behaved as on optical switch. This switch could easily be configured to trigger an alarm if required. The intention is to use the FBG sensor as an in-ground intrusion detection pressure switch to detect an intruder walking within range of the sensor. This type of intrusion detection system can be applied to both external (in soil, etc) and internal (within the foundations or flooring of the home) security systems. The results show that a person's footstep can clearly be detected through solid wood flooring, laminate flooring, and ceramic floor tiles.

Stable switching among high-order modes in polariton condensates

NASA Astrophysics Data System (ADS)

Sun, Yongbao; Yoon, Yoseob; Khan, Saeed; Ge, Li; Steger, Mark; Pfeiffer, Loren N.; West, Ken; Türeci, Hakan E.; Snoke, David W.; Nelson, Keith A.

2018-01-01

We report multistate optical switching among high-order bouncing-ball modes ("ripples") and whispering-gallery modes ("petals") of exciton-polariton condensates in a laser-generated annular trap. By tailoring the diameter and power of the annular trap, the polariton condensate can be switched among different trapped modes, accompanied by redistribution of spatial densities and superlinear increase in the emission intensities, implying that polariton condensates in this geometry could be exploited for an all-optical multistate switch. A model based on non-Hermitian modes of the generalized Gross-Pitaevskii equation reveals that this mode switching arises from competition between pump-induced gain and in-plane polariton loss. The parameters for reproducible switching among trapped modes have been measured experimentally, giving us a phase diagram for mode switching. Taken together, the experimental result and theoretical modeling advance our fundamental understanding of the spontaneous emergence of coherence and move us toward its practical exploitation.

Ultra-compact 32 × 32 strictly-non-blocking Si-wire optical switch with fan-out LGA interposer.

PubMed

Tanizawa, Ken; Suzuki, Keijiro; Toyama, Munehiro; Ohtsuka, Minoru; Yokoyama, Nobuyuki; Matsumaro, Kazuyuki; Seki, Miyoshi; Koshino, Keiji; Sugaya, Toshio; Suda, Satoshi; Cong, Guangwei; Kimura, Toshio; Ikeda, Kazuhiro; Namiki, Shu; Kawashima, Hitoshi

2015-06-29

We demonstrate a 32 × 32 path-independent-insertion-loss optical path switch that integrates 1024 thermooptic Mach-Zehnder switches and 961 intersections on a small, 11 × 25 mm2 die. The switch is fabricated on a 300-mm-diameter silicon-on-insulator wafer by a complementary metal-oxide semiconductor-compatible process with advanced ArF immersion lithography. For reliable electrical packaging, the switch chip is flip-chip bonded to a ceramic interposer that arranges the electrodes in a 0.5-mm pitch land grid array. The on-chip loss is measured to be 15.8 ± 1.0 dB, and successful switching is demonstrated for digital-coherent 43-Gb/s QPSK signals. The total crosstalk of the switch is estimated to be less than -20 dB at the center wavelength of 1545 nm. The bandwidth narrowing caused by dimensional errors that arise during fabrication is discussed.

Method and system for compact, multi-pass pulsed laser amplifier

DOEpatents

Erlandson, Alvin Charles

2014-11-25

A laser amplifier includes an input aperture operable to receive laser radiation having a first polarization, an output aperture coupled to the input aperture by an optical path, and a polarizer disposed along an optical path. A transmission axis of the polarizer is aligned with the first polarization. The laser amplifier also includes n optical switch disposed along the optical path. The optical switch is operable to pass the laser radiation when operated in a first state and to reflect the laser radiation when operated in a second state. The laser amplifier further includes an optical gain element disposed along the optical path and a polarization rotation device disposed along the optical path.

Broadband nonlinear optical response of monolayer MoSe2 under ultrafast excitation

NASA Astrophysics Data System (ADS)

Nie, Zhonghui; Trovatello, Chiara; Pogna, Eva A. A.; Dal Conte, Stefano; Miranda, Paulo B.; Kelleher, Edmund; Zhu, Chunhui; Turcu, Ion Crisitan Edmond; Xu, Yongbing; Liu, Kaihui; Cerullo, Giulio; Wang, Fengqiu

2018-01-01

Due to their strong light-matter interaction, monolayer transition metal dichalcogenides (TMDs) have proven to be promising candidates for nonlinear optics and optoelectronics. Here, we characterize the nonlinear absorption of chemical vapour deposition (CVD)-grown monolayer MoSe2 in the 720-810 nm wavelength range. Surprisingly, despite the presence of strong exciton resonances, monolayer MoSe2 exhibits a uniform modulation depth of ˜80 ± 3% and a saturation intensity of ˜2.5 ± 0.4 MW/cm2. In addition, pump-probe spectroscopy is performed to confirm the saturable absorption and reveal the photocarrier relaxation dynamics over hundreds of picoseconds. Our results unravel the unique broadband nonlinear absorptive behavior of monolayer MoSe2 under ultrafast excitation and highlight the potential of using monolayer TMDs as broadband ultrafast optical switches with customizable saturable absorption characteristics.

Optical network democratization.

PubMed

Nejabati, Reza; Peng, Shuping; Simeonidou, Dimitra

2016-03-06

The current Internet infrastructure is not able to support independent evolution and innovation at physical and network layer functionalities, protocols and services, while at same time supporting the increasing bandwidth demands of evolving and heterogeneous applications. This paper addresses this problem by proposing a completely democratized optical network infrastructure. It introduces the novel concepts of the optical white box and bare metal optical switch as key technology enablers for democratizing optical networks. These are programmable optical switches whose hardware is loosely connected internally and is completely separated from their control software. To alleviate their complexity, a multi-dimensional abstraction mechanism using software-defined network technology is proposed. It creates a universal model of the proposed switches without exposing their technological details. It also enables a conventional network programmer to develop network applications for control of the optical network without specific technical knowledge of the physical layer. Furthermore, a novel optical network virtualization mechanism is proposed, enabling the composition and operation of multiple coexisting and application-specific virtual optical networks sharing the same physical infrastructure. Finally, the optical white box and the abstraction mechanism are experimentally evaluated, while the virtualization mechanism is evaluated with simulation. © 2016 The Author(s).

Total internal reflection optical switch using the reverse breakdown of a pn junction in silicon.

PubMed

Kim, Jong-Hun; Park, Hyo-Hoon

2015-11-01

We demonstrate a new type of silicon total-internal-reflection optical switch with a simple pn junction functioning both as a reflector and a heater. The reflector is placed between asymmetrically y-branched multimode waveguides with an inclination angle corresponding to half of the branch angle. When the reflector is at rest, incident light is reflected in accordance to the refractive index difference due to the plasma dispersion effect of the pre-doped carriers. Switching to the transmission state is attained under a reverse breakdown of the pn junction by the thermo-optic effect which smears the refractive index difference. From this switching scheme, we confirmed the switching operation with a shallow total-internal-reflection region of 1 μm width. At a 6° branch angle, an extinction ratio of 12 dB and an insertion loss of -4.2  dB are achieved along with a thermal heating power of 151.5 mW.

Light driven optofluidic switch developed in a ZnO-overlaid microstructured optical fiber.

PubMed

Konidakis, Ioannis; Konstantaki, Maria; Tsibidis, George D; Pissadakis, Stavros

2015-11-30

A great challenge of Optofluidics remains the control of the fluidic properties of a photonic circuit by solely utilizing light. In this study, the development of a ZnO nanolayered microstructured optical fiber (MOF) Fabry-Perot interferometer is demonstrated, along with its fully reversible optofluidic switching behaviour. The actuation and switching principle is entirely based on the employment of light sources, i.e. UV 248 nm and green 532 nm lasers, while using modest irradiation doses. The synthesized ZnO within the MOF capillaries acts as a light triggered wettability transducer, allowing the controlled water filling and draining of the MOF Fabry-Perot cavity. The progression of the optofluidic cycle is monitored in situ with optical microscopy, while Fabry-Perot reflection spectra are monitored in real time to probe temporal infiltration behaviour. Finally, a first insight on the light triggered switching mechanism, employing photoluminescence and spectrophotometric measurements is presented. Results appear highly promising towards the design of smart in-fiber optofluidic light switching devices, suitable for actuating and sensing applications.

Optically activated switches for the generation of complex electrical waveforms with multigigahertz bandwidth

NASA Astrophysics Data System (ADS)

Skeldon, Mark D.; Okishev, Andrey V.; Letzring, Samuel A.; Donaldson, William R.; Green, Kenton; Seka, Wolf D.; Fuller, Lynn F.

1995-01-01

An electrical pulse-generation system using two optically activated Si photoconductive switches can generate shaped electrical pulses with multigigahertz bandwidth. The Si switches are activated by an optical pulse whose leading edge is steepened by stimulated Brillouin scattering (SBS) in CCl4. With the bandwidth generated by the SBS process, a laser having a 1- to 3-ns pulse width is used to generate electrical pulses with approximately 80-ps rise times (approximately 4-GHz bandwidth). Variable impedance microstrip lines are used to generate complex electrical waveforms that can be transferred to a matched load with minimal loss of bandwidth.

Optical switch

DOEpatents

Reedy, Robert P.

1987-01-01

An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

Optical switch using Risley prisms

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2003-04-15

An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

Optical Switch Using Risley Prisms

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2005-02-22

An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

A symmetry breaking phase transition-triggered high-temperature solid-state quadratic nonlinear optical switch coupled with a switchable dielectric constant in an organic-inorganic hybrid compound.

PubMed

Mei, Guang-Quan; Zhang, Han-Yue; Liao, Wei-Qiang

2016-09-25

An organic-inorganic hybrid compound, [NH3(CH2)5NH3]SbCl5, exhibits a switchable second harmonic generation (SHG) effect between SHG-OFF and SHG-ON states and tunable dielectric behaviors between high and low dielectric states, connected with the changes in the dynamics of 1,5-pentanediammonium cations during its centrosymmetric-to-noncentrosymmetric symmetry breaking phase transition at 365.4 K.

Novel optical switch with a reconfigurable dielectric liquid droplet.

PubMed

Ren, Hongwen; Xu, Su; Ren, Daqiu; Wu, Shin-Tson

2011-01-31

We demonstrated a novel optical switch with a reconfigurable dielectric liquid droplet. The device consists of a clear liquid droplet (glycerol) surrounded by a black liquid (dye-doped liquid crystal). In the voltage-off state, the incident light passing through the clear liquid droplet is absorbed by the black liquid, resulting in a dark state. In the voltage-on state, the dome of the clear liquid droplet is uplifted by the dielectric force to form a light pipe which in turn transmits the incident light. Upon removing the voltage, the droplet recovers to its original shape and the switch is closed. We also demonstrated a red color light switch with ~10:1 contrast ratio and ~300 ms response time. Devices based on such an operation mechanism will find attractive applications in light shutter, tunable iris, variable optical attenuators, and displays.

A compact thermo-optical multimode-interference silicon-based 1 × 4 nano-photonic switch.

PubMed

Zhou, Haifeng; Song, Junfeng; Chee, Edward K S; Li, Chao; Zhang, Huijuan; Lo, Guoqiang

2013-09-09

An ultra-compact multimode-interference (MMI)-based 1 × 4 nano-photonic switch is demonstrated by employing silicon thermo-optical effect on SOI platform. The device performance is systematically characterized by comprehensively investigating the constituent building blocks, including 1 × 4 power splitter, 4 × 4 MMI coupler and groove-isolated thermo-optical heaters. An instructive model is established to statistically estimate the required power consumption and investigate the influence of the power imbalance of the 4 × 4 MMI coupler on the switching performance. At the designed wavelength of 1550 nm, the average insertion loss of different switching states is 1.7 dB, and the transmission imbalance is 1.05 dB. The worst extinction ratio and crosstalk of all the output ports reach 11.48 dB and -11.38 dB, respectively.

THESEUS: A wavelength division multiplexed/microwave subcarrier multiplexed optical network, its ATM switch applications and device requirements

NASA Astrophysics Data System (ADS)

Xin, Wei

1997-10-01

A Terabit Hybrid Electro-optical /underline[Se]lf- routing Ultrafast Switch (THESEUS) has been proposed. It is a self-routing wavelength division multiplexed (WDM) / microwave subcarrier multiplexed (SCM) asynchronous transfer mode (ATM) switch for the multirate ATM networks. It has potential to be extended to a large ATM switch as 1000 x 1000 without internal blocking. Among the advantages of the hybrid implementation are flexibility in service upgrade, relaxed tolerances on optical filtering, protocol simplification and less processing overhead. For a small ATM switch, the subcarrier can be used as output buffers to solve output contention. A mathematical analysis was conducted to evaluate different buffer configurations. A testbed has been successfully constructed. Multirate binary data streams have been switched through the testbed and error free reception ([<]10-9 bit error rate) has been achieved. A simple, intuitive theoretical model has been developed to describe the heterodyne optical beat interference. A new concept of interference time and interference length has been introduced. An experimental confirmation has been conducted. The experimental results match the model very well. It shows that a large portion of optical bandwidth is wasted due to the beat interference. Based on the model, several improvement approaches have been proposed. The photo-generated carrier lifetime of silicon germanium has been measured using time-resolved reflectivity measurement. Via oxygen ion implantation, the carrier lifetime has been reduced to as short as 1 ps, corresponding to 1 THz of photodetector bandwidth. It has also been shown that copper dopants act as recombination centers in the silicon germanium.

Gas adsorption/absorption heat switch, phase 1

NASA Technical Reports Server (NTRS)

Chan, C. K.

1987-01-01

The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

Design of an All-Optical Network Based on LCoS Technologies

NASA Astrophysics Data System (ADS)

Cheng, Yuh-Jiuh; Shiau, Yhi

2016-06-01

In this paper, an all-optical network composed of the ROADMs (reconfigurable optical add-drop multiplexer), L2/L3 optical packet switches, and the fiber optical cross-connection for fiber scheduling and measurement based on LCoS (liquid crystal on silicon) technologies is proposed. The L2/L3 optical packet switches are designed with optical output buffers. Only the header of optical packets is converted to electronic signals to control the wavelength of input ports and the packet payloads can be transparently destined to their output ports. An optical output buffer is designed to queue the packets when more than one incoming packet should reach to the same destination output port. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The wavelength of input ports is designed for routing incoming packets using LCoS technologies. Finally, the proposed OFS (optical flow switch) with input buffers can quickly transfer the big data to the output ports and the main purpose of the OFS is to reduce the number of wavelength reflections. The all-optical content delivery network is comprised of the OFSs for a large amount of audio and video data transmissions in the future.

Compact conductively cooled electro-optical Q-switched Nd:YAG laser

NASA Astrophysics Data System (ADS)

Li, Chaoyang; Lu, Chengqiang; Li, Chuan; Zang, Yannan; Yang, Zhen; Han, Song; Li, Ye; Yang, Ning; Shi, Junfeng; Zhou, Zewu

2017-11-01

We report on a compact conductively cooled high-repetition-rate nanosecond Nd:YAG laser. The oscillator was an laser diode side-pumped electro-optical (EO) Q-switched Nd:YAG rod laser adopting unstable cavity with a variable reflectivity mirror. A pulse train of 142 mJ with duration of 10 ns, repetition rate of 80 Hz at 1064 nm has been achieved. Maximum pulse energy was obtained at the pump energy of 1380 mJ, corresponding to the optical-optical conversion efficiency of 10.3%. The peak power was deduced to be 14.2 MW. The near-field pattern demonstrated a nearly super Gaussian flat top profile. To our knowledge, this is the highest repetition rate operation for a conductively cooled EO Q-switched Nd:YAG rod laser.

Characteristic analysis of a polarization output coupling Porro prism resonator

NASA Astrophysics Data System (ADS)

Yang, Hailong; Meng, Junqing; Chen, Weibiao

2015-02-01

An Electro-optical Q-switched Nd:YAG slab laser with a crossed misalignment Porro prism resonator for space applications has been theoretically and experimentally investigated. The phase shift induced by the combination of different wave plates and Porro prism azimuth angles have been studied for creating high loss condition prior to Q-switching. The relationship of the effective output coupling reflectivity and the employed Q-switch driving voltage is explored by using Jones matrix optics. In the experiment, the maximum output pulse energy of 93 mJ with 14-ns pulse duration is obtained at the repetition rate of 20 Hz and the optical-to-optical conversion efficiency is 16.8%. The beam quality factors are M 2 x = 2.5 and M 2y = 2.2, respectively.

All-optical switch and transistor gated by one stored photon.

PubMed

Chen, Wenlan; Beck, Kristin M; Bücker, Robert; Gullans, Michael; Lukin, Mikhail D; Tanji-Suzuki, Haruka; Vuletić, Vladan

2013-08-16

The realization of an all-optical transistor, in which one "gate" photon controls a "source" light beam, is a long-standing goal in optics. By stopping a light pulse in an atomic ensemble contained inside an optical resonator, we realized a device in which one stored gate photon controls the resonator transmission of subsequently applied source photons. A weak gate pulse induces bimodal transmission distribution, corresponding to zero and one gate photons. One stored gate photon produces fivefold source attenuation and can be retrieved from the atomic ensemble after switching more than one source photon. Without retrieval, one stored gate photon can switch several hundred source photons. With improved storage and retrieval efficiency, our work may enable various new applications, including photonic quantum gates and deterministic multiphoton entanglement.

Novel optoelectronic devices; Proceedings of the Meeting, The Hague, Netherlands, Mar. 31-Apr. 2, 1987

NASA Technical Reports Server (NTRS)

Adams, Michael J. (Editor)

1987-01-01

The present conference on novel optoelectronics discusses topics in the state-of-the-art in this field in the Netherlands, quantum wells, integrated optics, nonlinear optical devices and fiber-optic-based devices, ultrafast optics, and nonlinear optics and optical bistability. Attention is given to the production of fiber-optics for telecommunications by means of PCVD, lifetime broadening in quantum wells, nonlinear multiple quantum well waveguide devices, tunable single-wavelength lasers, an Si integrated waveguiding polarimeter, and an electrooptic light modulator using long-range surface plasmons. Also discussed are backward-wave couplers and reflectors, a wavelength-selective all-fiber switching matrix, the impact of ultrafast optics in high-speed electronics, the physics of low energy optical switching, and all-optical logical elements for optical processing.

Study on multiple-hops performance of MOOC sequences-based optical labels for OPS networks

NASA Astrophysics Data System (ADS)

Zhang, Chongfu; Qiu, Kun; Ma, Chunli

2009-11-01

In this paper, we utilize a new study method that is under independent case of multiple optical orthogonal codes to derive the probability function of MOOCS-OPS networks, discuss the performance characteristics for a variety of parameters, and compare some characteristics of the system employed by single optical orthogonal code or multiple optical orthogonal codes sequences-based optical labels. The performance of the system is also calculated, and our results verify that the method is effective. Additionally it is found that performance of MOOCS-OPS networks would, negatively, be worsened, compared with single optical orthogonal code-based optical label for optical packet switching (SOOC-OPS); however, MOOCS-OPS networks can greatly enlarge the scalability of optical packet switching networks.

Device having two optical ports for switching applications

DOEpatents

Rosen, Ayre; Stabile, Paul J.

1991-09-24

A two-sided light-activatable semiconductor switch device having an optical port on each side thereof. The semiconductor device may be a p-i-n diode or of bulk intrinsic material. A two ported p-i-n diode, reverse-biased to "off" by a 1.3 kV dc power supply, conducted 192 A when activated by two 1 kW laser diode arrays, one for each optical port.

An actively Q-switched fiber laser with cylindrical vector beam generation

NASA Astrophysics Data System (ADS)

Zhang, Jiaojiao; Zhang, Zuxing; Cai, Yu; Wan, Hongdan; Wang, Zhiqiang; Zhang, Lin

2018-03-01

We demonstrate an actively Q-switched fiber laser with cylindrical vector beam (CVB) emission using a few-mode fiber Bragg grating as the mode selection component and an acousto-optic modulator to achieve Q-switching. To the best of our knowledge, this is the first such demonstration. Using a linear cavity configuration, an actively Q-switched CVB with a pulse width of about 64 ns, a pulse energy of 4.25 µJ and a repetition rate of 20 kHz has been obtained. Moreover, by tuning the polarization controllers radially and azimuthally, polarized Q-switched beams can be excited separately with a polarization purity of  >94.5%. This compact Q-switched fiber laser with ns CVB pulse output could find potential applications in the field of material processing, nonlinear optics and so on.

Compact, low-loss and low-power 8×8 broadband silicon optical switch.

PubMed

Chen, Long; Chen, Young-kai

2012-08-13

We demonstrated a 8×8 broadband optical switch on silicon for transverse-electrical polarization using a switch-and-selector architecture. The switch has a footprint of only 8 mm × 8 mm, minimum on-chip loss of about 4 dB, and a port-to-port insertion loss variation of only 0.8 dB near some spectral regions. The port-to-port isolation is above 30 dB over the entire 80-nm-wide spectral range or above 45 dB near the central 30 nm. We also demonstrated a switching power of less than 1.5 mW per element and a speed of 2 kHz, and estimated the upper bound of total power consumption to be less than 70 mW even without optimization of the default state of the individual switch elements.

High Speed Switching in Magnetic Recording Media.

NASA Astrophysics Data System (ADS)

He, Lin

The magnetization switching behavior of magnetic particulate and metal evaporated thin film recording tapes in the nanosecond regime is studied. The purpose is to characterize the switching behavior of the magnetization in current recording media and determine whether the recording media will be a limiting factor in future high performance recording systems. In this work, a pulse test system with field pulse width tau<=ss than 1 nanosecond was created for measuring switching behavior. Two ways were used to characterize the switching behavior of the media. The first is a traditional way in which the switching behavior is determined by a switching coefficient S_{rm w}. The second is more useful and convenient. The switching behavior is described in terms of the increase in remanent coercivity H_{rm CR}(tau) as the field pulse width tau decreases. For high magnetic viscosity materials, the experimental results are in good agreement with the thermally assisted switching model proposed by Sharrock if the attempt frequency f _0 = 10^9 Hz and the exponent n = 0.5. For low magnetic viscosity materials, the results are in reasonable agreement with the Landau-Lifshitz-Gilbert -damping-limited switching model but only if values of the damping constant alpha ~ 1 are assumed, in conflict with the reported values extracted from ferromagnetic resonance measurements. The fundamental relationship between the two models through the fluctuation-dissipation theorem is emphasized and the need for a comprehensive model identified. The results have significant implications for future media where thermal effects will become increasingly important.

3  ×  3 optical switch by exploiting vortex beam emitters based on silicon microrings with superimposed gratings.

PubMed

Scaffardi, Mirco; Malik, Muhammad N; Lazzeri, Emma; Klitis, Charalambos; Meriggi, Laura; Zhang, Ning; Sorel, Marc; Bogoni, Antonella

2017-10-01

A silicon-on-insulator microring with three superimposed gratings is proposed and characterized as a device enabling 3×3 optical switching based on orbital angular momentum and wavelength as switching domains. Measurements show penalties with respect to the back-to-back of <1  dB at a bit error rate of 10 -9 for OOK traffic up to 20 Gbaud. Different switch configuration cases are implemented, with measured power penalty variations of less than 0.5 dB at bit error rates of 10 -9 . An analysis is also carried out to highlight the dependence of the number of switch ports on the design parameters of the multigrating microring.

Raman laser with controllable suppression of parasitics

DOEpatents

George, E. Victor

1986-01-01

Method and apparatus for switching energy out of a Raman laser optical cavity. Coherent radiation at both the pump and first Stokes wave frequencies are introduced into the optical cavity from the same direction, and a second Stokes wave is utilized to switch the energy out of the cavity.

Raman laser with controllable suppression of parasitics

DOEpatents

George, E.V.

Method and apparatus for switching energy out of a Raman laser optical cavity. Coherent radiation at both the pump and first Stokes wave frequencies are introduced into the optical cavity from the same direction, and a second Stokes wave is utilized to switch the energy out of the cavity.

Photonic Switching Devices Using Light Bullets

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor)

1997-01-01

The present invention is directed toward a unique ultra-fast, all-optical switching device or switch made with readily available, relatively inexpensive, highly nonlinear photonic glasses. These photonic glasses have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counterpropagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide, and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. One advantage presented by the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another feature of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in highly nonlinear glasses.

Performance improvement of long-range surface plasmon structure for use in an all-optical switch

NASA Astrophysics Data System (ADS)

Jandaghian, Ali; Lotfalian, Ali; Kouhkan, Mohsen; Mohajerani, Ezeddin

2017-12-01

This paper presents important parameters in performance of long-range surface plasmon (LRSP) structure (SF4/PVA/silver/PMMA-DR1) that are improved. We select poly(vinyl alcohol) (PVA) as the first dielectric layer due to its water solubility and good optical properties. The thickness of PVA and silver layers is optimized by transfer matrix method based on Fresnel equations. Surface morphologies of PVA and silver surfaces are analyzed by AFM imaging due to their important role in the performance of an LRSP structure. Furthermore, the sensitivity of an all-optical switch based on plasmon is investigated. In order to compare the sensitivity of LRSP and conventional surface plasmon (SP) structures in switching mode, full wide of half maximum, resonance angles, and pump powers of both structures are measured by a custom-made optical setup based on angular interrogation with a precision of 0.01 deg. Finally, we conclude that for creating equal signal levels in both samples, the required pump power for LRSP structure was about three times less than that for conventional SP; thus, these results led to power savings in optical switches.

Electrowetting-actuated optical switch based on total internal reflection.

PubMed

Liu, Chao; Wang, Di; Yao, Li-Xiao; Li, Lei; Wang, Qiong-Hua

2015-04-01

In this paper we demonstrate a liquid optical switch based on total internal reflection. Two indium tin oxide electrodes are fabricated on the bottom substrate. A conductive liquid (Liquid 1) is placed on one side of the chamber and surrounded by a density-matched silicone oil (Liquid 2). In initial state, when the light beam illuminates the interface of the two liquids, it just meets the conditions of total internal reflection. The light is totally reflected by Liquid 2, and the device shows light-off state. When we apply a voltage to the other side of the indium tin oxide electrode, Liquid 1 stretched towards this side of the substrate and the curvature of the liquid-liquid interface changes. The light beam is refracted by Liquid 1 and the device shows light-on state. So the device can achieve the functions of an optical switch. Because the light beam can be totally reflected by the liquid, the device can attain 100% light intensity attenuation. Our experiments show that the response time from light-on (off) to light-off (on) are 130 and 132 ms, respectively. The proposed optical switch has potential applications in variable optical attenuators, information displays, and light shutters.

Nonlinear optical studies on 1,3-disubstituent chalcones doped polymer films

NASA Astrophysics Data System (ADS)

Poornesh, P.; Shettigar, Seetharam; Umesh, G.; Manjunatha, K. B.; Prakash Kamath, K.; Sarojini, B. K.; Narayana, B.

2009-04-01

We report the measurements of the third-order nonlinear optical properties of recently synthesized and characterized two different 1,3-disubstituent chalcones doped PMMA films, with the prospective of reaching a good compromise between processability and high nonlinear optical properties. The measurements were done using nanosecond Z-scan at 532 nm. The Z-scan spectra reveal a large negative nonlinear refraction coefficient n2 of the order 10 -11 esu and the molecular two photon absorption cross section is 10 -46 cm 4 s/photon. The doped films exhibit good optical power limiting property under nanosecond regime and the two photon absorption (TPA) is the dominating process leading to the nonlinear behavior. The improvement in the nonlinear properties has been observed when methylenedioxy group is replaced by dimethoxy group due to increase in conjugation length. The observed nonlinear parameters of chalcone derivatives doped PMMA film is comparable with stilbazolieum derivatives, a well-known class of optical materials for photonics and biophotonics applications, which suggests that, these moieties have potential for the application of all-optical limiting and switching devices.

A Laser Spark Plug Ignition System for a Stationary Lean-Burn Natural Gas Reciprocating Engine

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

McIntyre, D. L.

To meet the ignition system needs of large bore, high pressure, lean burn, natural gas engines a side pumped, passively Q-switched, Nd:YAG laser was developed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn, high compression engine. The laser and associated optics were designed with a passive Q-switch to eliminate the need for high voltage signaling and associated equipment. The laser was diode pumped to eliminate the need for high voltage flash lamps which have poor pumping efficiency. The independent and dependent parameters of the laser were identified and exploredmore » in specific combinations that produced consistent robust sparks in laboratory air. Prior research has shown that increasing gas pressure lowers the breakdown threshold for laser initiated ignition. The laser has an overall geometry of 57x57x152 mm with an output beam diameter of approximately 3 mm. The experimentation used a wide range of optical and electrical input parameters that when combined produced ignition in laboratory air. The results show a strong dependence of the output parameters on the output coupler reflectivity, Q-switch initial transmission, and gain media dopant concentration. As these three parameters were lowered the output performance of the laser increased leading to larger more brilliant sparks. The results show peak power levels of up to 3MW and peak focal intensities of up to 560 GW/cm 2. Engine testing was performed on a Ricardo Proteus single cylinder research engine. The goal of the engine testing was to show that the test laser performs identically to the commercially available flashlamp pumped actively Q-switched laser used in previous laser ignition testing. The engine testing consisted of a comparison of the in-cylinder, and emissions behavior of the engine using each of the lasers as an ignition system. All engine parameters were kept as constant as possilbe while the equivalence ratio (fueling), and hence the engine load, was varied between 0.8, 0.9, and 1.0. The test laser was constructed with a 30% output coupler, 32% Q-switch initial transmission, and a 0.5% Nd concentration rod all pumped by approximately 1000 Watts of optical power. The test laser single mode output pulse had an energy of approximately 23 mJ, with a pulsewidth of approximately 10 ns, and an M2 value of 6.55. This output produced focal intensity of approximately 270 GW/cm 2 with the modified on-engine optical arrangement. The commercial laser had similar output parameters and both laser systems operated the engine with similar results. Due to the shortening of the focal length of the on-engine optical setup both laser systems produced a spark well within the optical transfer cavity of the laser optics to spark plug adaptor. This shrouded spark led to a very long ignition delay and retarded combustion timing for all three values of equivalence ratio. This was evidenced by the in-cylinder pressure traces and the HRR waveforms. The emissions data indicate that both lasers produced very similar combustion. The ignition delay caused by the shrouded spark cause most of the combustion to happen after TDC which lead to poor combustion that produced high levels of CO and THC. The novelty of this work lies in the combination of the laser parameters to create a single high peak power laser output pulse for use as a spark ignition source. Similar configurations have been investigated in the literature but for different applications such as multiple output pulse trains for various industrial and communications applications. Another point of novelty is the investigation of the laser medium concentration on the output characteristics of a passively Q-switched laser system. This work has shown that lowering the Neodymium concentration in the active media within a passively Q-switched laser produces higher output energy values. This is significant because an actively Q-switched laser shows the opposite affect when the active ion concentration is varied.« less

Experimental demonstration of OSPF-TE extensions in muiti-domain OBS networks connected by GMPLS network

NASA Astrophysics Data System (ADS)

Tian, Chunlei; Yin, Yawei; Wu, Jian; Lin, Jintong

2008-11-01

The interworking network of Generalized Multi-Protocol Label Switching (GMPLS) and Optical Burst Switching (OBS) is attractive network architecture for the future IP/DWDM network nowadays. In this paper, OSPF-TE extensions for multi-domain Optical Burst Switching networks connected by GMPLS controlled WDM network are proposed, the corresponding experimental results such as the advertising latency are also presented by using an OBS network testbed. The experimental results show that it works effectively on the OBS/GMPLS networks.

Recent Advances in Optically Controlled Bulk Semiconductor Switches

DTIC Science & Technology

1985-06-01

REO!NT AIJifl,NCES IN (FTICALIX ~1Ra.LW IILK SHttiaHlOCIOR swrrams L. Bovino , T. Burke, R. Youmans, M. Weiner, J. Carter U.S. Ar~ Electronics...fabrication of all of our optically activated switches. B.e.fer.enc.es. 1. L. Bovino , R. Youmans, T. Burke, M.Weiner, "Modulator Circuits Using Q...tically Activated Switches", Record of 16th Power Modulator SYJll>o- siurn, pp 235-239, June 1984. 2. M. Weiner, T. Burke, R. Youmans, L. Bovino , J

Fully programmable and scalable optical switching fabric for petabyte data center.

PubMed

Zhu, Zhonghua; Zhong, Shan; Chen, Li; Chen, Kai

2015-02-09

We present a converged EPS and OCS switching fabric for data center networks (DCNs) based on a distributed optical switching architecture leveraging both WDM & SDM technologies. The architecture is topology adaptive, well suited to dynamic and diverse *-cast traffic patterns. Compared to a typical folded-Clos network, the new architecture is more readily scalable to future multi-Petabyte data centers with 1000 + racks while providing a higher link bandwidth, reducing transceiver count by 50%, and improving cabling efficiency by more than 90%.

Development of a switched integrator amplifier for high-accuracy optical measurements.

PubMed

Mountford, John; Porrovecchio, Geiland; Smid, Marek; Smid, Radislav

2008-11-01

In the field of low flux optical measurements, the development and use of large area silicon detectors is becoming more frequent. The current/voltage conversion of their photocurrent presents a set of problems for traditional transimpedance amplifiers. The switched integration principle overcomes these limitations. We describe the development of a fully characterized current-voltage amplifier using the switched integrator technique. Two distinct systems have been developed in parallel at the United Kingdom's National Physical Laboratory (NPL) and Czech Metrology Institute (CMI) laboratories. We present the circuit theory and best practice in the design and construction of switched integrators. In conclusion the results achieved and future developments are discussed.

Silicon Micromachining in RF and Photonic Applications

NASA Technical Reports Server (NTRS)

Lin, Tsen-Hwang; Congdon, Phil; Magel, Gregory; Pang, Lily; Goldsmith, Chuck; Randall, John; Ho, Nguyen

1995-01-01

Texas Instruments (TI) has developed membrane and micromirror devices since the late 1970s. An eggcrate space membrane was used as the spatial light modulator in the early years. Discrete micromirrors supported by cantilever beams created a new era for micromirror devices. Torsional micromirror and flexure-beam micromirror devices were promising for mass production because of their stable supports. TI's digital torsional micromirror device is an amplitude modulator (known as the digital micromirror device (DMD) and is in production development, discussed elsewhere. We also use a torsional device for a 4 x 4 fiber-optic crossbar switch in a 2 cm x 2 cm package. The flexure-beam micromirror device is an analog phase modulator and is considered more efficient than amplitude modulators for use in optical processing systems. TI also developed millimeter-sized membranes for integrated optical switches for telecommunication and network applications. Using a member in radio frequency (RF) switch applications is a rapidly growing area because of the micromechanical device performance in microsecond-switching characteristics. Our preliminary membrane RF switch test structure results indicate promising speed and RF switching performance. TI collaborated with MIT for modeling of metal-based micromachining.

Adaptive packet switch with an optical core (demonstrator)

NASA Astrophysics Data System (ADS)

Abdo, Ahmad; Bishtein, Vadim; Clark, Stewart A.; Dicorato, Pino; Lu, David T.; Paredes, Sofia A.; Taebi, Sareh; Hall, Trevor J.

2004-11-01

A three-stage opto-electronic packet switch architecture is described consisting of a reconfigurable optical centre stage surrounded by two electronic buffering stages partitioned into sectors to ease memory contention. A Flexible Bandwidth Provision (FBP) algorithm, implemented on a soft-core processor, is used to change the configuration of the input sectors and optical centre stage to set up internal paths that will provide variable bandwidth to serve the traffic. The switch is modeled by a bipartite graph built from a service matrix, which is a function of the arriving traffic. The bipartite graph is decomposed by solving an edge-colouring problem and the resulting permutations are used to configure the switch. Simulation results show that this architecture exhibits a dramatic reduction of complexity and increased potential for scalability, at the price of only a modest spatial speed-up k, 1

Electro-optic control of a PPLN-unpoled LiNbO3 boundary for low-voltage Q switching of an intracavity frequency-doubled Nd3+:YVO4 laser.

PubMed

Torregrosa, A J; Maestre, H; Fernández-Pousa, C R; Pereda, J A; Capmany, J

2009-08-01

We present a simple technique to integrate an electro-optic Q switch in a periodically poled bulk lithium niobate crystal bounded by two unpoled (monodomain) regions. The technique exploits the high sensitivity to low applied electric fields of the total internal reflection condition in the periodic poled-unpoled boundary for the small grazing incidence angles associated with the diffraction of a focused Gaussian beam that propagates in the periodically poled region with its axis parallel to the boundary. When the arrangement is placed intracavity to a 1064 nm diode-pumped Nd(3+):YVO(4) laser, it performs simultaneously as a Q switch and as a second-harmonic generator, with Q switching starting at applied voltages as low as 1 V over a 500 microm thickness and with no additional optical elements.

Quantum optics. All-optical routing of single photons by a one-atom switch controlled by a single photon.

PubMed

Shomroni, Itay; Rosenblum, Serge; Lovsky, Yulia; Bechler, Orel; Guendelman, Gabriel; Dayan, Barak

2014-08-22

The prospect of quantum networks, in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons. We realized a single-photon-activated switch capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single atom coupled to a fiber-coupled, chip-based microresonator. A single reflected control photon toggles the switch from high reflection (R ~ 65%) to high transmission (T ~ 90%), with an average of ~1.5 control photons per switching event (~3, including linear losses). No additional control fields are required. The control and target photons are both in-fiber and practically identical, making this scheme compatible with scalable architectures for quantum information processing. Copyright © 2014, American Association for the Advancement of Science.

Lidar Electro-Optic Beam Switch with a Liquid Crystal Variable Retarder

NASA Technical Reports Server (NTRS)

Baer, James

2012-01-01

A document discusses a liquid crystal variable retarder, an electro-optic element that changes the polarization of an optical beam in response to a low-voltage electronic signal. This device can be fabricated so that the element creates, among other states, a half-wave of retardance that can be reduced to a very small retardance. When aligned to a polarized source, this can act to rotate the polarization by 90 in one state, but generate no rotation in the other state. If the beam is then incident on a polarization beam splitter, it will efficiently switch from one path to the other when the voltage is applied. The laser beam switching system has no moving parts, improving reliability over mechanical switching. It is low cost, tolerant of high laser power density, and needs only simple drive electronics, minimizing the required system resources.

A unique all-optic switch based on an innovatively designed liquid crystal waveguide

NASA Astrophysics Data System (ADS)

Nam, Sung-Hyun; Su, Wei-Hung; Chavez, Jesus; Yin, Shizhuo

2003-10-01

A unique, all-optic switch based on an innovatively designed planar lightwave circuit (PLC) is presented in this paper. The switching function is achieved by using ultra large birefringence of nematic liquid crystals (NLC) filled at the trench of waveguides. The trench at the crossing forms a waveguide mirror or a matching medium when extraordinary and ordinary refractive indices of NLC are employed, respectively. The major advantages of our unique design are: (1) the limitation that refractive index of liquid crystal must be less than that of waveguide material itself is eliminated so that conventional NCL material such as E7 can be used; (2) it is a self aligned fabrication process that alleviates the tight tolerance of later tilt error; (3) the design is thermally stable. The successful fabrication of this unqiue switch could result in an enabling element for the next generation all-optic networks.

Actively Q-switched, thulium-holmium-codoped fiber laser incorporating a silicon-based, variable-optical-attenuator-based Q switch.

PubMed

Jung, Minwan; Han Lee, Ju

2013-04-20

An actively Q-switched thulium-holmium-codoped fiber laser incorporating an Si-based variable optical attenuator (VOA) is experimentally demonstrated. It has been shown that an Si-based VOA with a response time of hundreds of nanoseconds can be used as a cost-effective 2 μm Q switch due to its extremely wide operating bandwidth from 1.5 to 2 μm, and low electrical power consumption. In our study, the laser's slope efficiency was measured to be ~17% at an operating wavelength of 1.89 μm. The repetition rate tuning range was from 20 to 80 kHz, which was limited by the optical damage threshold and the response time. The minimum temporal pulsewidth was measured to be ~184 ns at a modulation frequency of 20 kHz, and the corresponding maximum peak power was ~10 W.

Model for multishot all-thermal all-optical switching in ferromagnets

NASA Astrophysics Data System (ADS)

Gorchon, J.; Yang, Y.; Bokor, J.

2016-07-01

All-optical magnetic switching (AOS) is a recently observed rich and puzzling phenomenon that offers promising technological applications. However, a fundamental understanding of the underlying mechanisms remains elusive. Here we present a model for multishot helicity-dependent AOS in ferromagnetic materials based on a purely heat-driven mechanism in the presence of magnetic circular dichroism (MCD). We predict that AOS should be possible with as little as 0.5% of MCD, after a minimum number of laser shots heat the sample close to the Curie temperature. Finally, we qualitatively reproduce the all-optically switched domain patterns observed experimentally by numerically simulating the result of multiple laser shots on an FePtC granular ferromagnetic film.

Optically-Switched Resonant Tunneling Diodes for Space-Based Optical Communication Applications

NASA Technical Reports Server (NTRS)

Moise, T. S.; Kao, Y. -C.; Jovanovic, D.; Sotirelis, P.

1995-01-01

We are developing a new type of digital photo-receiver that has the potential to perform high speed optical-to-electronic conversion with a factor of 10 reduction in component count and power dissipation. In this paper, we describe the room-temperature photo-induced switching of this InP-based device which consists of an InGaAs/AlAs resonant tunneling diode integrated with an InGaAs absorber layer. When illuminated at an irradiance of greater than 5 Wcm(exp -2) using 1.3 micromillimeter radiation, the resonant tunneling diode switches from a high-conductance to a low-conductance electrical state and exhibits a voltage swing of up to 800 mV.

All-optical switching in silicon-on-insulator photonic wire nano-cavities.

PubMed

Belotti, Michele; Galli, Matteo; Gerace, Dario; Andreani, Lucio Claudio; Guizzetti, Giorgio; Md Zain, Ahmad R; Johnson, Nigel P; Sorel, Marc; De La Rue, Richard M

2010-01-18

We report on experimental demonstration of all-optical switching in a silicon-on-insulator photonic wire nanocavity operating at telecom wavelengths. The switching is performed with a control pulse energy as low as approximately 0.1 pJ on a cavity device that presents very high signal transmission, an ultra-high quality-factor, almost diffraction-limited modal volume and a footprint of only 5 microm(2). High-speed modulation of the cavity mode is achieved by means of optical injection of free carriers using a nanosecond pulsed laser. Experimental results are interpreted by means of finite-difference time-domain simulations. The possibility of using this device as a logic gate is also demonstrated.

Monolithic mm-wave phase shifter using optically activated superconducting switches

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R. (Inventor); Bhasin, Kul B. (Inventor)

1992-01-01

A phase shifter is disclosed having a reference path and a delay path, light sources, and superconductive switches. Each of the superconductive switches is terminated in a virtual short circuit, which may be a radial stub. Switching between the reference path and delayed path is accomplished by illuminating the superconductive switches connected to the desired path, while not illuminating the superconductive switches connected to the other path.

Existence and switching behavior of bright and dark Kerr solitons in whispering-gallery mode resonators with zero group-velocity dispersion

NASA Astrophysics Data System (ADS)

Talla Mbé, Jimmi H.; Milián, Carles; Chembo, Yanne K.

2017-07-01

We use the generalized Lugiato-Lefever model to investigate the phenomenon of Kerr optical frequency comb generation when group-velocity dispersion is null. In that case, the first dispersion term that plays a leading role is third-order dispersion. We show that this term is sufficient to allow for the existence of both bright and dark solitons. We identify the areas in the parameter space where both kind of solitons can be excited inside the resonator. We also unveil a phenomenon of hysteretic switching between these two types of solitons when the power of the pump laser is cyclically varied. Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.

Casimir switch: steering optical transparency with vacuum forces.

PubMed

Liu, Xi-Fang; Li, Yong; Jing, H

2016-06-03

The Casimir force, originating from vacuum zero-point energy, is one of the most intriguing purely quantum effects. It has attracted renewed interests in current field of nanomechanics, due to the rapid size decrease of on-chip devices. Here we study the optomechanically-induced transparency (OMIT) with a tunable Casimir force. We find that the optical output rate can be significantly altered by the vacuum force, even terminated and then restored, indicating a highly-controlled optical switch. Our result addresses the possibility of designing exotic optical nano-devices by harnessing the power of vacuum.

Ultrafast Laser Beam Switching and Pulse Train Generation by Using Coupled Vertical-Cavity, Surface-Emitting Lasers (VCSELS)

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor); Ning, Cun-Zheng (Inventor)

2005-01-01

Ultrafast directional beam switching is achieved using coupled VCSELs. This approach is demonstrated to achieve beam switching frequencies of 40 GHz and more and switching directions of about eight degrees. This switching scheme is likely to be useful for ultrafast optical networks at frequencies much higher than achievable with other approaches.

Reversing Optical Damage In LiNbO3 Switches

NASA Technical Reports Server (NTRS)

Gee, C. M.; Thurmond, G. D.

1985-01-01

One symptom of optical damage in Ti-diffused LiNbO3 directional-coupler switch reversed by temporarily raising input illumination to higher-thannormal power level. Healing phenomenon used to restore normal operation, increase operating-power rating, and stabilize operating characteristics at lower powers. Higher operating power is tolerated after treatment.

Monolithic MZI-SOA hybrid switch for low-power and low-penalty operation.

PubMed

Cheng, Q; Wonfor, A; Wei, J L; Penty, R V; White, I H

2014-03-15

We report the first experimental demonstration of a monolithically integrated hybrid dilated 2×2 modular optical switch using Mach-Zehnder modulators as low-loss 1×2 switching elements and short semiconductor optical amplifiers to provide additional extinction and gain. An excellent 40 dB cross-talk/extinction ratio is recorded with data-modulated signal-to-noise ratios of up to 44 dB in a 0.1 nm bandwidth. A switching time of 3 ns is demonstrated. Bit error rate studies show extremely low subsystem penalties of less than 0.1 dB, and studies indicate that, by using this hybrid switch building block, an 8×8 port switch could be achieved with 14 dB input power dynamic range for subsystem penalties of less than 0.5 dB.

Principle and verification of novel optical virtual private networks over multiprotocol label switching/optical packet switching networks

NASA Astrophysics Data System (ADS)

Zhang, Chongfu; Wang, Zhengsuan; Jin, Wei; Qiu, Kun

2012-11-01

A novel realization method of the optical virtual private networks (OVPN) over multiprotocol label switching/optical packet switching (MPLS/OPS) networks is proposed. In this scheme, the introduction of MPLS control plane makes OVPN over OPS networks more reliable and easier; OVPN makes use of the concept of high reconfiguration of light-paths offered by MPLS, to set up secure tunnels of high bandwidth across intelligent OPS networks. Through resource management, the signal mechanism, connection control, and the architecture of the creation and maintenance of OVPN are efficiently realized. We also present an OVPN architecture with two traffic priorities, which is used to analyze the capacity, throughput, delay time of the proposed networks, and the packet loss rate performance of the OVPN over MPLS/OPS networks based on full mesh topology. The results validate the applicability of such reliable connectivity to high quality services in the OVPN over MPLS/OPS networks. Along with the results, the feasibility of the approach as the basis for the next generation networks is demonstrated and discussed.

Quantum key based burst confidentiality in optical burst switched networks.

PubMed

Balamurugan, A M; Sivasubramanian, A

2014-01-01

The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

PubMed Central

Balamurugan, A. M.; Sivasubramanian, A.

2014-01-01

The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks. PMID:24578663

Impairments Computation for Routing Purposes in a Transparent-Access Optical Network Based on Optical CDMA and WDM

NASA Astrophysics Data System (ADS)

Musa, Ahmed

2016-06-01

Optical access networks are becoming more widespread and the use of multiple services might require a transparent optical network (TON). Multiplexing and privacy could benefit from the combination of wavelength division multiplexing (WDM) and optical coding (OC) and wavelength conversion in optical switches. The routing process needs to be cognizant of different resource types and characteristics such as fiber types, fiber linear impairments such as attenuation, dispersion, etc. as well as fiber nonlinear impairments such as four-wave mixing, cross-phase modulation, etc. Other types of impairments, generated by optical nodes or photonic switches, also affect the signal quality (Q) or the optical signal to noise ratio (OSNR), which is related to the bit error rate (BER). Therefore, both link and switch impairments must be addressed and somehow incorporated into the routing algorithm. However, it is not practical to fully integrate all photonic-specific attributes in the routing process. In this study, new routing parameters and constraints are defined that reflect the distinct characteristics of photonic networking. These constraints are applied to the design phase of TON and expressed as a cost or metric form that will be used in the network routing algorithm.

Solution processable and optically switchable 1D photonic structures.

PubMed

Paternò, Giuseppe M; Iseppon, Chiara; D'Altri, Alessia; Fasanotti, Carlo; Merati, Giulia; Randi, Mattia; Desii, Andrea; Pogna, Eva A A; Viola, Daniele; Cerullo, Giulio; Scotognella, Francesco; Kriegel, Ilka

2018-02-23

We report the first demonstration of a solution processable, optically switchable 1D photonic crystal which incorporates phototunable doped metal oxide nanocrystals. The resulting device structure shows a dual optical response with the photonic bandgap covering the visible spectral range and the plasmon resonance of the doped metal oxide the near infrared. By means of a facile photodoping process, we tuned the plasmonic response and switched effectively the optical properties of the photonic crystal, translating the effect from the near infrared to the visible. The ultrafast bandgap pumping induces a signal change in the region of the photonic stopband, with recovery times of several picoseconds, providing a step toward the ultrafast optical switching. Optical modeling uncovers the importance of a complete modeling of the variations of the dielectric function of the photodoped material, including the high frequency region of the Drude response which is responsible for the strong switching in the visible after photodoping. Our device configuration offers unprecedented tunability due to flexibility in device design, covering a wavelength range from the visible to the near infrared. Our findings indicate a new protocol to modify the optical response of photonic devices by optical triggers only.

Demonstration of optically controlled data routing with the use of multiple-quantum-well bistable and electro-optical devices.

PubMed

Koppa, P; Chavel, P; Oudar, J L; Kuszelewicz, R; Schnell, J P; Pocholle, J P

1997-08-10

We present experimental results on a 1-to-64-channel free-space photonic switching demonstration system based on GaAs/GaAlAs multiple-quantum-well active device arrays. Two control schemes are demonstrated: data transparent optical self-routing usable in a packet-switching environment and direct optical control with potential signal amplification for circuit switching. The self-routing operation relies on the optical recognition of the binary destination address coded in each packet header. Address decoding is implemented with elementary optical bistable devices and modulator pixels as all-optical latches and electro-optical and gates, respectively. All 60 defect-free channels of the system could be operated one by one, but the simultaneous operation of only three channels could be achieved mainly because of the spatial nonhomogeneities of the devices. Direct-control operation is based on directly setting the bistable device reflectivity with a variable-control beam power. This working mode turned out to be much more tolerant of spatial noises: 37 channels of the system could be operated simultaneously. Further development of the system to a crossbar of N inputs and M outputs and system miniaturization are also considered.

Nonequilibrium optical control of dynamical states in superconducting nanowire circuits.

PubMed

Madan, Ivan; Buh, Jože; Baranov, Vladimir V; Kabanov, Viktor V; Mrzel, Aleš; Mihailovic, Dragan

2018-03-01

Optical control of states exhibiting macroscopic phase coherence in condensed matter systems opens intriguing possibilities for materials and device engineering, including optically controlled qubits and photoinduced superconductivity. Metastable states, which in bulk materials are often associated with the formation of topological defects, are of more practical interest. Scaling to nanosize leads to reduced dimensionality, fundamentally changing the system's properties. In one-dimensional superconducting nanowires, vortices that are present in three-dimensional systems are replaced by fluctuating topological defects of the phase. These drastically change the dynamical behavior of the superconductor and introduce dynamical periodic long-range ordered states when the current is driven through the wire. We report the control and manipulation of transitions between different dynamically stable states in superconducting δ 3 -MoN nanowire circuits by ultrashort laser pulses. Not only can the transitions between different dynamically stable states be precisely controlled by light, but we also discovered new photoinduced hidden states that cannot be reached under near-equilibrium conditions, created while laser photoexcited quasi-particles are outside the equilibrium condition. The observed switching behavior can be understood in terms of dynamical stabilization of various spatiotemporal periodic trajectories of the order parameter in the superconductor nanowire, providing means for the optical control of the superconducting phase with subpicosecond control of timing.

Optofluidic Modulation of Self-Associated Nanostructural Units Forming Planar Bragg Microcavities.

PubMed

Oliva-Ramirez, Manuel; Barranco, Angel; Löffler, Markus; Yubero, Francisco; González-Elipe, Agustin R

2016-01-26

Bragg microcavities (BMs) formed by the successive stacking of nanocolumnar porous SiO2 and TiO2 layers with slanted, zigzag, chiral, and vertical configurations are prepared by physical vapor deposition at oblique angles while azimuthally varying the substrate orientation during the multilayer growth. The slanted and zigzag BMs act as wavelength-selective optical retarders when they are illuminated with linearly polarized light, while no polarization dependence is observed for the chiral and vertical cavities. This distinct optical behavior is attributed to a self-nanostructuration mechanism involving a fence-bundling association of nanocolumns as observed by focused ion beam scanning electron microscopy in the slanted and zigzag microcavities. The outstanding retarder response of the optically active BMs can be effectively modulated by dynamic infiltration of nano- and mesopores with liquids of different refraction indices acting as a switch of the polarization behavior. The unprecedented polarization and tunable optofluidic properties of these nanostructured photonic systems have been successfully simulated with a simple model that assumes a certain birefringence for the individual stacked layers and accounts for the light interference phenomena developed in the BMs. The possibilities of this type of self-arranged nanostructured and optically active BMs for liquid sensing and monitoring applications are discussed.

Nonequilibrium optical control of dynamical states in superconducting nanowire circuits

PubMed Central

Madan, Ivan; Baranov, Vladimir V.

2018-01-01

Optical control of states exhibiting macroscopic phase coherence in condensed matter systems opens intriguing possibilities for materials and device engineering, including optically controlled qubits and photoinduced superconductivity. Metastable states, which in bulk materials are often associated with the formation of topological defects, are of more practical interest. Scaling to nanosize leads to reduced dimensionality, fundamentally changing the system’s properties. In one-dimensional superconducting nanowires, vortices that are present in three-dimensional systems are replaced by fluctuating topological defects of the phase. These drastically change the dynamical behavior of the superconductor and introduce dynamical periodic long-range ordered states when the current is driven through the wire. We report the control and manipulation of transitions between different dynamically stable states in superconducting δ3-MoN nanowire circuits by ultrashort laser pulses. Not only can the transitions between different dynamically stable states be precisely controlled by light, but we also discovered new photoinduced hidden states that cannot be reached under near-equilibrium conditions, created while laser photoexcited quasi-particles are outside the equilibrium condition. The observed switching behavior can be understood in terms of dynamical stabilization of various spatiotemporal periodic trajectories of the order parameter in the superconductor nanowire, providing means for the optical control of the superconducting phase with subpicosecond control of timing. PMID:29670935

Interface and thickness dependent domain switching and stability in Mg doped lithium niobate

DOE PAGES

Neumayer, Sabine M.; Ivanov, Ilia N.; Manzo, Michele; ...

2015-12-08

Controlling ferroelectric switching in Mg doped lithium niobate (Mg: LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switching properties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg: LN above buried PE phases that allow for precise ferroelectric patterning via domain growthmore » control. Furthermore, piezoresponse force microscopy (PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the "up" to the "down" state increases with increasing thickness in pure Mg: LN, whereas the voltage required for stable back switching to the original "up" state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg: LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg: LN layer above due to the presence of uncompensated polarization charge at the PE-Mg: LN boundary. Furthermore, these alterations in internal electric fields within the sample cause long-range lattice distortions in Mg: LN via electromechanical coupling, which were corroborated with complimentary Raman measurements.« less

Interface and thickness dependent domain switching and stability in Mg doped lithium niobate

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

Neumayer, Sabine M.; Rodriguez, Brian J., E-mail: gallo@kth.se, E-mail: brian.rodriguez@ucd.ie; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4

2015-12-14

Controlling ferroelectric switching in Mg doped lithium niobate (Mg:LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switching properties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg:LN above buried PE phases that allow for precise ferroelectric patterning via domain growth control. Furthermore,more » piezoresponse force microscopy (PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the “up” to the “down” state increases with increasing thickness in pure Mg:LN, whereas the voltage required for stable back switching to the original “up” state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg:LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg:LN layer above due to the presence of uncompensated polarization charge at the PE-Mg:LN boundary. These alterations in internal electric fields within the sample cause long-range lattice distortions in Mg:LN via electromechanical coupling, which were corroborated with complimentary Raman measurements.« less

Wavelet-frequency analysis for the detection of discontinuities in switched system models of human balance.

PubMed

Nema, Salam; Kowalczyk, Piotr; Loram, Ian

2017-01-01

This paper is concerned with detecting the presence of switching behavior in experimentally obtained posturographic data sets by means of a novel algorithm that is based on a combination of wavelet analysis and Hilbert transform. As a test-bed for the algorithm, we first use a switched model of human balance control during quiet standing with known switching behavior in four distinct configurations. We obtain a time-frequency representation of a signal generated by our model system. We are then able to detect manifestations of discontinuities (switchings) in the signal as spiking behavior. The frequency of switchings, measured by means of our algorithm and detected in our models systems, agrees with the frequency of spiking behavior found in the experimentally obtained posturographic data. Copyright © 2016. Published by Elsevier B.V.

Electric-field-controlled optical switch using Kerr effect and gradient of the composition ratio Nb/(Ta + Nb)

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

Gong, Dewei, E-mail: deweigong@hit.edu.cn; Liang, Yonggan; Ou, Wenjing

2016-03-15

Highlights: • An abnormal laser deflection phenomenon in KTN crystals is demonstrated. • The origin of the deflection phenomenon was discussed in detail. • By exploiting the deflection, we have designed an optical switch. • The g{sub 11}/g{sub 12} ratio (>10), wavelength range(491–1064 nm), and I–V characteristics (0–800 V) were studied. • The extinction ratio (0–1) and influence of the photorefractive effect were studied. - Abstract: By exploiting the Kerr effect and the gradient of the composition ratio m, Nb/(Ta + Nb) in mol%, in KTa{sub 1−x}Nb{sub x}O{sub 3} (KTN) crystals, we have designed an electric-field-controlled optical switch. The operatingmore » principle of the switch is described. During the switching process, the incident linearly polarized beam is orthogonally deflected as it propagates through the crystals. The g{sub 11}/g{sub 12} ratio (>10), wavelength range (491–1064 nm), I–V characteristics (0–800 V), extinction ratio (0–1), gradient of Curie temperature (21–22.9 °C), response time that may be in ns order, and influence of the photorefractive effect were studied. The results show that our design provides a new kind of optical switch with macro scale (mm order), adjustable extinction ratio (0–1), wide wavelength range (491–1064 nm).« less

Role of annealing on the structural and optical properties of nanostructured diaceto bis-benzimidazole Mn(II) complex thin films

NASA Astrophysics Data System (ADS)

Praveen, P. A.; Babu, R. Ramesh; Ramamurthi, K.

2017-02-01

A coordination complex, manganese incorporated benzimidazole, thin films were prepared by chemical bath deposition method. Structural characterization of the deposited films, carried out by Fourier transform infrared spectroscopy, Raman and electron paramagnetic resonance spectral analyses, reveals the distorted tetrahedral environment of the metal ion with bis-benzimidazole ligand. Further the molecular composition of the deposited metal complex was estimated by energy-dispersive X-ray spectroscopy. The prepared thin films were thermally treated to study the effect of annealing temperature on the surface morphology and the results showed that the surface homogeneity of the films increased for thermally treated films up to 150 °C. But distortion and voids were observed for the films annealed at 200 °C. The Raman analysis reveals the molecular hydrogen bond distortion which leads to the evaporation of the metal complex from the thin film surface with respect to annealing temperature. The linear and nonlinear optical properties of the as prepared and annealed films were studied using ultraviolet-visible transmittance spectroscopy, second harmonic generation and Z-scan analyses. Films annealed at 150 °C show a better linear transmittance in the visible region and larger SHG efficiency and third order nonlinear susceptibility when compared with the other samples. Further, the film annealed at 150 °C was subjected to optical switching analysis and demonstrated to have an inverted switching behavior.

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.

Investigation on nonautonomous soliton management in generalized external potentials via dispersion and nonlinearity

NASA Astrophysics Data System (ADS)

Vijayalekshmi, S.; Mani Rajan, M. S.; Mahalingam, A.; Uthayakumar, A.

2015-09-01

We investigate the controllable behavior of nonautonomous soliton in external potentials with variable dispersion and nonlinearity management functions, which describes the propagation of optical pulses in an inhomogeneous fiber system. We derive the Lax pair with a variable spectral parameter and the exact multi-soliton solution is generated via Darboux transformation. Based on these solutions, several novel optical solitons are constructed by selecting appropriate functions and the main evolution features of these waves are shown by some interesting figures with computer simulation. As few examples, breathers in periodic potential, soliton compression in an exponentially dispersion decreasing fiber and interaction of boomerang solitons are discussed. The presented results have applications in the study of nonautonomous soliton birefringence-managed switching architecture. These results are potentially useful in the management of nonautonomous soliton with external potentials in the optical soliton communications and long-haul telecommunication networks.

Effects of monoclinic symmetry on the properties of biaxial liquid crystals

NASA Astrophysics Data System (ADS)

Solodkov, Nikita V.; Nagaraj, Mamatha; Jones, J. Cliff

2018-04-01

Tilted smectic liquid crystal phases such as the smectic-C phase seen in calamitic liquid crystals are usually treated using the assumption of biaxial orthorhombic symmetry. However, the smectic-C phase has monoclinic symmetry, thereby allowing disassociation of the principal optic and dielectric axes based on symmetry and invariance principles. This is demonstrated here by comparing optical and dielectric measurements for two materials with highly first-order direct transitions from nematic to smectic-C phases. The results show a high difference between the orientations of the principal axes sets, which is interpreted as the existence of two distinct cone angles for optical and dielectric frequencies. Both materials exhibit an increasing degree of monoclinic behavior with decreasing temperature. Due to fast switching speeds, ferroelectric smectic-C* materials are important for fast modulators and LCoS devices, where the dielectric biaxiality influences device operation.

High pulse rate high resolution optical radar system

NASA Technical Reports Server (NTRS)

Goss, W. C.; Burns, R. H.; Chi, K. (Inventor)

1973-01-01

The system is composed of an optical cavity with a laser and a mode locking means to build up an optical pulse. An optical switch is also provided within the cavity to convert the polarization of the optical pulse generated within the cavity. The optical switch comprises an electro-optical crystal driven by a time delayed driver circuit which is triggered by a coincident signal made from an optical pulse signal and a gating pulse signal. The converted optical pulse strikes a polarization sensitive prism and is deflected out of the cavity toward the pending target in the form of a pulse containing most of the optical energy generated by the laser in the pulse build-up period. After striking the target, the reflected energy is picked up by a transceiver with the total travel time of the pulse being recorded.

Transient Evolutional Dynamics of Quantum-Dot Molecular Phase Coherence for Sensitive Optical Switching

NASA Astrophysics Data System (ADS)

Shen, Jian Qi; Gu, Jing

2018-04-01

Atomic phase coherence (quantum interference) in a multilevel atomic gas exhibits a number of interesting phenomena. Such an atomic quantum coherence effect can be generalized to a quantum-dot molecular dielectric. Two quantum dots form a quantum-dot molecule, which can be described by a three-level Λ-configuration model { |0> ,|1> ,|2> } , i.e., the ground state of the molecule is the lower level |0> and the highly degenerate electronic states in the two quantum dots are the two upper levels |1> ,|2> . The electromagnetic characteristics due to the |0>-|1> transition can be controllably manipulated by a tunable gate voltage (control field) that drives the |2>-|1> transition. When the gate voltage is switched on, the quantum-dot molecular state can evolve from one steady state (i.e., |0>-|1> two-level dressed state) to another steady state (i.e., three-level coherent-population-trapping state). In this process, the electromagnetic characteristics of a quantum-dot molecular dielectric, which is modified by the gate voltage, will also evolve. In this study, the transient evolutional behavior of the susceptibility of a quantum-dot molecular thin film and its reflection spectrum are treated by using the density matrix formulation of the multilevel systems. The present field-tunable and frequency-sensitive electromagnetic characteristics of a quantum-dot molecular thin film, which are sensitive to the applied gate voltage, can be utilized to design optical switching devices.

Optical 1's and 2's complement devices using lithium-niobate-based waveguide

NASA Astrophysics Data System (ADS)

Pal, Amrindra; Kumar, Santosh; Sharma, Sandeep

2016-12-01

Optical 1's and 2's complement devices are proposed with the help of lithium-niobate-based Mach-Zehnder interferometers. It has a powerful capability of switching an optical signal from one port to the other port with the help of an electrical control signal. The paper includes the optical conversion scheme using sets of optical switches. 2's complement is common in computer systems and is used in binary subtraction and logical manipulation. The operation of the circuits is studied theoretically and analyzed through numerical simulations. The truth table of these complement methods is verified with the beam propagation method and MATLAB® simulation results.

A novel all-optical label processing based on multiple optical orthogonal codes sequences for optical packet switching networks

NASA Astrophysics Data System (ADS)

Zhang, Chongfu; Qiu, Kun; Xu, Bo; Ling, Yun

2008-05-01

This paper proposes an all-optical label processing scheme that uses the multiple optical orthogonal codes sequences (MOOCS)-based optical label for optical packet switching (OPS) (MOOCS-OPS) networks. In this scheme, each MOOCS is a permutation or combination of the multiple optical orthogonal codes (MOOC) selected from the multiple-groups optical orthogonal codes (MGOOC). Following a comparison of different optical label processing (OLP) schemes, the principles of MOOCS-OPS network are given and analyzed. Firstly, theoretical analyses are used to prove that MOOCS is able to greatly enlarge the number of available optical labels when compared to the previous single optical orthogonal code (SOOC) for OPS (SOOC-OPS) network. Then, the key units of the MOOCS-based optical label packets, including optical packet generation, optical label erasing, optical label extraction and optical label rewriting etc., are given and studied. These results are used to verify that the proposed MOOCS-OPS scheme is feasible.

Probing the electrical switching of a memristive optical antenna by STEM EELS

PubMed Central

Schoen, David T.; Holsteen, Aaron L.; Brongersma, Mark L.

2016-01-01

The scaling of active photonic devices to deep-submicron length scales has been hampered by the fundamental diffraction limit and the absence of materials with sufficiently strong electro-optic effects. Plasmonics is providing new opportunities to circumvent this challenge. Here we provide evidence for a solid-state electro-optical switching mechanism that can operate in the visible spectral range with an active volume of less than (5 nm)3 or ∼10−6 λ3, comparable to the size of the smallest electronic components. The switching mechanism relies on electrochemically displacing metal atoms inside the nanometre-scale gap to electrically connect two crossed metallic wires forming a cross-point junction. These junctions afford extreme light concentration and display singular optical behaviour upon formation of a conductive channel. The active tuning of plasmonic antennas attached to such junctions is analysed using a combination of electrical and optical measurements as well as electron energy loss spectroscopy in a scanning transmission electron microscope. PMID:27412052

Optical switch based on tunable aperture.

PubMed

Li, Lei; Liu, Chao; Wang, Qiong-Hua

2012-08-15

We propose an optical switch based on the electrowetting effect. A transparent oil and a dye-doped water fill a cell. The two liquids are immiscible and form a curved interface. A transparent pillar-shaped platform with a round dome is fixed on the substrate. The dome of the platform is submerged in the water. As a result, light is highly absorbed by the covered water. When the shape of the water is changed, the oil can touch the dome of the platform due to the electrowetting effect. Then the transparent platform and the oil form a channel which can pass through the incident light. Our results show that the system can obtain a high optical attenuation (∼928:1) and reasonable response time (∼47  ms). The diameter of the aperture can be tuned from 0 to ∼3.0  mm. The proposed optical switch has potential application in light shutters, variable optical attenuators, and adaptive irises.

EIT-based all-optical switching and cross-phase modulation under the influence of four-wave mixing.

PubMed

Lee, Meng-Jung; Chen, Yi-Hsin; Wang, I-Chung; Yu, Ite A

2012-05-07

All-optical switching (AOS) or cross-phase modulation (XPM) based on the effect of electromagnetically induced transparency (EIT) makes one photon switched or phase-modulated by another possible. The existence of four-wave mixing (FWM) process greatly diminishes the switching or phase-modulation efficiency and hinders the single-photon operation. We proposed and experimentally demonstrated an idea that with an optimum detuning the EIT-based AOS can be completely intact even under the influence of FWM. The results of the work can be directly applied to the EIT-based XPM. Our work makes the AOS and XPM schemes more flexible and the single-photon operation possible in FWM-allowed systems.

Demonstration of optical computing logics based on binary decision diagram.

PubMed

Lin, Shiyun; Ishikawa, Yasuhiko; Wada, Kazumi

2012-01-16

Optical circuits are low power consumption and fast speed alternatives for the current information processing based on transistor circuits. However, because of no transistor function available in optics, the architecture for optical computing should be chosen that optics prefers. One of which is Binary Decision Diagram (BDD), where signal is processed by sending an optical signal from the root through a serial of switching nodes to the leaf (terminal). Speed of optical computing is limited by either transmission time of optical signals from the root to the leaf or switching time of a node. We have designed and experimentally demonstrated 1-bit and 2-bit adders based on the BDD architecture. The switching nodes are silicon ring resonators with a modulation depth of 10 dB and the states are changed by the plasma dispersion effect. The quality, Q of the rings designed is 1500, which allows fast transmission of signal, e.g., 1.3 ps calculated by a photon escaping time. A total processing time is thus analyzed to be ~9 ps for a 2-bit adder and would scales linearly with the number of bit. It is two orders of magnitude faster than the conventional CMOS circuitry, ~ns scale of delay. The presented results show the potential of fast speed optical computing circuits.

Structural characterizations, Hirshfeld surface analyses, and third-order nonlinear optical properties of two novel chalcone derivatives

NASA Astrophysics Data System (ADS)

Maidur, Shivaraj R.; Jahagirdar, Jitendra R.; Patil, Parutagouda Shankaragouda; Chia, Tze Shyang; Quah, Ching Kheng

2018-01-01

We report synthesis, characterizations, structure-property relationships, and third-order nonlinear optical studies for two new chalcone derivatives, (2E)-1-(anthracen-9-yl)-3-(4-bromophenyl)prop-2-en-1-one (Br-ANC) and (2E)-1-(anthracen-9-yl)-3-(4-chlorophenyl)prop-2-en-1-one (Cl-ANC). These derivatives were crystallized in the centrosymmetric monoclinic P21/c crystal structure. The intermolecular interactions of both the crystals were visualized by Hirshfeld surface analyses (HSA). The crystals are thermally stable up to their melting points (180.82 and 191.16 °C for Cl-ANC and Br-ANC, respectively). The geometry optimizations, FT-IR spectra, 1H and 13C NMR spectra, electronic absorption spectra, electronic transitions, and HOMO-LUMO energy gaps were studied by Density Functional Theory (DFT) at B3LYP/6-311+G(d, p) level. The theoretical results provide excellent agreement with experimental findings. The electric dipole moments, static polarizabilities, molecular electrostatic potentials (MEP) and global chemical reactivity descriptors (GCRD) were also theoretically computed. The materials exhibited good nonlinear absorption (NLA), nonlinear refraction (NLR) and optical limiting (OL) behavior under diode-pumped solid-state (DPSS) continuous wave (CW) laser excitation (532 nm and 200 mW). The NLO parameters such as NLA coefficient (β∼10-5 cmW-1), NLR index (n2∼10-10 cm2 W-1) and third-order NLO susceptibilities (χ(3) ∼10-7 esu) were measured. Further, we estimated one-photon and two-photon figures of merit, which satisfy the demands (W > 1 and T < 1) for all-optical switching. Thus, the present chalcone derivatives with anthracene moiety are potential materials for OL and optical switching applications.

Apparatus for weighing and identifying characteristics of a moving vehicle

DOEpatents

Muhs, Jeffrey D.; Jordan, John K.; Tobin, Jr., Kenneth W.; LaForge, John V.

1993-01-01

Apparatus for weighing a vehicle in motion is provided by employing a plurality of elongated fiber-optic sensors defined by an optical fiber embedded in an encasement of elastomeric material and disposed parallel to each other on the roadway in the path of moving vehicles. Each fiber-optic sensor is provided with contact grid means which can be selectively altered to provide the fiber-optic sensors with sensitivities to vehicular weight different from each other for weighing vehicles in an extended weight range. Switch means are used in conjunction with the fiber-optic sensors to provide signals indicative of the speed of the moving vehicle, the number of axles on the vehicle, weight distribution, tire position, and the wheelbase of the vehicle. The use of a generally N-shaped configuration of switch means also provides a determination of the number of tires on each axle and the tire footprint. When switch means in this configuration are formed of optical fibers, the extent of light transmission through the fibers during contact with the tires of the vehicle is indicative of the vehicle weight.

Apparatus for weighing and identifying characteristics of a moving vehicle

DOEpatents

Muhs, J.D.; Jordan, J.K.; Tobin, K.W. Jr.; LaForge, J.V.

1993-11-09

Apparatus for weighing a vehicle in motion is provided by employing a plurality of elongated fiber-optic sensors defined by an optical fiber embedded in an encasement of elastomeric material and disposed parallel to each other on the roadway in the path of moving vehicles. Each fiber-optic sensor is provided with contact grid means which can be selectively altered to provide the fiber-optic sensors with sensitivities to vehicular weight different from each other for weighing vehicles in an extended weight range. Switch means are used in conjunction with the fiber-optic sensors to provide signals indicative of the speed of the moving vehicle, the number of axles on the vehicle, weight distribution, tire position, and the wheelbase of the vehicle. The use of a generally N-shaped configuration of switch means also provides a determination of the number of tires on each axle and the tire footprint. When switch means in this configuration are formed of optical fibers, the extent of light transmission through the fibers during contact with the tires of the vehicle is indicative of the vehicle weight. 15 figures.

Multi-line triggering and interdigitated electrode structure for photoconductive semiconductor switches

DOEpatents

Mar, Alan [Albuquerque, NM; Zutavern, Fred J [Albuquerque, NM; Loubriel, Guillermo [Albuquerque, NM

2007-02-06

An improved photoconductive semiconductor switch comprises multiple-line optical triggering of multiple, high-current parallel filaments between the switch electrodes. The switch can also have a multi-gap, interdigitated electrode for the generation of additional parallel filaments. Multi-line triggering can increase the switch lifetime at high currents by increasing the number of current filaments and reducing the current density at the contact electrodes in a controlled manner. Furthermore, the improved switch can mitigate the degradation of switching conditions with increased number of firings of the switch.

3-DIMENSIONAL Optoelectronic

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Ashok Venketaraman

This thesis covers the design, analysis, optimization, and implementation of optoelectronic (N,M,F) networks. (N,M,F) networks are generic space-division networks that are well suited to implementation using optoelectronic integrated circuits and free-space optical interconnects. An (N,M,F) networks consists of N input channels each having a fanout F_{rm o}, M output channels each having a fanin F_{rm i}, and Log_{rm K}(N/F) stages of K x K switches. The functionality of the fanout, switching, and fanin stages depends on the specific application. Three applications of optoelectronic (N,M,F) networks are considered. The first is an optoelectronic (N,1,1) content -addressable memory system that achieves associative recall on two-dimensional images retrieved from a parallel-access optical memory. The design and simulation of the associative memory are discussed, and an experimental emulation of a prototype system using images from a parallel-readout optical disk is presented. The system design provides superior performance to existing electronic content-addressable memory chips in terms of capacity and search rate, and uses readily available optical disk and VLSI technologies. Next, a scalable optoelectronic (N,M,F) neural network that uses free-space holographic optical interconnects is presented. The neural architecture minimizes the number of optical transmitters needed, and provides accurate electronic fanin with low signal skew, and dendritic-type fan-in processing capability in a compact layout. Optimal data-encoding methods and circuit techniques are discussed. The implementation of an prototype optoelectronic neural system, and its application to a simple recognition task is demonstrated. Finally, the design, analysis, and optimization of a (N,N,F) self-routing, packet-switched multistage interconnection network is described. The network is suitable for parallel computing and broadband switching applications. The tradeoff between optical and electronic interconnects is examined quantitatively by varying the electronic switch size K. The performance of the (N,N,F) network versus the fanning parameter F, is also analyzed. It is shown that the optoelectronic (N,N,F) networks provide a range of performance-cost alternatives, and offer superior performance-per-cost to fully electronic switching networks and to previous networks designs.

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.

Electro-optic harmonic conversion to switch a laser beam out of a cavity

DOEpatents

Haas, Roger A.; Henesian, Mark A.

1987-01-01

The invention is a switch to permit a laser beam to escape a laser cavity through the use of an externally applied electric field across a harmonic conversion crystal. Amplification takes place in the laser cavity, and then the laser beam is switched out by the laser light being harmonically converted with dichroic or polarization sensitive elements present to alter the optical path of the harmonically converted laser light. Modulation of the laser beam can also be accomplished by varying the external electric field.

Beam Switching of an Nd:YAG Laser Using Domain-Engineered Prisms in Magnesium-Oxide-Doped Congruent Lithium Niobate

DTIC Science & Technology

2010-08-01

In this work, a novel electro - optic beam switch (EOBS) is designed, fabricated and demonstrated. The EOBS presented in this work is designed for a...consists of a series of electronically controlled prisms fabricated by ferroelectric domain inversion in an electro - optic crystal wafer. The prisms are

Fast all-optical switch

NASA Technical Reports Server (NTRS)

Shay, Thomas M. (Inventor); Poliakov, Evgeni Y. (Inventor); Hazzard, David A. (Inventor)

2001-01-01

An apparatus and method wherein polarization rotation in alkali vapors or other mediums is used for all-optical switching and digital logic and where the rate of operation is proportional to the amplitude of the pump field. High rates of speed are accomplished by Rabi flopping of the atomic states using a continuously operating monochromatic atomic beam as the pump.

High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

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

Chun, Young Tea; Chu, Daping, E-mail: dpc31@cam.ac.uk; Neeves, Matthew

2014-11-10

High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO{sub x} thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm{sup 2}, exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.

High-speed spectral domain polarization-sensitive OCT using a single InGaAs line-scan camera and an optical switch

NASA Astrophysics Data System (ADS)

Lee, Sang-Won; Jeong, Hyun-Woo; Kim, Beop-Min

2010-02-01

We demonstrated high-speed spectral domain polarization-sensitive optical coherence tomography (SD-PSOCT) using a single InGaAs line-scan camera and an optical switch at 1.3-μm region. The polarization-sensitive low coherence interferometer in the system was based on the original free-space PS-OCT system published by Hee et al. The horizontal and vertical polarization light rays split by polarization beam splitter were delivered and detected via an optical switch to a single spectrometer by turns instead of dual spectrometers. The SD-PSOCT system had an axial resolution of 8.2 μm, a sensitivity of 101.5 dB, and an acquisition speed of 23,496 Alines/s. We obtained the intensity, phase retardation, and fast axis orientation images of a biological tissue. In addition, we calculated the averaged axial profiles of the phase retardation in human skin.

Yb- and Er-doped fiber laser Q-switched with an optically uniform, broadband WS2 saturable absorber

PubMed Central

Zhang, M.; Hu, Guohua; Hu, Guoqing; Howe, R. C. T.; Chen, L.; Zheng, Z.; Hasan, T.

2015-01-01

We demonstrate a ytterbium (Yb) and an erbium (Er)-doped fiber laser Q-switched by a solution processed, optically uniform, few-layer tungsten disulfide saturable absorber (WS2-SA). Nonlinear optical absorption of the WS2-SA in the sub-bandgap region, attributed to the edge-induced states, is characterized by 3.1% and 4.9% modulation depths with 1.38 and 3.83 MW/cm2 saturation intensities at 1030 and 1558 nm, respectively. By integrating the optically uniform WS2-SA in the Yb- and Er-doped laser cavities, we obtain self-starting Q-switched pulses with microsecond duration and kilohertz repetition rates at 1030 and 1558 nm. Our work demonstrates broadband sub-bandgap saturable absorption of a single, solution processed WS2-SA, providing new potential efficacy for WS2 in ultrafast photonic applications. PMID:26657601

Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection

PubMed Central

Zhang, Qinduan; Chang, Jun; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

2017-01-01

We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f0 = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C2H2) to select the laser wavelength. The system achieved a linear response (R2 = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times. PMID:29295599

Novel Integration of a 6t Cryogen-Free Magneto-Optical System with a Variable Temperature Sample Using a Single Cryocooler

NASA Astrophysics Data System (ADS)

Berryhill, A. B.; Coffey, D. M.; McGhee, R. W.; Burkhardt, E. E.

2008-03-01

Cryomagnetics' new "C-Mag Optical" Magneto-Optic Property Measurement System is a versatile materials and device characterization system that allows the researcher to simultaneously control the applied magnetic field and temperature of a sample while studying its electrical and optic properties. The system integrates a totally liquid cryogen-free 6T superconducting split-pair magnet with a variable temperature sample space, both cooled using a single 4.2K pulse tube refrigerator. To avoid warming the magnet when operating a sample at elevated temperatures, a novel heat switch was developed. The heat switch allows the sample temperature to be varied from 10K to 300K while maintaining the magnet at 4.2K or below. In this paper, the design and performance of the overall magnet system and the heat switch will be presented. New concepts for the next generation system will also be discussed.

All-optical routing and switching for three-dimensional photonic circuitry

PubMed Central

Keil, Robert; Heinrich, Matthias; Dreisow, Felix; Pertsch, Thomas; Tünnermann, Andreas; Nolte, Stefan; Christodoulides, Demetrios N.; Szameit, Alexander

2011-01-01

The ability to efficiently transmit and rapidly process huge amounts of data has become almost indispensable to our daily lives. It turned out that all-optical networks provide a very promising platform to deal with this task. Within such networks opto-optical switches, where light is directed by light, are a crucial building block for an effective operation. In this article, we present an experimental analysis of the routing and switching behaviour of light in two-dimensional evanescently coupled waveguide arrays of Y- and T-junction geometries directly inscribed into fused silica using ultrashort laser pulses. These systems have the fundamental advantage of supporting three-dimensional network topologies, thereby breaking the limitations on complexity associated with planar structures while maintaining a high dirigibility of the light. Our results show how such arrays can be used to control the flow of optical signals within integrated photonic circuits. PMID:22355612

A liquid lens switching-based motionless variable fiber-optic delay line

NASA Astrophysics Data System (ADS)

Khwaja, Tariq Shamim; Reza, Syed Azer; Sheikh, Mumtaz

2018-05-01

We present a Variable Fiber-Optic Delay Line (VFODL) module capable of imparting long variable delays by switching an input optical/RF signal between Single Mode Fiber (SMF) patch cords of different lengths through a pair of Electronically Controlled Tunable Lenses (ECTLs) resulting in a polarization-independent operation. Depending on intended application, the lengths of the SMFs can be chosen accordingly to achieve the desired VFODL operation dynamic range. If so desired, the state of the input signal polarization can be preserved with the use of commercially available polarization-independent ECTLs along with polarization-maintaining SMFs (PM-SMFs), resulting in an output polarization that is identical to the input. An ECTL-based design also improves power consumption and repeatability. The delay switching mechanism is electronically-controlled, involves no bulk moving parts, and can be fully-automated. The VFODL module is compact due to the use of small optical components and SMFs that can be packaged compactly.

Monolithically integrated all-optical gate switch using intersubband transition in InGaAs/AlAsSb coupled double quantum wells.

PubMed

Akimoto, Ryoichi; Gozu, Shin-ichiro; Mozume, Teruo; Ishikawa, Hiroshi

2011-07-04

We have developed a compact all-optical gate switch with a footprint less than 1 mm2, in which an optical nonlinear waveguide using cross-phase-modulation associated with intersubband transition in InGaAs/AlGaAs/AlAsSb coupled double quantum wells and a Michelson interferometer (MI) are monolithically integrated on an InP chip. The MI configuration allows a transverse magnetic pump light direct access to an MI arm for phase modulation while passive photonic integrated circuits serve a transverse electric signal light. Full switching of the π-rad nonlinear phase shift is achieved with a pump pulse energy of 8.6 pJ at a 10-GHz repetition rate. We also demonstrate all-optical demultiplexing of a 160-Gb/s signal to a 40-Gb/s signal.

Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection.

PubMed

Zhang, Qinduan; Chang, Jun; Wang, Qiang; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

2017-12-25

We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f ₀ = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C₂H₂) to select the laser wavelength. The system achieved a linear response (R² = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

Sub-Shot-Noise Transmission Measurement Enabled by Active Feed-Forward of Heralded Single Photons

NASA Astrophysics Data System (ADS)

Sabines-Chesterking, J.; Whittaker, R.; Joshi, S. K.; Birchall, P. M.; Moreau, P. A.; McMillan, A.; Cable, H. V.; O'Brien, J. L.; Rarity, J. G.; Matthews, J. C. F.

2017-07-01

Harnessing the unique properties of quantum mechanics offers the possibility of delivering alternative technologies that can fundamentally outperform their classical counterparts. These technologies deliver advantages only when components operate with performance beyond specific thresholds. For optical quantum metrology, the biggest challenge that impacts on performance thresholds is optical loss. Here, we demonstrate how including an optical delay and an optical switch in a feed-forward configuration with a stable and efficient correlated photon-pair source reduces the detector efficiency required to enable quantum-enhanced sensing down to the detection level of single photons and without postselection. When the switch is active, we observe a factor of improvement in precision of 1.27 for transmission measurement on a per-input-photon basis compared to the performance of a laser emitting an ideal coherent state and measured with the same detection efficiency as our setup. When the switch is inoperative, we observe no quantum advantage.

All-optical switching in GaAs microdisk resonators by a femtosecond pump-probe technique through tapered-fiber coupling.

PubMed

Lin, Yen-Chih; Mao, Ming-Hua; Lin, You-Ru; Lin, Hao-Hsiung; Lin, Che-An; Wang, Lon A

2014-09-01

We demonstrate ultrafast all-optical switching in GaAs microdisk resonators using a femtosecond pump-probe technique through tapered-fiber coupling. The temporal tuning of the resonant modes resulted from the refractive index change due to photoexcited carrier density variation inside the GaAs microdisk resonator. Transmission through the GaAs microdisk resonator can be modulated by more than 10 dB with a switching time window of 8 ps in the switch-off operation using pumping pulses with energies as low as 17.5 pJ. The carrier lifetime was fitted to be 42 ps, much shorter than that of the bulk GaAs, typically of the order of nanoseconds. The above observation indicates that the surface recombination plays an important role in increasing the switching speed.

Programmable on-chip and off-chip network architecture on demand for flexible optical intra-datacenters.

PubMed

Rofoee, Bijan Rahimzadeh; Zervas, Georgios; Yan, Yan; Amaya, Norberto; Qin, Yixuan; Simeonidou, Dimitra

2013-03-11

The paper presents a novel network architecture on demand approach using on-chip and-off chip implementations, enabling programmable, highly efficient and transparent networking, well suited for intra-datacenter communications. The implemented FPGA-based adaptable line-card with on-chip design along with an architecture on demand (AoD) based off-chip flexible switching node, deliver single chip dual L2-Packet/L1-time shared optical network (TSON) server Network Interface Cards (NIC) interconnected through transparent AoD based switch. It enables hitless adaptation between Ethernet over wavelength switched network (EoWSON), and TSON based sub-wavelength switching, providing flexible bitrates, while meeting strict bandwidth, QoS requirements. The on and off-chip performance results show high throughput (9.86Ethernet, 8.68Gbps TSON), high QoS, as well as hitless switch-over.

BCAT (Binary Colloid Alloy Test) experiment documentation

NASA Image and Video Library

2009-05-02

ISS019-E-013241 (2 May 2009) --- Astronaut Michael Barratt, Expedition 19/20 flight engineer, prepares to photograph Binodal Colloidal Aggregation Test?4 (BCAT-4) experiment samples in the Destiny laboratory of the International Space Station. This experiment studies the long-term behavior of colloids ? fine particles suspended in a fluid in a microgravity environment, where the effects of sedimentation and convention are removed. Results from this study may lead to new colloid materials with applications in the communications and computer industries for switches, displays and optical devices with properties that could rival those of lasers.

BCAT (Binary Colloid Alloy Test) experiment documentation

NASA Image and Video Library

2009-05-02

ISS019-E-013240 (2 May 2009) --- Astronaut Michael Barratt, Expedition 19/20 flight engineer, conducts a session with the Binodal Colloidal Aggregation Test?4 (BCAT-4) in the Destiny laboratory of the International Space Station. This experiment studies the long-term behavior of colloids ? fine particles suspended in a fluid in a microgravity environment, where the effects of sedimentation and convention are removed. Results from this study may lead to new colloid materials with applications in the communications and computer industries for switches, displays and optical devices with properties that could rival those of lasers.

Behavioral plasticity through the modulation of switch neurons.

PubMed

Vassiliades, Vassilis; Christodoulou, Chris

2016-02-01

A central question in artificial intelligence is how to design agents capable of switching between different behaviors in response to environmental changes. Taking inspiration from neuroscience, we address this problem by utilizing artificial neural networks (NNs) as agent controllers, and mechanisms such as neuromodulation and synaptic gating. The novel aspect of this work is the introduction of a type of artificial neuron we call "switch neuron". A switch neuron regulates the flow of information in NNs by selectively gating all but one of its incoming synaptic connections, effectively allowing only one signal to propagate forward. The allowed connection is determined by the switch neuron's level of modulatory activation which is affected by modulatory signals, such as signals that encode some information about the reward received by the agent. An important aspect of the switch neuron is that it can be used in appropriate "switch modules" in order to modulate other switch neurons. As we show, the introduction of the switch modules enables the creation of sequences of gating events. This is achieved through the design of a modulatory pathway capable of exploring in a principled manner all permutations of the connections arriving on the switch neurons. We test the model by presenting appropriate architectures in nonstationary binary association problems and T-maze tasks. The results show that for all tasks, the switch neuron architectures generate optimal adaptive behaviors, providing evidence that the switch neuron model could be a valuable tool in simulations where behavioral plasticity is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

All-optical encryption based on interleaved waveband switching modulation for optical network security.

PubMed

Fok, Mable P; Prucnal, Paul R

2009-05-01

All-optical encryption for optical code-division multiple-access systems with interleaved waveband-switching modulation is experimentally demonstrated. The scheme explores dual-pump four-wave mixing in a 35 cm highly nonlinear bismuth oxide fiber to achieve XOR operation of the plaintext and the encryption key. Bit 0 and bit 1 of the encrypted data are represented by two different wavebands. Unlike on-off keying encryption methods, the encrypted data in this approach has the same intensity for both bit 0 and bit 1. Thus no plaintext or ciphertext signatures are observed.

Rapid updating of optical arbitrary waveforms via time-domain multiplexing.

PubMed

Scott, R P; Fontaine, N K; Yang, C; Geisler, D J; Okamoto, K; Heritage, J P; Yoo, S J B

2008-05-15

We demonstrate high-fidelity optical arbitrary waveform generation with 5 GHz waveform switching via time-domain multiplexing. Compact, integrated waveform shapers based on silica arrayed-waveguide grating pairs with 10 GHz channel spacing are used to shape (line-by-line) two different waveforms from the output of a 10-mode x 10 GHz optical frequency comb generator. Characterization of the time multiplexer's complex transfer function (amplitude and phase) by frequency-resolved optical gating permits compensation of its impact on the switched waveforms and matching of the measured and target waveforms to better than G'=5%.

Nanomechanical Optical Fiber with Embedded Electrodes Actuated by Joule Heating.

PubMed

Lian, Zhenggang; Segura, Martha; Podoliak, Nina; Feng, Xian; White, Nicholas; Horak, Peter

2014-07-31

Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We demonstrate optical switching between the two fiber cores by Joule heating of the electrodes with as little as 0.4 W electrical power, thereby demonstrating an electrically actuated all-fiber microelectromechanical system (MEMS). Simulations show that the main mechanism for optical switching is the transverse thermal expansion of the fiber structure.

Method of bistable optical information storage using antiferroelectric phase PLZT ceramics

DOEpatents

Land, Cecil E.

1990-01-01

A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.

Method of bistable optical information storage using antiferroelectric phase PLZT ceramics

DOEpatents

Land, C.E.

1990-07-31

A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field. 8 figs.

Realization of all-optical switch and diode via Raman gain process using a Kerr field

NASA Astrophysics Data System (ADS)

Abbas, Muqaddar; Qamar, Sajid; Qamar, Shahid

2016-08-01

The idea of optical photonic crystal, which is generated using two counter-propagating fields, is revisited to study gain-assisted all-optical switch and diode using Kerr field. Two counter-propagating fields with relative detuning Δ ν generate standing-wave field pattern which interacts with a four-level atomic system. The standing-wave field pattern acts like a static photonic crystal for Δ ν =0 , however, it behaves as a moving photonic crystal for Δ ν \

Phase-sensitive fiber-based parametric all-optical switch.

PubMed

Parra-Cetina, Josué; Kumpera, Aleš; Karlsson, Magnus; Andrekson, Peter A

2015-12-28

We experimentally demonstrate, for the first time, an all-optical switch in a phase-sensitive fiber optic parametric amplifier operated in saturation. We study the effect of phase variation of the signal and idler waves on the pump power depletion. By changing the phase of a 0.9 mW signal/idler pair wave by π/2 rad, a pump power extinction ratio of 30.4 dB is achieved. Static and dynamic characterizations are also performed and time domain results presented.

Tunable optical switching in the near-infrared spectral regime by employing plasmonic nanoantennas containing phase change materials.

PubMed

Savaliya, Priten B; Thomas, Arun; Dua, Rishi; Dhawan, Anuj

2017-10-02

We propose the design of switchable plasmonic nanoantennas (SPNs) that can be employed for optical switching in the near-infrared regime. The proposed SPNs consist of nanoantenna structures made up of a plasmonic metal (gold) such that these nanoantennas are filled with a switchable material (vanadium dioxide). We compare the results of these SPNs with inverted SPN structures that consist of gold nanoantenna structures surrounded by a layer of vanadium dioxide (VO 2 ) on their outer surface. These nanoantennas demonstrate switching of electric-field intensity enhancement (EFIE) between two states (On and Off states), which can be induced thermally, optically or electrically. The On and Off states of the nanoantennas correspond to the metallic and semiconductor states, respectively of the VO 2 film inside or around the nanoantennas, as the VO 2 film exhibits phase transition from its semiconductor state to the metallic state upon application of thermal, optical, or electrical energy. We employ finite-difference time-domain (FDTD) simulations to demonstrate switching in the EFIE for four different SPN geometries - nanorod-dipole, bowtie, planar trapezoidal toothed log-periodic, and rod-disk - and compare their near-field distributions for the On and Off states of the SPNs. We also demonstrate that the resonance wavelength of the EFIE spectra gets substantially modified when these SPNs switch between the two states.

A Solution-Processed Ultrafast Optical Switch Based on a Nanostructured Epsilon-Near-Zero Medium.

PubMed

Guo, Qiangbing; Cui, Yudong; Yao, Yunhua; Ye, Yuting; Yang, Yue; Liu, Xueming; Zhang, Shian; Liu, Xiaofeng; Qiu, Jianrong; Hosono, Hideo

2017-07-01

All the optical properties of materials are derived from dielectric function. In spectral region where the dielectric permittivity approaches zero, known as epsilon-near-zero (ENZ) region, the propagating light within the material attains a very high phase velocity, and meanwhile the material exhibits strong optical nonlinearity. The interplay between the linear and nonlinear optical response in these materials thus offers unprecedented pathways for all-optical control and device design. Here the authors demonstrate ultrafast all-optical modulation based on a typical ENZ material of indium tin oxide (ITO) nanocrystals (NCs), accessed by a wet-chemistry route. In the ENZ region, the authors find that the optical response in these ITO NCs is associated with a strong nonlinear character, exhibiting sub-picosecond response time (corresponding to frequencies over 2 THz) and modulation depth up to ≈160%. This large optical nonlinearity benefits from the highly confined geometry in addition to the ENZ enhancement effect of the ITO NCs. Based on these ENZ NCs, the authors successfully demonstrate a fiber optical switch that allows switching of continuous laser wave into femtosecond laser pulses. Combined with facile processibility and tunable optical properties, these solution-processed ENZ NCs may offer a scalable and printable material solution for dynamic photonic and optoelectronic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Approach to Realize of All Optical Frequency Encoded Dibit Based XOR and XNOR Logic Gates Using Optical Switches with Simulated Verification

NASA Astrophysics Data System (ADS)

Ghosh, B.; Hazra, S.; Haldar, N.; Roy, D.; Patra, S. N.; Swarnakar, J.; Sarkar, P. P.; Mukhopadhyay, S.

2018-03-01

Since last few decades optics has already proved its strong potentiality for conducting parallel logic, arithmetic and algebraic operations due to its super-fast speed in communication and computation. So many different logical and sequential operations using all optical frequency encoding technique have been proposed by several authors. Here, we have keened out all optical dibit representation technique, which has the advantages of high speed operation as well as reducing the bit error problem. Exploiting this phenomenon, we have proposed all optical frequency encoded dibit based XOR and XNOR logic gates using the optical switches like add/drop multiplexer (ADM) and reflected semiconductor optical amplifier (RSOA). Also the operations of these gates have been verified through proper simulation using MATLAB (R2008a).

Polarization and Thickness Dependent Absorption Properties of Black Phosphorus: New Saturable Absorber for Ultrafast Pulse Generation

PubMed Central

Li, Diao; Jussila, Henri; Karvonen, Lasse; Ye, Guojun; Lipsanen, Harri; Chen, Xianhui; Sun, Zhipei

2015-01-01

Black phosphorus (BP) has recently been rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of BP flakes. We observe that both the linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness in BP, completely different from other typical two-dimensional layered materials (e.g., graphene and the most studied transition metal dichalcogenides). We then use the nonlinear optical properties of BP for ultrafast (pulse duration down to ~786 fs in mode-locking) and large-energy (pulse energy up to >18 nJ in Q-switching) pulse generation in fiber lasers at the near-infrared telecommunication band ~1.5 μm. We observe that the output of our BP based pulsed lasers is linearly polarized (with a degree-of-polarization ~98% in mode-locking, >99% in Q-switching, respectively) due to the anisotropic optical property of BP. Our results underscore the relatively large optical nonlinearity of BP with unique polarization and thickness dependence, and its potential for polarized optical pulse generation, paving the way to BP based nonlinear and ultrafast photonic applications (e.g., ultrafast all-optical polarization switches/modulators, frequency converters etc.). PMID:26514090

Ultrafast optomechanical pulse picking

NASA Astrophysics Data System (ADS)

Lilienfein, Nikolai; Holzberger, Simon; Pupeza, Ioachim

2017-01-01

State-of-the-art optical switches for coupling pulses into and/or out of resonators are based on either the electro-optic or the acousto-optic effect in transmissive elements. In high-power applications, the damage threshold and other nonlinear and thermal effects in these elements impede further improvements in pulse energy, duration, and average power. We propose a new optomechanical switching concept which is based solely on reflective elements and is suitable for switching times down to the ten-nanosecond range. To this end, an isolated section of a beam path is moved in a system comprising mirrors rotating at a high angular velocity and stationary imaging mirrors, without affecting the propagation of the beam thereafter. We discuss three variants of the concept and exemplify practical parameters for its application in regenerative amplifiers and stack-and-dump enhancement cavities. We find that optomechanical pulse picking has the potential to achieve switching rates of up to a few tens of kilohertz while supporting pulse energies of up to several joules.

Three-dimensional structure and multistable optical switching of triple-twisted particle-like excitations in anisotropic fluids.

PubMed

Smalyukh, Ivan I; Lansac, Yves; Clark, Noel A; Trivedi, Rahul P

2010-02-01

Control of structures in soft materials with long-range order forms the basis for applications such as displays, liquid-crystal biosensors, tunable lenses, distributed feedback lasers, muscle-like actuators and beam-steering devices. Bistable, tristable and multistable switching of well-defined structures of molecular alignment is of special interest for all of these applications. Here we describe the facile optical creation and multistable switching of localized configurations in the molecular orientation field of a chiral nematic anisotropic fluid. These localized chiro-elastic particle-like excitations--dubbed 'triple-twist torons'--are generated by vortex laser beams and embed the localized three-dimensional (3D) twist into a uniform background. Confocal polarizing microscopy and computer simulations reveal their equilibrium internal structures, manifesting both skyrmion-like and Hopf fibration features. Robust generation of torons at predetermined locations combined with both optical and electrical reversible switching can lead to new ways of multistable structuring of complex photonic architectures in soft materials.

Efficient 2-μm Tm:YAP Q-switched and CW lasers

NASA Astrophysics Data System (ADS)

Hays, A. D.; Cole, Brian; King, Vernon; Goldberg, Lew

2018-02-01

Highly efficient, diode pumped Tm:YAP lasers generating emission in the 1.85-1.94 μm range are demonstrated and characterized. Laser optical efficiencies of 51% and 45%, and electrical efficiencies of 31% and 25% are achieved under CW and Q-switched operation, respectively. Laser performance was characterized for maximum average powers up to 20W with various cavity configurations, all using an intra-cavity lens to compensate for thermal lensing in the Tm:YAP crystal. Q-switched lasers incorportating a Cr:ZnS saturable absorber (SA), resonant mechanical mirror scanner, or acousto-optic modulator were characterized. To enable higher average output powers, measurements of the thermal lens were conducted for the Tm:YAP crystal as a function of pump power and were compared to values predicted by a finiteelement- analysis (FEA) thermal-optical model of the Tm:YAP crystal. A resonator model is developed to incorporate this calculated thermal lens and its effect on laser performance. This paper will address approaches for improving the performance of Tm:YAP lasers, and means for achieving increased average output powers while maintaining high optical efficiency for both SA and mechanical Q-switching.

Ultra-compact and wide-spectrum-range thermo-optic switch based on silicon coupled photonic crystal microcavities

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

Zhang, Xingyu, E-mail: xzhang@utexas.edu, E-mail: swapnajit.chakravarty@omegaoptics.com, E-mail: chenrt@austin.utexas.edu; Chung, Chi-Jui; Pan, Zeyu

2015-11-30

We design, fabricate, and experimentally demonstrate a compact thermo-optic gate switch comprising a 3.78 μm-long coupled L0-type photonic crystal microcavities on a silicon-on-insulator substrate. A nanohole is inserted in the center of each individual L0 photonic crystal microcavity. Coupling between identical microcavities gives rise to bonding and anti-bonding states of the coupled photonic molecules. The coupled photonic crystal microcavities are numerically simulated and experimentally verified with a 6 nm-wide flat-bottom resonance in its transmission spectrum, which enables wider operational spectrum range than microring resonators. An integrated micro-heater is in direct contact with the silicon core to efficiently drive the device. The thermo-opticmore » switch is measured with an optical extinction ratio of 20 dB, an on-off switching power of 18.2 mW, a thermo-optic tuning efficiency of 0.63 nm/mW, a rise time of 14.8 μs, and a fall time of 18.5 μs. The measured on-chip loss on the transmission band is as low as 1 dB.« less

Compact optical switch based on 2D photonic crystal and magneto-optical cavity.

PubMed

Dmitriev, Victor; Kawakatsu, Marcelo N; Portela, Gianni

2013-04-01

A compact optical switch based on a 2D photonic crystal (PhC) and a magneto-optical cavity is suggested and analyzed. The cavity is coupled to two parallel and misaligned PC waveguides and operates with dipole mode. When the cavity is nonmagnetized, the dipole mode excited by a signal in the input waveguide has a node in the output waveguide. Therefore, the input signal is reflected from the cavity. This corresponds to the state off of the switch. Normal to the plane of the PhC magnetization by a dc magnetic field produces a rotation of the dipole pattern in the cavity providing equal amplitudes of the electromagnetic fields in the input and the output waveguides. This corresponds to the state on with high transmission of the input signal. Numerical calculations show that at the 1.55 μm wavelength the device has the insertion loss -0.42 dB in the on state, the isolation -19 dB in the off state and the switch off and on ratio P(on)/P(off) about 72. The frequency band at the level of -15 dB of the resonance curve in off state is about 160 GHz.

Optical datacenter network employing slotted (TDMA) operation for dynamic resource allocation

NASA Astrophysics Data System (ADS)

Bakopoulos, P.; Tokas, K.; Spatharakis, C.; Patronas, I.; Landi, G.; Christodoulopoulos, K.; Capitani, M.; Kyriakos, A.; Aziz, M.; Reisis, D.; Varvarigos, E.; Zahavi, E.; Avramopoulos, H.

2018-02-01

The soaring traffic demands in datacenter networks (DCNs) are outpacing progresses in CMOS technology, challenging the bandwidth and energy scalability of currently established technologies. Optical switching is gaining traction as a promising path for sustaining the explosive growth of DCNs; however, its practical deployment necessitates extensive modifications to the network architecture and operation, tailored to the technological particularities of optical switches (i.e. no buffering, limitations in radix size and speed). European project NEPHELE is developing an optical network infrastructure that leverages optical switching within a software-defined networking (SDN) framework to overcome the bandwidth and energy scaling challenges of datacenter networks. An experimental validation of the NEPHELE data plane is reported based on commercial off-the-shelf optical components controlled by FPGA boards. To facilitate dynamic allocation of the network resources and perform collision-free routing in a lossless network environment, slotted operation is employed (i.e. using time-division multiple-access - TDMA). Error-free operation of the NEPHELE data plane is verified for 200 μs slots in various scenarios that involve communication between Ethernet hosts connected to custom-designed top-of-rack (ToR) switches, located in the same or in different datacenter pods. Control of the slotted data plane is obtained through an SDN framework comprising an OpenDaylight controller with appropriate add-ons. Communication between servers in the optical-ToR is demonstrated with various routing scenarios, concerning communication between hosts located in the same rack or in different racks, within the same or different datacenter pods. Error-free operation is confirmed for all evaluated scenarios, underpinning the feasibility of the NEPHELE architecture.

Application of the fractional Fourier transform to the design of LCOS based optical interconnects and fiber switches.

PubMed

Robertson, Brian; Zhang, Zichen; Yang, Haining; Redmond, Maura M; Collings, Neil; Liu, Jinsong; Lin, Ruisheng; Jeziorska-Chapman, Anna M; Moore, John R; Crossland, William A; Chu, D P

2012-04-20

It is shown that reflective liquid crystal on silicon (LCOS) spatial light modulator (SLM) based interconnects or fiber switches that use defocus to reduce crosstalk can be evaluated and optimized using a fractional Fourier transform if certain optical symmetry conditions are met. Theoretically the maximum allowable linear hologram phase error compared to a Fourier switch is increased by a factor of six before the target crosstalk for telecom applications of -40 dB is exceeded. A Gerchberg-Saxton algorithm incorporating a fractional Fourier transform modified for use with a reflective LCOS SLM is used to optimize multi-casting holograms in a prototype telecom switch. Experiments are in close agreement to predicted performance.

Optical bistability and optical response of an infrared quantum dot hybridized to VO2 nanoparticle

NASA Astrophysics Data System (ADS)

Zamani, Naser; Hatef, Ali; Nadgaran, Hamid; Keshavarz, Alireza

2017-08-01

In this work, we theoretically investigate optical bistability and optical response of a hybrid system consisting of semiconductor quantum dot (SQD) coupled with a vanadium dioxide nanoparticle (VO2NP) in the infrared (IR) regime. The VO2 material exists in semiconductor and metallic phases below and above the critical temperature, respectively where the particle optical properties dramatically change during this phase transition. In our calculations a filling fraction factor controls the VO2NP phase transition when the hybrid system interacts with a laser field. We demonstrate that the switch-up threshold for optical bistability is strongly controlled by filling fraction without changing the structure of the hybrid system. Also, it is shown that, the threshold of optical bistability increases when the VO2NP phases changes from semiconductor to metallic phase. The presented results have the potential to be applied in designing optical switching and optical storage.

Method of developing all-optical trinary JK, D-type, and T-type flip-flops using semiconductor optical amplifiers.

PubMed

Garai, Sisir Kumar

2012-04-10

To meet the demand of very fast and agile optical networks, the optical processors in a network system should have a very fast execution rate, large information handling, and large information storage capacities. Multivalued logic operations and multistate optical flip-flops are the basic building blocks for such fast running optical computing and data processing systems. In the past two decades, many methods of implementing all-optical flip-flops have been proposed. Most of these suffer from speed limitations because of the low switching response of active devices. The frequency encoding technique has been used because of its many advantages. It can preserve its identity throughout data communication irrespective of loss of light energy due to reflection, refraction, attenuation, etc. The action of polarization-rotation-based very fast switching of semiconductor optical amplifiers increases processing speed. At the same time, tristate optical flip-flops increase information handling capacity.

Micro optical fiber display switch based on the magnetohydrodynamic (MHD) principle

NASA Astrophysics Data System (ADS)

Lian, Kun; Heng, Khee-Hang

2001-09-01

This paper reports on a research effort to design, microfabricate and test an optical fiber display switch based on magneto hydrodynamic (MHD) principal. The switch is driven by the Lorentz force and can be used to turn on/off the light. The SU-8 photoresist and UV light source were used for prototype fabrication in order to lower the cost. With a magnetic field supplied by an external permanent magnet, and a plus electrical current supplied across the two inert sidewall electrodes, the distributed body force generated will produce a pressure difference on the fluid mercury in the switch chamber. By change the direction of current flow, the mercury can turn on or cut off the light pass in less than 10 ms. The major advantages of a MHD-based micro-switch are that it does not contain any solid moving parts and power consumption is much smaller comparing to the relay type switches. This switch can be manufactured by molding gin batch production and may have potential applications in extremely bright traffic control,, high intensity advertising display, and communication.

Optical limiting of high-repetition-rate laser pulses by carbon nanofibers suspended in polydimethylsiloxane

NASA Astrophysics Data System (ADS)

Videnichev, Dmitry A.; Belousova, Inna M.

2014-06-01

The optical limiting (OL) behavior of carbon nanofibers (CNFs) in polydimethylsiloxane (PDMS) was studied and compared with that of CNFs in water, and polyhedral multi-shell fullerene-like nanostructures (PMFNs) also in water. It was shown that when switching from single-shot to pulse-periodic regime of laser pulses (10 Hz), the CNF in PDMS suspension retains its OL characteristics, while in the aqueous suspensions, considerable degradation of OL characteristics is observed. It was also observed that a powerful laser pulse causes the CNF in PDMS suspension to become opaque for at least three seconds, while such a pulse brings out a bleaching effect in aqueous PMFN and CNF suspensions. The processes of OL degradation in aqueous suspensions, bleaching and darkening of the studied materials are discussed herein.

Threshold Switching Characteristics of Nb/NbO 2 /TiN Vertical Devices

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

Wang, Yuhan; Comes, Ryan B.; Wolf, Stuart A.

2016-01-01

Nb/NbO2/TiN vertical structures were synthesized in-situ and patterned to devices with different contact areas. The devices exhibited threshold resistive switching with minimal hysteresis and a small EThreshold (60~90 kV/cm). The switching behavior was unipolar, and demonstrated good repeatability. A less sharp but still sizable change in the device resistance was observed up to 150 °C. It was found that the resistive switching without Nb capping layer exhibited the hysteretic behavior and much larger EThreshold (~250 kV/cm) likely due to a 2-3 nm surface Nb2O5 layer. The stable threshold switching behavior well above room temperature shows the potential applications of thismore » device as an electronic switch.« less

Design and fabrication of GaAs OMIST photodetector

NASA Astrophysics Data System (ADS)

Kang, Xuejun; Lin, ShiMing; Liao, Qiwei; Gao, Junhua; Liu, Shi'an; Cheng, Peng; Wang, Hongjie; Zhang, Chunhui; Wang, Qiming

1998-08-01

We designed and fabricated GaAs OMIST (Optical-controlled Metal-Insulator-Semiconductor Thyristor) device. Using oxidation of AlAs layer that is grown by MBE forms the Ultra- Thin semi-Insulating layer (UTI) of the GAAS OMIST. The accurate control and formation of high quality semi-insulating layer (AlxOy) are the key processes for fabricating GaAs OMIST. The device exhibits a current-controlled negative resistance region in its I-V characteristics. When illuminated, the major effect of optical excitation is the reduction of the switching voltage. If the GaAs OMIST device is biased at a voltage below its dark switching voltage Vs, sufficient incident light can switch OMIST from high impedance low current 'off' state to low impedance high current 'on' state. The absorbing material of OMIST is GaAS, so if the wavelength of incident light within 600 to approximately 850 nm can be detected effectively. It is suitable to be used as photodetector for digital optical data process. The other attractive features of GaAs OMIST device include suitable conducted current, switching voltage and power levels for OEIC, high switch speed and high sensitivity to light or current injection.

N× N optical switch based on cascaded microring resonators

NASA Astrophysics Data System (ADS)

Li, Jing-sen; Lu, Huan-yu; Zhao, Yu-lin

2018-05-01

An N×N optical switch based on cascaded microring resonators on chip is proposed. As an example, the 4×4 optical switch is further investigated. It is successfully demonstrated that its insertion loss is relatively low as 2.2 dB, the crosstalk is negligible, and the extinction ratio ( ER) is as large as 130 dB. Thermal tuning is employed to make the microrings be in resonance or not, which leads to a response time of several hundred microseconds. Alternatively, doping the desired waveguide regions with p-type or n-type dopants is able to achieve a better response time of several nanoseconds. The proposed design is easily integrated to a large scale with less microring resonators, which ensures the compact size and the low power consumption.

Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

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

Alharthi, S. S., E-mail: ssmalh@essex.ac.uk; Henning, I. D.; Adams, M. J.

We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in futuremore » optical systems.« less

Optical bandwidth in coupling: the multicore photonic switch.

PubMed

Attard, Alfred E

2003-05-20

In the present study, the bandwidth of a photonic switch described previously [Appl. Opt. 37,2296 (1998); 38, 3239 (1999)] is evaluated. First the optical bandwidth is evaluated for coupling between two fiber-core waveguides, in which the cores are embedded within the same cladding. Then the coupling bandwidth is determined for a fiber-core-to-slab-core waveguide, in which the cores are embedded within the same cladding. These bandwidths are then compared and contrasted with the bandwidths of the photonic switch, which consists of two fiber cores and a control waveguide. Two configurations of the photonic switch are considered: one in which the control waveguide is a fiber core and one in which the control waveguide is a slab core. For the photonic switch, the bandwidth characteristics are more complicated than for the coupled pairs, and these characteristics are discussed in detail.

Pulse compression in an electro-optic Q-switched diode-pumped YVO4/Nd:YVO4 laser with a Cr4+:YAG saturable absorber.

PubMed

Li, Tao; Zhao, Shengzhi; Zhuo, Zhuang; Yang, Kejian; Li, Guiqiu; Li, Dechun

2009-04-20

A diode end-pumped doubly Q-switched YVO4/Nd:YVO4 laser has been realized for the first time to our knowledge by using both an electro-optic (EO) modulator and a Cr4):YAG saturable absorber. A 3.8 ns pulse width is generated by this laser under a pump power of 15 W at 2 kHz, which is obviously compressed in comparison with that of 8.8 ns from a single actively EO Q-switched laser. Under the same conditions, peak power values of 174.7 and 93 kW are also obtained. A coupled equation is given to theoretically analyze the experimental data. The experimental and theoretical results show that the doubly Q-switched laser has the advantages of a shorter pulse width and higher pulse peak power in contrast with a singly Q-switched laser.

High speed all-optical networks

NASA Technical Reports Server (NTRS)

Chlamtac, Imrich

1993-01-01

An inherent problem of conventional point-to-point WAN architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. This report presents the first solution to WDM based WAN networks that overcomes this limitation. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs.