Science.gov

Sample records for advanced optical modulation

  1. Linear semiconductor optical amplifiers for amplification of advanced modulation formats.

    PubMed

    Bonk, R; Huber, G; Vallaitis, T; Koenig, S; Schmogrow, R; Hillerkuss, D; Brenot, R; Lelarge, F; Duan, G-H; Sygletos, S; Koos, C; Freude, W; Leuthold, J

    2012-04-23

    The capability of semiconductor optical amplifiers (SOA) to amplify advanced optical modulation format signals is investigated. The input power dynamic range is studied and especially the impact of the SOA alpha factor is addressed. Our results show that the advantage of a lower alpha-factor SOA decreases for higher-order modulation formats. Experiments at 20 GBd BPSK, QPSK and 16QAM with two SOAs with different alpha factors are performed. Simulations for various modulation formats support the experimental findings.

  2. Applications of all optical signal processing for advanced optical modulation formats

    NASA Astrophysics Data System (ADS)

    Nuccio, Scott R.

    Increased data traffic demands, along with a continual push to minimize cost per bit, have recently motivated a paradigm shift away from traditional on-off keying (OOK) fiber transmission links towards systems utilizing more advanced modulation formats. In particular, modulation formats that utilize the phase of the optical signal, including differential phase shift keying (DPSK) and differential quadrature phase shift keying (DQPSK) along with polarization multiplexing (Pol-MUX), have recently emerged as the most popular means for transmitting information over long-haul and ultra-long haul fiber transmission systems. DPSK is motivated by an increase in receiver sensitivity compared to traditional OOK. DQPSK is motivated by a doubling of the spectral efficiency, along with increased tolerance to dispersion and nonlinear distortions. Coherent communications has also emerged as a primary means of transmitting and receiving optical data due to its support of formats that utilize both phase and amplitude to further increase the spectral efficiency (bits/sec/Hz) of the optical channel, including quadrature amplitude modulation (QAM). Polarization multiplexing of channels is a straight forward method to allow two channels to share the same wavelength by propagating on orthogonal polarization axis and is easily supported in coherent systems where the polarization tracking can be performed in the digital domain. Furthermore, the forthcoming IEEE 100 Gbit/s Ethernet Standard, 802.3ba, provides greater bandwidth, higher data rates, and supports a mixture of modulation formats. In particular, Pol-MUX (D)QPSK has grown in interest as the high spectral efficiency allows for 100 Gbit/s transmission while still occupying the current 50 GHz/channel allocation of current 10 Gbit/s OOK fiber systems. In this manner, 100 Gbit/s transfer speeds using current fiber links, amplifiers, and filters may be possible. In addition to advanced modulation formats, it is expected that optical

  3. Experimental demonstration of large capacity WSDM optical access network with multicore fibers and advanced modulation formats.

    PubMed

    Li, Borui; Feng, Zhenhua; Tang, Ming; Xu, Zhilin; Fu, Songnian; Wu, Qiong; Deng, Lei; Tong, Weijun; Liu, Shuang; Shum, Perry Ping

    2015-05-01

    Towards the next generation optical access network supporting large capacity data transmission to enormous number of users covering a wider area, we proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers with advanced modulation formats. As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers with 58.7km distance. As a cost-effective modulation scheme for access network, the optical OFDM-QPSK signal has been intensity modulated on the downstream transmission in the optical line terminal (OLT) and it was directly detected in the optical network unit (ONU) after MCF transmission. 10 wavelengths with 25GHz channel spacing from an optical comb generator are employed and each wavelength is loaded with 5Gb/s OFDM-QPSK signal. After amplification, power splitting, and fan-in multiplexer, 10-wavelength downstream signal was injected into six outer layer cores simultaneously and the aggregation downstream capacity reaches 300 Gb/s. -16 dBm sensitivity has been achieved for 3.8 × 10-3 bit error ratio (BER) with 7% Forward Error Correction (FEC) limit for all wavelengths in every core. Upstream signal from ONU side has also been generated and the bidirectional transmission in the same core causes negligible performance degradation to the downstream signal. As a universal platform for wired/wireless data access, our proposed architecture provides additional dimension for high speed mobile signal transmission and we hence demonstrated an upstream delivery of 20Gb/s per wavelength with QPSK modulation formats using the inner core of MCF emulating a mobile backhaul service. The IQ modulated data was coherently detected in the OLT side. -19 dBm sensitivity has been achieved under the FEC limit and more than 18 dB power budget is guaranteed.

  4. Research Studies on Advanced Optical Module/Head Designs for Optical Data Storage

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Preprints are presented from the recent 1992 Optical Data Storage meeting in San Jose. The papers are divided into the following topical areas: Magneto-optical media (Modeling/design and fabrication/characterization/testing); Optical heads (holographic optical elements); and Optical heads (integrated optics). Some representative titles are as follow: Diffraction analysis and evaluation of several focus and track error detection schemes for magneto-optical disk systems; Proposal for massively parallel data storage system; Transfer function characteristics of super resolving systems; Modeling and measurement of a micro-optic beam deflector; Oxidation processes in magneto-optic and related materials; and A modal analysis of lamellar diffraction gratings in conical mountings.

  5. Research Studies on Advanced Optical Module/Head Designs for Optical Disk Recording Devices

    NASA Technical Reports Server (NTRS)

    Burke, James J.; Seery, Bernard D.

    1993-01-01

    The Annual Report of the Optical Data Storage Center of the University of Arizona is presented. Summary reports on continuing projects are presented. Research areas include: magneto-optic media, optical heads, and signal processing.

  6. Research studies on advanced optical module/head designs for optical devices

    NASA Technical Reports Server (NTRS)

    Burke, James J.

    1991-01-01

    A summary is presented of research in optical data storage materials and of research at the center. The first section contains summary reports under the general headings of: (1) Magnetooptic media: modeling, design, fabrication, characterization, and testing; (2) Optical heads: holographic optical elements; and (3) Optical heads: integrated optics. The second section consist of a proposal entitled, Signal Processing Techniques for Optical Data Storage. And section three presents various publications prepared by the center.

  7. Advanced Adaptive Optics Technology Development

    SciTech Connect

    Olivier, S

    2001-09-18

    The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.

  8. Optical modulator including grapene

    DOEpatents

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  9. Digital optical conversion module

    DOEpatents

    Kotter, D.K.; Rankin, R.A.

    1988-07-19

    A digital optical conversion module used to convert an analog signal to a computer compatible digital signal including a voltage-to-frequency converter, frequency offset response circuitry, and an electrical-to-optical converter. Also used in conjunction with the digital optical conversion module is an optical link and an interface at the computer for converting the optical signal back to an electrical signal. Suitable for use in hostile environments having high levels of electromagnetic interference, the conversion module retains high resolution of the analog signal while eliminating the potential for errors due to noise and interference. The module can be used to link analog output scientific equipment such as an electrometer used with a mass spectrometer to a computer. 2 figs.

  10. Digital optical conversion module

    DOEpatents

    Kotter, Dale K.; Rankin, Richard A.

    1991-02-26

    A digital optical conversion module used to convert an analog signal to a computer compatible digital signal including a voltage-to-frequency converter, frequency offset response circuitry, and an electrical-to-optical converter. Also used in conjunction with the digital optical conversion module is an optical link and an interface at the computer for converting the optical signal back to an electrical signal. Suitable for use in hostile environments having high levels of electromagnetic interference, the conversion module retains high resolution of the analog signal while eliminating the potential for errors due to noise and interference. The module can be used to link analog output scientific equipment such as an electrometer used with a mass spectrometer to a computer.

  11. Optical modulators with 2D layered materials

    NASA Astrophysics Data System (ADS)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  12. Optical modulator system

    NASA Technical Reports Server (NTRS)

    Brand, J.

    1972-01-01

    The fabrication, test, and delivery of an optical modulator system which will operate with a mode-locked Nd:YAG laser indicating at either 1.06 or 0.53 micrometers is discussed. The delivered hardware operates at data rates up to 400 Mbps and includes a 0.53 micrometer electrooptic modulator, a 1.06 micrometer electrooptic modulator with power supply and signal processing electronics with power supply. The modulators contain solid state drivers which accept digital signals with MECL logic levels, temperature controllers to maintain a stable thermal environment for the modulator crystals, and automatic electronic compensation to maximize the extinction ratio. The modulators use two lithium tantalate crystals cascaded in a double pass configuration. The signal processing electronics include encoding electronics which are capable of digitizing analog signals between the limit of + or - 0.75 volts at a maximum rate of 80 megasamples per second with 5 bit resolution. The digital samples are serialized and made available as a 400 Mbps serial NRZ data source for the modulators. A pseudorandom (PN) generator is also included in the signal processing electronics. This data source generates PN sequences with lengths between 31 bits and 32,767 bits in a serial NRZ format at rates up to 400 Mbps.

  13. Optical terminal definition for the Future Service Growth (FSG) module of the Advanced Tracking and Data Relay Satellite (ATDRSS)

    NASA Technical Reports Server (NTRS)

    Bruno, Ronald C.; Kalil, Ford

    1992-01-01

    Results are presented from preliminary analyses and definition studies for an optical terminal's incorporation into the FSG module of the ATDRS system, which must support crosslinks between selected relay satellites of a modified ATDRS constellation and thereby allow the placement of a relay satellite at an orbital location which eliminates the zone of exclusion. These studies have attempted to identify alternative constellations by means of one or more crosslinks, and to formulate the service-routing requirement for the FSG terminal. Attention is given to an FSG optical terminal that furnishes the functionality and performance required for a crosslink terminal.

  14. Advanced Optical Network

    NASA Astrophysics Data System (ADS)

    Braun, Steve; Michael, Xuejun

    The following article describes an advanced dense wavelength division multiplexing (DWDM) Optical Network developed by L-3 Photonics. The network, configured as an amplified optical bus, carries traffic simultaneously in both directions, using multiple wavelengths. As a result, data distribution is of the form peer-to-multi-peer, it is protocol independent, and it is scalable. The network leverages the rapid growth in commercial optical technologies, including wavelength division multiplexing (WDM), and when applied to military and commercial platforms such as aircraft, ships, unmanned and other vehicles, provides a cost-effective, low-weight, high-speed, and high noise-immune data distribution system.

  15. Advanced optical instruments technology

    NASA Technical Reports Server (NTRS)

    Shao, Mike; Chrisp, Michael; Cheng, Li-Jen; Eng, Sverre; Glavich, Thomas; Goad, Larry; Jones, Bill; Kaarat, Philip; Nein, Max; Robinson, William

    1992-01-01

    The science objectives for proposed NASA missions for the next decades push the state of the art in sensitivity and spatial resolution over a wide range of wavelengths, including the x-ray to the submillimeter. While some of the proposed missions are larger and more sensitive versions of familiar concepts, such as the next generation space telescope, others use concepts, common on the Earth, but new to space, such as optical interferometry, in order to provide spatial resolutions impossible with other concepts. However, despite their architecture, the performance of all of the proposed missions depends critically on the back-end instruments that process the collected energy to produce scientifically interesting outputs. The Advanced Optical Instruments Technology panel was chartered with defining technology development plans that would best improve optical instrument performance for future astrophysics missions. At this workshop the optical instrument was defined as the set of optical components that reimage the light from the telescope onto the detectors to provide information about the spatial, spectral, and polarization properties of the light. This definition was used to distinguish the optical instrument technology issues from those associated with the telescope, which were covered by a separate panel. The panel identified several areas for optical component technology development: diffraction gratings; tunable filters; interferometric beam combiners; optical materials; and fiber optics. The panel also determined that stray light suppression instruments, such as coronagraphs and nulling interferometers, were in need of general development to support future astrophysics needs.

  16. COANP-fullerenes system for optical modulation

    NASA Astrophysics Data System (ADS)

    Likhomanova, S. V.; Kamanina, N. V.

    2016-08-01

    The advanced investigations of ϕ-conjugated organic molecule COANP sensitized with fullerenes have been revealed to consider this system as an affective medium for optical limiting and phase modulation. The special accent has been given to influence of the nanostructured relief at the interface on the spectral and photoconductive features.

  17. Advanced infrared laser modulator development

    NASA Technical Reports Server (NTRS)

    Cheo, P. K.; Wagner, R.; Gilden, M.

    1984-01-01

    A parametric study was conducted to develop an electrooptic waveguide modulator for generating continuous tunable sideband power from an infrared CO2 laser. Parameters included were the waveguide configurations, microstrip dimensions device impedance, and effective dielectric constants. An optimum infrared laser modulator was established and was fabricated. This modulator represents the state-of-the-art integrated optical device, which has a three-dimensional topology to accommodate three lambda/4 step transformers for microwave impedance matching at both the input and output terminals. A flat frequency response of the device over 20 HGz or = 3 dB) was achieved. Maximum single sideband to carrier power greater than 1.2% for 20 W microwave input power at optical carrier wavelength of 10.6 microns was obtained.

  18. Advanced Electro-Optic Surety Devices

    SciTech Connect

    Watterson, C.E.

    1997-05-01

    The Advanced Electro-Optic Surety Devices project was initiated in march 1991 to support design laboratory guidance on electro-optic device packaging and evaluation. Sandia National Laboratory requested AlliedSignal Inc., Kansas City Division (KCD), to prepare for future packaging efforts in electro-optic integrated circuits. Los Alamos National Laboratory requested the evaluation of electro-optic waveguide devices for nuclear surety applications. New packaging techniques involving multiple fiber optic alignment and attachment, binary lens array development, silicon V-groove etching, and flip chip bonding were requested. Hermetic sealing of the electro-optic hybrid and submicron alignment of optical components present new challenges to be resolved. A 10-channel electro-optic modulator and laser amplifier were evaluated for potential surety applications.

  19. Fly-by-light optical bus interface module (OBIM)

    NASA Astrophysics Data System (ADS)

    Gargano, Robert

    1995-05-01

    Driving the need for optics in flight control are the issues of wire weight, HIRF, and system bandwidth. With the advent of advanced Vehicle Management System (VMS) systems and the higher level of functional and physical integration of subsystems such as the More Electric Aircraft (MEA) and the Subsystem Utility Integration Technology (SUIT) program, optics in flight control offer attractive system benefits. Advanced VMS control functions generate large quantities of data to be transmitted over the VMS buses for processing. This paper will address the implementation of a module that will support the high throughput requirements of an advanced VMS system. The module is defined as the Optical Bus Interface Module (OBIM) and utilizes the AS1773A 20 mbps fiber optic bus for the VMS system bus. In addition, the module supports 5 mbps fiber optic Cross Channel Data Links (CCDLs) for the exchange of flight critical data in redundant architectures.

  20. Silicon high speed modulator for advanced modulation: device structures and exemplary modulator performance

    NASA Astrophysics Data System (ADS)

    Milivojevic, Biljana; Wiese, Stefan; Whiteaway, James; Raabe, Christian; Shastri, Anujit; Webster, Mark; Metz, Peter; Sunder, Sanjay; Chattin, Bill; Anderson, Sean P.; Dama, Bipin; Shastri, Kal

    2014-03-01

    Fiber optics is well established today due to the high capacity and speed, unrivaled flexibility and quality of service. However, state of the art optical elements and components are hardly scalable in terms of cost and size required to achieve competitive port density and cost per bit. Next-generation high-speed coherent optical communication systems targeting a data rate of 100-Gb/s and beyond goes along with innovations in component and subsystem areas. Consequently, by leveraging the advanced silicon micro and nano-fabrication technologies, significant progress in developing CMOS platform-based silicon photonic devices has been made all over the world. These achievements include the demonstration of high-speed IQ modulators, which are important building blocks in coherent optical communication systems. In this paper, we demonstrate silicon photonic QPSK modulator based on a metal-oxide-semiconductor (MOS) capacitor structure, address different modulator configuration structures and report our progress and research associated with highspeed advanced optical modulation in silicon photonics

  1. All-optical modulation in gallium arsenide integrated optical waveguides

    SciTech Connect

    McWright, G.; Ross, B.; Guthreau, W.; Lafaw, D.; Lowry, M.; Tindall, W.

    1988-01-27

    We have investigated all-optical modulators in gallium arsenide integrated optical waveguides; these modulators use electron-hole pair generation to alter the propagation characteristics of a guided light beam. 6 refs., 6 figs.

  2. Optical Electronics. Electronics Module 9. Instructor's Guide.

    ERIC Educational Resources Information Center

    Franken, Bill

    This module is the ninth of 10 modules in the competency-based electronics series. Introductory materials include a listing of competencies addressed in the module, a parts/equipment list, and a cross reference table of instructional materials. Five instructional units cover: fiber optic cable; optical coupler; lasers and masers; optical displays;…

  3. Polarization Independent Electro-Optic Modulator

    NASA Technical Reports Server (NTRS)

    Yao, Xiao-Tian Steve (Inventor)

    1997-01-01

    A polarization insensitive electro-optic modulator is constructed by providing a polarization beamsplitter to separate an incoming light beam into two orthogonally plane polarized beams. Each of the polarized beams passes through a separate electro-optic modulator where each beam is modulated by the same data signal. After modulation the beams are combined to yield a modulated beam having modulated components that are orthogonally polarized. Not only is this device insensitive to changes in polarization of the input beam, the final modulated beam can be detected by optical receivers without regard to polarization alignment of the modulated beam and the receiver.

  4. The input optics of Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Tanner, D. B.; Arain, M. A.; Ciani, G.; Feldbaum, D.; Fulda, P.; Gleason, J.; Goetz, R.; Heintze, M.; Martin, R. M.; Mueller, C. L.; Williams, L. F.; Mueller, G.; Quetschke, V.; Korth, W. Z.; Reitze, D. H.; Derosa, R. T.; Effler, A.; Kokeyama, K.; Frolov, V. V.; Mullavey, A.; Poeld, J.

    2016-03-01

    The Input Optics (IO) of advanced LIGO will be described. The IO consists of all the optics between the laser and the power recycling mirror. The scope of the IO includes the following hardware: phase modulators, power control, input mode cleaner, an in-vacuum Faraday isolator, and mode matching telescopes. The IO group has developed and characterized RTP-based phase modulators capable of operation at 180 W cw input power. In addition, the Faraday isolator is compensated for depolarization and thermal lensing effects up to the same power and is capable of achieving greater than 40 dB isolation. This research has been supported by the NSF through Grants PHY-1205512 and PHY-1505598. LIGO-G1600067.

  5. Modulation and detection of optical signals

    NASA Technical Reports Server (NTRS)

    Goodwin, F. E.

    1972-01-01

    A summary of information is presented which is related to the modulation and detection of information on optical carriers. It emphasizes the treatment of information transfer through an entire system. The most common configurations are considered: intensity modulation, amplitude modulation, frequency or phase modulation, and both direct and coherent detection. In assessing these configurations information capacity and message signal-to-noise ratio are used as a basis of comparison. The physical and geometric treatment of optical heterodyne (or coherent) detection is given.

  6. Stitching Techniques Advance Optics Manufacturing

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Because NASA depends on the fabrication and testing of large, high-quality aspheric (nonspherical) optics for applications like the James Webb Space Telescope, it sought an improved method for measuring large aspheres. Through Small Business Innovation Research (SBIR) awards from Goddard Space Flight Center, QED Technologies, of Rochester, New York, upgraded and enhanced its stitching technology for aspheres. QED developed the SSI-A, which earned the company an R&D 100 award, and also developed a breakthrough machine tool called the aspheric stitching interferometer. The equipment is applied to advanced optics in telescopes, microscopes, cameras, medical scopes, binoculars, and photolithography."

  7. Advanced optical manufacturing digital integrated system

    NASA Astrophysics Data System (ADS)

    Tao, Yizheng; Li, Xinglan; Li, Wei; Tang, Dingyong

    2012-10-01

    It is necessarily to adapt development of advanced optical manufacturing technology with modern science technology development. To solved these problems which low of ration, ratio of finished product, repetition, consistent in big size and high precision in advanced optical component manufacturing. Applied business driven and method of Rational Unified Process, this paper has researched advanced optical manufacturing process flow, requirement of Advanced Optical Manufacturing integrated System, and put forward architecture and key technology of it. Designed Optical component core and Manufacturing process driven of Advanced Optical Manufacturing Digital Integrated System. the result displayed effective well, realized dynamic planning Manufacturing process, information integration improved ratio of production manufactory.

  8. Nanosecond liquid crystalline optical modulator

    DOEpatents

    Borshch, Volodymyr; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2016-07-26

    An optical modulator includes a liquid crystal cell containing liquid crystal material having liquid crystal molecules oriented along a quiescent director direction in the unbiased state, and a voltage source configured to apply an electric field to the liquid crystal material wherein the direction of the applied electric field does not cause the quiescent director direction to change. An optical source is arranged to transmit light through or reflect light off the liquid crystal cell with the light passing through the liquid crystal material at an angle effective to undergo phase retardation in response to the voltage source applying the electric field. The liquid crystal material may have negative dielectric anisotropy, and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is transverse to the quiescent director direction. Alternatively, the liquid crystal material may have positive dielectric anisotropy and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is parallel with the quiescent director direction.

  9. Frequency modulated lasers for interferometric optical gyroscopes.

    PubMed

    Komljenovic, Tin; Tran, Minh A; Belt, Michael; Gundavarapu, Sarat; Blumenthal, Daniel J; Bowers, John E

    2016-04-15

    We study the use of frequency modulated lasers in interferometric optical gyroscopes and show that by exploiting various frequency modulation signals, the laser coherence can be controlled. We show that both angle random walk and bias stability of an interferometric optical gyroscope based on laser sources can be improved with this technique. PMID:27082342

  10. Dense optical-electrical interface module

    SciTech Connect

    Paul Chang

    2000-12-21

    The DOIM (Dense Optical-electrical Interface Modules) is a custom-designed optical data transmission module employed in the upgrade of Silicon Vertex Detector of CDF experiment at Fermilab. Each DOIM module consists of a transmitter (TX) converting electrical differential input signals to optical outputs, a middle segment of jacketed fiber ribbon cable, and a receiver (RX) which senses the light inputs and converts them back to electrical signals. The targeted operational frequency is 53 MHz, and higher rate is achievable. This article outlines the design goals, implementation methods, production test results, and radiation hardness tests of these modules.

  11. A graphene-based broadband optical modulator

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Yin, Xiaobo; Ulin-Avila, Erick; Geng, Baisong; Zentgraf, Thomas; Ju, Long; Wang, Feng; Zhang, Xiang

    2011-06-01

    Integrated optical modulators with high modulation speed, small footprint and large optical bandwidth are poised to be the enabling devices for on-chip optical interconnects. Semiconductor modulators have therefore been heavily researched over the past few years. However, the device footprint of silicon-based modulators is of the order of millimetres, owing to its weak electro-optical properties. Germanium and compound semiconductors, on the other hand, face the major challenge of integration with existing silicon electronics and photonics platforms. Integrating silicon modulators with high-quality-factor optical resonators increases the modulation strength, but these devices suffer from intrinsic narrow bandwidth and require sophisticated optical design; they also have stringent fabrication requirements and limited temperature tolerances. Finding a complementary metal-oxide-semiconductor (CMOS)-compatible material with adequate modulation speed and strength has therefore become a task of not only scientific interest, but also industrial importance. Here we experimentally demonstrate a broadband, high-speed, waveguide-integrated electroabsorption modulator based on monolayer graphene. By electrically tuning the Fermi level of the graphene sheet, we demonstrate modulation of the guided light at frequencies over 1GHz, together with a broad operation spectrum that ranges from 1.35 to 1.6µm under ambient conditions. The high modulation efficiency of graphene results in an active device area of merely 25µm2, which is among the smallest to date. This graphene-based optical modulation mechanism, with combined advantages of compact footprint, low operation voltage and ultrafast modulation speed across a broad range of wavelengths, can enable novel architectures for on-chip optical communications.

  12. Plasma optical modulators for intense lasers.

    PubMed

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D A; Mori, W B; Zhang, Jie

    2016-01-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 10(16) W cm(-2) to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations. PMID:27283369

  13. Plasma optical modulators for intense lasers

    NASA Astrophysics Data System (ADS)

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-06-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm-2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations.

  14. Plasma optical modulators for intense lasers

    PubMed Central

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-01-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm−2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations. PMID:27283369

  15. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development: Study of the Optical Setup of a Wide-Band Optical Modulation Spectrometer

    NASA Technical Reports Server (NTRS)

    Tolls, Volker; Stringfellow, Guy (Technical Monitor)

    2001-01-01

    The purpose of this study is to advance the design of the optical setup for a wide-band Optical Modulation Spectrometer (OMS) for use with astronomical heterodyne receiver systems. This report describes the progress of this investigation achieved from March until December 2001.

  16. Highly Sensitive Electro-Optic Modulators

    SciTech Connect

    DeVore, Peter S

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  17. The advanced LIGO input optics.

    PubMed

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design. PMID:26827334

  18. The advanced LIGO input optics.

    PubMed

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  19. Amplitude and phase modulation with waveguide optics

    SciTech Connect

    Burkhart, S.C.; Wilcox, R.B.; Browning, D.; Penko, F.A.

    1996-12-17

    We have developed amplitude and phase modulation systems for glass lasers using integrated electro-optic modulators and solid state high- speed electronics. The present and future generation of lasers for Inertial Confinement Fusion require laser beams with complex temporal and phase shaping to compensate for laser gain saturation, mitigate parametric processes such as transverse stimulated Brillouin scattering in optics, and to provide specialized drive to the fusion targets. These functions can be performed using bulk optoelectronic modulators, however using high-speed electronics to drive low voltage integrated optical modulators has many practical advantages. In particular, we utilize microwave GaAs transistors to perform precision, 250 ps resolution temporal shaping. Optical bandwidth is generated using a microwave oscillator at 3 GHz amplified by a solid state amplifier. This drives an integrated electrooptic modulator to achieve laser bandwidths exceeding 30 GHz.

  20. Modulational instability in optical-microwave interaction

    NASA Astrophysics Data System (ADS)

    Bubke, K.; Hutchings, D. C.; Peschel, U.; Lederer, F.

    2002-09-01

    The stability of continuous optical and microwave fields is studied in the presence of dispersion and second order nonlinearity. The cascade combination of optical rectification and the electro-optic effect induces modulational instability (MI) in a wide range of system parameters. It is demonstrated that MI can lead potentially to filamentation of high power optical pulses as well as the generation of terahertz radiation.

  1. Optical properties of KD*P modulators

    NASA Technical Reports Server (NTRS)

    West, E. A.; Bhatia, S. S.

    1990-01-01

    Longitudinal KD*P modulators are used in ground-based solar magnetographs to eliminate seeing effects. Although the modulators can be used as variable retarders, the optical properties when zero voltage is applied influences the performance on instruments requiring very accurate polarization measurements. Measurements at the Marshall Space Flight Center are discussed in terms of the optical properties of KD*P modulators when zero voltage is applied. The measurements can be used to predict the modulation characteristics of the devices and to determine the polarization accuracy that can be expected from the vector magnetograph.

  2. The optical module of Baikal-GVD

    NASA Astrophysics Data System (ADS)

    Avrorin, A. D.; Avrorin, A. V.; Aynutdinov, V. M.; Bannash, R.; Belolaptikov, I. A.; Bogorodsky, D. Yu.; Brudanin, V. B.; Budnev, N. M.; Danilchenko, I. A.; Domogatsky, G. V.; Doroshenko, A. A.; Dyachok, A. N.; Dzhilkibaev, Zh.-A. M.; Fialkovsky, S. V.; Gafarov, A. R.; Gaponenko, O. N.; Golubkov, K. V.; Gress, T. I.; Honz, Z.; Kebkal, K. G.; Kebkal, O. G.; Konischev, K. V.; Korobchenko, A. V.; Koshechkin, A. P.; Koshel, F. K.; Kozhin, A. V.; Kulepov, V. F.; Kuleshov, D. A.; Ljashuk, V. I.; Milenin, M. B.; Mirgazov, R. A.; Osipova, E. R.; Panfilov, A. I.; Pan'kov, L. V.; Pliskovsky, E. N.; Rozanov, M. I.; Rjabov, E. V.; Shaybonov, B. A.; Sheifler, A. A.; Shelepov, M. D.; Skurihin, A. V.; Smagina, A. A.; Suvorova, O. V.; Tabolenko, V. A.; Tarashansky, B. A.; Yakovlev, S. A.; Zagorodnikov, A. V.; Zhukov, V. A.; Zurbanov, V. L.

    2016-04-01

    The Baikal-GVD neutrino telescope in Lake Baikal is intended for studying astrophysical neutrino fluxes by recording the Cherenkov radiation of the secondary muons and showers generated in neutrino interactions. The first stage of Baikal-GVD will be equipped with about 2300 optical modules. We describe the design of the optical module, the front-end electronics and the laboratory characterization and calibration before deployment.

  3. Electro-optic resonant phase modulator

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung (Inventor); Hemmati, Hamid (Inventor); Robinson, Deborah L. (Inventor)

    1992-01-01

    An electro-optic resonant cavity is used to achieve phase modulation with lower driving voltages. Laser damage thresholds are inherently higher than with previously used integrated optics due to the utilization of bulk optics. Phase modulation is achieved at higher speeds with lower driving voltages than previously obtained with non-resonant electro-optic phase modulators. The instant scheme uses a data locking dither approach as opposed to the conventional sinusoidal locking schemes. In accordance with a disclosed embodiment, a resonant cavity modulator has been designed to operate at a data rate in excess of 100 megabits per sec. By carefully choosing the cavity finesse and its dimension, it is possible to control the pulse switching time to within 4 nano-sec. and to limit the required switching voltage to within 10 V. This cavity locking scheme can be applied by using only the random data sequence, and without the need of dithering of the cavity. Compared to waveguide modulators, the resonant cavity has a comparable modulating voltage requirement. Because of its bulk geometry, the resonant cavity modulator has the potential of accommodating higher throughput power. Mode matching into the bulk device is easier and typically can be achieved with higher efficiency. An additional control loop is incorporated into the modulator to maintain the cavity on resonance.

  4. Session: CSP Advanced Systems: Optical Materials (Presentation)

    SciTech Connect

    Kennedy, C.

    2008-04-01

    The Optical Materials project description is to characterize advanced reflector, perform accelerated and outdoor testing of commercial and experimental reflector materials, and provide industry support.

  5. Silicon pore optics mirror modules for inner and outer radii

    NASA Astrophysics Data System (ADS)

    Wille, Eric; Bavdaz, Marcos; Oosterbroek, Tim; Collon, Maximilien; Ackermann, Marcelo; Günther, Ramses; Vacanti, Giuseppe; Vervest, Mark; Yanson, Alexei; van Baren, Coen; Haneveld, Jeroen; Koelewijn, Arenda; Leenstra, Anne; Wijnperle, Maurice; Pareschi, Giovanni; Civitani, Marta; Conconi, Paolo; Spiga, Daniele; Valsecchi, Giuseppe; Marioni, Fabio; Zuknik, Karl-Heinz; Schweitzer, Mario

    2015-09-01

    Athena (Advanced Telescope for High Energy Astrophysics) is an x-ray observatory using a Silicon Pore Optics telescope and was selected as ESA's second L-class science mission for a launch in 2028. The x-ray telescope consists of several hundreds of mirror modules distributed over about 15-20 radial rings. The radius of curvature and the module sizes vary among the different radial positions of the rings resulting in different technical challenges for mirror modules for inner and outer radii. We present first results of demonstrating Silicon Pore Optics for the extreme radial positions of the Athena telescope. For the inner most radii (0.25 m) a new mirror plate design is shown which overcomes the challenges of larger curvatures, higher stress values and bigger plates. Preliminary designs for the mounting system and its mechanical properties are discussed for mirror modules covering all other radial positions up to the most outer radius of the Athena telescope.

  6. Spectrum-Modulating Fiber-Optic Sensors

    NASA Technical Reports Server (NTRS)

    Beheim, Glenn; Fritsch, Klaus

    1989-01-01

    Family of spectrum-modulating fiber-optic sensors undergoing development for use in aircraft-engine control systems. Fiber-optic sensors offer advantages of small size, high bandwidth, immunity to electromagnetic interference, and light weight. Furthermore, they reduce number of locations on aircraft to which electrical power has to be supplied.

  7. Optical wavelength modulation in free electron lasers

    SciTech Connect

    Mabe, R.M.; Wong, R.K.; Colson, W.B.

    1995-12-31

    An attribute of the free electron laser (FEL) is the continuous tunability of the optical wavelength by modulation of the electron beam energy. The variation of the wavelength and power of the optical beam is studied as a function of FEL operating parameters. These results will be applied to the Stanford SCA FEL and Boeing FEL.

  8. Electric modulation of optical absorption in nanowires

    NASA Astrophysics Data System (ADS)

    Sakr, M. R.

    2016-11-01

    We have calculated the effect of an external electric field on the intersubband optical absorption of a nanowire subjected to a perpendicular magnetic field and Rashba effect. The absorption peaks due to optical transitions that are forbidden in the absence of the intersubband coupling experience strong amplitude modulation. This effect is quadratic in electric fields applied along the direction of quantum confinement or perpendicularly to tune the Rashba parameter. The electric field also induces frequency modulation in the associated spectrum. On the other hand, transitions that are normally allowed show, to a large extent, a parallel band effect, and accordingly they are responsible for strong optical absorption.

  9. Optical imaging module for astigmatic detection system.

    PubMed

    Wang, Wei-Min; Cheng, Chung-Hsiang; Molnar, Gabor; Hwang, Ing-Shouh; Huang, Kuang-Yuh; Danzebrink, Hans-Ulrich; Hwu, En-Te

    2016-05-01

    In this paper, an optical imaging module design for an astigmatic detection system (ADS) is presented. The module is based on a commercial optical pickup unit (OPU) and it contains a coaxial illuminant for illuminating a specimen. Furthermore, the imaging module facilitates viewing the specimen and the detection laser spot of the ADS with a lateral resolution of approximately 1 μm without requiring the removal of an element of the OPU. Two polarizers and one infrared filter are used to eliminate stray laser light in the OPU and stray light produced by the illuminant. Imaging modules designed for digital versatile disks (DVDs) and Blu-ray DVDs were demonstrated. Furthermore, the module can be used for imaging a small cantilever with approximate dimensions of 2 μm (width) × 5 μm (length), and therefore, it has the potential to be used in high-speed atomic force microscopy. PMID:27250434

  10. Electric-optic resonant phase modulator

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung (Inventor); Robinson, Deborah L. (Inventor); Hemmati, Hamid (Inventor)

    1994-01-01

    An electro-optic resonant cavity is used to achieve phase modulation with lower driving voltages. Laser damage thresholds are inherently higher than with previously used integrated optics due to the utilization of bulk optics. Phase modulation is achieved at higher speeds with lower driving voltages than previously obtained with non-resonant electro-optic phase modulators. The instant scheme uses a data locking dither approach as opposed to the conventional sinusoidal locking schemes. In accordance with a disclosed embodiment, a resonant cavity modulator has been designed to operate at a data rate in excess of 100 Mbps. By carefully choosing the cavity finesse and its dimension, it is possible to control the pulse switching time to within 4 ns and to limit the required switching voltage to within 10 V. Experimentally, the resonant cavity can be maintained on resonance with respect to the input laser signal by monitoring the fluctuation of output intensity as the cavity is switched. This cavity locking scheme can be applied by using only the random data sequence, and without the need of additional dithering of the cavity. Compared to waveguide modulators, the resonant cavity has a comparable modulating voltage requirement. Because of its bulk geometry, resonant cavity modulator has the potential of accommodating higher throughput power. Furthermore, mode matching into a bulk device is easier and typically can be achieved with higher efficiency. On the other hand, unlike waveguide modulators which are essentially traveling wave devices, the resonant cavity modulator requires that the cavity be maintained in resonance with respect to the incoming laser signal. An additional control loop is incorporated into the modulator to maintain the cavity on resonance.

  11. Precision laser spectroscopy using acousto-optic modulators

    SciTech Connect

    Van Wijngaarden, W.A.

    1996-12-31

    This paper reports on a new spectroscopic method that uses a frequency-modulated laser to excite an atomic beam. It has an especially promising future given the rapid technological advances in developing new relatively inexpensive acousto-optic and electro-optic modulators. Most significantly, this new method is free of various systematic effects that have limited the accuracy of past experiments. This chapter is organized as follows. Section II briefly reviews some of the advances made in optical spectroscopy during the last few decades. Principally, it discusses the use of Fabry-Perot etalons in conjunction with laser atomic beam spectroscopy. Interferometers have been extensively employed by numerous groups to determine many different kinds of frequency shifts. Section III describes three possible experimental arrangements using optically modulated laser beams to make frequency measurements. The advantages and limitations of these approaches are illustrated in Section IV by three specific examples of experiments that determined isotope shifts and hyperfine structure. Section V discusses some precision Stark shift measurements for optical transitions. It concludes with a summary of polarizability data having uncertainties of less than 0.5%. Sections IV and V also compare the results obtained using a variety of competing spectroscopic techniques. Finally, Section VI gives concluding remarks. 96 refs., 15 figs., 6 tabs.

  12. Silicon-Based Optical Modulator with Ferroelectric Layer

    NASA Technical Reports Server (NTRS)

    Sheldon, Douglas

    2006-01-01

    According to a proposal, a silicon dioxide layer in a high-speed, low-power, silicon- based electro-optical modulator would be replaced by a layer of lead zirconate titanate or other ferroelectric oxide material. The purpose of this modification is to enhance the power performance and functionality of the modulator. In its unmodified form, the particular silicon- based electro-optical modulator is of an advanced design that overcomes the speed limitation of prior silicon-based electro- optical modulators. Whereas modulation frequencies of such devices had been limited to about 20 MHz, this modulator can operate at modulation frequencies as high as 1 GHz. This modulator can be characterized as a silicon-waveguide-based metal oxide/semiconductor (MOS) capacitor phase shifter in which modulation of the index of refraction in silicon is obtained by exploiting the free-charge-carrier-plasma dispersion effect. As shown in the figure, the modulator includes an n-doped crystalline silicon slab (the silicon layer of a silicon- on-insulator wafer) and a p-doped polycrystalline silicon rib with a gate oxide layer (the aforementioned silicon dioxide layer) sandwiched between them. Under accumulation conditions, the majority charge carriers in the silicon waveguide modify the index of refraction so that a phase shift is induced in the optical mode propagating in the waveguide. The advantage of using an MOS capacitor phase shifter is that it is possible to achieve high modulation speed because there are no slow carrier-generation or -recombination processes involved in the accumulation operation. The main advantage of the proposed substitution of a ferroelectric oxide layer for the silicon dioxide layer would arise from the spontaneous polarization effect of the ferroelectric layer: This spontaneous polarization would maintain accumulation conditions in the absence of applied voltage. Consequently, once the device had been switched to a given optical state, it would remain in

  13. Advanced Modulation and Coding Technology Conference

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The objectives, approach, and status of all current LeRC-sponsored industry contracts and university grants are presented. The following topics are covered: (1) the LeRC Space Communications Program, and Advanced Modulation and Coding Projects; (2) the status of four contracts for development of proof-of-concept modems; (3) modulation and coding work done under three university grants, two small business innovation research contracts, and two demonstration model hardware development contracts; and (4) technology needs and opportunities for future missions.

  14. Improvement of spatial light modulator optical input/output performance using microlens arrays.

    PubMed

    Chase, H; Handschy, M A; O'Callaghan, M J; Supon, F W

    1995-06-15

    Advanced spatial light modulators both detect incident light and modulate reflected light. Each pixel may contain multiple photodetectors, a modulator, control circuitry, and signal-processing circuitry. Because each detector and modulator occupies only a fraction of the area of a pixel the optical efficiency of these devices suffers. We have experimented with improving optical input/output performance by integrating a microlens array with a ferroelectric liquid-crystal VLSI spatial light modulator. We have studied the microlens VLSI spacing accuracy that must be achieved to yield minimum distortion of ref lected wave fronts and the best optical efficiency for Fourier-transform applications.

  15. Optics modules for circular accelerator design

    SciTech Connect

    Brown, K.L.; Servranckx, R.V.

    1986-05-01

    The first-order differential equations of motion for a single particle in a closed circular machine are solved, introducing the concepts of phase shift, beta functions, and the Courant-Snyder invariant. The transfer matrix between two points in the machine is derived as a function of the phase shift and the parameters contained in the Courant-Snyder invariant. Typical optical modules used in circular machine designs are introduced and related to their characteristic transfer matrix elements, the phase shift through them, and the Courant-Snyder-Twiss parameters. The systematics of some elementary phase ellipse matching problems between optical modules are discussed. Second-order optical modules are discussed, including how they are used to provide the momentum bandwidth needed for the design of a typical circular machine. (LEW)

  16. Investigation of direct integrated optics modulators

    NASA Technical Reports Server (NTRS)

    Batchman, T. E.; Mcwright, G. M.

    1981-01-01

    Direct optical modulation techniques applicable to integrated optical data preprocessors were studied. Emphasis was placed on the analysis and fabrication of a field effect type modulator. A series of computer modeling studies were performed to determine the effects of semiconductor cladding on the fields of propagating waves in planar dielectric waveguides. These studies predicted that changes in the propagation characteristics of waveguides clad with silicon and gallium arsenide could be made large enough to be useful in modulators. These effects are dependent on the complex permittivity and thickness of the cladding. Since the conductivity of the cladding can be changed by the photon generation of hole-electron pairs, incoherent light may be used as the input to modulate a coherent light beam. Waveguides were fabricated and silicon claddings were applied to verify the theoretical predictions.

  17. Diode amplifier of modulated optical beam power

    SciTech Connect

    D'yachkov, N V; Bogatov, A P; Gushchik, T I; Drakin, A E

    2014-11-30

    Analytical relations are obtained between characteristics of modulated light at the output and input of an optical diode power amplifier operating in the highly saturated gain regime. It is shown that a diode amplifier may act as an amplitude-to-phase modulation converter with a rather large bandwidth (∼10 GHz). The low sensitivity of the output power of the amplifier to the input beam power and its high energy efficiency allow it to be used as a building block of a high-power multielement laser system with coherent summation of a large number of optical beams. (lasers)

  18. Recent Advances in Photonic Devices for Optical Computing and the Role of Nonlinear Optics-Part II

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Frazier, Donald O.; Witherow, William K.; Banks, Curtis E.; Paley, Mark S.

    2007-01-01

    The twentieth century has been the era of semiconductor materials and electronic technology while this millennium is expected to be the age of photonic materials and all-optical technology. Optical technology has led to countless optical devices that have become indispensable in our daily lives in storage area networks, parallel processing, optical switches, all-optical data networks, holographic storage devices, and biometric devices at airports. This chapters intends to bring some awareness to the state-of-the-art of optical technologies, which have potential for optical computing and demonstrate the role of nonlinear optics in many of these components. Our intent, in this Chapter, is to present an overview of the current status of optical computing, and a brief evaluation of the recent advances and performance of the following key components necessary to build an optical computing system: all-optical logic gates, adders, optical processors, optical storage, holographic storage, optical interconnects, spatial light modulators and optical materials.

  19. Recent advances in optical measurement methods in physics and chemistry

    SciTech Connect

    Gerardo, J.B.

    1985-01-01

    Progress being made in the development of new scientific measurement tools based on optics and the scientific advances made possible by these new tools is impressive. In some instances, new optical-based measurement methods have made new scientific studies possible, while in other instances they have offered an improved method for performing these studies, e.g., better signal-to-noise ratio, increased data acquisition rate, remote analysis, reduced perturbation to the physical or chemical system being studied, etc. Many of these advances were made possible by advances in laser technology - spectral purity, spectral brightness, tunability, ultrashort pulse width, amplitude stability, etc. - while others were made possible by improved optical components - single-made fibers, modulators, detectors, wavelength multiplexes, etc. Attention is limited to just a few of many such accomplishments made recently at Sandia. 17 references, 16 figures.

  20. All-Optical Photochromic Spatial Light Modulators

    NASA Technical Reports Server (NTRS)

    Beratan, David N.; Perry, Joseph W.

    1989-01-01

    Photochemical transfer of electrons enables fast reading and writing. New concept based on transfer of electrons between donor and acceptor molecules randomly distributed or covalently linked and dispersed in glassy-polymer host material. Transfer causes significant changes in optical-transmission characteristics of material and used to modulate transmission of reading beam of light impinging on material.

  1. Photovoltaic driven multiple quantum well optical modulator

    NASA Technical Reports Server (NTRS)

    Maserjian, Joseph (Inventor)

    1990-01-01

    Multiple quantum well (MQW) structures (12) are utilized to provide real-time, reliable, high-performance, optically-addressed spatial-light modulators (SLM) (10). The optically-addressed SLM comprises a vertical stack of quantum well layers (12a) within the penetration depth of an optical write signal 18, a plurality of space charge barriers (12b) having predetermined tunneling times by control of doping and thickness. The material comprising the quantum well layers has a lower bandgap than that of the space charge barrier layers. The write signal modulates a read signal (20). The modulation sensitivity of the device is high and no external voltage source is required. In a preferred embodiment, the SLM having interleaved doped semiconductor layers for driving the MQW photovoltaically is characterized by the use of a shift analogous to the Moss-Burnstein shift caused by the filling of two-dimensional states in the multiple quantum wells, thus allowing high modulation sensitivity in very narrow wells. Arrays (30) may be formed with a plurality of the modulators.

  2. Space photovoltaic modules based on reflective optics

    NASA Technical Reports Server (NTRS)

    Andreev, V. M.; Larionov, V. R.; Rumyantsev, V. D.; Shvarts, M. Z.

    1995-01-01

    The conceptual design and experimental results for two types of space application concentrator photovoltaic modules, employing reflective optical elements, are presented. The first type is based on the use of compound parabolic concentrators, the second type is based on the use of line-focus parabolic troughs. Lightweight concentrators are formed with nickel foil coated silver with a diamond-like carbon layer protection. Secondary optical elements, including lenses and cones, are introduced for a better matching of concentrators and solar cells. Both types of modules are characterized by concentration ratios in the range 20x to 30x, depending on the chosen range of misorientation angles. The estimated specific parameters of these modules operating with single junction AlGaAs/GaAs solar cells are 240 W/sq m and 3 kg/sq m.

  3. Instruction manual, Optical Effects Module, Model OEM

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The Optical Effects Module Model OEM-1, a laboratory prototype instrument designed for the automated measurement of radiation transmission and scattering through optical samples, is described. The system comprises two main components: the Optical Effects Module Enclosure (OEME) and the Optical Effects Module Electronic Controller and Processor (OEMCP). The OEM is designed for operation in the near UV at approximately 2540A, corresponding to the most intense spectral line activated by the mercury discharge lamp used for illumination. The radiation from this source is detected in transmission and reflection through a number of selectable samples. The basic objective of this operation is to monitor in real time the accretion of possible contamination on the surface of these samples. The optical samples are exposed outside of the OEME proper to define exposure conditions and to separate exposure and measurement environments. Changes in the transmissivity of the sample are attributable to surface contamination or to bulk effects due to radiation. Surface contamination will increase radiation scattering due to Rayleigh-Gans effect or to other phenomena, depending on the characteristics size of the particulate contaminants. Thus, also scattering from the samples becomes a part of the measurement program.

  4. Multilayer Dielectric Transmissive Optical Phase Modulator

    NASA Technical Reports Server (NTRS)

    Keys, Andrew Scott; Fork, Richard Lynn

    2004-01-01

    A multilayer dielectric device has been fabricated as a prototype of a low-loss, low-distortion, transmissive optical phase modulator that would provide as much as a full cycle of phase change for all frequency components of a transmitted optical pulse over a frequency band as wide as 6.3 THz. Arrays of devices like this one could be an alternative to the arrays of mechanically actuated phase-control optics (adaptive optics) that have heretofore been used to correct for wave-front distortions in highly precise optical systems. Potential applications for these high-speed wave-front-control arrays of devices include agile beam steering, optical communications, optical metrology, optical tracking and targeting, directional optical ranging, and interferometric astronomy. The device concept is based on the same principle as that of band-pass interference filters made of multiple dielectric layers with fractional-wavelength thicknesses, except that here there is an additional focus on obtaining the desired spectral phase profile in addition to the device s spectral transmission profile. The device includes a GaAs substrate, on which there is deposited a stack of GaAs layers alternating with AlAs layers, amounting to a total of 91 layers. The design thicknesses of the layers range from 10 nm to greater than 1 micrometer. The number of layers and the thickness of each layer were chosen in a computational optimization process in which the wavelength dependences of the indices of refraction of GaAs and AlAs were taken into account as the design was iterated to maximize the transmission and minimize the group-velocity dispersion for a wavelength band wide enough to include all significant spectral components of the pulsed optical signal to be phase modulated.

  5. Electro-optic modulator material

    DOEpatents

    Adams, John J.; Ebbers, Chris A.

    2005-02-22

    An electro-optic device for use with a laser beam. A crystal has a first face and a second face. Means are provided for applying a voltage across the crystal to obtain a net phase retardation on the polarization of the laser beam when the laser beam is passed through the crystal. In one embodiment the crystal is composed of a compound having the chemical formula ReAe40(BO3)3 where: RE consists of one or more of the following elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and two other elements Y and Sc; and where Ae is from the list of Ca, Sr, or Ba.

  6. Effects of modulation phase of ultrasound-modulated light on the ultrasound-modulated optical image in turbid media.

    PubMed

    Weng, Cuncheng; Zhang, Jing

    2012-04-01

    In this paper, our investigations suggest that the modulation phase of ultrasound-modulated light escaping from the different locations in the ultrasonic field is different. In turbid media, the modulation phase causes the ultrasound-modulated light intensity collected outside the media to fluctuate. However, the ultrasound-modulated optical technology uses the ultrasound-modulated light signals to image. Consequently, the modulation phase affects the quality of ultrasound-modulated optical imaging.

  7. Efficiently poled electro-optic polymer modulators.

    PubMed

    Qiu, Feng; Yokoyama, Shiyoshi

    2016-08-22

    A titanium dioxide (TiO2) / electro-optic (EO) polymer hybrid waveguide modulator was designed and fabricated. This modulator possessed a significant advantage for realizing high poling efficiency regardless of the EO polymer resistivity. The in-device EO coefficient was measured to be 100 pm/V, which was 32% higher than that of the thin polymer film. As a result, the phase modulator displayed a VπL figure of merit of 3.5 V∙cm at 1550 nm, which can be reduced further in a push-pull Mach-Zehnder interferometer structure. Temporal stability test of the modulator at 85°C indicated only 8% change of Vπ over 500 hours. The propagation loss in the waveguide was measured as ~3 dB/cm. PMID:27557181

  8. Continuous-wave phase-matched molecular optical modulator

    PubMed Central

    Zaitsu, Shin-ichi; Izaki, Hirotomo; Tsuchiya, Takao; Imasaka, Totaro

    2016-01-01

    In optical modulation, the highest available modulation rate is basically limited to the GHz frequency range at best. This is because optical modulation is often performed using electro-optic or acousto-optic effects that require application of an external signal to solid-state nonlinear optical materials. Here we describe optical modulation of continuous-wave radiation at frequencies exceeding 10 THz based on ultrafast variation of molecule polarizability arising from coherent molecular motion. The optical modulation efficiency is extensively enhanced by fulfilling phase-matching conditions with the help of dispersion control of the optical cavity, generating sidebands with a highest ratio of 7.3 × 10−3. These results will pave the way for development of versatile optical modulation-based techniques in a wide range of research fields in optical sciences, such as mode-locked lasers operating in the THz range. PMID:26887500

  9. Continuous-wave phase-matched molecular optical modulator.

    PubMed

    Zaitsu, Shin-ichi; Izaki, Hirotomo; Tsuchiya, Takao; Imasaka, Totaro

    2016-01-01

    In optical modulation, the highest available modulation rate is basically limited to the GHz frequency range at best. This is because optical modulation is often performed using electro-optic or acousto-optic effects that require application of an external signal to solid-state nonlinear optical materials. Here we describe optical modulation of continuous-wave radiation at frequencies exceeding 10 THz based on ultrafast variation of molecule polarizability arising from coherent molecular motion. The optical modulation efficiency is extensively enhanced by fulfilling phase-matching conditions with the help of dispersion control of the optical cavity, generating sidebands with a highest ratio of 7.3 × 10(-3). These results will pave the way for development of versatile optical modulation-based techniques in a wide range of research fields in optical sciences, such as mode-locked lasers operating in the THz range. PMID:26887500

  10. All optical binary delta-sigma modulator

    NASA Astrophysics Data System (ADS)

    Sayeh, Mohammad R.; Siahmakoun, Azad

    2005-09-01

    This paper describes a novel A/D converter called "Binary Delta-Sigma Modulator" (BDSM) which operates only with nonnegative signal with positive feedback and binary threshold. This important modification to the conventional delta-sigma modulator makes the high-speed (>100GHz) all-optical implementation possible. It has also the capability to modify its own sampling frequency as well as its input dynamic range. This adaptive feature helps designers to optimize the system performance under highly noisy environment and also manage the power consumption of the A/D converters.

  11. Polarisation-Insensitive Optical Fibre Phase Modulator

    NASA Astrophysics Data System (ADS)

    Kreit, Darran; Youngquist, Robert C.; Giles, Ian P.

    1987-10-01

    An acoustic fibre phase modulator, operating up to a few MHz, is described which employs a piezoelectric plate in a squeezing action. A novel construction using two machined brass v-grooves results in a much reduced sensitivity to optical polarisation and the optimum groove angle is independent of the level of friction on the walls of each groove. A normalised birefringence of 0.04 was achieved at 1.5MHz, with a modulation efficiency of approximately 0.23 rad/Vrms., for a 2cm long device.

  12. Virtual k -Space Modulation Optical Microscopy

    NASA Astrophysics Data System (ADS)

    Kuang, Cuifang; Ma, Ye; Zhou, Renjie; Zheng, Guoan; Fang, Yue; Xu, Yingke; Liu, Xu; So, Peter T. C.

    2016-07-01

    We report a novel superresolution microscopy approach for imaging fluorescence samples. The reported approach, termed virtual k -space modulation optical microscopy (VIKMOM), is able to improve the lateral resolution by a factor of 2, reduce the background level, improve the optical sectioning effect and correct for unknown optical aberrations. In the acquisition process of VIKMOM, we used a scanning confocal microscope setup with a 2D detector array to capture sample information at each scanned x -y position. In the recovery process of VIKMOM, we first modulated the captured data by virtual k -space coding and then employed a ptychography-inspired procedure to recover the sample information and correct for unknown optical aberrations. We demonstrated the performance of the reported approach by imaging fluorescent beads, fixed bovine pulmonary artery endothelial (BPAE) cells, and living human astrocytes (HA). As the VIKMOM approach is fully compatible with conventional confocal microscope setups, it may provide a turn-key solution for imaging biological samples with ˜100 nm lateral resolution, in two or three dimensions, with improved optical sectioning capabilities and aberration correcting.

  13. Tunable storage of optical data packets modulated in spectrally efficient formats

    NASA Astrophysics Data System (ADS)

    Schneider, Thomas

    2013-03-01

    An all-optical telecommunications network requires all-optical routers. These routers would be able to process optical signals directly, without the transformation to the electrical domain. Thus, optical routers have the potential to accelerate telecommunications, i.e. to enhance the data rate and to minimize the latency times. Furthermore, since the double transformation at each network node can be omitted, they could be able to reduce the energy consumption of telecommunications. Key elements of optical routers are optical buffers, which are able to store the optical packets prior to processing in order to avoid congestion. Therefore, many different concepts for the realization of optical buffers have been presented so far. Most of these can just store or delay on-off keyed (OOK) signals. However, in optical telecommunications advanced modulation formats will be increasingly used because they are able to improve the transmission properties and to take advantage of the capacity of optical fibers. Thus, advanced modulation formats can drastically increase the transmissible data rates. Most of these advanced formats modulate the carrier's phase or are a combination of amplitude and phase modulation. Here the storage of amplitude and phase modulated data packets with the so called quasi-light-storage (QLS) method will be shown. The QLS relies on the time-bandwidth coherence of each signal. Thus, as long as the sampling theorem in the frequency domain is not violated, a distortion-free storage of optical data packets with a delay-bandwidth product (DBP) of several thousand bits is possible. Here we will discuss the applicability of the QLS method to advanced modulation formats and we show experimental results of the tunable alloptical storage of OOK modulated signals with a DBP of 160 bit and the storage of phase shift keyed signals with a DBP of 60 bits.

  14. Monolithic electro-optic modulator array

    NASA Technical Reports Server (NTRS)

    Robinson, Deborah L. (Inventor); Marshall, William K. (Inventor); Katz, Joseph (Inventor)

    1988-01-01

    A PIN GaAlAs diode structure is provided with parameters for index guiding of light in a single mode. The index of refraction of the central layer I (which in practice may be lightly doped .pi. or .nu.) is greater than the p- and n-layers to create a slab waveguide in the transverse direction. Stripe contacts define separate waveguide channels that are separated electrically and optically by implanting protons or etching grooves between the stripe contacts in the upper layer. Separate reverse biasing voltages may be applied to the stripe contacts for modulation of the light in proportions to the voltage, either with absorption modulation, if the light wavelength is within about 500.ANG. of the bandgap of the .pi.-material, or phase-delay modulation, if the wavelength is separated from the bandgap of the .pi.-material by at least 900.ANG..

  15. Advanced centering of mounted optics

    NASA Astrophysics Data System (ADS)

    Wenzel, Christian; Winkelmann, Ralf; Klar, Rainer; Philippen, Peter; Garden, Ron; Pearlman, Sasha; Pearlman, Guy

    2016-03-01

    Camera objectives or laser focusing units consist of complex lens systems with multiple lenses. The optical performance of such complex lens systems is dependent on the correct positioning of lenses in the system. Deviations in location or angle within the system directly affect the achievable image quality. To optimize the achievable performance of lens systems, these errors can be corrected by machining the mount of the lens with respect to the optical axis. The Innolite GmbH and Opto Alignment Technology have developed a novel machine for such center turning operation. A confocal laser reflection measurement sensor determines the absolute position of the optical axis with reference to the spindle axis. As a strong advantage compared to autocollimator measurements the utilized Opto Alignment sensor is capable of performing centration and tilt measurements without changing objectives on any radius surface from 2 mm to infinity and lens diameters from 0.5 mm to 300 mm, including cylinder, aspheric, and parabolic surfaces. In addition, it performs significantly better on coated lenses. The optical axis is skewed and offset in reference to the spindle axis as determined by the measurement. Using the information about the mount and all reference surfaces, a machine program for an untrue turning process is calculated from this data in a fully automated manner. Since the optical axis is not collinear with the spindle axis, the diamond tool compensates for these linear and tilt deviations with small correction movements. This results in a simple machine setup where the control system works as an electronic alignment chuck. Remaining eccentricity of <1 μm and angular errors of < 10 sec are typical alignment results.

  16. Optical antennas with sinusoidal modulation in width.

    PubMed

    Dikken, Dirk Jan; Segerink, Frans B; Korterik, Jeroen P; Pfaff, Stefan S; Prangsma, Jord C; Herek, Jennifer L

    2016-08-01

    Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in width. We experimentally show that by changing the phase of the width-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm. Using simulations we show how this simple design can create resonance shifts greater than 600 nm. The versatility of this design is further shown by creating asymmetric structures with two different modulation amplitudes, which we experimentally and numerically show to give rise to two resonances. Our results on both the symmetric and asymmetric antennas show the capability to control the localization of the fields outside the antenna, while still maintaining the freedom to change the antenna resonance wavelength. The antenna design we tested combines a large spectral tunability with a small footprint: all the antenna dimensions are factor 7 to 13 smaller than the wavelength, and hold potential as a design element in meta-surfaces for beam shaping. PMID:27505755

  17. Optical antennas with sinusoidal modulation in width.

    PubMed

    Dikken, Dirk Jan; Segerink, Frans B; Korterik, Jeroen P; Pfaff, Stefan S; Prangsma, Jord C; Herek, Jennifer L

    2016-08-01

    Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in width. We experimentally show that by changing the phase of the width-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm. Using simulations we show how this simple design can create resonance shifts greater than 600 nm. The versatility of this design is further shown by creating asymmetric structures with two different modulation amplitudes, which we experimentally and numerically show to give rise to two resonances. Our results on both the symmetric and asymmetric antennas show the capability to control the localization of the fields outside the antenna, while still maintaining the freedom to change the antenna resonance wavelength. The antenna design we tested combines a large spectral tunability with a small footprint: all the antenna dimensions are factor 7 to 13 smaller than the wavelength, and hold potential as a design element in meta-surfaces for beam shaping.

  18. Electro-optic Charon polymeric microring modulators.

    PubMed

    Rezzonico, Daniele; Jazbinsek, Mojca; Guarino, Andrea; Kwon, O-Pil; Günter, Peter

    2008-01-21

    We propose and demonstrate a new type of electro-optic polymeric microring resonators, where the shape of the transmission spectrum is controlled by losses and phase shifts induced at the asymmetric directional coupler between the cavity and the bus waveguide. The theoretical analysis of such Charon microresonators shows, depending on the coupler design, three different transmission characteristics: normal Lorentzian dips, asymmetric Fano resonances, and Lorentzian peaks. The combination of the active azo-stilbene based polyimide SANDM2 surrounded by the hybrid polymer Ormocomp allowed the first experimental demonstration of electro-optic modulation in Charon microresonators. The low-loss modulators (down to 0.6 dB per round trip), with a radius of 50 microm, were produced by micro-embossing and exhibit either highly asymmetric and steep Fano resonances with large 43-GHz modulation bandwidth or strong resonances with 11-dB extinction ratio. We show that Charon microresonators can lead to 1-V half wave voltage all-polymer micrometer-scale devices with larger tolerances to coupler fabrication limitations and wider modulation bandwidths than classical ring resonators.

  19. Optical frequency-modulated continuous-wave interferometers.

    PubMed

    Zheng, Jesse

    2006-04-20

    I discuss optical frequency-modulated continuous-wave (FMCW) interferometers, including their principles, characteristics, specific requirements, procedure for their construction, optical configurations, primary applications, optical sources, resolution, measurement range, and stability. PMID:16633422

  20. Parallel optical interconnects utilizing VLSI/FLC spatial light modulators

    NASA Astrophysics Data System (ADS)

    Genco, Sheryl M.

    1991-12-01

    Interconnection architectures are a cornerstone of parallel computing systems. However, interconnections can be a bottleneck in conventional computer architectures because of queuing structures that are necessary to handle the traffic through a switch at very high data rates and bandwidths. These issues must find new solutions to advance the state of the art in computing beyond the fundamental limit of silicon logic technology. Today's optoelectronic (OE) technology in particular VLSI/FLC spatial light modulators (SLMs) can provide a unique and innovative solution to these issues. This paper reports on the motivations for the system, describes the major areas of architectural requirements, discusses interconnection topologies and processor element alternatives, and documents an optical arbitration (i.e., control) scheme using `smart' SLMs and optical logic gates. The network topology is given in section 2.1 `Architectural Requirements -- Networks,' but it should be noted that the emphasis is on the optical control scheme (section 2.4) and the system.

  1. Optical effects module and passive sample array

    NASA Technical Reports Server (NTRS)

    Linton, R. C.

    1983-01-01

    The Optical Effects Module (OEM) has the objective to monitor the effects of the deposition and adhesion of both molecular species and particles on optical surfaces in the Shuttle cargo bay environment. The OEM performs inflight measurements of the ultraviolet (253.7 nm) transmittance and diffuse reflectance of five optical samples at regular intervals throughout the orbital mission. Most of the obtained results indicates or implies the absence of a significant accumulation of contamination other than particulates on the samples. The contaminant species (or particulates) adhering to the samples of the Passive Sample Array (PSA) were identified by means of Auger and X-ray energy dispersive analyses. The elements silicon, chlorine, and phosphorus were discovered.

  2. Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

    NASA Astrophysics Data System (ADS)

    Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

    2008-02-01

    Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

  3. Advanced rotorcraft helmet display sighting system optics

    NASA Astrophysics Data System (ADS)

    Raynal, Francois; Chen, Muh-Fa

    2002-08-01

    Kaiser Electronics' Advanced Rotorcraft Helmet Display Sighting System is a Biocular Helmet Mounted Display (HMD) for Rotary Wing Aviators. Advanced Rotorcraft HMDs requires low head supported weight, low center of mass offsets, low peripheral obstructions of the visual field, large exit pupils, large eye relief, wide field of view (FOV), high resolution, low luning, sun light readability with high contrast and low prismatic deviations. Compliance with these safety, user acceptance and optical performance requirements is challenging. The optical design presented in this paper provides an excellent balance of these different and conflicting requirements. The Advanced Rotorcraft HMD optical design is a pupil forming off axis catadioptric system that incorporates a transmissive SXGA Active Matrix liquid Crystal Display (AMLCD), an LED array backlight and a diopter adjustment mechanism.

  4. Applications of advanced diffractive optical elements

    NASA Technical Reports Server (NTRS)

    Welch, W. Hudson; Morris, James E.; Feldman, Michael R.

    1993-01-01

    Digital Optics Corporation is a UNC-Charlotte spin-off company, established to transfer technology developed at UNC-Charlotte for the design and manufacture Computer Generated Holograms (CGH's) and to market products based on CGH technology. DOC acquired core technologies from UNC-Charlotte including: (1) a CGH encoding process that can provide holograms with extremely high diffraction efficiency; (2) a low cost, high precision CGH manufacturing process; and (3) extensive holographic and refractive element design capabilities for design and evaluation of complex optical systems. These technologies have been used to design and/or manufacture optical components for a variety of applications including: (1) generation of Spot arrays; (2) fiber optic coupling elements; (3) optical interconnects between VLSI chips within and between multichip modules; and (4) imaging systems for head-mounted displays (HMD's).

  5. Advanced micromoulding of optical components

    NASA Astrophysics Data System (ADS)

    Bauer, Hans-Dieter; Ehrfeld, Wolfgang; Paatzsch, Thomas; Smaglinski, Ingo; Weber, Lutz

    1999-09-01

    There is a growing need for micro-optical components in the field of tele- and datacom applications. Such components have to be very precise and should be available in reasonable numbers. Microtechnology provides manufacturing techniques that fulfill both requirements. Using micro electro discharge machining, laser micromachining, ultra precision milling and deep lithography with subsequent electroforming methods, complex tools for the replication of highly precise plastic parts have been manufactured. In many cases a combination of methods enumerated above gives a tool which shows both functionality and cost-efficiency. As examples we present the realization of integrated-optical components with passive fiber-waveguide coupling used as components in optical networks and as velocity sensors for two-phase flows, like liquids containing small gas bubbles or particles. In the first case multimode 4 X 4 star couplers have been manufactured in a pilot series that show excess loss values below 3 dB and a uniformity better than 3 dB at 830 nm. This performance becomes possible by using a compression molding process. By stamping the microstructured mold into a semifinished PMMA plate exact replication of the molds as well as very low surface roughness of the waveguide side walls could be observed. In the second case the waveguide channels of the flow sensors show dimensions of between 20 micrometer and 100 micrometer and an aspect ratio of about 20. These structures have been replicated by injection molding of PMMA using variotherm process treatment with a cycle time of about 2 - 3 min.

  6. Advanced fiber-optic acoustic sensors

    NASA Astrophysics Data System (ADS)

    Teixeira, João G. V.; Leite, Ivo T.; Silva, Susana; Frazão, Orlando

    2014-09-01

    Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified — fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Pérot configurations — and their recent developments are summarized.

  7. Advanced Geothermal Optical Transducer (AGOT)

    SciTech Connect

    2004-09-01

    Today's geothermal pressure-temperature measuring tools are short endurance, high value instruments, used sparingly because their loss is a major expense. In this project LEL offered to build and test a rugged, affordable, downhole sensor capable ofretuming an uninterrupted data stream at pressures and of 10,000 psi and temperatures up to 250 C, thus permitting continuous deep-well logging. It was proposed to meet the need by specializing LEL's patented 'Twin Column Transducer' technology to satisfy the demands of geothermal pressure/temperature measurements. TCT transducers have very few parts, none of which are moving parts, and all of which can be fabricated from high-temperature super alloys or from ceramics; the result is an extremely rugged device, essentially impervious to chemical attack and readily modified to operate at high pressure and temperature. To measure pressure and temperature they capitalize on the relative expansion of optical elements subjected to thermal or mechanical stresses; if one element is maintained at a reference pressure while the other is opened to ambient, the differential displacement then serves as a measure of pressure. A transducer responding to temperature rather than pressure is neatly created by 'inverting' the pressure-measuring design so that both deflecting structures see identical temperatures and temperature gradients, but whose thermal expansion coefficients are deliberately mismatched to give differential expansion. The starting point for development of a PT Tool was the company's model DPT feedback-stabilized 5,000 psi sensor (U.S. Patent 5,311,014, 'Optical Transducer for Measuring Downhole Pressure', claiming a pressure transducer capable of measuring static, dynamic, and true bi-directional differential pressure at high temperatures), shown in the upper portion of Figure 1. The DPT occupies a 1 x 2 x 4-inch volume, weighs 14 ounces, and is accurate to 1 percent of full scale. Employing a pair of identical, low

  8. Linearization of acousto-optic modulator transmission function

    NASA Astrophysics Data System (ADS)

    Korol, G.; Moskaletz, D.; Moskaletz, O.

    2016-08-01

    The procedure of linearization of nonlinear transmission function of the optical transparency in the form of an acousto-optic modulator by the methods of nonlinear functional analysis is described. The transmission function of a pair of acousto-optic modulators is linearized in the context of generalized superposition principle.

  9. Advances in modulation spectroscopy: State-of-art photoreflectance metrology

    NASA Astrophysics Data System (ADS)

    Murtagh, M. E.; Ward, S.; Nee, D.; Kelly, P. V.

    2006-10-01

    In this paper, technological advances of modulation spectroscopy are presented, exploiting the sensitivity, room-temperature resolution, as well as the rapid and non-contact (non-destructive) nature of laser-induced photoreflectance (PR). A novel method of asynchronous (switching) modulation is presented to overcome laser-induced non-PR background effects, which limit or even obscure the complex (phase) PR response. The solid-state, acousto-optic based method may even be employed for non-uniform samples, and moreover, exhibits evidence for improved signal-to-noise level. Also presented is a novel optical design in order to achieve multiple, independent and simultaneous spectral acquisition, including auto-calibration. Results are demonstrated for heavily doped n-type and p-type GaAs substrates, and also technologically important HBT device structures, with further applications also emphasised for HEMTs, LEDs, etc. The results demonstrate the importance and role of PR as a successful commercial metrology tool for existing state-of-art, as well as next generation semiconductor characterisation and statistical-process-control (SPC) equipment.

  10. Advanced optics in an interdisciplinary graduate program

    NASA Astrophysics Data System (ADS)

    Nic Chormaic, S.

    2014-07-01

    The Okinawa Institute of Science and Technology Graduate University, established in November 2011, provides a 5- year interdisciplinary PhD program, through English, within Japan. International and Japanese students entering the program undertake coursework and laboratory rotations across a range of topics, including neuroscience, molecular science, physics, chemistry, marine science and mathematics, regardless of previous educational background. To facilitate interdisciplinarity, the university has no departments, ensuring seamless interactions between researchers from all sectors. As part of the PhD program a course in Advanced Optics has been developed to provide PhD students with the practical and theoretical skills to enable them to use optics tools in any research environment. The theoretical aspect of the course introduces students to procedures for complex beam generation (e.g. Laguerre-Gaussian), optical trapping, beam analysis and photon optics, and is supported through a practical program covering introductory interference/diffraction experiments through to more applied fiber optics. It is hoped that, through early exposure to optics handling and measurement techniques, students will be able to develop and utilize optics tools regardless of research field. In addition to the formal course in Advanced Optics, a selection of students also undertakes 13 week laboratory rotations in the Light-Matter Interactions research laboratory, where they work side-by-side with physicists in developing optics tools for laser cooling, photonics or bio-applications. While currently in the first year, conclusive results about the success of such an interdisciplinary PhD training are speculative. However, initial observations indicate a rich cross-fertilization of ideas stemming from the diverse backgrounds of all participants.

  11. Advances in optical imaging for pharmacological studies

    PubMed Central

    Arranz, Alicia; Ripoll, Jorge

    2015-01-01

    Imaging approaches are an essential tool for following up over time representative parameters of in vivo models, providing useful information in pharmacological studies. Main advantages of optical imaging approaches compared to other imaging methods are their safety, straight-forward use and cost-effectiveness. A main drawback, however, is having to deal with the presence of high scattering and high absorption in living tissues. Depending on how these issues are addressed, three different modalities can be differentiated: planar imaging (including fluorescence and bioluminescence in vivo imaging), optical tomography, and optoacoustic approaches. In this review we describe the latest advances in optical in vivo imaging with pharmacological applications, with special focus on the development of new optical imaging probes in order to overcome the strong absorption introduced by different tissue components, especially hemoglobin, and the development of multimodal imaging systems in order to overcome the resolution limitations imposed by scattering. PMID:26441646

  12. Multiplexing electro-optic architectures for advanced aircraft integrated flight control systems

    NASA Technical Reports Server (NTRS)

    Seal, D. W.

    1989-01-01

    This report describes the results of a 10 month program sponsored by NASA. The objective of this program was to evaluate various optical sensor modulation technologies and to design an optimal Electro-Optic Architecture (EOA) for servicing remote clusters of sensors and actuators in advanced aircraft flight control systems. The EOA's supply optical power to remote sensors and actuators, process the modulated optical signals returned from the sensors, and produce conditioned electrical signals acceptable for use by a digital flight control computer or Vehicle Management System (VMS) computer. This study was part of a multi-year initiative under the Fiber Optic Control System Integration (FOCSI) program to design, develop, and test a totally integrated fiber optic flight/propulsion control system for application to advanced aircraft. Unlike earlier FOCSI studies, this program concentrated on the design of the EOA interface rather than the optical transducer technology itself.

  13. Chemical Approaches for Advanced Optical Imaging

    NASA Astrophysics Data System (ADS)

    Chen, Zhixing

    Advances in optical microscopy have been constantly expanding our knowledge of biological systems. The achievements therein are a result of close collaborations between physicists/engineers who build the imaging instruments and chemists/biochemists who design the corresponding probe molecules. In this work I present a number of chemical approaches for the development of advanced optical imaging methods. Chapter 1 provides an overview of the recent advances of novel imaging approaches taking advantage of chemical tag technologies. Chapter 2 describes the second-generation covalent trimethoprim-tag as a viable tool for live cell protein-specific labeling and imaging. In Chapter 3 we present a fluorescence lifetime imaging approach to map protein-specific micro-environment in live cells using TMP-Cy3 as a chemical probe. In Chapter 4, we present a method harnessing photo-activatable fluorophores to extend the fundamental depth limit in multi-photon microscopy. Chapter 5 describes the development of isotopically edited alkyne palette for multi-color live cell vibrational imaging of cellular small molecules. These studies exemplify the impact of modern chemical approaches in the development of advanced optical microscopies.

  14. Optical Fiber Sensors for Advanced Civil Structures

    NASA Astrophysics Data System (ADS)

    de Vries, Marten Johannes Cornelius

    1995-01-01

    The objective of this dissertation is to develop, analyze, and implement optical fiber-based sensors for the nondestructive quantitative evaluation of advanced civil structures. Based on a comparative evaluation of optical fiber sensors that may be used to obtain quantitative information related to physical perturbations in the civil structure, the extrinsic Fabry-Perot interferometric (EFPI) optical fiber sensor is selected as the most attractive sensor. The operation of the EFPI sensor is explained using the Kirchhoff diffraction approach. As is shown in this dissertation, this approach better predicts the signal-to-noise ratio as a function of gap length than methods employed previously. The performance of the optical fiber sensor is demonstrated in three different implementations. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in cooperation with researchers at the United States Bureau of Mines in Spokane, Washington, used optical fiber sensors to monitor the performance of roof bolts used in mines. The last implementation, performed in cooperation with researchers at the Turner-Fairbanks Federal Highway Administration Research Center in McLean, Virginia, used optical fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. Multiplexing techniques including time, frequency and wavelength division multiplexing are briefly discussed, whereas the principles of operation of spread spectrum and optical time domain reflectometery (OTDR) are discussed in greater detail. Results demonstrating that spread spectrum and OTDR techniques can be used to multiplex optical fiber sensors are presented. Finally, practical

  15. Advanced optical blade tip clearance measurement system

    NASA Technical Reports Server (NTRS)

    Ford, M. J.; Honeycutt, R. E.; Nordlund, R. E.; Robinson, W. W.

    1978-01-01

    An advanced electro-optical system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in an operating gas turbine engine. This system is applicable to fan, compressor, and turbine blade tip clearance measurement requirements, and the system probe is particularly suitable for operation in the extreme turbine environment. A study of optical properties of blade tips was conducted to establish measurement system application limitations. A series of laboratory tests was conducted to determine the measurement system's operational performance characteristics and to demonstrate system capability under simulated operating gas turbine environmental conditions. Operational and environmental performance test data are presented.

  16. Advance lightpath provisioning in interdomain optical networks

    NASA Astrophysics Data System (ADS)

    Hafid, A.; Maach, A.; Khair, M. G.; Drissi, J.

    2005-11-01

    In interconnected optical networks, users submit lightpath requests at the time they wish to establish the lightpath. The service provider consults the information gathered by the interdomain routing protocols for available resources. For each request, the network must decide immediately whether to accept or reject the request. In this model, there is always the uncertainty of whether the user will be able to establish the desired lightpath at the desired time or not. Furthermore, in the context of a number of applications, e.g., grid applications, users need to set up lightpaths in advance to perform their activities that are planned in advance. We propose a new interdomain routing protocol called Advance Optical Routing Border Gateway Protocol (AORBGP) and a scheme that allows the setup of interdomain lightpaths in advance. AORBGP allows gathering information about interdomain paths and availability of wavelengths in the future. The proposed advance lightpath setup scheme makes use of AORBGP to get information about available resources (i.e., wavelengths) required to process lightpath setup requests. One of the key innovations of the scheme is that it provides the user with alternatives, carefully selected, when his or her request cannot be accommodated because of resource shortages. Indeed, the scheme provides the user with options to set up a lightpath later than the requested start time or with shorter duration than the requested duration. We performed a set of simulations to evaluate the benefits of the proposed scheme and the effect of a number of parameters on the performance of AORBGP.

  17. Electronic band-gap modified passive silicon optical modulator at telecommunications wavelengths.

    PubMed

    Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Liu, Xiangdong; Lu, Qingming; Wang, Jiyang

    2015-01-01

    The silicon optical modulator is considered to be the workhorse of a revolution in communications. In recent years, the capabilities of externally driven active silicon optical modulators have dramatically improved. Self-driven passive modulators, especially passive silicon modulators, possess advantages in compactness, integration, low-cost, etc. Constrained by a large indirect band-gap and sensitivity-related loss, the passive silicon optical modulator is scarce and has been not advancing, especially at telecommunications wavelengths. Here, a passive silicon optical modulator is fabricated by introducing an impurity band in the electronic band-gap, and its nonlinear optics and applications in the telecommunications-wavelength lasers are investigated. The saturable absorption properties at the wavelength of 1.55 μm was measured and indicates that the sample is quite sensitive to light intensity and has negligible absorption loss. With a passive silicon modulator, pulsed lasers were constructed at wavelengths at 1.34 and 1.42 μm. It is concluded that the sensitive self-driven passive silicon optical modulator is a viable candidate for photonics applications out to 2.5 μm.

  18. Electronic band-gap modified passive silicon optical modulator at telecommunications wavelengths

    PubMed Central

    Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Liu, Xiangdong; Lu, Qingming; Wang, Jiyang

    2015-01-01

    The silicon optical modulator is considered to be the workhorse of a revolution in communications. In recent years, the capabilities of externally driven active silicon optical modulators have dramatically improved. Self-driven passive modulators, especially passive silicon modulators, possess advantages in compactness, integration, low-cost, etc. Constrained by a large indirect band-gap and sensitivity-related loss, the passive silicon optical modulator is scarce and has been not advancing, especially at telecommunications wavelengths. Here, a passive silicon optical modulator is fabricated by introducing an impurity band in the electronic band-gap, and its nonlinear optics and applications in the telecommunications-wavelength lasers are investigated. The saturable absorption properties at the wavelength of 1.55 μm was measured and indicates that the sample is quite sensitive to light intensity and has negligible absorption loss. With a passive silicon modulator, pulsed lasers were constructed at wavelengths at 1.34 and 1.42 μm. It is concluded that the sensitive self-driven passive silicon optical modulator is a viable candidate for photonics applications out to 2.5 μm. PMID:26563679

  19. Electronic band-gap modified passive silicon optical modulator at telecommunications wavelengths

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Liu, Xiangdong; Lu, Qingming; Wang, Jiyang

    2015-11-01

    The silicon optical modulator is considered to be the workhorse of a revolution in communications. In recent years, the capabilities of externally driven active silicon optical modulators have dramatically improved. Self-driven passive modulators, especially passive silicon modulators, possess advantages in compactness, integration, low-cost, etc. Constrained by a large indirect band-gap and sensitivity-related loss, the passive silicon optical modulator is scarce and has been not advancing, especially at telecommunications wavelengths. Here, a passive silicon optical modulator is fabricated by introducing an impurity band in the electronic band-gap, and its nonlinear optics and applications in the telecommunications-wavelength lasers are investigated. The saturable absorption properties at the wavelength of 1.55 μm was measured and indicates that the sample is quite sensitive to light intensity and has negligible absorption loss. With a passive silicon modulator, pulsed lasers were constructed at wavelengths at 1.34 and 1.42 μm. It is concluded that the sensitive self-driven passive silicon optical modulator is a viable candidate for photonics applications out to 2.5 μm.

  20. Applications of ``PV Optics`` for solar cell and module design

    SciTech Connect

    Sopori, B.L.; Madjdpour, J.; Chen, W.

    1998-09-01

    This paper describes some applications of a new optics software package, PV Optics, developed for the optical design of solar cells and modules. PV Optics is suitable for the analysis and design of both thick and thin solar cells. It also includes a feature for calculation of metallic losses related to contacts and back reflectors.

  1. Digital polarization holography advancing geometrical phase optics.

    PubMed

    De Sio, Luciano; Roberts, David E; Liao, Zhi; Nersisyan, Sarik; Uskova, Olena; Wickboldt, Lloyd; Tabiryan, Nelson; Steeves, Diane M; Kimball, Brian R

    2016-08-01

    Geometrical phase or the fourth generation (4G) optics enables realization of optical components (lenses, prisms, gratings, spiral phase plates, etc.) by patterning the optical axis orientation in the plane of thin anisotropic films. Such components exhibit near 100% diffraction efficiency over a broadband of wavelengths. The films are obtained by coating liquid crystalline (LC) materials over substrates with patterned alignment conditions. Photo-anisotropic materials are used for producing desired alignment conditions at the substrate surface. We present and discuss here an opportunity of producing the widest variety of "free-form" 4G optical components with arbitrary spatial patterns of the optical anisotropy axis orientation with the aid of a digital spatial light polarization converter (DSLPC). The DSLPC is based on a reflective, high resolution spatial light modulator (SLM) combined with an "ad hoc" optical setup. The most attractive feature of the use of a DSLPC for photoalignment of nanometer thin photo-anisotropic coatings is that the orientation of the alignment layer, and therefore of the fabricated LC or LC polymer (LCP) components can be specified on a pixel-by-pixel basis with high spatial resolution. By varying the optical magnification or de-magnification the spatial resolution of the photoaligned layer can be adjusted to an optimum for each application. With a simple "click" it is possible to record different optical components as well as arbitrary patterns ranging from lenses to invisible labels and other transparent labels that reveal different images depending on the side from which they are viewed. PMID:27505793

  2. Advancements in metro optical network architectures

    NASA Astrophysics Data System (ADS)

    Paraschis, Loukas

    2005-02-01

    This paper discusses the innovation in network architectures, and optical transport, that enables metropolitan networks to cost-effectively scale to hundreds Gb/s of capacity, and to hundreds km of reach, and to also meet the diverse service needs of enterprise and residential applications. A converged metro network, where Ethernet/IP services, and traditional TDM traffic operate over an intelligent WDM transport layer is increasingly becoming the most attractive architecture addressing the primary need of network operators for significantly improved capital and operational network cost. At the same time, this converged network has to leverage advanced technology, and introduce intelligence in order to significantly improve the deployment and manageability of WDM transport. The most important system advancements and the associated technology innovations that enhance the cost-effectiveness of metropolitan optical networks are being reviewed.

  3. Recent advances in optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ding, Zhihua; Wang, Chuan; Shen, Yi; Huang, Liangming; Wu, Lan; Du, Chixin

    2012-12-01

    This paper reports recent advances in spectral domain Doppler optical coherence tomography (SD-DOCT) in our group. A high speed SD-DOCT system is developed and applied to animal study and microchip evaluation. Further improvements concerning SD-DOCT are presented, those including higher-order cross-correlation for phase retrieval, transit-time analysis for velocity quantification, and orthogonal dispersive SD-OCT for depth extension.

  4. Optically Modulated Fluorescence Bioimaging: Visualizing Obscured Fluorophores in High Background

    PubMed Central

    2015-01-01

    Conspectus Fluorescence microscopy and detection have become indispensible for understanding organization and dynamics in biological systems. Novel fluorophores with improved brightness, photostability, and biocompatibility continue to fuel further advances but often rely on having minimal background. The visualization of interactions in very high biological background, especially for proteins or bound complexes at very low copy numbers, remains a primary challenge. Instead of focusing on molecular brightness of fluorophores, we have adapted the principles of high-sensitivity absorption spectroscopy to improve the sensitivity and signal discrimination in fluorescence bioimaging. Utilizing very long wavelength transient absorptions of kinetically trapped dark states, we employ molecular modulation schemes that do not simultaneously modulate the background fluorescence. This improves the sensitivity and ease of implementation over high-energy photoswitch-based recovery schemes, as no internal dye reference or nanoparticle-based fluorophores are needed to separate the desired signals from background. In this Account, we describe the selection process for and identification of fluorophores that enable optically modulated fluorescence to decrease obscuring background. Differing from thermally stable photoswitches using higher-energy secondary lasers, coillumination at very low energies depopulates transient dark states, dynamically altering the fluorescence and giving characteristic modulation time scales for each modulatable emitter. This process is termed synchronously amplified fluorescence image recovery (SAFIRe) microscopy. By understanding and optically controlling the dye photophysics, we selectively modulate desired fluorophore signals independent of all autofluorescent background. This shifts the fluorescence of interest to unique detection frequencies with nearly shot-noise-limited detection, as no background signals are collected. Although the fluorescence

  5. Advanced Indoor Module Light-Soaking Facility

    SciTech Connect

    del Cueto, J. A.; Osterwald, C.; Pruett, J.

    2005-01-01

    An overview of the accelerated, indoor light-soaking test station is presented in this paper, along with data obtained for six modules that underwent exposure. The station comprises a climate-controlled chamber equipped with a solar simulator that allows 1-sun light intensity exposure. Concurrently, we monitor the electrical characteristics of multiple PV modules and exercise active control over their electrical bias using programmable electronic loads, interfaced to a data acquisition system that acquires power-tracking and current-voltage data. This capability allows us to the test different bias conditions and to cyclically alternate between them. Additionally, we can vary the light intensity and module temperatures to garner realistic temperature coefficients of module performance. Data obtained on cadmium telluride (CdTe) and amorphous silicon (a-Si) modules are presented.

  6. RF modulated fiber optic sensing systems and their applications

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory; Eustace, John G.

    1992-01-01

    A fiber optic sensing system with an intensity sensor and a Radio Frequency (RF) modulated source was shown to have sensitivity and resolution much higher than a comparable system employing low modulating frequencies or DC mode of operation. Also the RF modulation with an appropriate configuration of the sensing system provides compensation for the unwanted intensity losses. The basic principles and applications of a fiber optic sensing system employing an RF modulated source are described. In addition the paper discusses various configurations of the system itself, its components, and modulation and detection schemes. Experimental data are also presented.

  7. Module optical analyzer: Identification of defects on the production line

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Askins, Stephen; Antón, Ignacio; Sala, Gabriel; Araki, Kenji; Nagai, Hirokazu

    2014-09-01

    The usefulness of the module optical analyzer when identifying module defects on production line is presented in this paper. Two different case studies performed with two different kind of CPV modules are presented to show the use of MOA both in IES-UPM and Daido Steel facilities.

  8. Graphene based All-Optical Spatial Terahertz Modulator

    PubMed Central

    Wen, Qi-Ye; Tian, Wei; Mao, Qi; Chen, Zhi; Liu, Wei-Wei; Yang, Qing-Hui; Sanderson, Matthew; Zhang, Huai-Wu

    2014-01-01

    We demonstrate an all-optical terahertz modulator based on single-layer graphene on germanium (GOG), which can be driven by a 1.55 μm CW laser with a low-level photodoping power. Both the static and dynamic THz transmission modulation experiments were carried out. A spectrally wide-band modulation of the THz transmission is obtained in a frequency range from 0.25 to 1 THz, and a modulation depth of 94% can be achieved if proper pump power is applied. The modulation speed of the modulator was measured to be ~200 KHz using a 340 GHz carrier. A theoretical model is proposed for the modulator and the calculation results indicate that the enhanced THz modulation is mainly due to the third order nonlinear effect in the optical conductivity of the graphene monolayer. PMID:25491194

  9. Analysis of optical frequency-modulated continuous-wave interference.

    PubMed

    Zheng, Jesse

    2004-07-20

    I systematically analyze the theory of optical frequency-modulated continuous-wave (FMCW) interference. There are three different versions of optical FMCW interference, discussed in detail: sawtooth-wave optical FMCW interference, triangular-wave optical FMCW interference, and sinusoidal-wave optical FMCW interference. The essential concepts and technical terms are clearly defined, the necessary simplifications are introduced according to the characteristics of optical waves, and the formulas used to calculate the signal intensities under two different situations (static and dynamic) are properly derived. Advantages and limitations of each version of optical FMCW interference are also discussed. PMID:15291063

  10. Monolithically integrated quantum dot optical modulator with Semiconductor optical amplifier for short-range optical communications

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

    2015-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed. Broadband QD optical gain material was used to achieve Gbps-order high-speed optical data transmission, and an optical gain change as high as approximately 6-7 dB was obtained with a low OGM voltage of 2.0 V. Loss of optical power due to insertion of the device was also effectively compensated for by the SOA section. Furthermore, it was confirmed that the QD-OGM/SOA device helped achieve 6.0-Gbps error-free optical data transmission over a 2.0-km-long photonic crystal fiber. We also successfully demonstrated generation of Gbps-order, high-speed, and error-free optical signals in the >5.5-THz broadband optical frequency bandwidth larger than the C-band. These results suggest that the developed monolithically integrated QD-OGM/SOA device will be an advantageous and compact means of increasing the usable optical frequency channels for short-reach communications.

  11. Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks

    NASA Astrophysics Data System (ADS)

    Lacava, C.; Liu, Z.; Thomson, D.; Ke, Li; Fedeli, J. M.; Richardson, D. J.; Reed, G. T.; Petropoulos, P.

    2016-02-01

    Communication traffic grows relentlessly in today's networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission.

  12. Modulation properties of optically injection-locked quantum cascade lasers.

    PubMed

    Wang, Cheng; Grillot, Fédéric; Kovanis, Vassilios I; Bodyfelt, Joshua D; Even, Jacky

    2013-06-01

    A rate equation analysis on the modulation response of an optical injection-locked quantum cascade laser is outlined. It is found that the bifurcation diagram exhibits both bistable and unstable locked regions. In addition, the stable locked regime widens as the linewidth enhancement factor increases. It is also shown that both positive and negative optical detunings as well as strong injection strength enhance the 3 dB modulation bandwidth by as much as 30 GHz. Finally, the peak in the modulation response is significantly influenced by the optical frequency detuning.

  13. Advanced Structural and Inflatable Hybrid Spacecraft Module

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor); delaFuente, Horacio M. (Inventor); Edeen, Gregg A. (Inventor); Kennedy, Kriss J. (Inventor); Lester, James D. (Inventor); Gupta, Shalini (Inventor); Hess, Linda F. (Inventor); Lin, Chin H. (Inventor); Malecki, Richard H. (Inventor); Raboin, Jasen L. (Inventor)

    2001-01-01

    An inflatable module comprising a structural core and an inflatable shell, wherein the inflatable shell is sealingly attached to the structural core. In its launch configuration, the wall thickness of the inflatable shell is collapsed by vacuum. Also in this configuration, the inflatable shell is collapsed and efficiently folded around the structural core. Upon deployment, the wall thickness of the inflatable shell is inflated; whereby the inflatable shell itself, is thereby inflated around the structural core, defining therein a large enclosed volume. A plurality of removable shelves are arranged interior to the structural core in the launch configuration. The structural core also includes at least one longeron that, in conjunction with the shelves, primarily constitute the rigid, strong, and lightweight load-bearing structure of the module during launch. The removable shelves are detachable from their arrangement in the launch configuration so that, when the module is in its deployed configuration and launch loads no longer exist, the shelves can be rearranged to provide a module interior arrangement suitable for human habitation and work. In the preferred embodiment, to provide efficiency in structural load paths and attachments, the shape of the inflatable shell is a cylinder with semi-toroidal ends.

  14. Advanced optic fabrication using ultrafast laser radiation

    NASA Astrophysics Data System (ADS)

    Taylor, Lauren L.; Qiao, Jun; Qiao, Jie

    2016-03-01

    Advanced fabrication and finishing techniques are desired for freeform optics and integrated photonics. Methods including grinding, polishing and magnetorheological finishing used for final figuring and polishing of such optics are time consuming, expensive, and may be unsuitable for complex surface features while common photonics fabrication techniques often limit devices to planar geometries. Laser processing has been investigated as an alternative method for optic forming, surface polishing, structure writing, and welding, as direct tuning of laser parameters and flexible beam delivery are advantageous for complex freeform or photonics elements and material-specific processing. Continuous wave and pulsed laser radiation down to the nanosecond regime have been implemented to achieve nanoscale surface finishes through localized material melting, but the temporal extent of the laser-material interaction often results in the formation of a sub-surface heat affected zone. The temporal brevity of ultrafast laser radiation can allow for the direct vaporization of rough surface asperities with minimal melting, offering the potential for smooth, final surface quality with negligible heat affected material. High intensities achieved in focused ultrafast laser radiation can easily induce phase changes in the bulk of materials for processing applications. We have experimentally tested the effectiveness of ultrafast laser radiation as an alternative laser source for surface processing of monocrystalline silicon. Simulation of material heating associated with ultrafast laser-material interaction has been performed and used to investigate optimized processing parameters including repetition rate. The parameter optimization process and results of experimental processing will be presented.

  15. Recent Advances in Miniaturized Optical Gyroscopes

    NASA Astrophysics Data System (ADS)

    Dell'Olio, F.; Tatoli, T.; Ciminelli, C.; Armenise, M. N.

    2014-03-01

    Low-cost chip-scale optoelectronic gyroscopes having a resolution ≤ 10 °/h and a good reliability also in harsh environments could have a strong impact on the medium/high performance gyro market, which is currently dominated by well-established bulk optical angular velocity sensors. The R&D activity aiming at the demonstration of those miniaturized sensors is crucial for aerospace/defense industry, and thus it is attracting an increasing research effort and notably funds. In this paper the recent technological advances on the compact optoelectronic gyroscopes with low weight and high energy saving are reviewed. Attention is paid to both the so-called gyroscope-on-a-chip, which is a novel sensor, at the infantile stage, whose optical components are monolithically integrated on a single indium phosphide chip, and to a new ultra-high Q ring resonator for gyro applications with a configuration including a 1D photonic crystal in the resonant path. The emerging field of the gyros based on passive ring cavities, which have already shown performance comparable with that of optical fiber gyros, is also discussed.

  16. Strong squeezing in periodically modulated optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Adamyan, Hayk H.; Bergou, János A.; Gevorgyan, Narine T.; Kryuchkyan, Gagik Yu.

    2015-11-01

    We consider specific signatures of squeezing for time-modulated light fields and propose the scheme of an optical parametric oscillator driven by a continuously modulated pump field. The application of a periodically modulated driving field instead of a continuous wave field drastically improves the degree of quadrature integral squeezing. This quantity goes below the standard limit of 50% relative to the level of vacuum fluctuations. We develop semiclassical and quantum theories of an optical parametric oscillator under the influence of a pump field with harmonically modulated amplitude for all operational regimes, including numerical simulations at the threshold point. The results can be directly applied in time-resolved quantum communication protocols.

  17. Advanced Optical Technologies for Space Exploration

    NASA Technical Reports Server (NTRS)

    Clark, Natalie

    2007-01-01

    NASA Langley Research Center is involved in the development of photonic devices and systems for space exploration missions. Photonic technologies of particular interest are those that can be utilized for in-space communication, remote sensing, guidance navigation and control, lunar descent and landing, and rendezvous and docking. NASA Langley has recently established a class-100 clean-room which serves as a Photonics Fabrication Facility for development of prototype optoelectronic devices for aerospace applications. In this paper we discuss our design, fabrication, and testing of novel active pixels, deformable mirrors, and liquid crystal spatial light modulators. Successful implementation of these intelligent optical devices and systems in space, requires careful consideration of temperature and space radiation effects in inorganic and electronic materials. Applications including high bandwidth inertial reference units, lightweight, high precision star trackers for guidance, navigation, and control, deformable mirrors, wavefront sensing, and beam steering technologies are discussed. In addition, experimental results are presented which characterize their performance in space exploration systems.

  18. Modulated Fourier Transform Raman Fiber-Optic Spectroscopy

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor); Cooper, John B. (Inventor); Wise, Kent L. (Inventor)

    2000-01-01

    A modification to a commercial Fourier Transform (FT) Raman spectrometer is presented for the elimination of thermal backgrounds in the FT Raman spectra. The modification involves the use of a mechanical optical chopper to modulate the continuous wave laser, remote collection of the signal via fiber optics, and connection of a dual-phase digital-signal-processor (DSP) lock-in amplifier between the detector and the spectrometer's collection electronics to demodulate and filter the optical signals. The resulting Modulated Fourier Transform Raman Fiber-Optic Spectrometer is capable of completely eliminating thermal backgrounds at temperatures exceeding 300 C.

  19. Advances in optics for biotechnology, medicine and surgery.

    PubMed

    Fitzmaurice, Maryann; Pogue, Brian W; Tearney, Guillermo J; Tunnell, James W; Yang, Changhuei

    2014-02-01

    The guest editors introduce a Biomedical Optics Express feature issue that includes contributions from participants at the 2013 conference on Advances in Optics for Biotechnology, Medicine and Surgery XIII.

  20. Advances in optics for biotechnology, medicine and surgery.

    PubMed

    Fitzmaurice, Maryann; Pogue, Brian W; Tearney, Guillermo J; Tunnell, James W; Yang, Changhuei

    2014-02-01

    The guest editors introduce a Biomedical Optics Express feature issue that includes contributions from participants at the 2013 conference on Advances in Optics for Biotechnology, Medicine and Surgery XIII. PMID:24575348

  1. Advances in optics for biotechnology, medicine and surgery

    PubMed Central

    Fitzmaurice, Maryann; Pogue, Brian W.; Tearney, Guillermo J.; Tunnell, James W.; Yang, Changhuei

    2014-01-01

    The guest editors introduce a Biomedical Optics Express feature issue that includes contributions from participants at the 2013 conference on Advances in Optics for Biotechnology, Medicine and Surgery XIII. PMID:24575348

  2. High-Power, High-Speed Electro-Optic Pockels Cell Modulator

    NASA Technical Reports Server (NTRS)

    Hawthorne, Justin; Battle, Philip

    2013-01-01

    Electro-optic modulators rely on a change in the index of refraction for the optical wave as a function of an applied voltage. The corresponding change in index acts to delay the wavefront in the waveguide. The goal of this work was to develop a high-speed, high-power waveguide- based modulator (phase and amplitude) and investigate its use as a pulse slicer. The key innovation in this effort is the use of potassium titanyl phosphate (KTP) waveguides, making the highpower, polarization-based waveguide amplitude modulator possible. Furthermore, because it is fabricated in KTP, the waveguide component will withstand high optical power and have a significantly higher RF modulation figure of merit (FOM) relative to lithium niobate. KTP waveguides support high-power TE and TM modes - a necessary requirement for polarization-based modulation as with a Pockels cell. High-power fiber laser development has greatly outpaced fiber-based modulators in terms of its maturity and specifications. The demand for high-performance nonlinear optical (NLO) devices in terms of power handling, efficiency, bandwidth, and useful wavelength range has driven the development of bulk NLO options, which are limited in their bandwidth, as well as waveguide based LN modulators, which are limited by their low optical damage threshold. Today, commercially available lithium niobate (LN) modulators are used for laser formatting; however, because of photorefractive damage that can reduce transmission and increase requirements on bias control, LN modulators cannot be used with powers over several mW, dependent on wavelength. The high-power, high-speed modulators proposed for development under this effort will enable advancements in several exciting fields including lidarbased remote sensing, atomic interferometry, free-space laser communications, and others.

  3. A capillary optical fiber modulator derivates from magnetic fluid

    NASA Astrophysics Data System (ADS)

    Yang, Xinghua; Liu, Yanxin; Zheng, Yao; Li, Shouzhu; Yuan, Libo; Yuan, Tingting; Tong, Chengguo

    2013-09-01

    A novel in-fiber integrated modulator based on magnetic fluid is proposed. The Fe3O4 magnetic fluid is encapsulated into a specially designed capillary optical fiber with a circular waveguide. Experimental results show that the light at 632.8 nm in the circular waveguide can be modulated by only 2.17×10-2 μL of the magnetic fluid under magnetic field. A wide range of modulation-depth from 44% to 75% can be obtained by adjusting the external magnetic field strength, temperature and the concentration of the magnetic fluid. In addition, the modulator shows good stability and repeatability. This work has great potentials in the integrated optical devices such as tunable in-fiber modulators, optical switches and magnetic sensors.

  4. Optical modulator based on coupled photonic crystal cavities

    NASA Astrophysics Data System (ADS)

    Serafimovich, Pavel G.; Kazanskiy, Nikolay L.

    2016-07-01

    We propose and numerically investigate an optical signal modulator based on two-photonic crystal nanobeam cavities coupled through a waveguide. The suggested modulator shifts the resonant frequency over a scalable range. We design a compact optical modulator based on photonic crystal nanobeams cavities that exhibits high stability to manufacturing. Photonic crystal waveguide tuning in the low-intensity region of the resonant mode is demonstrated. The advantages of the suggested approach over the single-resonator optical modulator approaches include the possibilities to shift the modulator frequency over a scalable range that depends on switching energy level and to effectively electrically tune the device in the low-intensity region of the resonant mode.

  5. Noise in an acoustic-optic modulated laser source

    SciTech Connect

    Kachelmyer, A.L.; Eng, R.S.

    1989-01-01

    This paper considers the measurement of amplitude modulation (AM) and phase modulation (PM) noise in a tunable CO{sub 2} laser source. Theoretical and experimental heterodyned output power spectrums are used to evaluate the quality of the acousto-optically tuned source.

  6. Fabrication and characterization of a hybrid SOI 1×4 silicon-slot optical modulator array incorporating EO polymers for optical phased-array antenna applications

    NASA Astrophysics Data System (ADS)

    Kim, Richard S.; Szep, Attila; Usechak, Nicholas G.; Chen, Antao; Sun, Haishan; Shi, Shouyuan; Abeysinghe, Don; You, Young-Hwan; Dalton, Larry R.

    2012-03-01

    Optical phased arrays are promising candidates for both RF signal processing and optical beam forming and steering. These platforms not only enable accurate electrically controlled beam steering at high frequencies but also have the potential to significantly improve the performance of future free-space optical communications systems. In this work we exploit recent advancements in both nano-scale hybrid silicon-slot waveguides and electro-optic (EO) polymers to demonstrate an integrated optical phased-array antenna. Specifically, we create a hybrid integrated "photonic circuit" that connects an array of optical phase modulators, fed by a common optical signal and a 1x4 splitter, to a compact optical waveguide diffraction array for optical beam steering applications. The fundamental characteristics of the resulting integrated optical beam former, including the optical insertion loss, driving voltage, and phase control from the waveguide aperture are summarized in this letter.

  7. Advanced electro-optical tracker/ranger

    NASA Astrophysics Data System (ADS)

    Bennett, R. A.; Defoe, D. N.

    1980-06-01

    The preliminary engineering design study of an Advanced Electro-Optical Tracker/Ranger (AEOTR) to provide passive target tracking and rangefinding for air to air gun fire control is described. Area correlation processing is used in the comparison of stereo image pairs for stereometric ranging and in the comparison of successive images for tracking. The application of these techniques to the AEOTR, the limitations imposed by packaging, environmental and state-of-the-art sensor and processing hardware constraints, and the projected performance are evaluated. Principal emphasis is given to the use of AEOTR in the gun director engagement mode in which target track and range data is provided to a gun fire control computer. The feasibility of use of the AEOTR to provide target video as an aid to visual target identification, and to provide automatic airborne target detection, is also evaluated. The necessary functions and subsystems are defined and integrated into a preliminary design, whose performance is estimated and compared with the program goals. In addition, a preliminary mounting location study for the F-15, F-16 and F-18 advanced fighters is included. CAI-built hardware was used to successfully demonstrate the feasibility of the ranging and tracking concepts employed in the AEOTR.

  8. Influence of large signal modulation on photonic UWB generation based on electro-optic modulator.

    PubMed

    Gu, Rong; Pan, Shilong; Chen, Xiangfei; Pan, Minghai; Ben, De

    2011-07-01

    Various schemes based on electro-optic modulators have been reported to generate ultra-wideband (UWB) signals in the optical domain, but the availability of these methods always relies on small signal modulation. In this paper, the influence of large signal modulation on two typical schemes, representing two major categories of external-modulator-based photonic UWB generation schemes, is analytically and numerically studied. While the quasi single-sideband UWB (QSSB-UWB) pulse can maintain its shape, the Gaussian UWB (GUWB) generation scheme suffers serious modulation distortion when the phase modulation index is greater than π/6. The modulation distortion would have negative impact on the receiver sensitivity when the signal is sent to a correlation receiver.

  9. Optical control of MMIC-based T/R modules

    NASA Astrophysics Data System (ADS)

    Herczfeld, P. R.; Paolella, A.; Daryoush, A. S.; Jemison, W.; Rosen, A.

    1988-05-01

    Some of the basic issues of optical control and interconnects of MMICs are discussed with special consideration given to the application of optical technology to the new generation of phased-array antennas utilizing a very large number of individually controlled MMIC T/R modules. In these antennas, the fiber optic links are used to achieve synchronization of the T/R modules and signal coding; in optical beamforming in the microwave domain, where the control elements, such as microwave phase shifters and attennuators are activated by control signals transmitted via optical fibers; and in beamforming in the optical domain. Optial fibers are also used in control of passive microwave components such as microstrip lines and dielectric resonators.

  10. Dynamic optical arbitrary waveform shaping based on cascaded optical modulators of single FBG.

    PubMed

    Chen, Jingyuan; Li, Peili

    2015-08-10

    A dynamic optical arbitrary waveform generation (O-AWG) with amplitude and phase independently controlled in optical modulators of single fiber Bragg Grating (FBG) has been proposed. This novel scheme consists of several optical modulators. In the optical modulator (O-MOD), a uniform FBG is used to filter spectral component of the input signal. The amplitude is controlled by fiber stretcher (FS) in Mach-Zehnder interference (MZI) structure through interference of two MZI arms. The phase is manipulated via the second FS in the optical modulator. This scheme is investigated by simulation. Consequently, optical pulse trains with different waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width within each period are obtained through FSs adjustment to alter the phase shifts of signal in each O-MOD. PMID:26367920

  11. Triggerable electro-optic amplitude modulator bias stabilizer for integrated optical devices

    DOEpatents

    Conder, Alan D.; Haigh, Ronald E.; Hugenberg, Keith F.

    1995-01-01

    An improved Mach-Zehnder integrated optical electro-optic modulator is achieved by application and incorporation of a DC bias box containing a laser synchronized trigger circuit, a DC ramp and hold circuit, a modulator transfer function negative peak detector circuit, and an adjustable delay circuit. The DC bias box ramps the DC bias along the transfer function curve to any desired phase or point of operation at which point the RF modulation takes place.

  12. Triggerable electro-optic amplitude modulator bias stabilizer for integrated optical devices

    DOEpatents

    Conder, A.D.; Haigh, R.E.; Hugenberg, K.F.

    1995-09-26

    An improved Mach-Zehnder integrated optical electro-optic modulator is achieved by application and incorporation of a DC bias box containing a laser synchronized trigger circuit, a DC ramp and hold circuit, a modulator transfer function negative peak detector circuit, and an adjustable delay circuit. The DC bias box ramps the DC bias along the transfer function curve to any desired phase or point of operation at which point the RF modulation takes place. 7 figs.

  13. Integrated optical modulators and switches using coherent perfect loss.

    PubMed

    Grote, Richard R; Driscoll, Jeffrey B; Osgood, Richard M

    2013-08-15

    We propose a new type of amplitude modulator for integrated optics based on phase-controllable coherent perfect loss (CPL) from a resonant cavity. Temporal coupled-mode theory is employed to derive a simple set of equations that describe the device operation, and finite-difference time-domain simulations are used to verify these equations. Two examples of CPL modulators are described with this formalism: a ring resonator and a 1D photonic crystal cavity. We show that internal resonator loss, and thus critical coupling, are not strict requirements for CPL operation. These devices are simple to design and can act as compact switches and modulators for integrated optics. PMID:24104632

  14. Invited Article: Polarization diversity and modulation for high-speed optical communications: architectures and capacity

    NASA Astrophysics Data System (ADS)

    Shieh, William; Khodakarami, Hamid; Che, Di

    2016-07-01

    Polarization is one of the fundamental properties of optical waves. To cope with the exponential growth of the Internet traffic, optical communications has advanced by leaps and bounds within the last decade. For the first time, the polarization domain has been extensively explored for high-speed optical communications. In this paper, we discuss the general principle of polarization modulation in both Jones and Stokes spaces. We show that there is no linear optical device capable of transforming an arbitrary input polarization into one that is orthogonal to itself. This excludes the receiver self-polarization diversity architecture by splitting the signal into two branches, and then transferring one of the branches into orthogonal polarization. We next propose a novel Stokes vector (SV) detection architecture using four single-ended photodiodes (PD) that can recover a full set of SV. We then derive a closed-form expression for the information capacity of different SV detection architectures and compare the capacity of our proposed architectures with that of intensity-modulated directly-detected (IM/DD) method. We next study the 3-PD SV detection architecture where a subset of SV is detected, and devise a novel modulation algorithm that can achieve 2-dimensional modulation with the 3-PD detection. By using cost-effective SV receivers, polarization modulation and multiplexing offers a powerful solution for short-reach optical networks where the wavelength domain is quickly exhausted.

  15. The Design and Implementation of NASA's Advanced Flight Computing Module

    NASA Technical Reports Server (NTRS)

    Alkakaj, Leon; Straedy, Richard; Jarvis, Bruce

    1995-01-01

    This paper describes a working flight computer Multichip Module developed jointly by JPL and TRW under their respective research programs in a collaborative fashion. The MCM is fabricated by nCHIP and is packaged within a 2 by 4 inch Al package from Coors. This flight computer module is one of three modules under development by NASA's Advanced Flight Computer (AFC) program. Further development of the Mass Memory and the programmable I/O MCM modules will follow. The three building block modules will then be stacked into a 3D MCM configuration. The mass and volume of the flight computer MCM achieved at 89 grams and 1.5 cubic inches respectively, represent a major enabling technology for future deep space as well as commercial remote sensing applications.

  16. Investigation of direct integrated optics modulators. [applicable to data preprocessors

    NASA Technical Reports Server (NTRS)

    Batchman, T. E.

    1980-01-01

    Direct modulation techniques applicable to integrated optics data preprocessors were investigated. Several methods of modulating a coherent optical beam by interaction with an incoherent beam were studied. It was decided to investigate photon induced conductivity changes in thin semiconductor cladding layers on optical waveguides. Preliminary calculations indicate significant changes can be produced in the phase shift in a propagating wave when the conductivity is changed by ten percent or more. Experimental devices to verify these predicted phase changes and experiments designed to prove the concept are described.

  17. Hybrid silicon-vanadium dioxide electro-optic modulators

    NASA Astrophysics Data System (ADS)

    Miller, Kevin J.; Markov, Petr; Marvel, Robert E.; Haglund, Richard F.; Weiss, Sharon M.

    2016-03-01

    Small-footprint, low-power devices that can modulate optical signals at THz speeds would transform next-generation onchip photonics. We describe a hybrid silicon-vanadium dioxide (Si-VO2) electro-optic ring resonator modulator as a candidate platform for achieving this performance benchmark. Vanadium dioxide (VO2) is a strongly correlated material exhibiting a semiconductor-to-metal transition (SMT) accompanied by large changes in electrical and optical properties. While VO2 can be switched optically on a sub-picosecond time scale, the ultimate electrical switching speed remains to be determined. In a 5 μm radius Si-VO2 ring resonator, we achieve 1.5 dB modulation in response to a 10 ns square voltage pulse of 2.5 V. In the steady state regime, we report a modulation depth of 10 dB. The larger modulation depth at longer timescales is attributed to a Joule heating contribution. Experimental results, corroborated by FDTD simulations, reveal the relationship between the portion of a VO2 patch undergoing the SMT and the resulting effects on the Si-VO2 device performance. This work indicates that with further reduction of VO2 patch sizes and increase in resonator Q factor, there is promise for the Si-VO2 ring resonator electro-optic modulator as a competitive option for on-chip photonics technology.

  18. Hybrid integrated optic modules for real-time signal processing

    NASA Technical Reports Server (NTRS)

    Tsai, C. S.

    1984-01-01

    The most recent progress on four relatively new hybrid integrated optic device modules in LiNbO3 waveguides and one in YIG/GGG waveguide that are currently being studied are discussed. The five hybrid modules include a time-integrating acoustooptic correlator, a channel waveguide acoustooptic frequency shifter/modulator, an electrooptic channel waveguide total internal reflection moculator/switch, an electrooptic analog-to-digital converter using a Fabry-Perot modulator array, and a noncollinear magnetooptic modulator using magnetostatic surface waves. All of these devices possess the desirable characteristics of very large bandwidth (GHz or higher), very small substrate size along the optical path (typically 1.5 cm or less), single-mode optical propagation, and low drive power requirement. The devices utilize either acoustooptic, electrooptic or magnetooptic effects in planar or channel waveguides and, therefore, act as efficient interface devices between a light wave and temporal signals. Major areas of application lie in wideband multichannel optical real-time signal processing and communications. Some of the specific applications include spectral analysis and correlation of radio frequency (RF) signals, fiber-optic sensing, optical computing and multiport switching/routing, and analog-to-digital conversion of wide RF signals.

  19. Performance Study of optical Modulator based on electrooptic effect

    NASA Astrophysics Data System (ADS)

    Palodiya, V.; Raghuwanshi, S. K.

    2016-08-01

    In this paper, we have studied and derive performance parameter of highly integrated Lithium Niobate optical modulator. This is a chirp free modulator having low switching voltage and large bandwidth. For an external modulator in which travelling-wave electrodes length L imposed the modulating switching voltage, the product of Vπ and L is fixed for a given electro optic material Lithium Niobate. We investigate to achieve a low Vπ by both magnitude of the electro-optic coefficient for a wide variety of electro-optic materials. A Sellmeier equation for the extraordinary index of congruent lithium niobate is derived. For phase-matching, predictions are accmate for temperature between room temperature 250°C and wavelength ranging from 0.4 to 5µm. The Sellmeier equations predict more accmately refractive indices at long wavelengths. Theoretical result is confirmed by simulated results. We have analysed the various parameters such as switching voltage, device performance index, time constant, transmittance, cut-off frequency, 3-dB bandwidth, power absorption coefficient and transmission bit rate of Lithium Niobate optical Modulator based on electro -optic effect.

  20. Advanced coding and modulation schemes for TDRSS

    NASA Technical Reports Server (NTRS)

    Harrell, Linda; Kaplan, Ted; Berman, Ted; Chang, Susan

    1993-01-01

    This paper describes the performance of the Ungerboeck and pragmatic 8-Phase Shift Key (PSK) Trellis Code Modulation (TCM) coding techniques with and without a (255,223) Reed-Solomon outer code as they are used for Tracking Data and Relay Satellite System (TDRSS) S-Band and Ku-Band return services. The performance of these codes at high data rates is compared to uncoded Quadrature PSK (QPSK) and rate 1/2 convolutionally coded QPSK in the presence of Radio Frequency Interference (RFI), self-interference, and hardware distortions. This paper shows that the outer Reed-Solomon code is necessary to achieve a 10(exp -5) Bit Error Rate (BER) with an acceptable level of degradation in the presence of RFI. This paper also shows that the TCM codes with or without the Reed-Solomon outer code do not perform well in the presence of self-interference. In fact, the uncoded QPSK signal performs better than the TCM coded signal in the self-interference situation considered in this analysis. Finally, this paper shows that the E(sub b)/N(sub 0) degradation due to TDRSS hardware distortions is approximately 1.3 dB with a TCM coded signal or a rate 1/2 convolutionally coded QPSK signal and is 3.2 dB with an uncoded QPSK signal.

  1. Advanced optical network architecture for integrated digital avionics

    NASA Astrophysics Data System (ADS)

    Morgan, D. Reed

    1996-12-01

    For the first time in the history of avionics, the network designer now has a choice in selecting the media that interconnects the sources and sinks of digital data on aircraft. Electrical designs are already giving way to photonics in application areas where the data rate times distance product is large or where special design requirements such as low weight or EMI considerations are critical. Future digital avionic architectures will increasingly favor the use of photonic interconnects as network data rates of one gigabit/second and higher are needed to support real-time operation of high-speed integrated digital processing. As the cost of optical network building blocks is reduced and as temperature-rugged laser sources are matured, metal interconnects will be forced to retreat to applications spanning shorter and shorter distances. Although the trend is already underway, the widespread use of digital optics will first occur at the system level, where gigabit/second, real-time interconnects between sensors, processors, mass memories and displays separated by a least of few meters will be required. The application of photonic interconnects for inter-printed wiring board signalling across the backplane will eventually find application for gigabit/second applications since signal degradation over copper traces occurs before one gigabit/second and 0.5 meters are reached. For the foreseeable future however, metal interconnects will continue to be used to interconnect devices on printed wiring boards since 5 gigabit/second signals can be sent over metal up to around 15 centimeters. Current-day applications of optical interconnects at the system level are described and a projection of how advanced optical interconnect technology will be driven by the use of high speed integrated digital processing on future aircraft is presented. The recommended advanced network for application in the 2010 time frame is a fiber-based system with a signalling speed of around 2

  2. Wide-band analog frequency modulation of optic signals using indirect techniques

    NASA Technical Reports Server (NTRS)

    Fitzmartin, D. J.; Balboni, E. J.; Gels, R. G.

    1991-01-01

    The wideband frequency modulation (FM) of an optical carrier by a radio frequency (RF) or microwave signal can be accomplished independent of laser type when indirect modulation is employed. Indirect modulators exploit the integral relation of phase to frequency so that phase modulators can be used to impress frequency modulation on an optical carrier. The use of integrated optics phase modulators, which are highly linear, enables the generation of optical wideband FM signals with very low intermodulation distortion. This modulator can be used as part of an optical wideband FM link for RF and microwave signals. Experimental results from the test of an indirect frequency modulator for an optical carrier are discussed.

  3. Project T.E.A.M. (Technical Education Advancement Modules). Advanced Statistical Process Control.

    ERIC Educational Resources Information Center

    Dunlap, Dale

    This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 20-hour advanced statistical process control (SPC) and quality improvement course designed to develop the following competencies: (1) understanding quality systems; (2) knowing the process; (3) solving quality problems; and (4)…

  4. Electro-optic modulator capable of generating simultaneous amplitude and phase modulations.

    PubMed

    Cusack, Benedict J; Sheard, Benjamin S; Shaddock, Daniel A; Gray, Malcolm B; Lam, Ping Koy; Whitcomb, Stan E

    2004-09-10

    We report on the analysis and prototype characterization of a dual-electrode electro-optic modulator that can generate both amplitude and phase modulations with a selectable relative phase, termed a quadrature variable modulator (QVM). All modulation states can be reached by tuning only the electrical inputs, facilitating real-time tuning, and the device has shown good suppression and stability properties. A mathematical analysis is presented, including the development of a geometric-phase representation for modulation. The experimental characterization of the device shows that relative suppressions of 38, 39, and 30 dB for phase, single sideband, and carrier-suppressed modulations, respectively, can be obtained as well as that the device is well behaved when scanning continuously through the parameter space of modulations. The QVM is compared with existing optical configurations that can produce amplitude and phase-modulation combinations in the context of applications such as the tuning of lock points in optical-locking schemes, single-sideband applications, modulation fast-switching applications, and applications requiring combined modulations. PMID:15468710

  5. 1060-nm VCSEL-based parallel-optical modules for optical interconnects

    NASA Astrophysics Data System (ADS)

    Nishimura, N.; Nagashima, K.; Kise, T.; Rizky, A. F.; Uemura, T.; Nekado, Y.; Ishikawa, Y.; Nasu, H.

    2015-03-01

    The capability of mounting a parallel-optical module onto a PCB through solder-reflow process contributes to reduce the number of piece parts, simplify its assembly process, and minimize a foot print for both AOC and on-board applications. We introduce solder-reflow-capable parallel-optical modules employing 1060-nm InGaAs/GaAs VCSEL which leads to the advantages of realizing wider modulation bandwidth, longer transmission distance, and higher reliability. We demonstrate 4-channel parallel optical link performance operated at a bit stream of 28 Gb/s 231-1 PRBS for each channel and transmitted through a 50-μm-core MMF beyond 500 m. We also introduce a new mounting technology of paralleloptical module to realize maintaining good coupling and robust electrical connection during solder-reflow process between an optical module and a polymer-waveguide-embedded PCB.

  6. Subpicosecond-pulse generation through cross-phase-modulation-induced modulational instability in optical fibers.

    PubMed

    Gouveia-Neto, A S; Faldon, M E; Sombra, A S; Wigley, P G; Taylor, J R

    1988-10-01

    We report subpicosecond-pulse generation at 1.319 microm in a single-mode optical fiber by modulational instability induced through cross-phase modulation by 1.06-microm pulses propagating in the normal dispersion regime. Pulse-repetition rates approaching 300 GHz were achieved.

  7. Overview of advanced components for fiber optic systems

    NASA Technical Reports Server (NTRS)

    Depaula, Ramon P.; Stowe, David W.

    1986-01-01

    The basic operating principles and potential performance of several state-of-the-art fiber-optic devices are illustrated with diagrams and briefly characterized. Technologies examined include high-birefringence polarization-maintaining fibers and directional couplers, single-mode fiber polarizers and cut-off polarizers, optical-fiber modulators with radially poled piezoactive polymer (PVF2) jackets, and piezoelectric-squeezer polarization modulators. The need for improved manufacturing techniques to make such fiber-optic devices cost-competitive with their thin-film integrated-optics analogs is indicated.

  8. Electro-Optical Modulator Bias Control Using Bipolar Pulses

    NASA Technical Reports Server (NTRS)

    Farr, William; Kovalik, Joseph

    2007-01-01

    An improved method has been devised for controlling the DC bias applied to an electro-optical crystal that is part of a Mach-Zehnder modulator that generates low-duty-cycle optical pulses for a pulse-position modulation (PPM) optical data-communication system. In such a system, it is desirable to minimize the transmission of light during the intervals between pulses, and for this purpose, it is necessary to maximize the extinction ratio of the modulator (the ratio between the power transmitted during an "on" period and the power transmitted during an "off" period). The present method is related to prior dither error feedback methods, but unlike in those methods, there is no need for an auxiliary modulation subsystem to generate a dithering signal. Instead, as described below, dither is effected through alternation of the polarity of the modulation signal. The upper part of Figure 1 schematically depicts a Mach-Zehnder modulator. The signal applied to the electro-optical crystal consists of a radio-frequency modulating pulse signal, VRF, superimposed on a DC bias Vbias. Maximum extinction occurs during the off (VRF = 0) period if Vbias is set at a value that makes the two optical paths differ by an odd integer multiple of a half wavelength so that the beams traveling along the two paths interfere destructively at the output beam splitter. Assuming that the modulating pulse signal VRF has a rectangular waveform, maximum transmission occurs during the "on" period if the amplitude of VRF is set to a value, V , that shifts the length of the affected optical path by a half wavelength so that now the two beams interfere constructively at the output beam splitter. The modulating pulse signal is AC-coupled from an amplifier to the electro-optical crystal. Sometimes, two successive pulses occur so close in time that the operating point of the amplifier drifts, one result being that there is not enough time for the signal level to return to ground between pulses. Also, the

  9. Optically Addressed Spatial Light Modulators for 3d Display

    NASA Astrophysics Data System (ADS)

    Collings, N.

    An optically addressed spatial light modulator (OASLM) records the image on a write beam and transfers it to a read beam. Some example application areas are: image transduction; optical correlation; adaptive optics; and optical neural networks. Current interest in OASLMs has been generated by the work of Qinetiq on 3D display. This work is based on Active tiling, where an image can be recorded in one part of the device and is memorised, whilst the remainder of the device is updated with images. This paper will explain this system and survey the technological alternatives for this application.

  10. Biwavelength transceiver module for parallel simultaneous bidirectional optical interconnections

    NASA Astrophysics Data System (ADS)

    Nguyen, Nga T. H.; Ukaegbu, Ikechi A.; Sangirov, Jamshid; Cho, Mu-Hee; Lee, Tae-Woo; Park, Hyo-Hoon

    2013-12-01

    The design of a biwavelength transceiver (TRx) module for parallel simultaneous bidirectional optical interconnects is described. The TRx module has been implemented using two different wavelengths, 850 and 1060 nm, to send and receive signals simultaneously through a common optical interface while optimizing cost and performance. Filtering mirrors are formed in the optical fibers which are embedded on a V-grooved silicon substrate for reflecting and filtering optical signals from/to vertical-cavity surface-emitting laser (VCSEL)/photodiode (PD). The VCSEL and PD are flip-chip bonded on individual silicon optical benches, which are attached on the silicon substrate for optical signal coupling from the VCSEL to fiber and from fiber to the PD. A high-speed and low-loss ceramic printed circuit board, which has a compact size of 0.033 cc, has been designed to carry transmitter and receiver chips for easy packaging of the TRx module. Applied for quad small form-factor pluggable applications at 40-Gbps operation, the four-channel biwavelength TRx module showed clear eye diagrams with a bit error rate (BER) of 10-12 at input powers of -5 and -5.8 dBm for 1060 and 850 nm operation modes, respectively.

  11. Connection cube modules for optical backplanes and fiber networks.

    PubMed

    Kostuk, R K; Ramsey, D L; Kim, T J

    1997-07-10

    A modular free-space optical system, called the connection cube, for connecting arrays of electro-optic transceivers and fiber-array connectors is presented. The connection cube module provides bidirectional data transfer between four processing nodes on a cube face and can be used as a basic building block for optical backplanes and interconnect networks. An experimental system for connecting four processing nodes is presented and used to examine alignment and packaging issues. An analysis of the dimensional requirements and scaling capability for systems based on this module is conducted. This analysis shows that, when the connection cube module is adapted to vertical-cavity surface-emitting-laser-based point-to-point fiber-array links currently under development, it can connect up to 14 processing nodes with an aggregate data transfer capacity of 112 Gbits/s with 19.6-W power consumption. PMID:18259270

  12. Silicon Modulators, Switches and Sub-systems for Optical Interconnect

    NASA Astrophysics Data System (ADS)

    Li, Qi

    Silicon photonics is emerging as a promising platform for manufacturing and integrating photonic devices for light generation, modulation, switching and detection. The compatibility with existing CMOS microelectronic foundries and high index contrast in silicon could enable low cost and high performance photonic systems, which find many applications in optical communication, data center networking and photonic network-on-chip. This thesis first develops and demonstrates several experimental work on high speed silicon modulators and switches with record performance and novel functionality. A 8x40 Gb/s transmitter based on silicon microrings is first presented. Then an end-to-end link using microrings for Binary Phase Shift Keying (BPSK) modulation and demodulation is shown, and its performance with conventional BPSK modulation/ demodulation techniques is compared. Next, a silicon traveling-wave Mach- Zehnder modulator is demonstrated at data rate up to 56 Gb/s for OOK modulation and 48 Gb/s for BPSK modulation, showing its capability at high speed communication systems. Then a single silicon microring is shown with 2x2 full crossbar switching functionality, enabling optical interconnects with ultra small footprint. Then several other experiments in the silicon platform are presented, including a fully integrated in-band Optical Signal to Noise Ratio (OSNR) monitor, characterization of optical power upper bound in a silicon microring modulator, and wavelength conversion in a dispersion-engineered waveguide. The last part of this thesis is on network-level application of photonics, specically a broadcast-and-select network based on star coupler is introduced, and its scalability performance is studied. Finally a novel switch architecture for data center networks is discussed, and its benefits as a disaggregated network are presented.

  13. Interferometric sensors based on sinusoidal optical path length modulation

    NASA Astrophysics Data System (ADS)

    Knell, Holger; Schake, Markus; Schulz, Markus; Lehmann, Peter

    2014-05-01

    Sinusoidal optical path length modulation of the reference or the measurement arm of an interferometer is a technique which is a fast alternative to white light or phase shifting interferometry. In this paper three different sensors using this periodical modulation are presented. In addition, signal processing algorithms based on Discrete Fourier Transform, Hilbert Transform and parameter estimation are analyzed. These algorithms are used to obtain measurement results which demonstrate the capabilities of the presented interferometric sensors.

  14. An electro-optic polymer modulator for radio photonics

    NASA Astrophysics Data System (ADS)

    Denisyuk, I. Yu.; Burunkova, Yu. E.; Pozdnyakova, S. A.; Balya, V. K.; Zhuk, D. I.; Fokina, M. I.

    2015-10-01

    A method for developing an electro-optic polymer Mach‒Zehnder modulator based on polymethylmethacrylate- disperse red copolymer has been investigated. The inverse scheme is chosen as the basis for preparing a microstrip structure. This scheme entails the formation of microgrooves in the lower cladding layer by combining photolithography and reactive-ion etching (RIE), with subsequent deposition of an active electro-optic layer by centrifugation. The processes of forming layers and electrodes, the interaction between layers, the light transmission through the microstrip structure, and the modulator characteristics are considered.

  15. Radiation resistance of electro-optic polymer-based modulators

    SciTech Connect

    Taylor, Edward W.; Nichter, James E.; Nash, Fazio D.; Haas, Franz; Szep, Attila A.; Michalak, Richard J.; Flusche, Brian M.; Cook, Paul R.; McEwen, Tom A.; McKeon, Brian F.; Payson, Paul M.; Brost, George A.; Pirich, Andrew R.; Castaneda, Carlos; Tsap, Boris; Fetterman, Harold R.

    2005-05-16

    Mach-Zehnder interferometric electro-optic polymer modulators composed of highly nonlinear phenyltetraene bridge-type chromophores within an amorphous polycarbonate host matrix were investigated for their resistance to gamma rays and 25.6 MeV protons. No device failures were observed and the majority of irradiated modulators exhibited decreases in half-wave voltage and optical insertion losses compared to nonirradiated control samples undergoing aging processes. Irradiated device responses were attributed to scission, cross-linking, and free volume processes. The data suggests that strongly poled devices are less likely to de-pole under the influence of ionizing radiation.

  16. Spatial optical phase-modulating metadevice with subwavelength pixelation.

    PubMed

    Cencillo-Abad, Pablo; Plum, Eric; Rogers, Edward T F; Zheludev, Nikolay I

    2016-08-01

    Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays - with variable focal distance and numerical aperture - without unwanted diffraction.

  17. Spatial optical phase-modulating metadevice with subwavelength pixelation.

    PubMed

    Cencillo-Abad, Pablo; Plum, Eric; Rogers, Edward T F; Zheludev, Nikolay I

    2016-08-01

    Dynamic control over optical wavefronts enables focusing, diffraction and redirection of light on demand, however, sub-wavelength resolution is required to avoid unwanted diffracted beams that are present in commercial spatial light modulators. Here we propose a realistic metadevice that dynamically controls the optical phase of reflected beams with sub-wavelength pixelation in one dimension. Based on reconfigurable metamaterials and nanomembrane technology, it consists of individually moveable metallic nanowire actuators that control the phase of reflected light by modulating the optical path length. We demonstrate that the metadevice can provide on-demand optical wavefront shaping functionalities of diffraction gratings, beam splitters, phase-gradient metasurfaces, cylindrical mirrors and mirror arrays - with variable focal distance and numerical aperture - without unwanted diffraction. PMID:27505842

  18. Feedback module for evaluating optical-power stabilization methods

    NASA Astrophysics Data System (ADS)

    Downing, John

    2016-03-01

    A feedback module for evaluating the efficacy of optical-power stabilization without thermoelectric coolers (TECs) is described. The module comprises a pickoff optic for sampling a light beam, a photodiode for converting the sample power to electrical current, and a temperature sensor. The components are mounted on an optical bench that makes accurate (0.05°) beam alignment practical as well as providing high thermal-conductivity among the components. The module can be mounted on existing light sources or the components can be incorporated in new designs. Evaluations of optical and electronic stabilization methods are also reported. The optical method combines a novel, weakly reflective, weakly polarizing coating on the pickoff optic with a photodiode and an automatic-power-control (APC) circuit in a closed loop. The shift of emitter wavelength with temperature, coupled with the wavelength-dependent reflectance of the pickoff optic, enable the APC circuit to compensate for temperature errors. In the electronic method, a mixed-signal processor in a quasiclosed loop generates a control signal from temperature and photocurrent inputs and feeds it back to an APC circuit to compensate for temperature errors. These methods result in temperature coefficients less than 20 ppm/°C and relative rms power equal to 05% for the optical method and 0.02% for the electronic method. The later value represents an order of magnitude improvement over rms specifications for cooled, laser-diode modules and a five-fold improvement in wall-plug efficiency is achieved by eliminating TECs.

  19. Method and apparatus for optical communication by frequency modulation

    DOEpatents

    Priatko, Gordon J.

    1988-01-01

    Laser optical communication according to this invention is carried out by producing multi-frequency laser beams having different frequencies, splitting one or more of these constituent beams into reference and signal beams, encoding information on the signal beams by frequency modulation and detecting the encoded information by heterodyne techniques. Much more information can be transmitted over optical paths according to the present invention than with the use of only one path as done previously.

  20. All-optical atomic magnetometers based on nonlinear magneto-optical rotation with amplitude modulated light

    NASA Astrophysics Data System (ADS)

    Pustelny, Szymon; Wojciechowski, Adam; Kotyrba, Mateusz; Sycz, Krystian; Zachorowski, Jerzy; Gawlik, Wojciech; Cingoz, Arman; Leefer, Nathan; Higbie, James M.; Corsini, Eric; Ledbetter, Micah P.; Rochester, Simon M.; Sushkov, Alexander O.; Budker, Dmitry

    2007-03-01

    We demonstrate a magnetometric technique based on nonlinear magneto-optical rotation using amplitude modulated light. The magnetometers can be operated in either open-loop (typical nonlinear magneto-optical rotation with amplitude-modulated light) or closed-loop (self-oscillating) modes. The latter mode is particularly well suited for conditions where the magnetic field is changing by large amounts over a relatively short timescale.

  1. Extreme Universe Space Observatory (EUSO) Optics Module

    NASA Technical Reports Server (NTRS)

    Young, Roy; Christl, Mark

    2008-01-01

    A demonstration part will be manufactured in Japan on one of the large Toshiba machines with a diameter of 2.5 meters. This will be a flat PMMA disk that is cut between 0.5 and 1.25 meters radius. The cut should demonstrate manufacturing the most difficult parts of the 2.5 meter Fresnel pattern and the blazed grating on the diffractive surface. Optical simulations, validated with the subscale prototype, will be used to determine the limits on manufacturing errors (tolerances) that will result in optics that meet EUSO s requirements. There will be limits on surface roughness (or errors at high spatial frequency); radial and azimuthal slope errors (at lower spatial frequencies) and plunge cut depth errors in the blazed grating. The demonstration part will be measured to determine whether it was made within the allowable tolerances.

  2. Integrated-optic polarization controllers incorporating polymer waveguide birefringence modulators.

    PubMed

    Kim, Jun-Whee; Park, Su-Hyun; Chu, Woo-Sung; Oh, Min-Cheol

    2012-05-21

    Polarization controllers based on polymer waveguide technology are demonstrated by incorporating thermo-optic birefringence modulators (BMs) and thin-film wave plates. Highly birefringent polymer materials are used to increase the efficiency of birefringence modulation in proportion to the heating power. Thin-film quarter-wave plates are fabricated by using a crosslinkable liquid crystal, reactive mesogen, and inserted between the BMs to produce static phase retardation and polarization coupling. By applying a triangular AC signal to one BM and a DC signal to another, the polarization states of the output light are modulated to cover the entire surface of the Poincaré sphere. PMID:22714231

  3. Driver-receiver combined optical transceiver modules for bidirectional optical interconnection

    NASA Astrophysics Data System (ADS)

    Park, Hyo-Hoon; Kang, Sae-Kyoung; Kim, Do-Won; Nga, Nguyen T. H.; Hwang, Sung-Hwan; Lee, Tae-Woo

    2008-02-01

    We review a bidirectional optical link scheme for memory-interface applications. A driver-receiver combined optical transceiver (TRx) modules was demonstrated on an optical printed-circuit board (OPCB) platform. To select the bidirectional electric input/output signals, a driver-receiver combined TRx IC with a switching function was designed in 0.18-μm CMOS technology. The TRx IC was integrated with VCSEL/PD chips for optical link in the TRx module. The optical TRx module was assembled on a fiber-embedded OPCB, employing a 90°-bent fiber connector for 90° deflection of light beams between the TRx module and the OPCB. The TRx module and the 90° connector were passively assembled on the OPCB, using ferrule-type guide pins/ holes. Employing these constituent components, the bidirectional optical link between a pair of TRx modules has been successfully demonstrated up to 1.25 Gb/s on the OPCB.

  4. High-dimensional modulation for coherent optical communications systems.

    PubMed

    Millar, David S; Koike-Akino, Toshiaki; Arık, Sercan Ö; Kojima, Keisuke; Parsons, Kieran; Yoshida, Tsuyoshi; Sugihara, Takashi

    2014-04-01

    In this paper, we examine the performance of several modulation formats in more than four dimensions for coherent optical communications systems. We compare two high-dimensional modulation design methodologies based on spherical cutting of lattices and block coding of a 'base constellation' of binary phase shift keying (BPSK) on each dimension. The performances of modulation formats generated with these methodologies is analyzed in the asymptotic signal-to-noise ratio regime and for an additive white Gaussian noise (AWGN) channel. We then study the application of both types of high-dimensional modulation formats to standard single-mode fiber (SSMF) transmission systems. For modulation with spectral efficiencies comparable to dual-polarization (DP-) BPSK, polarization-switched quaternary phase shift keying (PS-QPSK) and DP-QPSK, we demonstrate SNR gains of up to 3 dB, 0.9 dB and 1 dB respectively, at a BER of 10(-3).

  5. Modulation index optimization for optical fringe suppression in wavelength modulation spectroscopy.

    PubMed

    Xiong, Bo; Du, Zhenhui; Li, Jinyi

    2015-11-01

    Optical fringes constitute one of the major obstacles in the gas detection based on wavelength modulation spectroscopy (WMS). In order to suppress optical fringes, a convenient method of modulation index optimization was presented, using the signal-fringe ratio as a criterion. In addition to suppressing optical fringes, the optimized modulation index enables the detection of gas absorption. This method was demonstrated in a WMS based oxygen sensor. By comparing the sensor performances with and without the use of the optimized modulation index, we showed that the optical fringes are reduced by using the optimized modulation index; furthermore, the system stability and detection limit are improved. More specifically, the long-term fluctuation of the sensor measurement is dramatically reduced by a factor of 8, and a detection limit of as low as 120 ppm (with effective optical path length of 32 cm and integral time of 2.6 s), characterized by the Allan variance, was derived. This method can be applied in other existing WMS systems without the need for additional devices or complex algorithms and has the potential to be used in both laboratory and industrial settings.

  6. Modulation index optimization for optical fringe suppression in wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Xiong, Bo; Du, Zhenhui; Li, Jinyi

    2015-11-01

    Optical fringes constitute one of the major obstacles in the gas detection based on wavelength modulation spectroscopy (WMS). In order to suppress optical fringes, a convenient method of modulation index optimization was presented, using the signal-fringe ratio as a criterion. In addition to suppressing optical fringes, the optimized modulation index enables the detection of gas absorption. This method was demonstrated in a WMS based oxygen sensor. By comparing the sensor performances with and without the use of the optimized modulation index, we showed that the optical fringes are reduced by using the optimized modulation index; furthermore, the system stability and detection limit are improved. More specifically, the long-term fluctuation of the sensor measurement is dramatically reduced by a factor of 8, and a detection limit of as low as 120 ppm (with effective optical path length of 32 cm and integral time of 2.6 s), characterized by the Allan variance, was derived. This method can be applied in other existing WMS systems without the need for additional devices or complex algorithms and has the potential to be used in both laboratory and industrial settings.

  7. Advanced acousto-optic signal processors

    NASA Technical Reports Server (NTRS)

    Casasent, D.

    1983-01-01

    The basic acousto-optic signal processing architectures (spectrum analyzer, space-integrating, time-integrating, and triple product processor) systems and algorithms such as the chirp-Z transform are reviewed. New acousto-optic data processing systems and applications that utilze these basic architectures and new ones are described. These include a matched spatial filter acousto-optic processor, two new hybrid time and space-integrating systems, a triple product processor, and four new matrix-vector iterative feedback systems.

  8. The optical-mechanical design of DMD modulation imaging device

    NASA Astrophysics Data System (ADS)

    Li, Tianting; Xu, Xiping; Qiao, Yang; Li, Lei; Pan, Yue

    2014-09-01

    In order to avoid the phenomenon of some image information were lost, which is due to the jamming signals, such as incident laser, make the pixels dot on CCD saturated. In this article a device of optical-mechanical structure was designed, which utilized the DMD (Digital Micro mirror Device) to modulate the image. The DMD reflection imaging optical system adopts the telecentric light path. However, because the design is not only required to guarantee a 66° angle between the optical axis of the relay optics and the DMD, but also to ensure that the optical axis of the projection system keeps parallel with the perpendicular bisector of the micro-mirror which is in the "flat" state, so the TIR prism is introduced,and making the relay optics and the DMD satisfy the optical institution's requirements. In this paper, a mechanical structure of the imaging optical system was designed and at the meanwhile the lens assembly has been well connected and fixed and fine-tuned by detailed structural design, which included the tilt decentered lens, wedge flanges, prisms. By optimizing the design, the issues of mutual restraint between the inverting optical system and the projecting system were well resolved, and prevented the blocking of the two systems. In addition, the structure size of the whole DMD reflection imaging optical system was minimized; it reduced the energy loss and ensured the image quality.

  9. Multi-scale reflection modulator-based optical interconnects

    NASA Astrophysics Data System (ADS)

    Nair, Rohit

    This dissertation describes the design, analysis, and experimental validation of micro- and macro-optical components for implementing optical interconnects at multiple scales for varied applications. Three distance scales are explored: millimeter, centimeter, and meter-scales. At the millimeter-scale, we propose the use of optical interconnects at the intra-chip level. With the rapid scaling down of CMOS critical dimensions in accordance to Moore's law, the bandwidth requirements of global interconnects in microprocessors has exceeded the capabilities of metal links. These are the wires that connect the most remote parts of the chip and are disproportionately problematic in terms of chip area and power consumption. Consequently, in the mid-2000s, we saw a shift in the chip architecture: a move towards multicore designs. However, this only delays the inevitable communication bottleneck between cores. To satisfy this bandwidth, we propose to replace the global metal interconnects with optical interconnects. We propose to use the hybrid integration of silicon with GaAs/AlAs-based multiple quantum well devices as optical modulators and photodetectors along with polymeric waveguides to transport the light. We use grayscale lithography to fabricate curved facets into the waveguides to couple light into the modulators and photodetectors. Next, at the chip-to-chip level in high-performance multiprocessor computing systems, communication distances vary from a few centimeters to tens of centimeters. An optical design for coupling light from off-chip lasers to on-chip surface-normal modulators is proposed in order to implement chip-to-chip free-space optical interconnects. The method uses a dual-prism module constructed from prisms made of two different glasses. The various alignment tolerances of the proposed system are investigated and found to be well within pick-and-place accuracies. For the off-chip lasers, vertical cavity surface emitting lasers (VCSELs) are proposed

  10. Frequency modulation via the Doppler effect in optical fibers.

    PubMed

    Oberson, P; Huttner, B; Gisin, N

    1999-04-01

    We present the principle of optical frequency modulation via the Doppler effect obtained by rapidly stretching an optical fiber and thus modifying the optical path of the light propagating in the fiber. This procedure creates a pure frequency shift, with no degradation of the spectrum. Moreover, the effect is wavelength independent and can therefore be applied to any type of light source. We show an experimental realization in which a frequency excursion of ~100 MHz was obtained with a bobbin vibrating at 180 Hz.

  11. Design of the Subaru laser guide star adaptive optics module

    NASA Astrophysics Data System (ADS)

    Watanabe, Makoto; Takami, Hideki; Takato, Naruhisa; Colley, Stephen; Eldred, Michael; Kane, Thomas; Guyon, Olivier; Hattori, Masayuki; Goto, Miwa; Iye, Masanori; Hayano, Yutaka; Kamata, Yukiko; Arimoto, Nobuo; Kobayashi, Naoto; Minowa, Yosuke

    2004-10-01

    The laser guide star adaptive optics (AO) module for the Subaru Telescope will be installed at the f/13.9 IR Nasmyth focus, and provides the compensated image for the science instrument without change of the focal ratio. The optical components are mounted on an optical bench, and the flexure depending on the telescope pointing is eliminated. The transferred field of view for the science instrument is 2 arcmin diameter, but a 2.7 arcmin diameter field is available for tip-tilt sensing. The science path of the AO module contains five mirrors, including a pair of off-axis parabolic mirrors and a deformable mirror. It has also three additional mirrors for an image rotator. The AO module has a visible 188-element curvature based wavefront sensor (WFS) with photon-counting avalanche photodiode (APD) modules. It measures high-order terms of wavefront using either of a single laser (LGS) or natural guide star (NGS) within a 2 arcmin diameter field. The AO module has also a visible 2 x 2 sub-aperture Shack-Hartmann WFS with 16 APD modules. It measures tip-tilt and slow defocus terms of wavefront by using a single NGS within a 2.7 arcmin diameter field when a LGS is used for high-order wavefront sensing. The module has also an infrared 2 x 2 sub-aperture Shack-Hartmann WFS with a HgCdTe array as an option. Both high- and low-order visible WFSs have their own guide star acquisition units with two steering fold mirrors. The AO module has also a source simulator. It simulates LGS and NGS beams, simultaneously, with and without atmospheric turbulence by two turbulent layer at about 0 and 6 km altitudes, and reproduces the isoplanatism and the cone effect for the LGS beam.

  12. Advanced Packaging Materials and Techniques for High Power TR Module: Standard Flight vs. Advanced Packaging

    NASA Technical Reports Server (NTRS)

    Hoffman, James Patrick; Del Castillo, Linda; Miller, Jennifer; Jenabi, Masud; Hunter, Donald; Birur, Gajanana

    2011-01-01

    The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires advances in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and compared to standard technologies.

  13. An introduction to NASA's advanced computing program: Integrated computing systems in advanced multichip modules

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi; Alkalai, Leon

    1996-01-01

    Recent changes within NASA's space exploration program favor the design, implementation, and operation of low cost, lightweight, small and micro spacecraft with multiple launches per year. In order to meet the future needs of these missions with regard to the use of spacecraft microelectronics, NASA's advanced flight computing (AFC) program is currently considering industrial cooperation and advanced packaging architectures. In relation to this, the AFC program is reviewed, considering the design and implementation of NASA's AFC multichip module.

  14. Indium-Tin-Oxide for High-performance Electro-optic Modulation

    NASA Astrophysics Data System (ADS)

    Ma, Zhizhen; Li, Zhuoran; Liu, Ke; Ye, Chenran; Sorger, Volker J.

    2015-06-01

    Advances in opto-electronics are often led by discovery and development of materials featuring unique properties. Recently, the material class of transparent conductive oxides (TCO) has attracted attention for active photonic devices on-chip. In particular, indium tin oxide (ITO) is found to have refractive index changes on the order of unity. This property makes it possible to achieve electrooptic modulation of sub-wavelength device scales, when thin ITO films are interfaced with optical light confinement techniques such as found in plasmonics; optical modes are compressed to nanometer scale to create strong light-matter interactions. Here we review efforts towards utilizing this novel material for high performance and ultra-compact modulation. While high performance metrics are achieved experimentally, there are open questions pertaining to the permittivity modulation mechanism of ITO. Finally, we review a variety of optical and electrical properties of ITO for different processing conditions, and show that ITO-based plasmonic electro-optic modulators have the potential to significantly outperform diffractionlimited devices.

  15. Optical design of a color film recorder with PLZT modulators

    NASA Astrophysics Data System (ADS)

    Carson, John F.

    1990-08-01

    A continuous tone colour film recorder was constructed that exposes 8 x 10 inch ISO 100 daylight-balanced sheet film in ten minutes at a resolution of 1000 pixels/inch. A rotating drum is used for line scan and a leadscrew driven by a stepper motor for page scan. Film loading and unloading is automatic. Light from a stationary xenon arc lamp is split into red green and blue channel components and conducted to a translating optical system by multimode optical fiber cables. Each colour component is then modulated by a small-area PLZT light valve. An annular portion of the modulated light beam is reflected to a photodetector whose signal is used for closed-loop modulator control. The central transmitted portion of the modulated beam is combined with the other colour components into a single beam. This beam illuminates an aperture that is imaged onto the film. An overview of the mechanical electrical and optical concepts will be presented with emphasis on the optical design. 1.

  16. The KM3NeT Digital Optical Module

    NASA Astrophysics Data System (ADS)

    Vivolo, Daniele

    2016-04-01

    KM3NeT is a European deep-sea multidisciplinary research infrastructure in the Mediterranean Sea. It will host a km3-scale neutrino telescope and dedicated instruments for long-term and continuous measurements for Earth and Sea sciences. The KM3NeT neutrino telescope is a 3-dimensional array of Digital Optical Modules, suspended in the sea by means of vertical string structures, called Detection Units, supported by two pre-stretched Dyneema ropes, anchored to the seabed and kept taut with a system of buoys. The Digital Optical Module represents the active part of the neutrino telescope. It is composed by a 17-inch, 14 mm thick borosilicate glass (Vitrovex) spheric vessel housing 31 photomultiplier tubes with 3-inch photocathode diameter and the associated front-end and readout electronics. The technical solution adopted for the KM3NeT optical modules is characterized by an innovative design, considering that existing neutrino telescopes, Baikal, IceCube and ANTARES, all use large photomultipliers, typically with a diameter of 8″ or 10″. It offers several advantages: higher sensitive surface (1260 cm2), weaker sensitivity to Earth's magnetic field, better distinction between single-photon and multi-photon events (photon counting) and directional information with an almost isotropic field of view. In this contribution the design and the performance of the KM3NeT Digital Optical Modules are discussed, with a particular focus on enabling technologies and integration procedure.

  17. Evaluation of misalignments within a concentrator photovoltaic module by the module optical analyzer: A case of study concerning temperature effects on the module performance

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Askins, Stephen; Antón, Ignacio; Sala, Gabriel

    2015-08-01

    Instituto de Energía Solar, Universidad Politécnica de Madrid (IES-UPM) has developed a method [referred to as the luminescence inverse (LI) method] and equipment [called module optical analyzer (MOA)] to fast measure the optical-angular properties of a CPV module without illumination system nor module movement. This paper presents how the MOA can investigate the optical performance of concentrator photovoltaic (CPV) modules optical-angular performance (in particular, misalignments between the optical components comprising the module) at different temperature conditions.

  18. Cost, performance, and reliability simulator for optical transceiver modules.

    PubMed

    Stirk, C W; Delen, N; Fedor, A; Ball, M; Hooker, R B; Wu, J S; Hareb, S; Ju, T H; Lee, Y C

    1998-09-10

    The program couple combines simulators for optical performance, mechanical reliability, and production cost under a graphical-user interface to design, simulate, and evaluate micro-optomechanical structures. The thermal simulator predicts the package temperature distribution on the basis of the materials and the geometry as well as on heat sources, sinks, and boundary conditions. The thermal distribution is input to the mechanical simulator, which calculates the stresses or strains and displacements caused by differential thermal expansion. The optical simulator predicts the impact on the optical efficiency and the cross talk of mechanical and optical parameter variations such as solder heights, misalignments, and wavelength distributions. The cost simulator represents the manufacturing process flow and calculates the final cost and the cost sensitivity on basis of the cost and the yield of each process step. By means of balancing detector and coupling yield, cosimulation from optical to cost domains determines the optimum detector size to produce the lowest-cost transceiver module. PMID:18286112

  19. Optical protocols for advanced spacecraft networks

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.

    1991-01-01

    Most present day fiber optic networks are in fact extensions of copper wire networks. As a result, their speed is still limited by electronics even though optics is capable of running three orders of magnitude faster. Also, the fact that photons do not interact with one another (as electrons do) provides optical communication systems with some unique properties or new functionality that is not readily taken advantage of with conventional approaches. Some of the motivation for implementing network protocols in the optical domain, a few possible approaches including optical code-division multiple-access (CDMA), and how this class of networks can extend the technology life cycle of the Space Station Freedom (SSF) with increased performance and functionality are described.

  20. Optical accelerometer based on grating interferometer with phase modulation technique.

    PubMed

    Zhao, Shuangshuang; Zhang, Juan; Hou, Changlun; Bai, Jian; Yang, Guoguang

    2012-10-10

    In this paper, an optical accelerometer based on grating interferometer with phase modulation technique is proposed. This device architecture consists of a laser diode, a sensing chip and an optoelectronic processing circuit. The sensing chip is a sandwich structure, which is composed of a grating, a piezoelectric translator and a micromachined silicon structure consisting of a proof mass and four cantilevers. The detected signal is intensity-modulated with phase modulation technique and processed with a lock-in amplifier for demodulation. Experimental results show that this optical accelerometer has acceleration sensitivity of 619 V/g and high-resolution acceleration detection of 3 μg in the linear region. PMID:23052079

  1. Polarization-sensitive optical coherence tomography using continuous polarization modulation with arbitrary phase modulation amplitude

    NASA Astrophysics Data System (ADS)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2012-03-01

    We demonstrate theoretically and experimentally that the phase retardance and relative optic-axis orientation of a sample can be calculated without prior knowledge of the actual value of the phase modulation amplitude when using a polarization-sensitive optical coherence tomography system based on continuous polarization modulation (CPM-PS-OCT). We also demonstrate that the sample Jones matrix can be calculated at any values of the phase modulation amplitude in a reasonable range depending on the system effective signal-to-noise ratio. This has fundamental importance for the development of clinical systems by simplifying the polarization modulator drive instrumentation and eliminating its calibration procedure. This was validated on measurements of a three-quarter waveplate and an equine tendon sample by a fiber-based swept-source CPM-PS-OCT system.

  2. Highly Automated Module Production Incorporating Advanced Light Management

    SciTech Connect

    Perelli-Minetti, Michael; Roof, Kyle

    2015-08-11

    The objective was to enable a high volume, cost effective solution for increasing the amount of light captured by PV modules through utilization of an advanced Light Re-directing Film and to follow a phased approach to develop and implement this new technology in order to achieve an expected power gain of up to 12 watts per module. Full size PV modules were manufactured using a new Light Redirecting Film (LRF) material applied to two different areas of PV modules in order to increase the amount of light captured by the modules. One configuration involved applying thin strips of LRF film over the tabbing ribbon on the cells in order to redirect the light that is normally absorbed by the tabbing ribbon to the active areas of the cells. A second configuration involved applying thin strips of LRF film over the white spaces between cells within a module in order to capture some of the light that is normally reflected from the white areas back through the front glass of the modules. Significant power increases of 1.4% (3.9 watts) and 1.0% (3.2 watts), respectively, compared to standard PV modules were measured under standard test conditions. The performance of PV modules with LRF applied to the tabbing ribbon was modeled. The results showed that the power increase provided by LRF depended greatly on the angle of incident light with the optimum performance only occurring when the light was within a narrow range of being perpendicular to the solar module. The modeling showed that most of the performance gain would be lost when the angle of incident light was greater than 28 degrees off axis. This effect made the orientation of modules with LRF applied to tabbing ribbons very important as modules mounted in “portrait” mode were predicted to provide little to no power gain from LRF under real world conditions. Based on these results, modules with LRF on tabbing ribbons would have to be mounted in “landscape” mode to realize a performance advantage. In addition

  3. Optical vector network analyzer based on amplitude-phase modulation

    NASA Astrophysics Data System (ADS)

    Morozov, Oleg G.; Morozov, Gennady A.; Nureev, Ilnur I.; Kasimova, Dilyara I.; Zastela, Mikhail Y.; Gavrilov, Pavel V.; Makarov, Igor A.; Purtov, Vadim A.

    2016-03-01

    The article describes the principles of optical vector network analyzer (OVNA) design for fiber Bragg gratings (FBG) characterization based on amplitude-phase modulation of optical carrier that allow us to improve the measurement accuracy of amplitude and phase parameters of the elements under test. Unlike existing OVNA based on a single-sideband and unbalanced double sideband amplitude modulation, the ratio of the two side components of the probing radiation is used for analysis of amplitude and phase parameters of the tested elements, and the radiation of the optical carrier is suppressed, or the latter is used as a local oscillator. The suggested OVNA is designed for the narrow band-stop elements (π-phaseshift FBG) and wide band-pass elements (linear chirped FBG) research.

  4. Advances in GaAs bistable optical devices

    NASA Astrophysics Data System (ADS)

    Jewell, J. L.; Tarng, S. S.; Gibbs, H. M.; Tai, K.; Weinberger, D. A.; Gossard, A. C.; McCall, S. L.; Passner, A.; Venkatesan, T. N. C.; Weigmann, W.

    1984-01-01

    Bistable optical devices (BOD's) using GaAs as the nonlinear medium are viable candidators for the achievement of fast ( ns), room temperature, low-power (mw), externally controllable optical switches which are easily fabricated and operated. Advances were made in all of these areas and efforts are in progress to improve performances in ways that are simultaneously compatible.

  5. Extraction Kickers and Modulators for the advanced Hydrodynamic Facility

    SciTech Connect

    Walstrom, P L; Cook, E G

    2001-06-12

    In order to exploit the full potential of the Advanced Hydrodynamic Facility (AHF) facility to produce a time sequence of proton transmission radiographs throughout the dynamic event, a kicker/modulator for extraction from the 50 GeV ring that is capable of generating a string of 25 pulse pairs at arbitrary times within a total time duration of 100 microseconds or more is desired. The full range of desired pulse-train requirements cannot be met with the commonly used pulse-forming cables or networks (PFNs) switched with thyratrons. The preferred modulator design approach at present is a transformer voltage-adder concept with primary-side pulses formed with MOSFET-switched capacitors. This modulator will be a scale-up of an existing modulator that has been developed by Lawrence Livermore National Laboratory for use in DARHT, an electron induction accelerator facility at Los Alamos National Laboratory. Before the voltage-adder concept can be adopted for use in AHF, a working prototype that meets the AHF requirements for the pulse voltage, current, rise and fall time, and total pulse number must be built and tested. Additional requirements for pulse-to-pulse flattop height variation and baseline shift must also be met. A development and testing plan for the voltage-adder kicker modulator for AHF is described.

  6. A New OEO Design Using Optical Phase Modulation and Modulation Suppression

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Yu, Nan

    2006-01-01

    We present the design for a phase-modulated Opto-Electronic Oscillator (OEO) that incorporates asymmetric Mach- Zehnder (AMZ) interferometers as phase demodulators together with PM modulation suppression. The new design promises to obtain in the electro-optical domain the low-noise advantages previously achieved in RF and microwave oscillators by the use of carrier suppression but which have been achieved only to a limited extent in OEO's.

  7. Recent advances in digital camera optics

    NASA Astrophysics Data System (ADS)

    Ishiguro, Keizo

    2012-10-01

    The digital camera market has extremely expanded in the last ten years. The zoom lens for digital camera is especially the key determining factor of the camera body size and image quality. Its technologies have been based on several analog technological progresses including the method of aspherical lens manufacturing and the mechanism of image stabilization. Panasonic is one of the pioneers of both technologies. I will introduce the previous trend in optics of zoom lens as well as original optical technologies of Panasonic digital camera "LUMIX", and in addition optics in 3D camera system. Besides, I would like to suppose the future trend in digital cameras.

  8. Design guideline for plasmonic 16-QAM optical modulator

    NASA Astrophysics Data System (ADS)

    Al-mfrji, Alhuda A.; Tawfeeq, Shelan K.; Fyath, Raad S.

    2016-09-01

    This paper presents the design and investigation of 16-QAM optical modulator based on plasmonic-polymer hybrid slot waveguides. The design is CMOS-compatible and uses dual-parallel Mach-Zehnder modulator (DPMZM) followed by a phase modulator (PM). Careful consideration is given to design low loss photonic-plasmonic interfaces to ensure efficient coupling between silicon and plasmonic waveguide. The effect of slot widths on device performance is investigated comprehensively using COMSOL software simulation along with analytical analysis for both gold and silver contact. The results can be used as a guideline to design compact and high speed all-plasmonic 16-QAM modulators for 1550 nm wavelength communication systems.

  9. Cancellation of laser dither modulation from optical frequency standards.

    PubMed

    Taubman, M S; Hall, J L

    2000-03-01

    We demonstrate the removal of the dither modulation from an iodine-stabilized He-Ne laser by using a frequency-modulated acousto-optic modulator and feed-forward techniques. This procedure reduces the linewidth of the beat between this laser and a flywheel He-Ne laser from 6 MHz to 8 kHz, the undithered beat linewidth being ~7 kHz. Dither suppression greatly reduces counter errors during beat measurements from stroboscopic effects between the counter's gate and the frequency of the dither modulation and increases the utility of the already formidable array of dithered laser frequency standards by making locking to them an easier task. PMID:18059864

  10. Optical properties of a vibrationally modulated solid state Mott insulator.

    PubMed

    Kaiser, S; Clark, S R; Nicoletti, D; Cotugno, G; Tobey, R I; Dean, N; Lupi, S; Okamoto, H; Hasegawa, T; Jaksch, D; Cavalleri, A

    2014-01-01

    Optical pulses at THz and mid-infrared frequencies tuned to specific vibrational resonances modulate the lattice along chosen normal mode coordinates. In this way, solids can be switched between competing electronic phases and new states are created. Here, we use vibrational modulation to make electronic interactions (Hubbard-U) in Mott-insulator time dependent. Mid-infrared optical pulses excite localized molecular vibrations in ET-F2TCNQ, a prototypical one-dimensional Mott-insulator. A broadband ultrafast probe interrogates the resulting optical spectrum between THz and visible frequencies. A red-shifted charge-transfer resonance is observed, consistent with a time-averaged reduction of the electronic correlation strength U. Secondly, a sideband manifold inside of the Mott-gap appears, resulting from a periodically modulated U. The response is compared to computations based on a quantum-modulated dynamic Hubbard model. Heuristic fitting suggests asymmetric holon-doublon coupling to the molecules and that electron double-occupancies strongly squeeze the vibrational mode.

  11. Multichip transmitter/receiver module for fiber optical sensors

    NASA Astrophysics Data System (ADS)

    Waegli, Peter; Morel, Philippe

    1997-09-01

    Amongst the various sensing principles studied for use in optical fiber sensors, color coding has proven to be successful in commercial applications. Color coded sensors are based on commercially available and easy to handle components (i.e. LED's, lasers, multimode fibers) and the same basic optoelectronics can be used for a wide variety of applications. Such applications are: the remote measurement of chemical composition (pH, hydrogen, oxygen, aromatic hydrocarbons, humidity etc.), biochemical reactions and physical parameters (e.g. temperature, pressure, etc.) in medical applications (e.g. blood gas analysis, immunosensors, etc.), environmental monitoring, process control and on the factory floor. A versatile transmitter/receiver-module, which can be easily customized, has been developed as a multi chip module (MCM). This MCM can be directly mounted onto the printed circuit board, is small in size (50 X 50 X 12 mm3) and contains all optical, optoelectronic and electronic components and circuits to interface optically with the sensors and electrically with the microprocessor and its associated circuitry used for data analysis. Up to four sensors can be connected to one module and individually interrogated under software control. The design and the characteristics of the MCM as well as its application in possible sensor arrangements will be discussed with special emphasis on its use in a four channel fiber optic temperature sensor.

  12. Optical filtering in directly modulated/detected OOFDM systems.

    PubMed

    Sánchez, C; Ortega, B; Wei, J L; Capmany, J

    2013-12-16

    This work presents a theoretical investigation on the performance of directly modulated/detected (DM/DD) optical orthogonal frequency division multiplexed (OOFDM) systems subject to optical filtering. The impact of both linear and nonlinear distortion effects are taken into account to calculate the effective signal-to-noise ratio of each subcarrier. These results are then employed to optimize the design parameters of two simple optical filtering structures: a Mach Zehnder interferometer and a uniform fiber Bragg grating, leading to a significant optical power budget improvement given by 3.3 and 3dB, respectively. These can be further increased to 5.5 and 4.2dB respectively when balanced detection configurations are employed. We find as well that this improvement is highly dependent on the clipping ratio. PMID:24514636

  13. Optical Peaking Enhancement in High-Speed Ring Modulators

    PubMed Central

    Müller, J.; Merget, F.; Azadeh, S. Sharif; Hauck, J.; García, S. Romero; Shen, B.; Witzens, J.

    2014-01-01

    Ring resonator modulators (RRM) combine extreme compactness, low power consumption and wavelength division multiplexing functionality, making them a frontrunner for addressing the scalability requirements of short distance optical links. To extend data rates beyond the classically assumed bandwidth capability, we derive and experimentally verify closed form equations of the electro-optic response and asymmetric side band generation resulting from inherent transient time dynamics and leverage these to significantly improve device performance. An equivalent circuit description with a commonly used peaking amplifier model allows straightforward assessment of the effect on existing communication system architectures. A small signal analytical expression of peaking in the electro-optic response of RRMs is derived and used to extend the electro-optic bandwidth of the device above 40 GHz as well as to open eye diagrams penalized by intersymbol interference at 32, 40 and 44 Gbps. Predicted peaking and asymmetric side band generation are in excellent agreement with experiments. PMID:25209255

  14. Optical pulse compression reflectometry based on single-sideband modulator driven by electrical frequency-modulated pulse

    NASA Astrophysics Data System (ADS)

    Zou, Weiwen; Yu, Lei; Yang, Shuo; Chen, Jianping

    2016-05-01

    We propose a novel scheme to generate a linear frequency-modulated optical pulse with high extinction ratio based on an electrical frequency-modulated pulse and optical single-sideband modulator. This scheme is proved to improve the stability and accuracy of optical pulse compression reflectometry (OPCR). In the experiment, a high spatial resolution of 10 cm and a long measurement range of 10.8 km using a laser source with 2-km coherence length are demonstrated.

  15. Advanced Imaging Optics Utilizing Wavefront Coding.

    SciTech Connect

    Scrymgeour, David; Boye, Robert; Adelsberger, Kathleen

    2015-06-01

    Image processing offers a potential to simplify an optical system by shifting some of the imaging burden from lenses to the more cost effective electronics. Wavefront coding using a cubic phase plate combined with image processing can extend the system's depth of focus, reducing many of the focus-related aberrations as well as material related chromatic aberrations. However, the optimal design process and physical limitations of wavefront coding systems with respect to first-order optical parameters and noise are not well documented. We examined image quality of simulated and experimental wavefront coded images before and after reconstruction in the presence of noise. Challenges in the implementation of cubic phase in an optical system are discussed. In particular, we found that limitations must be placed on system noise, aperture, field of view and bandwidth to develop a robust wavefront coded system.

  16. Optical interference fringe reduction in frequency-modulation spectroscopy experiments

    NASA Astrophysics Data System (ADS)

    Hjelme, Dag Roar; Neegard, Steinar; Vartdal, Erling

    1995-08-01

    We show both theoretically and experimentally that interference fringe signals can always be suppressed to improve the signal-to-noise ratio, provided that the modulation frequency is of the order of the absorption linewidth or higher. Suppression of optical interference fringes by more than 1 order of magnitude and signal-to-noise ratio enhancement of more than 13 dB is demonstrated by use of a proper choice of laser modulation frequency. A further fringe reduction of 10 dB is possible by adjustment of the local oscillator phase.

  17. Interactive online optics modules for the college physics course

    NASA Astrophysics Data System (ADS)

    Hoeling, Barbara M.

    2012-04-01

    A new learning tool for geometrical optics is presented which has been developed for an algebra based introductory college physics course for life science majors. The interactive online learning module contains images, videos of problem solutions, short animated videos, and interactive animations, which allow students to actively explore the physics content beyond the pictures in a textbook. These elements are accompanied by narration and a transcript to guide the students while allowing them to navigate freely between the different parts of the module. The results of student learning, a comparison with a control group, and a survey of student attitudes toward this new instruction method are discussed.

  18. Inspirations from biological optics for advanced photonic systems.

    PubMed

    Lee, Luke P; Szema, Robert

    2005-11-18

    Observing systems in nature has inspired humans to create technological tools that allow us to better understand and imitate biology. Biomimetics, in particular, owes much of its current development to advances in materials science and creative optical system designs. New investigational tools, such as those for microscopic imaging and chemical analyses, have added to our understanding of biological optics. Biologically inspired optical science has become the emerging topic among researchers and scientists. This is in part due to the availability of polymers with customizable optical properties and the ability to rapidly fabricate complex designs using soft lithography and three-dimensional microscale processing techniques.

  19. Transparent conducting oxides for electro-optical plasmonic modulators

    NASA Astrophysics Data System (ADS)

    Babicheva, Viktoriia E.; Boltasseva, Alexandra; Lavrinenko, Andrei V.

    2015-06-01

    The ongoing quest for ultra-compact optical devices has reached a bottleneck due to the diffraction limit in conventional photonics. New approaches that provide subwavelength optical elements, and therefore lead to miniaturization of the entire photonic circuit, are urgently required. Plasmonics, which combines nanoscale light confinement and optical-speed processing of signals, has the potential to enable the next generation of hybrid information-processing devices, which are superior to the current photonic dielectric components in terms of speed and compactness. New plasmonic materials (other than metals), or optical materials with metal-like behavior, have recently attracted a lot of attention due to the promise they hold to enable low-loss, tunable, CMOScompatible devices for photonic technologies. In this review, we provide a systematic overview of various compact optical modulator designs that utilize a class of the most promising new materials as the active layer or core— namely, transparent conducting oxides. Such modulators can be made low-loss, compact, and exhibit high tunability while offering low cost and compatibility with existing semiconductor technologies. A detailed analysis of different configurations and their working characteristics, such as their extinction ratio, compactness, bandwidth, and losses, is performed identifying the most promising designs.

  20. Optical module to extend any Fourier-domain optical coherence tomography system into a polarisation-sensitive system

    NASA Astrophysics Data System (ADS)

    Rivet, Sylvain; Marques, Manuel J.; Bradu, Adrian; Podoleanu, Adrian

    2016-06-01

    This article presents a theoretical study on an optical module (OM) that can be inserted between an object under investigation and a Fourier-domain optical coherence tomography system, transforming the latter into a polarisation-sensitive optical coherence tomography optical coherence tomography (OCT) system. The module consists of two electro-optic modulators, a Faraday rotator, a linear polariser and a quarter-wave plate. A detailed description on how the module can be used to extract both the net retardance and the fast axis orientation of a linear birefringent sample is presented. This is achieved by taking two sequential measurements for different values of retardance produced by the electro-optic modulator. The module keeps measurements free from undesired polarimetric effects due to birefringence in the single-mode optical fibre and diattenuation in fibre-based couplers within OCT systems. Simulations have been carried out in order to evaluate the effects of chromatic behaviour of the components within the OM.

  1. Dynamic Optical Grating Device and Associated Method for Modulating Light

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Chu, Sang-Hyon (Inventor)

    2012-01-01

    A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity fo the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

  2. Phase-coherent orthogonally polarized optical single sideband modulation with arbitrarily tunable optical carrier-to-sideband ratio.

    PubMed

    Wang, Wen Ting; Liu, Jian Guo; Mei, Hai Kuo; Zhu, Ning Hua

    2016-01-11

    We propose and experimentally verify a novel approach to achieve phase-coherence orthogonally polarized optical single sideband (OSSB) modulation with a tunable optically carrier-to-sideband ratio (OCSR). In our scheme, the orthogonally polarized OSSB signal is achieved using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator without an optical band-pass filter (OBPF). Therefore, the proposed method is wavelength independent. The DP-QPSK modulator includes two parallel QPSK modulators locating on its two arms. The upper QPSK modulator of the DP-QPSK modulator is driven by two quadrature sinusoidal microwave signals and works at the frequency shifting condition whose bias voltages are optimized to suppress the optical. The lower QPSK modulator of that works at the maximum transmission point and the optical carrier is not modulated. The OCSR is continuously tunable by simply adjusting the bias voltages of the lower modulator. The frequency shifting optical signal from the upper QPSK modulator and the optical carrier from the lower QPSK modulator are combined together at the output of the DP-QPSK modulator. The optical carrier and sideband are polarized orthogonally. The generated OSSB signals could be used to shift and code the phase of the microwave signal and generate ultra-wideband (UWB) microwave pulse. The proposed method is analyzed and experimental demonstrated.

  3. Optically Modulated Fluorophores for Selective Fluorescence Signal Recovery

    PubMed Central

    Richards, Chris I.; Hsiang, Jung-Cheng; Senapati, Dulal; Patel, Sandeep; Yu, Junhua; Vosch, Tom; Dickson, Robert M.

    2009-01-01

    Fluorescence imaging in biological sciences is hindered by significant depth-dependent signal attenuation and high fluorescent backgrounds. We have developed optically modulated near-IR-emitting few-atom Ag nanodots that are selectively and dynamically photobrightened upon simultaneous excitation with a secondary laser enabling high sensitivity image extraction to reveal only the demodulated fluorophores. Image demodulation is demonstrated in high background environments to extract weak signals from completely obscuring background emission. PMID:19284790

  4. Time domain referencing in intensity modulation fiber optic sensing systems

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.

    1986-01-01

    Intensity modulation sensors are classified depending on the way in which the reference and signal channels are separated: in space, wavelength (frequency), or time domains. To implement the time domain referencing different types of fiber optic (FO) loops have been used. A pulse of short duration sent into the loop results in a series of pulses of different amplitudes. The information about the measured parameter is retrieved from the relative amplitudes of pulses in the same train.

  5. Advanced fiber optic seismic sensors (geophone) research

    NASA Astrophysics Data System (ADS)

    Zhang, Yan

    The systematical research on the fiber optic seismic sensors based on optical Fiber Bragg Grating (FBG) sensing technology is presented in this thesis. Optical fiber sensors using fiber Bragg gratings have a number of advantages such as immunity to electromagnetic interference, lightweight, low power consumption. The FBG sensor is intrinsically sensitive to dynamic strain signals and the strain sensitivity can approach sub micro-strain. Furthermore, FBG sensors are inherently suited for multiplexing, which makes possible networked/arrayed deployment on a large scale. The basic principle of the FBG geophone is that it transforms the acceleration of ground motion into the strain signal of the FBG sensor through mechanical design, and after the optical demodulation generates the analog voltage output proportional to the strain changes. The customized eight-channel FBG seismic sensor prototype is described here which consists of FBG sensor/demodulation grating pairs attached on the spring-mass mechanical system. The sensor performance is evaluated systematically in the laboratory using the conventional accelerometer and geophone as the benchmark, Two major applications of FBG seismic sensor are demonstrated. One is in the battlefield remote monitoring system to detect the presence of personnel, wheeled vehicles, and tracked vehicles. The other application is in the seismic reflection survey of oilfield exploration to collect the seismic waves from the earth. The field tests were carried out in the air force base and the oilfield respectively. It is shown that the FBG geophone has higher frequency response bandwidth and sensitivity than conventional moving-coil electromagnetic geophone and the military Rembass-II S/A sensor. Our objective is to develop a distributed FBG seismic sensor network to recognize and locate the presence of seismic sources with high inherent detection capability and a low false alarm rate in an integrated system.

  6. Optical modulation of quantum cascade laser with optimized excitation wavelength.

    PubMed

    Yang, Tao; Chen, Gang; Tian, Chao; Martini, Rainer

    2013-04-15

    The excitation wavelength for all-optical modulation of a 10.6 μm mid-infrared (MIR) quantum cascade laser (QCL) was varied in order to obtain maximum modulation depth. Both amplitude and wavelength modulation experiments were conducted at 820 nm and 1550 nm excitation respectively, whereby the latter matches the interband transition in the QCL active region. Experimental results show that for continuous-wave mode-operated QCL, the efficiency of free carrier generation is doubled under 1550 nm excitation compared with 820 nm excitation, resulting in an increase of the amplitude modulation index from 19% to 36%. At the same time, the maximum wavelength shift is more than doubled from 1.05 nm to 2.80 nm. Furthermore, for the first time to our knowledge, we demonstrated the optical switching of a QCL operated in pulse mode by simple variation of the excitation wavelength.

  7. Direct electrical-to-optical conversion and light modulation in micro whispering-gallery-mode resonators

    NASA Technical Reports Server (NTRS)

    Maleki, Lute (Inventor); Levi, Anthony F. J. (Inventor)

    2005-01-01

    Techniques for directly converting an electrical signal into an optical signal by using a whispering gallery mode optical resonator formed of a dielectric material that allows for direct modulation of optical absorption by the electrical signal.

  8. Design of Optical Pulse Position Modulation (PPM) Translating Receiver

    SciTech Connect

    Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V

    2009-06-19

    M-ary pulse position modulation (M-ary PPM) signaling is a means of transmitting multiple bits per symbol in an intensity modulated/direct detection (IM/DD) system. PPM is used in applications with average power limitations. In optical communication systems, PPM becomes challenging to implement at gigabit rates and/or large M, since pulsed signaling requires higher electronic processing bandwidths than the fundamental transmission rate. they have thus been exploring techniques for PPM communications using optical processing. Previous work described a transmitter algorithm that directly translates a bit sequence of N digital bits to the optical pulse position m for any M = 2{sup N}. It has been considerably more difficult to define a similar receiver algorithm that translates the received optical pulse position directly back to a bit sequence with minimal electronic processing. Designs for specific Ms (e.g., 4-ary) have been shown and implemented, but are difficult to scale to larger M. In this work, they present for the first time a generalized PPM translating receiver that is applicable to all M and data rates.

  9. High contrast 40Gbit/s optical modulation in silicon.

    PubMed

    Thomson, D J; Gardes, F Y; Hu, Y; Mashanovich, G; Fournier, M; Grosse, P; Fedeli, J-M; Reed, G T

    2011-06-01

    Data interconnects are on the verge of a revolution. Electrical links are increasingly being pushed to their limits with the ever increasing demand for bandwidth. Data transmission in the optical domain is a leading candidate to satisfy this need. The optical modulator is key to most applications and increasing the data rate at which it operates is important for reducing power consumption, increasing channel bandwidth limitations and improving the efficiency of infrastructure usage. In this work silicon based devices of lengths 3.5mm and 1mm operating at 40Gbit/s are demonstrated with extinction ratios of up to 10dB and 3.5dB respectively. The efficiency and optical loss of the phase shifter is 2.7V.cm and 4dB/mm (or 4.5dB/mm including waveguide loss) respectively.

  10. Phased-array optical whispering gallery mode modulation and method

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry V. (Inventor)

    2009-01-01

    A whispering gallery mode (WGM) resonator device and method capable of filtering sidebands of optical modulators are provided. The method includes providing an optical resonator adapted to support whispering gallery modes and forming a first field and a second field from a first location and a second location, respectively, at the circumference of the optical resonator and being separated by an arc angle, .alpha.. The method includes adjusting relative phase between the first field and the second field in accordance to a differential phase, .beta., and combining the first and the second fields into an output. Particular selection of the arc angle, .alpha., and the differential phase, .beta., can determine the function of the output.

  11. Advances in Optical Spectroscopy and Imaging of Breast Lesions

    SciTech Connect

    Demos, S; Vogel, A J; Gandjbakhche, A H

    2006-01-03

    A review is presented of recent advances in optical imaging and spectroscopy and the use of light for addressing breast cancer issues. Spectroscopic techniques offer the means to characterize tissue components and obtain functional information in real time. Three-dimensional optical imaging of the breast using various illumination and signal collection schemes in combination with image reconstruction algorithms may provide a new tool for cancer detection and monitoring of treatment.

  12. Recent advancement in optical fiber sensing for aerospace composite structures

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Takeda, Nobuo

    2013-12-01

    Optical fiber sensors have attracted considerable attention in health monitoring of aerospace composite structures. This paper briefly reviews our recent advancement mainly in Brillouin-based distributed sensing. Damage detection, life cycle monitoring and shape reconstruction systems applicable to large-scale composite structures are presented, and new technical concepts, "smart crack arrester" and "hierarchical sensing system", are described as well, highlighting the great potential of optical fiber sensors for the structural health monitoring (SHM) field.

  13. Advanced Sensors Boost Optical Communication, Imaging

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Brooklyn, New York-based Amplification Technologies Inc. (ATI), employed Phase I and II SBIR funding from NASA s Jet Propulsion Laboratory to forward the company's solid-state photomultiplier technology. Under the SBIR, ATI developed a small, energy-efficient, extremely high-gain sensor capable of detecting light down to single photons in the near infrared wavelength range. The company has commercialized this technology in the form of its NIRDAPD photomultiplier, ideal for use in free space optical communications, lidar and ladar, night vision goggles, and other light sensing applications.

  14. Recent advances in optically pumped semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Chilla, Juan; Shu, Qi-Ze; Zhou, Hailong; Weiss, Eli; Reed, Murray; Spinelli, Luis

    2007-02-01

    Optically pumped semiconductor lasers offer significant advantages with respect to all traditional diode-pumped solid state lasers (including fiber lasers) in regards to wavelength flexibility, broad pump tolerance, efficient spectral and spatial brightness conversion and high power scaling. In this talk we will describe our recent progress in the lab and applying this technology to commercial systems. Results include diversified wavelengths from 460 to 570nm, power scaling to >60W of CW 532nm, and the launch of a low cost 5W CW visible source for forensic applications.

  15. Integrated modeling of advanced optical systems

    NASA Astrophysics Data System (ADS)

    Briggs, Hugh C.; Needels, Laura; Levine, B. Martin

    1993-02-01

    This poster session paper describes an integrated modeling and analysis capability being developed at JPL under funding provided by the JPL Director's Discretionary Fund and the JPL Control/Structure Interaction Program (CSI). The posters briefly summarize the program capabilities and illustrate them with an example problem. The computer programs developed under this effort will provide an unprecedented capability for integrated modeling and design of high performance optical spacecraft. The engineering disciplines supported include structural dynamics, controls, optics and thermodynamics. Such tools are needed in order to evaluate the end-to-end system performance of spacecraft such as OSI, POINTS, and SMMM. This paper illustrates the proof-of-concept tools that have been developed to establish the technology requirements and demonstrate the new features of integrated modeling and design. The current program also includes implementation of a prototype tool based upon the CAESY environment being developed under the NASA Guidance and Control Research and Technology Computational Controls Program. This prototype will be available late in FY-92. The development plan proposes a major software production effort to fabricate, deliver, support and maintain a national-class tool from FY-93 through FY-95.

  16. Recent advances in ALON optical ceramic

    NASA Astrophysics Data System (ADS)

    Wahl, Joseph M.; Hartnett, Thomas M.; Goldman, Lee M.; Twedt, Richard; Warner, Charles

    2005-05-01

    Aluminum Oxynitride (ALONTM Optical Ceramic) is a transparent ceramic material which combines transparency from the UV to the MWIR with excellent mechanical properties. ALON"s optical and mechanical properties are isotropic by virtue of its cubic crystalline structure. Consequently, ALON is transparent in its polycrystalline form and can be made by conventional powder processing techniques. This combination of properties and manufacturability make ALON suitable for a range of applications from IR windows, domes and lenses to transparent armor. The technology for producing transparent ALON was developed at Raytheon and has been transferred to Surmet Corporation where it is currently in production. Surmet is currently selling ALON into a number of military (e.g., windows and domes) and commercial (e.g., supermarket scanner windows) applications. The capability to manufacture large ALON windows for both sensor window and armor applications is in place. ALON windows up to 20x30 inches have been fabricated. In addition, the capability to shape and polish these large and curved windows is being developed and demonstrated at Surmet. Complex shapes, both hyper-hemispherical and conformal, are also under development and will be described.

  17. Low power MEMS modulating retroreflectors for optical communication

    NASA Astrophysics Data System (ADS)

    Stewart, Jason B.; Freedman, David; Cornelissen, Steven; Horenstein, Mark N.; Woskov, Peter; Tang, Jonathan

    2010-02-01

    We report on the design, development and testing of a new low-power, light-weight and low-cost modulating retroreflector system for free-space covert optical communication and remote sensor interrogation. The central component of the system is a MEMS modulator mirror, which is physically similar to a very low modulation reflective diffraction grating that has actively controlled groove depth and can operate at frequencies up to 1MHz. One facet of the hollow corner cube retroreflector consists of the MEMS mirror, providing intensity modulation of a reflected interrogating beam by switching from an unpowered flat mirror state to a powered diffractive state. The system is optimized for performance at 1550nm and has a field of view of 60 degrees. For covert operation it uses "wake-up" circuitry to control a low-power shutter that remains closed between data transfers. The system's compact driver electronics employs power scavenging and resonant properties for minimal power consumption and extended autonomous operational life. Interrogation field test results for the modulating retroreflector will be presented.

  18. Effects and correction of magneto-optic spatial light modulator phase errors in an optical correlator

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Hine, Butler P.; Reid, Max B.

    1992-01-01

    The optical phase errors introduced into an optical correlator by the input and filter plane magnetooptic spatial light modulators have been studied. The magnitude of these phase errors is measured and characterized, their effects on the correlation results are evaluated, and a means of correction by a design modification of the binary phase-only optical-filter function is presented. The efficacy of the phase-correction technique is quantified and is found to restore the correlation characteristics to those obtained in the absence of errors, to a high degree. The phase errors of other correlator system elements are also discussed and treated in a similar fashion.

  19. Optical logic gates based on electro-optic modulation with Sagnac interferometer.

    PubMed

    Li, Qiliang; Zhu, Mengyun; Li, Dongqiang; Zhang, Zhen; Wei, Yizhen; Hu, Miao; Zhou, Xuefang; Tang, Xianghong

    2014-07-20

    In this work, we present a new structure to realize optical logic operation in a Sagnac interferometer with electro-optical modulation. In the scheme, we divide two counterpropagation signals in a Sagnac loop to two different arms with the electro-optical crystal by using two circulators. Lithium niobate materials whose electro-optical coefficient can be as large as 32.2×10(-12)  m/V make up the arms of the waveguides. Using the transfer matrix of the fiber coupler, we analyze the propagation of signals in this system and obtain the transmission characteristic curves and the extinction ratio. The results indicate that this optical switching has a high extinction ratio of about 60 dB and an ultrafast response time of 2.036 ns. In addition, the results reveal that the change of the dephasing between the two input signals and the modification of the modulation voltage added to the electro-optical crystal leads to the change of the extinction ratio. We also conclude that, in cases of the dephasing of two initial input signals Δφ=0, we can obtain the various logical operations, such as the logical operations D=A¯·B, D=A·B¯, C=A+B, and D=A⊕B in ports C and D of the system by adjusting the modulation voltage. When Δφ≠0, we obtain the arithmetic operations D=A+B, C=A⊕B, D=A·B¯, and C=A¯·B in ports C and D. This study is significant for the design of all optical networks by adjusting the modulation voltage.

  20. EDITORIAL: Special issue on optical neural engineering: advances in optical stimulation technology Special issue on optical neural engineering: advances in optical stimulation technology

    NASA Astrophysics Data System (ADS)

    Shoham, Shy; Deisseroth, Karl

    2010-08-01

    a single spine, with two-photon uncaging) and in rapid, flexible spatial-temporal patterns [10-14]. Nevertheless, current technology generally requires damaging doses of UV or violet illumination and the continuous re-introduction of the caged compound, which, despite interest, makes for a difficult transition beyond in vitro preparations. Thus, the tremendous progress in the in vivo application of photo-stimulation tools over the past five years has been largely facilitated by two 'exciting' new photo-stimulation technologies: photo-biological stimulation of a rapidly increasing arsenal of light-sensitive ion channels and pumps ('optogenetic' probes[15-18]) and direct photo-thermal stimulation of neural tissue with an IR laser [19-21]. The Journal of Neural Engineering has dedicated a special section in this issue to highlight advances in optical stimulation technology, which includes original peer-reviewed contributions dealing with the design of modern optical systems for spatial-temporal control of optical excitation patterns and with the biophysics of neural-thermal interaction mediated by electromagnetic waves. The paper by Nikolenko, Peterka and Yuste [22] presents a compact design of a microscope-photo-stimulator based on a transmissive phase-modulating spatial-light modulator (SLM). Computer-generated holographic photo-stimulation using SLMs [12-14, 23] allows the efficient parallel projection of intense sparse patterns of light, and the welcome development of compact, user-friendly systems will likely reduce the barrier to its widespread adoption. The paper by Losavio et al [24] presents the design and functional characteristics of their acousto-optical deflector (AOD) systems for studying spatial-temporal dendritic integration in single neurons in vitro. Both single-photon (UV) and two-photon (femtosecond pulsed IR) AOD uncaging systems are described in detail. The paper presents an excellent overview of the current state of the art and limitations of

  1. Laser Metrology for an Optical-Path-Length Modulator

    NASA Technical Reports Server (NTRS)

    Gursel, Yekta

    2005-01-01

    Laser gauges have been developed to satisfy requirements specific to monitoring the amplitude of the motion of an optical-path-length modulator that is part of an astronomical interferometer. The modulator includes a corner-cube retroreflector driven by an electromagnetic actuator. During operation of the astronomical interferometer, the electromagnet is excited to produce linear reciprocating motion of the corner-cube retroreflector at an amplitude of 2 to 4 mm at a frequency of 250, 750, or 1,250 Hz. Attached to the corner-cube retroreflector is a small pick-off mirror. To suppress vibrations, a counterweight having a mass equal to that of the corner-cube retroreflector and pick-off mirror is mounted on another electromagnetic actuator that is excited in opposite phase. Each gauge is required to measure the amplitude of the motion of the pick-off mirror, assuming that the motions of the pick-off mirror and the corner-cube retroreflector are identical, so as to measure the amplitude of motion of the corner- cube retroreflector to within an error of the order of picometers at each excitation frequency. Each gauge is a polarization-insensitive heterodyne interferometer that includes matched collimators, beam separators, and photodiodes (see figure). The light needed for operation of the gauge comprises two pairs of laser beams, the beams in each pair being separated by a beat frequency of 80 kHz. The laser beams are generated by an apparatus, denoted the heterodyne plate, that includes stabilized helium-neon lasers, acousto-optical modulators, and associated optical and electronic subsystems. The laser beams are coupled from the heterodyne plate to the collimators via optical fibers.

  2. Method to Enhance the Operation of an Optical Inspection Instrument Using Spatial Light Modulators

    NASA Technical Reports Server (NTRS)

    Trolinger, James; Lal, Amit; Jo, Joshua; Kupiec, Stephen

    2012-01-01

    For many aspheric and freeform optical components, existing interferometric solutions require a custom computer-generated hologram (CGH) to characterize the part. The overall objective of this research is to develop hardware and a procedure to produce a combined, dynamic, Hartmann/ Digital Holographic interferometry inspection system for a wide range of advanced optical components, including aspheric and freeform optics. This new instrument would have greater versatility and dynamic range than currently available measurement systems. The method uses a spatial light modulator to pre-condition wavefronts for imaging, interferometry, and data processing to improve the resolution and versatility of an optical inspection instrument. Existing interferometers and Hartmann inspection systems have either too small a dynamic range or insufficient resolution to characterize conveniently unusual optical surfaces like aspherical and freeform optics. For interferometers, a specially produced, computer-generated holographic optical element is needed to transform the wavefront to within the range of the interferometer. A new hybrid wavefront sensor employs newly available spatial light modulators (SLMs) as programmable holographic optical elements (HOEs). The HOE is programmed to enable the same instrument to inspect an optical element in stages, first by a Hartmann measurement, which has a very large dynamic range but less resolution. The first measurement provides the information required to precondition a reference wave that avails the measurement process to the more precise phase shifting interferometry. The SLM preconditions a wavefront before it is used to inspect an optical component. This adds important features to an optical inspection system, enabling not just wavefront conditioning for null testing and dynamic range extension, but also the creation of hybrid measurement procedures. This, for example, allows the combination of dynamic digital holography and Hartmann

  3. Potential for integrated optical circuits in advanced aircraft with fiber optic control and monitoring systems

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert

    1991-01-01

    The current Fiber Optic Control System Integration (FOCSI) program is reviewed and the potential role of IOCs in FOCSI applications is described. The program is intended for building, environmentally testing, and demonstrating operation in piggyback flight tests (no active control with optical sensors) of a representative sensor system for propulsion and flight control. The optical sensor systems are to be designed to fit alongside the bill-of-materials sensors for comparison. The sensors are to be connected to electrooptic architecture cards which will contain the optical sources and detectors to recover and process the modulated optical signals. The FOCSI program is to collect data on the behavior of passive optical sensor systems in a flight environment and provide valuable information on installation amd maintenance problems for this technology, as well as component survivability (light sources, connectors, optical fibers, etc.).

  4. BPSK optical mm-wave signal generation by septupling frequency via a single optical phase modulator

    NASA Astrophysics Data System (ADS)

    Wu, Peng; Ma, Jianxin

    2016-09-01

    In this paper, we have proposed a novel and simple scheme to generate the BPSK optical millimeter wave (MMW) signal with frequency septupling by using an optical phase modulator (PM) and a wavelength selective switch (WSS). In this scheme, the PM is driven by a radio frequency (RF) BPSK signal at the optimized modulation index of 4.89 to assure the 4th and 3rd-order sidebands have equal amplitudes. An wavelength selective switch (WSS) is used to abstract the -4th and +3rd-order sidebands from the spectrum generated by RF BPSK signal modulating the lightwave to form the BPSK optical MMW signal with frequency septupling the driving RF signal. In these two tones, only the +3rd-order sideband bears the BPSK signal while the -4th-order sideband is unmodulated since the phase information is canceled by the even times multiplication of the phase of BPSK signal. The MMW signal can avoid the pulse walk-off effect and the amplitude fading effect caused by the fiber chromatic dispersion. By adjusting the modulation index to assure the two tones have equal amplitude, the generated optical MMW signal has the maximal opto-electrical conversion efficiency and good transmission performance.

  5. Advanced NDE research in electromagnetic, thermal, and coherent optics

    NASA Technical Reports Server (NTRS)

    Skinner, S. Ballou

    1992-01-01

    A new inspection technology called magneto-optic/eddy current imaging was investigated. The magneto-optic imager makes readily visible irregularities and inconsistencies in airframe components. Other research observed in electromagnetics included (1) disbond detection via resonant modal analysis; (2) AC magnetic field frequency dependence of magnetoacoustic emission; and (3) multi-view magneto-optic imaging. Research observed in the thermal group included (1) thermographic detection and characterization of corrosion in aircraft aluminum; (2) a multipurpose infrared imaging system for thermoelastic stress detection; (3) thermal diffusivity imaging of stress induced damage in composites; and (4) detection and measurement of ice formation on the space shuttle main fuel tank. Research observed in the optics group included advancements in optical nondestructive evaluation (NDE).

  6. Optical diagnosis of mammary ductal carcinoma using advanced optical technology

    NASA Astrophysics Data System (ADS)

    Wu, Yan; Fu, Fangmeng; Lian, Yuane; Nie, Yuting; Zhuo, Shuangmu; Wang, Chuan; Chen, Jianxin

    2015-02-01

    Clinical imaging techniques for diagnosing breast cancer mainly include X-ray mammography, ultrasound, and magnetic resonance imaging (MRI), which have respective drawbacks. Multiphoton microscopy (MPM) has become a potentially attractive optical technique to bridge the current gap in clinical utility. In this paper, MPM was used to image normal and ductal cancerous breast tissues, based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Our results showed that MPM has the ability to exhibit the microstructure of normal breast tissue, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) lesions at the molecular level comparable to histopathology. These findings indicate that, with integration of MPM into currently accepted clinical imaging system, it has the potential to make a real-time histological diagnosis of mammary ductal carcinoma in vivo.

  7. Numerical Modeling and Analysis of Optical Response of Electro-optic Modulators

    SciTech Connect

    Hussein, Y

    2004-04-14

    This paper presents an analysis of a LiNbO{sub 3} electro-optic modulator using the Finite Difference Time Domain (FDTD) technique, and also a new and efficient multiresolution time-domain technique for fast and accurate modeling of photonic devices. The electromagnetic fields computed by FDTD are coupled to standard electro-optic relations that characterize electro-optic interactions. This novel approach to LiNbO{sub 3} electro-optic modulators using a coupled FDTD technique allows for previously unattainable investigations into device operating bandwidth and data transmission speed. On the other hand, the proposed multiresolution approach presented in this paper solves Maxwell's Equations on nonuniform self-adaptive grids, obtained by applying wavelet transforms followed by hard thresholding. The developed technique is employed to simulate a coplanar waveguide CPW, which represents an electro-optic modulator. Different numerical examples are presented showing more than 75% CPU-time reduction, while maintaining the same degree of accuracy of standard FDTD techniques.

  8. All-optical DAC using counter-propagating optical and electrical pulses in a Mach-Zehnder modulator.

    PubMed

    Lowery, Arthur James

    2014-10-20

    A novel method of converting binary-level electrical pulses into multi-level optical pulses using only a conventional traveling-wave optical modulator is presented. The method provides low inter-pulse interference due to the counter-propagating pulses, low amplitude noise, and a timing jitter determined chiefly by the quality of the optical pulse source. The method only requires one electrical drive per modulator and provides low-jitter variable-amplitude optical pulses that are suitable for shaping into a wide variety of modulation formats using a programmable optical filter.

  9. Optical lattice modulation spectroscopy for spin-orbit coupled bosons

    NASA Astrophysics Data System (ADS)

    De Sarkar, Sangita; Sensarma, Rajdeep; Sengupta, K.

    2015-11-01

    Interacting bosons with two "spin" states in a lattice show superfluid-insulator phase transitions in the presence of spin-orbit coupling. Depending on the parameter regime, bosons in the superfluid phase can condense to either a zero-momentum state or to one or multiple states with finite momentum, leading to an unconventional superfluid phase. We study the response of such a system to modulation of the optical lattice potential. We show that the change in momentum distribution after lattice modulation shows distinct patterns in the Mott and the superfluid phase and these patterns can be used to detect these phases and the quantum phase transition between them. Further, the momentum-resolved optical modulation spectroscopy can identify both the gapless (Goldstone) and gapped amplitude (Higgs) mode of the superfluid phase and clearly distinguish between the superfluid phases with a zero-momentum condensate and a twisted superfluid phase by looking at the location of these modes in the Brillouin zone. We discuss experiments which can test our theory.

  10. Single layer liquid crystal optically addressed spatial light modulators

    NASA Astrophysics Data System (ADS)

    Collings, N.; Trushkevych, O.; Crossland, W. A.; Wilkinson, T. D.

    2006-08-01

    Traditionally, the light receptor and light modulation aspects of Optically Addressed Spatial Light Modulators (OASLMs) occur in separate layers. Due to the progress that has been made in the study of nonlinearity in liquid crystal cell doped with chromophores in the past 20 years, it is appropriate to consider in what ways they themselves may be useful as OASLMs. The light reception and modulation aspects coexist within the same layer in these cells. We have been studying a variety of chromophore-doped systems (azo and anthraquinone dyes, buckminsterfullerene, and carbon nanotubes) over the past four years. Dynamic holographic grating formation is observed under conditions of low power laser light both with and without external fields. The majority of the samples are planar aligned and normal incidence of light can be used. They possess very good lifetime stability and no degradation even under high write light intensities. We understand how to avoid permanent recordings using appropriate alignment surfaces. This is important in OASLM applications where real-time updating of written information is required (dynamic holography, all-optical switching). The resolution of the devices is superior to the thickness of the liquid crystal layer, and comparable to the best traditional OASLMs. We are currently working on understanding the dynamics in order to address the issue of speed of response. The report will include latest results on diffraction efficiency from our OASLM characterization set-up.

  11. An investigation of the influence of residual amplitude modulation in phase electro-optic modulator on the signal of fiber-optic gyroscope

    NASA Astrophysics Data System (ADS)

    Pogorelaya, D. A.; Smolovik, M. A.; Strigalev, V. E.; Aleynik, A. S.; Deyneka, I. G.

    2016-08-01

    The investigation is devoted to residual amplitude modulation (RAM) of phase electro-optic modulator, which guides are made in LiNbO3 crystal by Ti diffusion technology. An analysis is presented that shows influence of RAM on the signal of fiber-optic gyroscope. The RAM compensation method is offered.

  12. KM3NeT Digital Optical Module electronics

    NASA Astrophysics Data System (ADS)

    Real, Diego

    2016-04-01

    The KM3NeT collaboration is currently building of a neutrino telescope with a volume of several cubic kilometres at the bottom of the Mediterranean Sea. The telescope consists of a matrix of Digital Optical Modules that will detect the Cherenkov light originated by the interaction of the neutrinos in the proximity of the detector. This contribution describes the main components of the read-out electronics of the Digital Optical Module: the Power Board, which delivers all the power supply required by the Digital Optical Molule electronics; the Central Logic Board, the main core of the read-out system, hosting 31 Time to Digital Converters with 1 ns resolution and the White Rabbit protocol embedded in the Central Logic Board Field Programmable Gate Array; the Octopus boards, that transfer the Low Voltage Digital Signals from the PMT bases to the Central Logic Board and finally the PMT bases, in charge of converting the analogue signal produced in the 31 3" PMTs into a Low Voltage Digital Signal.

  13. WDM up-conversion employing frequency quadrupling in optical modulator.

    PubMed

    Shih, Po-Tsung; Lin, Chun-Ting; Jiang, Wen-Jr; Chen, Jason Jyehong; Huang, Han-Sheng; Chen, Yu-Hung; Peng, Peng-Chun; Chi, Sien

    2009-02-01

    This work presents an optical up-conversion system with frequency quadrupling for wavelength-division-multiplexing (WDM) communication systems using a dual-parallel Mach-Zehnder modulator without optical filtering. Four-channel 1.25-Gb/s wired fiber-to-the-x (FTTx) and wireless radio-over-fiber (RoF) signals are generated and transmitted simultaneously. Moreover, the decline in receiver sensitivities due to Mach-Zehnder modulator bias drifts is also investigated. Receiver power penalties of the 20-GHz up-converted WDM signals and baseband (BB) FTTx signals are less than 1 dB when bias deviation voltage is less the 20% of the half-wave voltage. After transmission over a 50-km SSMF, the receiver power penalties of both the BB and 20-GHz RF OOK signals are less than 1 dB. Notably, 60-GHz optical up-conversion can be achieved using 15-GHz radio frequency (RF) components and equipment. PMID:19189002

  14. Quantitation and mapping of tissue optical properties using modulated imaging

    NASA Astrophysics Data System (ADS)

    Cuccia, David J.; Bevilacqua, Frederic; Durkin, Anthony J.; Ayers, Frederick R.; Tromberg, Bruce J.

    2009-03-01

    We describe the development of a rapid, noncontact imaging method, modulated imaging (MI), for quantitative, wide-field characterization of optical absorption and scattering properties of turbid media. MI utilizes principles of frequency-domain sampling and model-based analysis of the spatial modulation transfer function (s-MTF). We present and compare analytic diffusion and probabilistic Monte Carlo models of diffuse reflectance in the spatial frequency domain. Next, we perform MI measurements on tissue-simulating phantoms exhibiting a wide range of l* values (0.5 mm to 3 mm) and (μs'/μa) ratios (8 to 500), reporting an overall accuracy of approximately 6% and 3% in absorption and reduced scattering parameters, respectively. Sampling of only two spatial frequencies, achieved with only three camera images, is found to be sufficient for accurate determination of the optical properties. We then perform MI measurements in an in vivo tissue system, demonstrating spatial mapping of the absorption and scattering optical contrast in a human forearm and dynamic measurements of a forearm during venous occlusion. Last, metrics of spatial resolution are assessed through both simulations and measurements of spatially heterogeneous phantoms.

  15. Advanced optical interference filters based on metal and dielectric layers.

    PubMed

    Begou, Thomas; Lemarchand, Fabien; Lumeau, Julien

    2016-09-01

    In this paper, we investigate the design and the fabrication of an advanced optical interference filter based on metal and dielectric layers. This filter respects the specifications of the 2016 OIC manufacturing problem contest. We study and present all the challenges and solutions that allowed achieving a low deviation between the fabricated prototype and the target. PMID:27607695

  16. Enabling Technologies for Direct Detection Optical Phase Modulation Formats

    NASA Astrophysics Data System (ADS)

    Xu, Xian

    Phase modulation formats are believed to be one of the key enabling techniques for next generation high speed long haul fiber-optic communication systems due to the following main advantages: (1) with a balanced detection, a better receiver sensitivity over conventional intensity modulation formats, e.g., a ˜3-dB sensitivity improvement using differential phase shift keying (DPSK) and a ˜1.3-dB sensitivity improvement using differential quadrature phase shift keying (DQPSK); (2) excellent robustness against fiber nonlinearities; (3) high spectrum efficiency when using multilevel phase modulation formats, such as DQPSK. As the information is encoded in the phase of the optical field, the phase modulation formats are sensitive to the phase-related impairments and the deterioration induced in the phase-intensity conversion. This consequently creates new challenging issues. The research objective of this thesis is to depict some of the challenging issues and provide possible solutions. The first challenge is the cross-phase modulation (XPM) penalty for the phase modulated channels co-propagating with the intensity modulated channels. The penalty comes from the pattern dependent intensity fluctuations of the neighboring intensity modulated channels being converted into phase noise in the phase modulation channels. We propose a model to theoretically analyze the XPM penalty dependence on the walk off effect. From this model, we suggest that using fibers with large local dispersion or intentionally introducing some residual dispersion per span would help mitigate the XPM penalty. The second challenge is the polarization dependent frequency shift (PDf) induced penalty during the phase-intensity conversion. The direct detection DPSK is usually demodulated in a Mach-Zehnder delay interferometer (DI). The polarization dependence of DI introduces a PDf causing a frequency offset between the laser's frequency and the transmissivity peak of DI, degrading the demodulated DPSK

  17. Reception of modulated optical radiation using radio heterodyning in a photomultiplier tube and double light modulation

    NASA Astrophysics Data System (ADS)

    Dianova, V. A.; Mustel', E. R.; Rudnykh, S. I.

    1987-11-01

    Two systems for the reception of modulated optical radiation which are based on modulation-frequency conversion are investigated experimentally in the 10-150 MHz range: (1) radio heterodyning in a photomultiplier tube and (2) double light modulation (DLM). The radio-heterodyning technique can produce frequency conversion using low control voltages of 1-3 V. The maximum frequency that can be received through the use of the radio heterodyning technique exceeds 100 MHz; this band is significantly higher than the amplitude-frequency response band of a standard photomultiplier tube. The DLM system requires considerably higher control voltages but is characterized by a greater noise immunity than the radio heterodyning system.

  18. Symbol rate identification for auxiliary amplitude modulation optical signal

    NASA Astrophysics Data System (ADS)

    Wei, Junyu; Dong, Zhi; Huang, Zhiping; Zhang, Yimeng

    2016-09-01

    In this paper, we creatively propose and demonstrate a method for symbol rate identification (SRI) of auxiliary amplitude modulation (AAM) optical signal based on asynchronous delay-tap sampling (ADTS) and average magnitude difference function (AMDF). The method can accurately estimate symbol rate and has large transmission impairments tolerance. Furthermore, it can be realized in the digital signal processor (DSP) with low logical resources because of multiplication-free. In order to improve the accuracy of SRI, the peak to valley ratio (PTVR) of AMDF is introduced into our method for blind chromatic dispersion (CD) compensation. The results of the numerical simulations show that the overall maximum SRI error is smaller 0.079% for return-to-zero (RZ) on-off keying (OOK), RZ differential phase-shift keying (DPSK), RZ differential quadrature phase-shift keying (DQPSK) and RZ 16-ary quadrature amplitude modulation (QAM) with 50% duty cycles.

  19. A simple intensity modulation based fiber-optic accelerometer

    NASA Astrophysics Data System (ADS)

    Guozhen, Yao; Yongqian, Li; Zhi, Yang

    2016-05-01

    A fiber-optic accelerometer with simple structure and high performance based on intensity modulation is proposed. Using only a length of single mode fiber compressed by a cantilever, the intensity of reflected light is modulated by the vibration acceleration applied to it. The effects of the fiber location, the dimension parameters of the cantilever on frequency response and sensitivity are investigated. The experimental results demonstrate that the accelerometer has a flat frequency response over a 4700 Hz bandwidth and a sensitivity of 21.24 mV/g with a cantilever dimension of 30 × 8 × 1.6 mm3 and a distance of 5 mm between the fiber location and the suspended cantilever end; the coefficient of determination is better than 0.999. In addition, the effect of temperature and the stability of the sensing system are investigated.

  20. An advanced optical system for laser ablation propulsion in space

    NASA Astrophysics Data System (ADS)

    Bergstue, Grant; Fork, Richard; Reardon, Patrick

    2014-03-01

    We propose a novel space-based ablation driven propulsion engine concept utilizing transmitted energy in the form of a series of ultra-short optical pulses. Key differences are generating the pulses at the transmitting spacecraft and the safe delivery of that energy to the receiving spacecraft for propulsion. By expanding the beam diameter during transmission in space, the energy can propagate at relatively low intensity and then be refocused and redistributed to create an array of ablation sites at the receiver. The ablation array strategy allows greater control over flight dynamics and eases thermal management. Research efforts for this transmission and reception of ultra-short optical pulses include: (1) optical system design; (2) electrical system requirements; (3) thermal management; (4) structured energy transmission safety. Research has also been focused on developing an optical switch concept for the multiplexing of the ultra-short pulses. This optical switch strategy implements multiple reflectors polished into a rotating momentum wheel device to combine the pulses from different laser sources. The optical system design must minimize the thermal load on any one optical element. Initial specifications and modeling for the optical system are being produced using geometrical ray-tracing software to give a better understanding of the optical requirements. In regards to safety, we have advanced the retro-reflective beam locking strategy to include look-ahead capabilities for long propagation distances. Additional applications and missions utilizing multiplexed pulse transmission are also presented. Because the research is in early development, it provides an opportunity for new and valuable advances in the area of transmitted energy for propulsion as well as encourages joint international efforts. Researchers from different countries can cooperate in order to find constructive and safe uses of ordered pulse transmission for propulsion in future space

  1. Modulation of optical spatial coherence by surface plasmon polaritons.

    PubMed

    Divitt, Shawn; Frimmer, Martin; Visser, Taco D; Novotny, Lukas

    2016-07-01

    The interference pattern observed in Young's double-slit experiment is intimately related to the statistical correlations of the waves emitted by the slits. As the waves in the slits become more correlated, the visibility of the interference pattern increases. Here, we experimentally modulate the statistical correlations between the optical fields emitted by a pair of slits in a metal film. The interaction between the slits is mediated by surface plasmon polaritons and can be tuned by the slit separation, which allows us to either increase or decrease the spatial coherence of the emerging fields relative to that of the incoming fields.

  2. Compact multiwavelength transmitter module for multimode fiber optic ribbon cable

    DOEpatents

    Deri, Robert J.; Pocha, Michael D.; Larson, Michael C.; Garrett, Henry E.

    2002-01-01

    A compact multiwavelength transmitter module for multimode fiber optic ribbon cable, which couples light from an M.times.N array of emitters onto N fibers, where the M wavelength may be distributed across two or more vertical-cavity surface-emitting laser (VCSEL) chips, and combining emitters and multiplexer into a compact package that is compatible with placement on a printed circuit board. A key feature is bringing together two emitter arrays fabricated on different substrates--each array designed for a different wavelength--into close physical proximity. Another key feature is to compactly and efficiently combine the light from two or more clusters of optical emitters, each in a different wavelength band, into a fiber ribbon.

  3. Advanced Optical Burst Switched Network Concepts

    NASA Astrophysics Data System (ADS)

    Nejabati, Reza; Aracil, Javier; Castoldi, Piero; de Leenheer, Marc; Simeonidou, Dimitra; Valcarenghi, Luca; Zervas, Georgios; Wu, Jian

    In recent years, as the bandwidth and the speed of networks have increased significantly, a new generation of network-based applications using the concept of distributed computing and collaborative services is emerging (e.g., Grid computing applications). The use of the available fiber and DWDM infrastructure for these applications is a logical choice offering huge amounts of cheap bandwidth and ensuring global reach of computing resources [230]. Currently, there is a great deal of interest in deploying optical circuit (wavelength) switched network infrastructure for distributed computing applications that require long-lived wavelength paths and address the specific needs of a small number of well-known users. Typical users are particle physicists who, due to their international collaborations and experiments, generate enormous amounts of data (Petabytes per year). These users require a network infrastructures that can support processing and analysis of large datasets through globally distributed computing resources [230]. However, providing wavelength granularity bandwidth services is not an efficient and scalable solution for applications and services that address a wider base of user communities with different traffic profiles and connectivity requirements. Examples of such applications may be: scientific collaboration in smaller scale (e.g., bioinformatics, environmental research), distributed virtual laboratories (e.g., remote instrumentation), e-health, national security and defense, personalized learning environments and digital libraries, evolving broadband user services (i.e., high resolution home video editing, real-time rendering, high definition interactive TV). As a specific example, in e-health services and in particular mammography applications due to the size and quantity of images produced by remote mammography, stringent network requirements are necessary. Initial calculations have shown that for 100 patients to be screened remotely, the network

  4. Bulk acousto-optic wavelength agile filter module for a wavelength-multiplexed optical scanner.

    PubMed

    Yaqoob, Zahid; Riza, Nabeel A

    2005-05-01

    An acousto-optic tunable filter-based wavelength-selection module with features optimized for a wavelength-multiplexed optical scanner (W-MOS) is proposed and demonstrated. The W-MOS produces high-speed multiple scan beams if it is engaged with an agile tunable source with multiwavelength generation capability. In particular, the proposed fiber-connected module features high-speed, low-loss, narrow-linewidth, and single-multiple wavelength selection by means of radio frequency drive signal control for single- or multiple-beam scan operations. The unique module offers input laser beam power control that in turn delivers the desired scanned laser beam power shaping. Experimental results match module design theory and demonstrate a fast 5.4-micros wavelength selection speed, a low (1.53-dB) fiber-to-fiber optical insertion loss, a 5.55-nm 3-dB spectral width, and a 1500-1600-nm agile wavelength operational band.

  5. Advanced magneto-optical materials and devices

    NASA Astrophysics Data System (ADS)

    Kang, Shaoying

    The magneto-optical materials with both high Faraday rotation and high transmittance capabilities are greatly desired in high speed switches, isolators, and visible imaging systems. In this thesis work, new magneto-optical materials that possess both high Faraday effect and high transmittance in the visible range of the spectrum were studied and synthesized. New Bismuth iron gallium garnet thin-films (Bi3Fe4Ga 1O12, BIGG) have been successfully deposited on gadolinium gallium garnet substrates with a pulsed laser deposition technique in our lab. X-ray diffraction analyses have proven that the BIGG films are of good epitaxial quality with a lattice constant close to 12.61+/-0.01Á. The bandwidth of BIGG's transmittance spectrum has been extended and its left edge has been shifted about 50nm towards the shorter wavelengths relative to those of Bi3Fe5O12 (BIG) films. The BIGG film is more transparent than a BIG film although BIGG's Faraday rotation angle is slightly less than that of a BIG film. The figure of merit of the BIGG garnet film has reached 16.5°, which is about 1.8 times that of a typical BIG film. Currently, the switches using BIGG films were tested and a 2.4 ns response time had been reached with a phi1 mm circular aperture at the wavelength of 532 nm. Iron Borate (FeBO3) is another material that is far superior in terms of the transmittance in the visible spectrum at room temperature to most garnet materials. The FeBO3 is one of the orthoferrites with a large natural birefringence for the light propagated along the magnetization direction. The effect of birefringence on Faraday rotation reduced the maximum obtainable rotation. In order to eliminate the birefringence and further improve the transmittance, a high energy ball-milling technique was used to synthesize FeBO3 nanoparticles. Our numerical simulation shows the nanoparticles could eliminate the birefringence, and concurrently keep the intrinsic Faraday rotation. After milling and centrifuging

  6. An Innovative Context-Based Module to Introduce Students to the Optical Properties of Materials

    ERIC Educational Resources Information Center

    Testa, I.; Lombardi, S.; Monroy, G.; Sassi, E.

    2011-01-01

    A context-based module to introduce secondary school students to the study of the optical properties of materials and geometric optics is presented. The module implements an innovative teaching approach in which the behaviour of the chosen application, in this article, the optical fibre, is iteratively explored and modelled by means of a…

  7. Advanced materials and techniques for fibre-optic sensing

    NASA Astrophysics Data System (ADS)

    Henderson, Philip J.

    2014-06-01

    Fibre-optic monitoring systems came of age in about 1999 upon the emergence of the world's first significant commercialising company - a spin-out from the UK's collaborative MAST project. By using embedded fibre-optic technology, the MAST project successfully measured transient strain within high-performance composite yacht masts. Since then, applications have extended from smart composites into civil engineering, energy, military, aerospace, medicine and other sectors. Fibre-optic sensors come in various forms, and may be subject to embedment, retrofitting, and remote interrogation. The unique challenges presented by each implementation require careful scrutiny before widespread adoption can take place. Accordingly, various aspects of design and reliability are discussed spanning a range of representative technologies that include resonant microsilicon structures, MEMS, Bragg gratings, advanced forms of spectroscopy, and modern trends in nanotechnology. Keywords: Fibre-optic sensors, fibre Bragg gratings, MEMS, MOEMS, nanotechnology, plasmon.

  8. Engineering novel infrared glass ceramics for advanced optical solutions

    NASA Astrophysics Data System (ADS)

    Richardson, K.; Buff, A.; Smith, C.; Sisken, L.; Musgraves, J. David; Wachtel, P.; Mayer, T.; Swisher, A.; Pogrebnyakov, A.; Kang, M.; Pantano, C.; Werner, D.; Kirk, A.; Aiken, S.; Rivero-Baleine, C.

    2016-05-01

    Advanced photonic devices require novel optical materials that serve specified optical function but also possess attributes which can be tailored to accommodate specific optical design, manufacturing or component/device integration constraints. Multi-component chalcogenide glass (ChG) materials have been developed which exhibit broad spectral transparency with a range of physical properties that can be tuned to vary with composition, material microstructure and form. Specific tradeoffs that highlight the impact of material morphology and optical properties including transmission, loss and refractive index, are presented. This paper reports property evolution in a representative 20 GeSe2-60 As2Se3-20 PbSe glass material including a demonstration of a 1D GRIN profile through the use of controlled crystallization.

  9. Large dynamic range optical vector analyzer based on optical single-sideband modulation and Hilbert transform

    NASA Astrophysics Data System (ADS)

    Xue, Min; Pan, Shilong; Zhao, Yongjiu

    2016-07-01

    A large dynamic range optical vector analyzer (OVA) based on optical single-sideband modulation is proposed and demonstrated. By dividing the optical signal after optical device under test into two paths, reversing the phase of one swept sideband using a Hilbert transformer in one path, and detecting the two signals from the two paths with a balanced photodetector, the measurement errors induced by the residual -1st-order sideband and the high-order sidebands can be eliminated and the dynamic range of the measurement is increased. In a proof-of-concept experiment, the stimulated Brillouin scattering and a fiber Bragg grating are measured by OVAs with and without the Hilbert transform and balanced photodetection. Results show that about 40-dB improvement in the measurement dynamic range is realized by the proposed OVA.

  10. Phase-sensitive detection of optical resonances by using an acousto-optic modulator in the Raman - Nath diffraction mode

    SciTech Connect

    Baryshev, V N; Domnin, Yu S; Kopylov, L N

    2007-11-30

    A new method for frequency control of an external cavity diode laser without direct modulation of the injection current is proposed. The Pound - Drever optical heterodyne technique or the method of frequency control by frequency-modulated sidebands, in which an acousto-optic modulator operating in the Raman - Nath diffraction mode is used as an external phase modulator, can be employed to obtain error signals upon automatic frequency locking of the diode laser to the saturated absorption resonances within the D{sub 2} line of cesium atoms or to the optical cavity resonances. (control of laser radiation parameters)

  11. Monolithically integrated quantum dot optical modulator with semiconductor optical amplifier for thousand and original band optical communication

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Matsumoto, Atsushi; Kawanishi, Tetsuya

    2016-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed with T-band (1.0 µm waveband) and O-band (1.3 µm waveband) QD optical gain materials for Gbps-order, high-speed optical data generation. The insertion loss due to coupling between the device and the optical fiber was effectively compensated for by the SOA section. It was also confirmed that the monolithic QD-OGM/SOA device enabled >4.8 Gbps optical data generation with a clear eye opening in the T-band. Furthermore, we successfully demonstrated error-free 4.8 Gbps optical data transmissions in each of the six wavelength channels over a 10-km-long photonic crystal fiber using the monolithic QD-OGM/SOA device in multiple O-band wavelength channels, which were generated by the single QD gain chip. These results suggest that the monolithic QD-OGM/SOA device will be advantageous in ultra-broadband optical frequency systems that utilize the T+O-band for short- and medium-range optical communications.

  12. MT-compatible red VCSEL module for parallel optical interconnections

    NASA Astrophysics Data System (ADS)

    Van Hove, An; Van de Putte, Koen; Naessens, Kris; Dhoedt, Bart; Baets, Roel G.; Van Daele, Peter

    2000-04-01

    In this paper we present the design, fabrication and characterization of a module which directly connectorizes a 1 by 8 red VCSEL array to a small diameter polymer optical fiber array, using a standard MT ferrule. The facets of the POF are prepared by a hot knife cutting, followed by a short polishing step. First coupling results show total losses in the range of 1.1 dB/channel for a 30 cm POF link. Optical crosstalk between adjacent channels is below -45 dB. Plastic micromachined parts surrounding the VCSEL chip ensure the correct alignment of the connector, using the connector, using the connector guiding points. The parts themselves are aligned to the chip with a n index-alignment technique, using an excimer laser ablated mastertool. In a deconnectorizable version of the module, a thin, flat glue layer on the chip acts as a window between the VCSEL chip and the MT terminated POF array. Integrated in a standard ceramic package, clear eye diagrams have been measured at 150 MHz for a 10m POF link, coupled to the VCSEL array. Further efforts on higher speed measurements using dedicated drivers, will also be presented.

  13. Optical design and characterization of an advanced computational imaging system

    NASA Astrophysics Data System (ADS)

    Shepard, R. Hamilton; Fernandez-Cull, Christy; Raskar, Ramesh; Shi, Boxin; Barsi, Christopher; Zhao, Hang

    2014-09-01

    We describe an advanced computational imaging system with an optical architecture that enables simultaneous and dynamic pupil-plane and image-plane coding accommodating several task-specific applications. We assess the optical requirement trades associated with custom and commercial-off-the-shelf (COTS) optics and converge on the development of two low-cost and robust COTS testbeds. The first is a coded-aperture programmable pixel imager employing a digital micromirror device (DMD) for image plane per-pixel oversampling and spatial super-resolution experiments. The second is a simultaneous pupil-encoded and time-encoded imager employing a DMD for pupil apodization or a deformable mirror for wavefront coding experiments. These two testbeds are built to leverage two MIT Lincoln Laboratory focal plane arrays - an orthogonal transfer CCD with non-uniform pixel sampling and on-chip dithering and a digital readout integrated circuit (DROIC) with advanced on-chip per-pixel processing capabilities. This paper discusses the derivation of optical component requirements, optical design metrics, and performance analyses for the two testbeds built.

  14. Dual electro-optical modulator polarimeter based on adaptive optics scanning laser ophthalmoscope.

    PubMed

    Song, Hongxin; Qi, Xiaofeng; Zou, Weiyao; Zhong, Zhangyi; Burns, Stephen A

    2010-10-11

    We constructed a high speed and high-resolution Stokes vector retinal imaging polarimeter with dual electro-optical modulators based on adaptive optics scanning laser ophthalmoscope. By varying the voltages on the EO crystals line by line, we were able to measure over 500,000 Stokes vectors per second. We used this system in three human subjects demonstrating the capability of the system to be employed in vivo. The high speed effectively decreases the adverse impact of eye motion induced errors in polarization calculations, improving the contrast of retinal structures based on their polarization properties. PMID:20941089

  15. 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.

  16. An evolutionary Bayesian search scheme for ultrasound modulated optical tomography

    NASA Astrophysics Data System (ADS)

    Venugopal, Mamatha; Roy, Debasish; Vasu, Ram Mohan

    2016-04-01

    Ultrasound modulated optical tomography (UMOT) combines high optical contrast with high ultrasound resolution to image soft tissues. A focused ultrasound beam introduced to a specific region of interest (ROI) in the object modulates the mean position of the scattering centers locally. This in turn modulates the overall decay of the specific intensity of an incident coherent light beam as it passes through the insonified region. The inverse problem of UMOT aims to recover the mean-squared displacements of the scattering centers from the measured amplitude autocorrelation of light. We propose an evolutionary Bayesian search scheme to invert the measurements through repeated solves of the correlation diffusion equation so as to drive the resultant measurement-prediction misfit to a zero-mean Brownian process. The discretized parameter vector evolves as a stochastic process with respect to an iteration variable and follows a recursive prediction-update algorithm. The conventional multiplicative-weight-based Bayesian update schemes suffer from sample degeneracy and are consequently ill-equipped to solve large dimensional problems in imaging. The key idea of this work is to incorporate a derivative-free additive correction to the predicted parameter process via a gain term that is functionally analogous to the weights. The numerical results for simulated data indicate that the proposed scheme substantively improves the reconstruction accuracy vis-à-vis a popularly adopted regularized Gauss-Newton approach. The advantage of a derivative-free scheme is particularly highlighted in cases characterized by low sensitivity of measurements to variations in the parameters. Moreover, the proposed scheme circumvents the tedious Jacobian calculations involved in a Gauss-Newton approach.

  17. Flexible multi-dimensional modulation method for elastic optical networks

    NASA Astrophysics Data System (ADS)

    He, Zilong; Liu, Wentao; Shi, Sheping; Shen, Bailin; Chen, Xue; Gao, Xiqing; Zhang, Qi; Shang, Dongdong; Ji, Yongning; Liu, Yingfeng

    2016-01-01

    We demonstrate a flexible multi-dimensional modulation method for elastic optical networks. We compare the flexible multi-dimensional modulation formats PM-kSC-mQAM with traditional modulation formats PM-mQAM using numerical simulations in back-to-back and wavelength division multiplexed (WDM) transmission (50 GHz-spaced) scenarios at the same symbol rate of 32 Gbaud. The simulation results show that PM-kSC-QPSK and PM-kSC-16QAM can achieve obvious back-to-back sensitivity gain with respect to PM-QPSK and PM-16QAM at the expense of spectral efficiency reduction. And the WDM transmission simulation results show that PM-2SC-QPSK can achieve 57.5% increase in transmission reach compared to PM-QPSK, and 48.5% increase for PM-2SC-16QAM over PM-16QAM. Furthermore, we also experimentally investigate the back to back performance of PM-2SC-QPSK, PM-4SC-QPSK, PM-2SC-16QAM and PM-3SC-16QAM, and the experimental results agree well with the numerical simulations.

  18. Effect of input phase modulation to a phase-sensitive optical amplifier.

    PubMed

    Li, Tian; Anderson, Brian E; Horrom, Travis; Jones, Kevin M; Lett, Paul D

    2016-08-22

    Many optical applications depend on amplitude modulating optical beams using devices such as acousto-optical modulators (AOMs) or optical choppers. Methods to add amplitude modulation (AM) often inadvertently impart phase modulation (PM) onto the light as well. While this PM is of no consequence to many phase-insensitive applications, phase-sensitive processes can be affected. Here we study the effects of input phase and amplitude modulation on the output of a quantum-noise limited phase-sensitive optical amplifier (PSA) realized in hot 85Rb vapor. We investigate the dependence of PM on AOM alignment and demonstrate a novel approach to quantifying PM by using the PSA as a diagnostic tool. We then use this method to measure the alignment-dependent PM of an optical chopper which arises due to diffraction effects as the chopper blade passes through the optical beam. PMID:27557263

  19. Effect of input phase modulation to a phase-sensitive optical amplifier

    NASA Astrophysics Data System (ADS)

    Li, Tian; Anderson, Brian E.; Horrom, Travis; Jones, Kevin M.; Lett, Paul D.

    2016-08-01

    Many optical applications depend on amplitude modulating optical beams using devices such as acousto-optical modulators (AOMs) or optical choppers. Methods to add amplitude modulation (AM) often inadvertently impart phase modulation (PM) onto the light as well. While this PM is of no consequence to many phase-insensitive applications, phase-sensitive processes can be affected. Here we study the effects of input phase and amplitude modulation on the output of a quantum-noise limited phase-sensitive optical amplifier (PSA) realized in hot $^{85}$Rb vapor. We investigate the dependence of PM on AOM alignment and demonstrate a novel approach to quantifying PM by using the PSA as a diagnostic tool. We then use this method to measure the alignment-dependent PM of an optical chopper which arises due to diffraction effects as the chopper blade passes through the optical beam.

  20. Femtojoule-Scale All-Optical Latching and Modulation via Cavity Nonlinear Optics

    NASA Astrophysics Data System (ADS)

    Kwon, Yeong-Dae; Armen, Michael A.; Mabuchi, Hideo

    2013-11-01

    We experimentally characterize Hopf bifurcation phenomena at femtojoule energy scales in a multiatom cavity quantum electrodynamical (cavity QED) system and demonstrate how such behaviors can be exploited in the design of all-optical memory and modulation devices. The data are analyzed by using a semiclassical model that explicitly treats heterogeneous coupling of atoms to the cavity mode. Our results highlight the interest of cavity QED systems for ultralow power photonic signal processing as well as for fundamental studies of mesoscopic nonlinear dynamics.

  1. Advanced intensity-modulation continuous-wave lidar techniques for ASCENDS CO2 column measurements

    NASA Astrophysics Data System (ADS)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. W.; Obland, Michael D.; Meadows, Byron

    2015-10-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  2. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for ASCENDS O2 Column Measurements

    NASA Technical Reports Server (NTRS)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Meadows, Byron

    2015-01-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  3. Programmable logic controller optical fibre sensor interface module

    NASA Astrophysics Data System (ADS)

    Allwood, Gary; Wild, Graham; Hinckley, Steven

    2011-12-01

    Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

  4. Signal restoration in intensity-modulated optical OFDM access systems.

    PubMed

    Vanin, Evgeny

    2011-11-15

    It is well known that deliberate signal clipping in an intensity-modulated (IM) laser transmitter helps to overcome the optical orthogonal frequency division multiplexing (OFDM) system performance limitation that is related to the signal high peak-to-average power ratio. The amplitude of a clipped OFDM signal has to be optimized in order to minimize the optical power that is required to achieve a specified system performance. However, the signal clipping introduces nonlinear distortion (so-called clipping noise) and leads to a system performance penalty. In this Letter, the performance of the IM optical OFDM system with digital baseband clipping distortion in the transmitter and clipping noise compensation by means of signal restoration in the digital signal processing unit of the system receiver is analytically evaluated. It is demonstrated that the system bit-error ratio can be reduced by more than an order of magnitude, from 10(-3) to 3.5×10(-5), by applying only the first iteration of the signal restoration algorithm proposed in this Letter. The results of the analytical analysis are verified with brute-force numerical simulations based on direct error counting. PMID:22089556

  5. Phase Modulator with Terahertz Optical Bandwidth Formed by Multi-Layered Dielectric Stack

    NASA Technical Reports Server (NTRS)

    Keys, Andrew S. (Inventor); Fork, Richard L. (Inventor)

    2005-01-01

    An optical phase modulator includes a bandpass multilayer stack, formed by a plurality of dielectric layers, preferably of GaAs and AlAs, and having a transmission function related to the refractive index of the layers of the stack, for receiving an optical input signal to be phase modulated. A phase modulator device produces a nonmechanical change in the refractive index of each layer of the stack by, e.g., the injection of free carrier, to provide shifting of the transmission function so as to produce phase modulation of the optical input signal and to thereby produce a phase modulated output signal.

  6. Precise modulation of laser radiation by an acousto-optic modulator for stabilisation of the Nd : YAG laser on optical resonances in molecular iodine

    NASA Astrophysics Data System (ADS)

    Denisov, V. I.; Ignatovich, S. M.; Kvashnin, N. L.; Skvortsov, M. N.; Farnosov, S. A.

    2016-05-01

    A system of precise frequency modulation of laser radiation by an acousto-optic modulator, which makes it possible to stabilise the radiation power and simultaneously suppress the residual amplitude modulation to a level of 10-8 of the total laser power at the third harmonic of modulation frequency (~500 Hz), is presented. The use of this system for the Nd : YAG/I2 optical frequency standard and application of digital signal synthesis and processing methods provided a level of frequency standard instability as small as ~10-15 for ~6 × 104 s.

  7. Project T.E.A.M. (Technical Education Advancement Modules). Fundementals of Workplace Integration.

    ERIC Educational Resources Information Center

    Kraeling, Vicki

    This module is one of a series of instructional guides developed by Project TEAM (Technical Education Advancement Modules), a cooperative demonstration program for high technology training for unemployed, underemployed, and existing industrial employees whose basic technical skills are in need of upgrading. The module is a 27-hour overview course…

  8. Special Features of the Advanced Loans Module of the ABCD Integrated Library System

    ERIC Educational Resources Information Center

    de Smet, Egbert

    2011-01-01

    Purpose: The "advanced loans" module of the relatively new library software, ABCD, is an addition to the normal loans module and it offers a "generic transaction decision-making engine" functionality. The module requires extra installation effort and parameterisation, so this article aims to explain to the many potentially interested libraries,…

  9. Project T.E.A.M. (Technical Education Advancement Modules). Job Search Skills.

    ERIC Educational Resources Information Center

    Mason, Joan S.

    This module is one of a series developed by Project TEAM (Technical Education Advancement Modules), a cooperative demonstration program for high technology training for unemployed, underemployed, and existing industrial employees needing upgrading. This module is a 3-hour overview course intended to develop competencies in the following job search…

  10. 76 FR 12144 - Advanced Optics Electronics, Inc.; Order of Suspension of Trading

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ... COMMISSION Advanced Optics Electronics, Inc.; Order of Suspension of Trading March 2, 2011. It appears to the... securities of Advanced Optics Electronics, Inc. because it has not filed any periodic reports since the... of investors require a suspension of trading in Advanced Optics Electronics, Inc. Therefore, it...

  11. Compact acousto-optic modulator operatingin the purely Raman - Nath diffraction regime as a phase modulator in FM spectroscopy

    SciTech Connect

    Baryshev, Vyacheslav N; Epikhin, V M

    2010-08-03

    We report fabrication of a new acousto-optic modulator (AOM-RN) operating purely in the Raman - Nath diffraction regime. This device can be used as an external phase modulator in frequency-modulation (FM) optical heterodyne spectroscopy for fast and broadband frequency control of diode lasers. The AOM-RN design is significantly simplified, and its dimensions are minimised due to a decrease (by almost an order of magnitude in comparison with the existing AOMs) in the acousto-optic interaction length and the absence of impedance matching circuit. The FM spectroscopy based on AOM-RN makes it possible to analyse both absorption and dispersion properties of optical resonances under study; this possibility is shown by the example of saturated-absorption resonances in cesium vapour. The possibility of detecting coherent population trapping resonances using FM spectroscopy with AOM-RN as an external phase modulator is experimentally demonstrated.

  12. Advanced simulations of optical transition and diffraction radiation

    NASA Astrophysics Data System (ADS)

    Aumeyr, T.; Billing, M. G.; Bobb, L. M.; Bolzon, B.; Bravin, E.; Karataev, P.; Kruchinin, K.; Lefevre, T.; Mazzoni, S.

    2015-04-01

    Charged particle beam diagnostics is a key task in modern and future accelerator installations. The diagnostic tools are practically the "eyes" of the operators. The precision and resolution of the diagnostic equipment are crucial to define the performance of the accelerator. Transition and diffraction radiation (TR and DR) are widely used for electron beam parameter monitoring. However, the precision and resolution of those devices are determined by how well the production, transport and detection of these radiation types are understood. This paper reports on simulations of TR and DR spatial-spectral characteristics using the physical optics propagation (POP) mode of the Zemax advanced optics simulation software. A good consistency with theory is demonstrated. Also, realistic optical system alignment issues are discussed.

  13. Lamb wave acousto-optic modulator in ZnO/MgO multiple quantum wells and comparison with classical modulator.

    PubMed

    Gryba, T; Lefebvre, J-E; Elmaimouni, L; Ratolojanahary, F E

    2015-10-10

    An analysis of a ZnO/MgO multiple quantum well (MQW) acousto-optic modulator with Lamb waves is performed. With the MQW thickness in the range of 0.2 times the Lamb wavelength, the only observed Lamb modes are the lowest-order symmetric S0 and antisymmetric A0 modes. These modes induce strain and electric field components which influence the absorption coefficient of the modulator by the associated variation of the excitonic energies of MQW. The optical absorption coefficient spectra of the modulator as a function of the Lamb waves' power is presented. The Lamb-wave-based modulator gives a better absorption coefficient than the Rayleigh-wave-based one. An analysis of a classical acousto-optic modulator is also performed for comparison of performance. PMID:26479819

  14. DWDM VSB modulation-format optical transmission: Effects of optical filtering and electrical equalization

    NASA Astrophysics Data System (ADS)

    Binh, Le Nguyen

    2008-10-01

    The transmission of 40 Gb/s wavelength multiplexed channels under vestigial single side band modulation format is transmitted over long haul optically amplified fiber systems. Bit-error-rate (BER) of 10 -12 or better can be achieved across all channels. Optical filters are designed with asymmetric roll-off bands. Simulations of the transmission performance, BER versus receiver sensitivity are demonstrated with wavelength channel spacing of 20-40 GHz. An optical filter, whose passband is 28 GHz and 20 dB cut-off band, performs best for 40 Gb/s bit rate due to optimum filtering and minimum noise contribution. Furthermore the single-sideband property of VSB format can assist linear equalization by electronic processing. The transmission performance is accurately evaluated based on the eye opening using a fast statistical method based on an equivalent Gaussian probability density distribution (pdf) which is derived from multiple peaks pdf of distorted eye diagram.

  15. Measurement of MODIS optics effective focal length, distortion, and modulation transfer function

    NASA Astrophysics Data System (ADS)

    Thurlow, Paul E.; Cline, Richard W.

    1993-08-01

    A combination MODIS optics characteristics, short back focal length, and relatively distorting optics, has required major revisions in techniques used earlier to characterize effective focal length (EFL) and modulation transfer function (MTF) in the thematic mapper (TM) project. This paper compares measurement approaches used to characterize TM optics and revised methodology intended to characterize MODIS optics at an integration and assembly level.

  16. Laser-modulated scatter from optical surfaces using fiber detection

    NASA Astrophysics Data System (ADS)

    Natoli, Jean-Yves; Deumie, Carole; Amra, Claude

    2000-03-01

    The improvement of optical components for high power laser applications is still topical. Indeed the different signal cant progress made these last years, had allowed to improve the damage resistance of optical components by in particular, the identification of micronic precursors centers. A new challenge today is the identification of precursor centers of damage with size in the range of few nanometers. This kind of defects seems to play an important role in the laser damage process. In any case the challenge is to find an efficient tool able to detect these defects which are invisible with usual techniques as optical microscope or standard scattering. The technique of Laser Modulated Scattering (LMS) has been performed to reach this challenge. This new tool presented last year in the Boulder symposium, is based on a very high sensitivity detection of photothermal response of the defect. The LMS has been performed via two different setup arrangements. The first one uses tow beams as in the configuration of a standard Photothermal microscope, and the second one uses only one beam. In this article we first briefly remind the principle of the LMS technique with one and two beams. Then we will show by different results, the advantages of using an optical fiber to collect the scatted light instead of a block beam system used before. One of the main advantages of the setup using a fiber, is that it is easily possible to realize an angular study of scattering which allows a best understanding of the physical origin of the defect-induced scattered signal. The last part of this work consists of a series of stimulation of angular scattering LMS curve, in order to quantify the sensitivity and the powerfulness of this technique.

  17. Microcantilever Displacement Measurement Using a Mechanically Modulated Optical Feedback Interferometer.

    PubMed

    Azcona, Francisco J; Jha, Ajit; Yáñez, Carlos; Atashkhooei, Reza; Royo, Santiago

    2016-01-01

    Microcantilever motion detection is a useful tool for the characterization of the physical, chemical and biological properties of materials. In the past, different approaches have been proposed and tested to enhance the behavior, size and simplicity of microcantilever motion detectors. In this paper, a new approach to measure microcantilever motion with nanometric resolution is presented. The proposed approach is based on the concept of mechanically-modulated optical feedback interferometry, a technique that has shown displacement measurement capabilities well within the nanometric scale and that, due to its size, compactness and low cost, may be a suitable choice for measuring nanometric motions in cantilever-like sensors. It will be shown that the sensor, in its current state of development, is capable of following a cantilever sinusoidal trajectory at different sets of frequencies ranging up to 200 Hz and peak to peak amplitudes up to λ / 2 with experimental resolutions in the λ / 100 range. PMID:27367702

  18. Diffuse optical imaging using spatially and temporally modulated light

    PubMed Central

    O’Sullivan, Thomas D.; Cerussi, Albert E.; Cuccia, David J.

    2012-01-01

    Abstract. The authors describe the development of diffuse optical imaging (DOI) technologies, specifically the use of spatial and temporal modulation to control near infrared light propagation in thick tissues. We present theory and methods of DOI focusing on model-based techniques for quantitative, in vivo measurements of endogenous tissue absorption and scattering properties. We specifically emphasize the common conceptual framework of the scalar photon density wave for both temporal and spatial frequency-domain approaches. After presenting the history, theoretical foundation, and instrumentation related to these methods, we provide a brief review of clinical and preclinical applications from our research as well as our outlook on the future of DOI technology. PMID:22894472

  19. Microcantilever Displacement Measurement Using a Mechanically Modulated Optical Feedback Interferometer

    PubMed Central

    Azcona, Francisco J.; Jha, Ajit; Yáñez, Carlos; Atashkhooei, Reza; Royo, Santiago

    2016-01-01

    Microcantilever motion detection is a useful tool for the characterization of the physical, chemical and biological properties of materials. In the past, different approaches have been proposed and tested to enhance the behavior, size and simplicity of microcantilever motion detectors. In this paper, a new approach to measure microcantilever motion with nanometric resolution is presented. The proposed approach is based on the concept of mechanically-modulated optical feedback interferometry, a technique that has shown displacement measurement capabilities well within the nanometric scale and that, due to its size, compactness and low cost, may be a suitable choice for measuring nanometric motions in cantilever-like sensors. It will be shown that the sensor, in its current state of development, is capable of following a cantilever sinusoidal trajectory at different sets of frequencies ranging up to 200 Hz and peak to peak amplitudes up to λ/2 with experimental resolutions in the λ/100 range. PMID:27367702

  20. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan (Technical Monitor); Tolls, Volker

    2004-01-01

    The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

  1. Methods and devices for optimizing the operation of a semiconductor optical modulator

    DOEpatents

    Zortman, William A.

    2015-07-14

    A semiconductor-based optical modulator includes a control loop to control and optimize the modulator's operation for relatively high data rates (above 1 GHz) and/or relatively high voltage levels. Both the amplitude of the modulator's driving voltage and the bias of the driving voltage may be adjusted using the control loop. Such adjustments help to optimize the operation of the modulator by reducing the number of errors present in a modulated data stream.

  2. Continued analysis of optical frequency-modulated continuous-wave interference.

    PubMed

    Zheng, Jesse

    2005-02-10

    I continue to analyze systematically the theory of optical frequency-modulated continuous-wave (FMCW) interference. Two special cases, multiple-beam optical FMCW interference and multiple-wavelength optical FMCW interference, are discussed in detail. Multiple-beam optical FMCW interference generates a signal with multiple frequencies because of mutual interference among the waves. Multiple-wavelength optical FMCW interference produces a signal whose amplitude is modulated by a synthetic wave. The applications of both types of optical FMCW interference are also discussed. PMID:15751857

  3. Fabrication of a deoxyribonucleic acid polymer ridge waveguide electro-optic modulator by nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Fehrman Cory, Emily Marie

    coupling. Incompatibility with standard polishing techniques has led to the study of focused ion-beam milling (FIB) as a technique for polishing the DNA-CTMA film edge. This dissertation presents a demonstration at 633 nm and 1550 nm of an inverted ridge waveguide patterned by NIL in the DNA-CTMA cladding. Optical modulation in a slab waveguide structure consisting of the same polymer layers as the inverted ridge waveguide is also demonstrated, which together with waveguiding in an inverted ridge waveguide presents the case for the DNA-CTMA clad Mach Zehnder modulator. In this dissertation the FIB polishing technique for DNA-CTMA is demonstrated as a means to overcome the challenges of mechanically polishing the DNA-CTMA polymer. A study of the optical and mechanical effects of environmental exposure for DNA-CTMA and SEO110 is presented along with an analysis polymer film stresses as a result of fabrication processes and environmental exposures. This dissertation represents a significant advancement in fabrication techniques for DNA-CTMA thin films with the development of NIL for DNA-CTMA and is a significant step towards fully patterned DNA-CTMA EO waveguide devices.

  4. Material optimization for electro-optic modulation and cascading

    NASA Astrophysics Data System (ADS)

    Reyes, Jorge; Darracq, Bruno; Canva, Michael; Blanchard-Desce, Mireille H.; Chaput, Frederic; Lahlil, Khalid; Boilot, Jean-Pierre; Brun, Alain; Levy, Yves

    2000-11-01

    A large effort has been devoted to the preparation of organic polymeric materials for electro-optic modulation and more recently for cascading based processes. These materials contain push-pull chromophores either incorporated as guest in a high Tg polymeric matrix (doped polymers) or grafted onto the polymeric matrix. These systems present several advantages but require significant improvement at the molecular level- by designing optimized chromophores with very large molecular figure of merit specific to each application targeted. The sol-gel route was used to prepare hybrid organic-inorganic materials, for the fabrication of amorphous solids of various shapes (bulk, think films...). The results obtained on optimized chromophore-doped poled thin films emphasize that intermolecular interactions have to be taken into account, as already pointed out by Dalton and coworkers. By combining a molecular engineering strategy for getting large molecular figure of merit and by controlling the intermolecular dipole-dipole interactions via both tuning the push-pull chromophore concentration and the incorporation screening carbazole moieties in high concentration. This strategy allows us to obtain a r33 of about 50 pm/V at 831 nm for a new optimized chromophore structure. In parallel, these thin films are being processed to be used as passive components for integrated optics.

  5. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 Measurements

    NASA Astrophysics Data System (ADS)

    Campbell, J. F.; Lin, B.; Nehrir, A. R.; Obland, M. D.; Liu, Z.; Browell, E. V.; Chen, S.; Kooi, S. A.; Fan, T. F.

    2015-12-01

    Global and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and Atmospheric Carbon and Transport (ACT) - America airborne investigation are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are being investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the mission science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of intervening optically thin clouds, thereby minimizing bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the Earth's surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques and provides very high (at sub-meter level) range resolution. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These techniques are used in a new data processing architecture to support the ASCENDS CarbonHawk Experiment Simulator (ACES) and ACT-America programs.

  6. Nanocomposites for high-speed optical modulators and plasmonic thermal mid-infrared emitters

    NASA Astrophysics Data System (ADS)

    Demir, Veysi

    Demand for high-speed optical modulators and narrow-bandwidth infrared thermal emitters for numerous applications continues to rise and new optical devices are needed to deal with massive data flows, processing powers, and fabrication costs. Conventional techniques are usually hindered by material limitations or electronic interconnects and advances in organic nanocomposite materials and their integration into photonic integrated circuits (PICs) have been acknowledged as a promising alternative to single crystal techniques. The work presented in this thesis uses plasmonic and magneto-optic effects towards the development of novel optical devices for harnessing light and generating high bandwidth signals (>40GHz) at room and cryogenic temperatures (4.2°K). Several publications have resulted from these efforts and are listed at the end of the abstract. In our first published research we developed a narrow-bandwidth mid-infrared thermal emitter using an Ag/dielectric/Ag thin film structure arranged in hexagonal planar lattice structures. PECVD produced nanoamorphous carbon (NAC) is used as a dielectric layer. Spectrally tunable (>2 mum) and narrow bandwidth (<0.5 mum) emission peaks in the range of 4-7 mum were demonstrated by decreasing the resistivity of NAC from 1012 and 109 O.cm with an MoSi2 dopant and increasing the emitter lattice constant from 4 to 7 mum. This technique offers excellent flexibility for developing cost-effective mid-IR sources as compared to costly fiber and quantum cascade lasers (QCLs). Next, the effect of temperature on the Verdet constant for cobalt-ferrite polymer nanocomposites was measured for a series of temperatures ranging from 40 to 200°K with a Faraday rotation polarimeter. No visual change was observed in the films during thermal cycling, and ˜4x improvement was achieved at 40°K. The results are promising and further analysis is merited at 4.2°K to assess the performance of this material for cryogenic magneto-optic modulators

  7. Electro-optic study of PZT ferroelectric ceramics using modulation of reflected light

    NASA Astrophysics Data System (ADS)

    Kniazkov, A. V.

    2016-04-01

    Electro-optic coefficients of variations in the refractive index of PZT and PLZT ceramic materials induced by ac electric field are estimated using modulation of reflected light. The electro-optic coefficients of PLZT ceramics measured with the aid of conventional birefringence using the phase shift of transmitted radiation and the proposed method of birefringence using the modulation of reflected light are compared.

  8. Bandwidth-length trade-off figures of merit for electro-optic traveling wave modulators.

    PubMed

    Ibarra Fuste, Jose A; Santos Blanco, Maria C

    2013-05-01

    Closed-form expressions explicitly relating modulation bandwidth and active length in electro-optic traveling wave modulators are presented which fully account for skin-effect electrode loss and optical-electrical wave velocities mismatch. Four operative margins have been identified where the bandwidth-length trade-off figure of merit takes simple forms.

  9. Design-oriented analytic model of phase and frequency modulated optical links

    NASA Astrophysics Data System (ADS)

    Monsurrò, Pietro; Saitto, Antonio; Tommasino, Pasquale; Trifiletti, Alessandro; Vannucci, Antonello; Cimmino, Rosario F.

    2016-07-01

    An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare performance of the different architectures in terms of linearity and SFDR.

  10. Fiber-optic tunable multiwavelength variable attenuator and routing module designs that use bulk acousto-optics.

    PubMed

    Riza, Nabeel A; Mughal, M Junaid

    2005-02-10

    A compact fiber-coupled bulk acousto-optical multiwavelength variable optical attenuator module design that uses a retroreflective double-pass geometry within a single bulk acousto-optic tunable filter device is presented. The proposed attenuator module demonstrates a high 17-dB notch dynamic range at a low 100-mW drive power and uses a single bulk collinear-interaction acousto-optic tunable-filter device. Experiments show a low (<1.8-dB) fiber-to-fiber insertion loss with a fast 34-micros speed within a wide 1520-1640-nm agile multinotch band. The basic broadband attenuator module design is extended to allow for efficient architectures for routing modules such as agile drop filters, analog hitless tap filters, and digital add-drop switches.

  11. Advanced modulation technology development for earth station demodulator applications

    NASA Technical Reports Server (NTRS)

    Davis, R. C.; Wernlund, J. V.; Gann, J. A.; Roesch, J. F.; Wright, T.; Crowley, R. D.

    1989-01-01

    The purpose of this contract was to develop a high rate (200 Mbps), bandwidth efficient, modulation format using low cost hardware, in 1990's technology. The modulation format chosen is 16-ary continuous phase frequency shift keying (CPFSK). The implementation of the modulation format uses a unique combination of a limiter/discriminator followed by an accumulator to determine transmitted phase. An important feature of the modulation scheme is the way coding is applied to efficiently gain back the performance lost by the close spacing of the phase points.

  12. Advanced MEMS systems for optical communication and imaging

    NASA Astrophysics Data System (ADS)

    Horenstein, M. N.; Stewart, J. B.; Cornelissen, S.; Sumner, R.; Freedman, D. S.; Datta, M.; Kani, N.; Miller, P.

    2011-06-01

    Optical communication and adaptive optics have emerged as two important uses of micro-electromechanical (MEMS) devices based on electrostatic actuation. Each application uses a mirror whose surface is altered by applying voltages of up to 300 V. Previous generations of adaptive-optic mirrors were large (~1 m) and required the use of piezoelectric transducers. Beginning in the mid-1990s, a new class of small MEMS mirrors (~1 cm) were developed. These mirrors are now a commercially available, mature technology. This paper describes three advanced applications of MEMS mirrors. The first is a mirror used for corona-graphic imaging, whereby an interferometric telescope blocks the direct light from a distant star so that nearby objects such as planets can be seen. We have developed a key component of the system: a 144-channel, fully-scalable, high-voltage multiplexer that reduces power consumption to only a few hundred milliwatts. In a second application, a MEMS mirror comprises part of a two-way optical communication system in which only one node emits a laser beam. The other node is passive, incorporating a retro-reflective, electrostatic MEMS mirror that digitally encodes the reflected beam. In a third application, the short (~100-ns) pulses of a commercially-available laser rangefinder are returned by the MEMS mirror as a digital data stream. Suitable low-power drive systems comprise part of the system design.

  13. Ribbon plastic optical fiber linked optical transmitter and receiver modules featuring a high alignment tolerance.

    PubMed

    Lee, Hak-Soon; Park, Jun-Young; Cha, Sang-Mo; Lee, Sang-Shin; Hwang, Gyo-Sun; Son, Yung-Sung

    2011-02-28

    Ribbon plastic optical fiber (POF) linked four-channel optical transmitter (Tx) and receiver (Rx) modules have been proposed and realized featuring an excellent alignment tolerance. The two modules share a common configuration involving an optical sub-assembly (OSA) with vertical cavity surface emitting lasers (VCSELs)/photodetectors (PDs), and their driver ICs, which are integrated onto a single printed circuit board (PCB) substrate. The OSA includes an alignment structure, a beam router and a fiber guide, which were produced by using plastic injection molding. We have accomplished a fully passive alignment between the VCSELs/PDs and the ribbon POF by taking advantage of the alignment structure that serves as a reference during the alignment of the constituent parts of the OSA. The electrical link, which largely determines the operation speed, has been remarkably shortened, due to a direct wire-bonding between the VCSELs/PDs and the driver circuits. The light sources and the detectors can be individually positioned, thereby overcoming the pitch limitations of the ribbon POF, which is made up of perfluorinated graded-index (GI) POF with a 62.5 μm core diameter. The overall alignment tolerance was first assessed by observing the optical coupling efficiency in terms of VCSEL/PD misalignment. The horizontal and vertical 3-dB alignment tolerances were about 20 μm and 150 μm for the Tx and 50 μm and over 200 μm for the Rx, respectively. The VCSEL-to-POF coupling loss for the Tx and the POF-to-PD loss for the Rx were 3.25 dB and 1.35 dB at a wavelength of 850 nm, respectively. Subsequently, a high-speed signal at 3.2 Gb/s was satisfactorily delivered via the Tx and Rx modules over a temperature range of -30 to 70°C with no significant errors; the channel crosstalk was below -30 dB. Finally, the performance of the prepared modules was verified by transmitting a 1080p HDMI video supplied by a Bluelay player to an LCD TV.

  14. Hybrid silicon-electro-optic-polymer integrated high-performance optical modulator

    NASA Astrophysics Data System (ADS)

    Zhang, Xingyu; Hosseini, Amir; Luo, Jingdong; Jen, Alex K.-Y.; Chen, Ray T.

    2014-03-01

    We design and demonstrate a compact and low-power band-engineered electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW) modulator. The EO polymer is engineered for large EO activity and nearinfrared transparency. A PCW step coupler is used for optimum coupling to the slow-light mode of the bandengineered PCW. The half-wave switching-voltage is measured to be Vπ=0.97+/-0.02V over optical spectrum range of 8nm, corresponding to the effective in-device r33 of 1190pm/V and Vπ×L of 0.291+/-0.006V×mm in a push-pull configuration. Excluding the slow-light effect, we estimate the EO polymer is poled with an efficiency of 89pm/V in the slot.

  15. Integrated optical modulator for signal up-conversion over radio-on-fiber link.

    PubMed

    Kim, Woo-Kyung; Kwon, Soon-Woo; Jeong, Woo-Jin; Son, Geun-Sik; Lee, Kwang-Hyun; Choi, Woo-Young; Yang, Woo-Seok; Lee, Hyung-Man; Lee, Han-Young

    2009-02-16

    An integrated optical modulator, which consists of a dual-sideband suppressed carrier (DSB-SC) modulator cascaded with a single-sideband (SSB) modulator, is proposed for signal up-conversion over Radio-on-Fiber. Utilizing a single-drive domain inverted structure in both modulators, balanced modulations were obtained without complicated radio frequency (RF) driving circuits and delicate RF phase adjustments. Intermediate frequency (IF) band signal was up-conversed to 60GHz band by using the fabricated device and was transmitted over optical fiber. Experiment results show that the proposed device enables millimeter wave generation and signal transmission without any power penalty caused by chromatic dispersion.

  16. Advanced Silicon Microring Resonator Devices for Optical Signal Processing

    NASA Astrophysics Data System (ADS)

    Masilamani, Ashok Prabhu

    Chip level optical interconnects has gained momentum with recent demonstrations of silicon-on-insulator (SOI) based photonic modules such as lasers, modulators, wavelength division multiplexing (WDM) filters, etc. A fundamental building block that has enabled many of these silicon photonic modules is the compact, high Q factor microring resonator cavity. However, most of these demonstrations have WDM processing components based on simple add-drop filters that cannot realize the dense WDM systems required for the chip level interconnects. Dense WDM filters have stringent spectral shape requirements such as flat-top filter passband, steep band transition etc. Optical filters that can meet these specifications involve precise placement of the poles and zeros of the filter transfer function. Realization of such filters requires the use of multiple coupled microring resonators arranged in complex coupling topologies. In this thesis we have proposed and demonstrated new multiple coupled resonator topologies based on compact microring resonators in SOI material system. First we explored novel microring architectures which resulted in the proposal of two new coupled microring architectures, namely, the general 2D microring array topology and the general cascaded microring network topology. We also developed the synthesis procedures for these two microring architectures. The second part of this thesis focussed on the demonstration of the proposed architectures in the SOI material system. To accomplish this, a fabrication process for SOI was developed at the UofA Nanofab facility. Using this process, ultra-compact single microring filters with microring radii as small as 1mum were demonstrated. Higher order filter demonstration with multiple microrings necessitated post-fabrication microring resonance tuning. We developed additional fabrication steps to install micro heaters on top of the microrings to thermally tune its resonance. Subsequently, a thermally tuned fourth

  17. A hybrid silicon membrane spatial light modulator for optical information processing

    NASA Technical Reports Server (NTRS)

    Pape, D. R.; Hornbeck, L. J.

    1984-01-01

    A new two dimensional, fast, analog, electrically addressable, silicon based membrane spatial light modulator (SLM) was developed for optical information processing applications. Coherent light reflected from the mirror elements is phase modulated producing an optical Fourier transform of an analog signal input to the device. The DMD architecture and operating parameters related to this application are presented. A model is developed that describes the optical Fourier transform properties of the DMD.

  18. Advanced Stabilization. Training Module 2.226.3.77.

    ERIC Educational Resources Information Center

    Paulson, W. L.

    This document is an instructional module package prepared in objective form for use by an instructor knowledgeable in the chemistry of water stabilization and familiar with control of deposition and corrosion in a water supply system. This is the second level of a two module series. Included are objectives, instructor guides, student handouts and…

  19. Advanced Mathematics. Training Module 1.303.3.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module prepared in objective form for use by an instructor familiar with mathematics as applied to water and wastewater treatment plant operation. Included are objectives, instructor guides and student handouts. This is the third level of a three module series and is concerned with statistics, total head, steady…

  20. Advanced Trickling Filters. Training Module 2.112.4.77.

    ERIC Educational Resources Information Center

    Layton, Ronald F.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation and maintenance of a trickling filter wastewater treatment plant. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series and considers…

  1. Advanced Activated Sludge. Training Module 2.117.4.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series and considers design and operation…

  2. Coherence analysis of optical frequency-modulated continuous-wave interference.

    PubMed

    Zheng, Jesse

    2006-06-01

    I analyze the coherence of optical frequency-modulated continuous-wave (FMCW) interference. With a simple model modified from the classical coherence theory, I successfully derive the relationships among the frequency bandwidth, coherence length, and coherence time of the practical optical source, and the contrast of the beat signal in optical FMCW interference. PMID:16724123

  3. SiC Optically Modulated Field-Effect Transistor

    NASA Technical Reports Server (NTRS)

    Tabib-Azar, Massood

    2009-01-01

    An optically modulated field-effect transistor (OFET) based on a silicon carbide junction field-effect transistor (JFET) is under study as, potentially, a prototype of devices that could be useful for detecting ultraviolet light. The SiC OFET is an experimental device that is one of several devices, including commercial and experimental photodiodes, that were initially evaluated as detectors of ultraviolet light from combustion and that could be incorporated into SiC integrated circuits to be designed to function as combustion sensors. The ultraviolet-detection sensitivity of the photodiodes was found to be less than desired, such that it would be necessary to process their outputs using high-gain amplification circuitry. On the other hand, in principle, the function of the OFET could be characterized as a combination of detection and amplification. In effect, its sensitivity could be considerably greater than that of a photodiode, such that the need for amplification external to the photodetector could be reduced or eliminated. The experimental SiC OFET was made by processes similar to JFET-fabrication processes developed at Glenn Research Center. The gate of the OFET is very long, wide, and thin, relative to the gates of typical prior SiC JFETs. Unlike in prior SiC FETs, the gate is almost completely transparent to near-ultraviolet and visible light. More specifically: The OFET includes a p+ gate layer less than 1/4 m thick, through which photons can be transported efficiently to the p+/p body interface. The gate is relatively long and wide (about 0.5 by 0.5 mm), such that holes generated at the body interface form a depletion layer that modulates the conductivity of the channel between the drain and the source. The exact physical mechanism of modulation of conductivity is a subject of continuing research. It is known that injection of minority charge carriers (in this case, holes) at the interface exerts a strong effect on the channel, resulting in amplification

  4. Advanced integrated spectrometer designs for miniaturized optical coherence tomography systems

    NASA Astrophysics Data System (ADS)

    Akca, B. I.; Považay, B.; Chang, L.; Alex, A.; Wörhoff, K.; de Ridder, R. M.; Drexler, W.; Pollnau, M.

    2013-06-01

    Optical coherence tomography (OCT) has enabled clinical applications that revolutionized in vivo medical diagnostics. Nevertheless, its current limitations owing to cost, size, complexity, and the need for accurate alignment must be overcome by radically novel approaches. Exploiting integrated optics, the central components of a spectral-domain OCT (SD-OCT) system can be integrated on a chip. Arrayed-waveguide grating (AWG) spectrometers with their high spectral resolution and compactness are excellent candidates for on-chip SD-OCT systems. However, specific design-related issues of AWG spectrometers limit the performance of on-chip SD-OCT systems. Here we present advanced AWG designs which could overcome the limitations arising from free spectral range, polarization dependency, and curved focal plane of the AWG spectrometers. Using these advanced AWG designs in an SD-OCT system can provide not only better overall performance but also some unique aspects that a commercial system does not have. Additionally, a partially integrated OCT system comprising an AWG spectrometer and an integrated beam splitter, as well as the in vivo imaging using this system are demonstrated.

  5. Advances in optics in the medieval Islamic world

    NASA Astrophysics Data System (ADS)

    Al-Khalili, Jim

    2015-04-01

    This paper reviews the state of knowledge in the field of optics, mainly in catoptrics and dioptrics, before the birth of modern science and the well-documented contributions of men such as Kepler and Newton. The paper is not intended to be a comprehensive survey of the subject such as one might find in history of science journals; instead, it is aimed at the curious physicist who has probably been taught that nothing much of note was understood about the behaviour of light, beyond outdated philosophical musings, prior to the seventeenth century. The paper will focus on advances during the medieval period between the ninth and fourteenth centuries, in both the east and the west, when the theories of the Ancient Greeks were tested, advanced, corrected and mathematised. In particular, it concentrates on a multivolume treatise on optics written one thousand years ago by the Arab scholar, Ibn al-Haytham, and examines how it influenced our understanding of the nature of reflection and refraction of light. Even the well-informed physicist should find a few surprises here, which will alter his or her view of the debt we owe to these forgotten scholars.

  6. Realization of pure frequency modulation of DFB laser via combined optical and electrical tuning.

    PubMed

    Tian, Chao; Chen, I-Chun Anderson; Park, Seong-Wook; Martini, Rainer

    2013-04-01

    In this paper we present a novel approach to convert AM signal into FM signal in semiconductor lasers via off resonance optical pumping and report on experimental results obtained with a commercial DFB laser. Aside of demonstrating discrete and fast frequency modulation, we achieve pure frequency modulation through combination with electrical modulation suppressing the associated amplitude modulation, which is detrimental to application such as spectroscopy and communication.

  7. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale.

    PubMed

    Luo, Guoping; Ren, Xingang; Zhang, Su; Wu, Hongbin; Choy, Wallace C H; He, Zhicai; Cao, Yong

    2016-03-23

    Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin-film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures. PMID:26856789

  8. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale.

    PubMed

    Luo, Guoping; Ren, Xingang; Zhang, Su; Wu, Hongbin; Choy, Wallace C H; He, Zhicai; Cao, Yong

    2016-03-23

    Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin-film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures.

  9. Microwave vector signal transmission over an optical fiber based on IQ modulation and coherent detection.

    PubMed

    Chen, Yang; Shao, Tong; Wen, Aijun; Yao, Jianping

    2014-03-15

    A novel approach to transmitting two vector signals using a single optical carrier based on IQ modulation and coherent detection is proposed and demonstrated. In the proposed system, two quadrature phase-shift keying (QPSK) signals are IQ modulated on an optical carrier with one polarization state using a dual-parallel Mach-Zehnder modulator (DP-MZM). The optical carrier with an orthogonal polarization state is not modulated but transmitted with the modulated optical wave. At the receiver, the two orthogonally polarized light waves are separated and sent to a coherent detector, where the two QPSK signals are separated and demodulated. An experiment is performed. The transmission of two QPSK signals at 2 GHz with a data rate of 1 Gbps is implemented over a 25 km single-mode fiber. The performance of the transmission in terms of error vector magnitude is evaluated.

  10. Advanced optical fiber communication simulations in electrotechnical engineering education

    NASA Astrophysics Data System (ADS)

    Vervaeke, Michael; Nguyen Thi, Cac; Thienpont, Hugo

    2004-10-01

    We present our efforts in education to apply advanced optical communication simulation software into our Electrical Engineering curriculum by implementing examples from theoretical courses with commercially available simulation software. Photonic design software is an interesting tool for the education of Engineers: these tools are able to simulate a huge variety of photonic components without major investments in student lab hardware. Moreover: some exotic phenomena ,which would usually involve specialty hardware, can be taught. We chose to implement VPItransmissionMaker from VPIsystems in the lab exercises for graduating Electrotechnical Engineers with majors in Photonics. The guideline we develop starts with basic examples provided by VPIsystems. The simplified simulation schemes serve as an introduction to the simulation techniques. Next, we highlight examples from the theoretical courses on Optical Telecommunications. A last part is an assignment where students have to design and simulate a system using real life component datasheets. The aim is to train them to interpret datasheets, to make design choices for their optical fiber system and to enhance their management skills. We detail our approach, highlight the educational aspects, the insight gained by the students, and illustrate our method with different examples.

  11. Advances of optical coherence tomography in myopia and pathologic myopia.

    PubMed

    Ng, D S C; Cheung, C Y L; Luk, F O; Mohamed, S; Brelen, M E; Yam, J C S; Tsang, C W; Lai, T Y Y

    2016-07-01

    The natural course of high-axial myopia is variable and the development of pathologic myopia is not fully understood. Advancements in optical coherence tomography (OCT) technology have revealed peculiar intraocular structures in highly myopic eyes and unprecedented pathologies that cause visual impairment. New OCT findings include posterior precortical vitreous pocket and precursor stages of posterior vitreous detachment; peripapillary intrachoroidal cavitation; morphological patterns of scleral inner curvature and dome-shaped macula. Swept source OCT is capable of imaging deeper layers in the posterior pole for investigation of optic nerve pits, stretched and thinned lamina cribrosa, elongated dural attachment at posterior scleral canal, and enlargement of retrobulbar subarachnoid spaces. This has therefore enabled further evaluation of various visual field defects in high myopia and the pathogenesis of glaucomatous optic neuropathy. OCT has many potential clinical uses in managing visual impairing conditions in pathologic myopia. Understanding how retinal nerve fibers are redistributed in axial elongation will allow the development of auto-segmentation software for diagnosis and monitoring progression of glaucoma. OCT is indispensable in the diagnosis of various conditions associated with myopic traction maculopathy and monitoring of post-surgical outcomes. In addition, OCT is commonly used in the multimodal imaging assessment of myopic choroidal neovascularization. Biometry and topography of the retinal layers and choroid will soon be validated for the classification of myopic maculopathy for utilization in epidemiological studies as well as clinical trials. PMID:27055674

  12. A Comprehensive Microfluidics Device Construction and Characterization Module for the Advanced Undergraduate Analytical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Piunno, Paul A. E.; Zetina, Adrian; Chu, Norman; Tavares, Anthony J.; Noor, M. Omair; Petryayeva, Eleonora; Uddayasankar, Uvaraj; Veglio, Andrew

    2014-01-01

    An advanced analytical chemistry undergraduate laboratory module on microfluidics that spans 4 weeks (4 h per week) is presented. The laboratory module focuses on comprehensive experiential learning of microfluidic device fabrication and the core characteristics of microfluidic devices as they pertain to fluid flow and the manipulation of samples.…

  13. Project T.E.A.M. (Technical Education Advancement Modules). Introduction to Statistical Process Control.

    ERIC Educational Resources Information Center

    Billings, Paul H.

    This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 6-hour introductory module on statistical process control (SPC), designed to develop competencies in the following skill areas: (1) identification of the three classes of SPC use; (2) understanding a process and how it works; (3)…

  14. Development and investigation of a CPV module with Cassegrain mirror optics

    NASA Astrophysics Data System (ADS)

    Dreger, Max; Wiesenfarth, Maike; Kisser, Arne; Schmid, Tobias; Bett, Andreas W.

    2014-09-01

    One approach to concentrate the sunlight in concentrating photovoltaic (CPV) modules is using Cassegrain mirror optics. The advantage is that a passively cooled solar cell can be mounted to a large heat spreader that does not shade the primary optics. In addition, the height of the module, hence weight, can be low. The design was selected on the basis of the results of a design study comparing different CPV module approaches presented in [1]. In this work, we present the development of a new prototype micro dish module. First results of the characterization are shown. Besides of the electrical performance, a machined optics and an injection molded was investigated regarding sensitivity to misalignment errors between the optical elements as well as measurement of the acceptance angle in- and outdoors. The machined optics was used as reference.

  15. Polarization-sensitive optical coherence tomography measurements with different phase modulation amplitude when using continuous polarization modulation

    NASA Astrophysics Data System (ADS)

    Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

    2012-01-01

    We demonstrate theoretically and experimentally that the phase retardance and relative optic-axis orientation of a sample can be calculated without prior knowledge of the actual value of the phase modulation amplitude when using a polarization-sensitive optical coherence tomography system based on continuous polarization modulation (CPM-PS-OCT). We also demonstrate that the sample Jones matrix can be calculated at any values of the phase modulation amplitude in a reasonable range depending on the system effective signal-to-noise ratio. This has fundamental importance for the development of clinical systems by simplifying the polarization modulator drive instrumentation and eliminating its calibration procedure. This was validated on measurements of a three-quarter waveplate and an equine tendon sample by a fiber-based swept-source CPM-PS-OCT system.

  16. Design of a novel high-speed magneto-optic modulator

    NASA Astrophysics Data System (ADS)

    Wan, Jin; Huang, Yuanqing; Weng, Zihua; Yan, Huangping; Wang, Yiju; Wu, Zhaoxi; Ye, Ruifang

    2007-11-01

    A novel high-speed magneto-optic (MO) modulator which consists of an integrated wire grid polarizer (WGP), Bi-YIG waveguide with cladding layer and conducting micro-strip line is proposed. With the integrated WGP, this MO modulator is faster, more accurate and more stable because it is not only completely driven by electric signals but also has no mechanically moving parts. Moreover, it is compact-structured and low-cost. Large Faraday rotation is obtained with specific arrangement of the directions of the bias magnetic field and the modulation RF magnetic field. Optical route and optic-electrical detect circuit are also designed and analyzed.

  17. The design of the optical modules of the KM3NeT-Italia project towers

    NASA Astrophysics Data System (ADS)

    Leonora, Emanuele; Aiello, Sebastiano; Giordano, Valentina

    2016-07-01

    The KM3NeT-Italia project aims to construct a large volume underwater neutrino telescope, to be installed in the depths of the Mediterranean Sea. The R&D and mass production phases of the detection elements of the telescope, the optical modules, were entirely performed in the INFN-LNS site in the harbour of Catania. In November 2014 a first tower of 14 storeys equipped with 84 optical modules was successfully deployed in the Mediterranean Sea site. The design of the optical modules and their main components are described in this paper.

  18. Experimental modules covering imaging, diffraction, Fourier optics and polarization based on a liquid-crystal cell SLM

    NASA Astrophysics Data System (ADS)

    Hermerschmidt, Andreas

    2009-06-01

    In close collaboration with four German universities, we have developed tutorials for experiments based on a transmissive liquid-crystal spatial light modulator (SLM). The experimental tutorials are grouped in six project modules, which cover a wide range of phenomena and have different levels of difficulty. At a basic level, students can investigate the SLM in its probably most well-known application as an image-generating element in a simple optical projector setup. At more advanced levels, the application as an adaptive optical element can be investigated in three different projects covering wave-optical phenomena. The fields covered include Fourier Optics using the SLM as a dynamic fan-out beam-splitter or kinoform, Computer-Generated Holography and basic Interferometry. For the support of these projects, software was developed which permits the generation of adaptive optical structures by the student with a user-friendly interface, while the underlying algorithms are explained in the theoretical tutorial. The modulation of the light by the twisted-neumatic liquid crystal cells of the SLM can be investigated in the two most advanced projects. In the first one, the parameters of the cell and the components of its Jones matrix can be derived from transmission measurements with rotatable polarizers at a number of different wavelengths. This project gives insight to the Jones matrix calculus at the level required for the analysis. In the second one, the complex-valued transmission of the SLM is determined by measuring the diffraction efficiency of dynamically addressed Ronchi gratings.

  19. Optimization of coherent optical OFDM transmitter using DP-IQ modulator with nonlinear response

    NASA Astrophysics Data System (ADS)

    Chang, Sun Hyok; Kang, Hun-Sik; Moon, Sang-Rok; Lee, Joon Ki

    2016-07-01

    In this paper, we investigate the performance of dual polarization orthogonal frequency division multiplexing (DP-OFDM) signal generation when the signal is generated by a DP-IQ optical modulator. The DP-IQ optical modulator is made of four parallel Mach-Zehnder modulators (MZMs) which have nonlinear responses and limited extinction ratios. We analyze the effects of the MZM in the DP-OFDM signal generation by numerical simulation. The operating conditions of the DP-IQ modulator are optimized to have the best performance of the DP-OFDM signal.

  20. Advanced packaging methods for high-power LED modules

    NASA Astrophysics Data System (ADS)

    Jordan, Rafael C.; Weber, Constanze; Ehrhardt, Christian; Wilke, Martin

    2014-02-01

    LED luminaires are already beyond retrofit systems, which are limited in heat dissipation due to the old fitting standards. Actual LED luminaries are based on new LED packages and modules. Heat dissipation through the first and second level interconnect is a key issue for a successful LED package. Therefore the impact of known bonding technologies as gluing and soldering and new technologies like sintering and transient liquid phase soldering were analyzed and compared. A realized hermetic high power LED package will be shown as example. The used new techniques result in a module extremely stable against further assembly processes and harsh operating conditions.

  1. Terahertz modulation of the Faraday rotation by laser pulses via the optical Kerr effect

    NASA Astrophysics Data System (ADS)

    Subkhangulov, R. R.; Mikhaylovskiy, R. V.; Zvezdin, A. K.; Kruglyak, V. V.; Rasing, Th.; Kimel, A. V.

    2016-02-01

    The magneto-optical Faraday effect played a crucial role in the elucidation of the electromagnetic nature of light. Today it is powerful means to probe magnetism and the basic operational principle of magneto-optical modulators. Understanding the mechanisms allowing for modulation of the magneto-optical response at terahertz frequencies may have far-reaching consequences for photonics, ultrafast optomagnetism and magnonics, as well as for future development of ultrafast Faraday modulators. Here we suggest a conceptually new approach for an ultrafast tunable magneto-optical modulation with the help of counter-propagating laser pulses. Using terbium gallium garnet (Tb3Ga5O12) we demonstrate the feasibility of such magneto-optical modulation with a frequency up to 1.1 THz, which is continuously tunable by means of an external magnetic field. Besides the novel concept for ultrafast magneto-optical polarization modulation, our findings reveal the importance of accounting for propagation effects in the interpretation of pump-probe magneto-optical experiments.

  2. Advances in lasers and optical micro-nano-systems

    NASA Astrophysics Data System (ADS)

    Laurell, F.; Fazio, E.

    2010-09-01

    manipulation of the writing-reading optical beam can push holography toward storages at higher data densities, as presented by Norihiko Ishii et al (Wavefront compensation method using novel index in holographic data storage). Along a similar direction Furlan et al describe a very innovative technique for producing optical traps using novel Devil micro-lenses (Volumetric multiple optical traps produced by Devil's lenses). Vynnyk et al presented an interesting application of electron microscopy for monitoring sub-micrometric structures in 3D configurations (3D-measurement with the stereo scanning electron microscope on sub-micrometer structure). Finally, S. Rao et al present two interesting papers on integrated structures compatible with silicon technology: one describes the realisation of low-loss waveguides using amorphous silicon, a relatively novel material with many applications in very different domains (Low-loss amorphous silicon waveguid! es grown by PECVD on indium tin oxide), and one on the realisation of a electrically drivable device with affective compatibility with CMOS technology (Electro-optical modulating multistack device based on the CMOS-compatible technology of amorphous silicon). We hope that this special issue of the Journal of the European Optical Society will reflect the interest of the European Scientific Community toward these fundamental and applied topics and will demonstrate to readers some of the actual directions of research. We express our full appreciation to the authors that participated to this initiative which acts only as a primer for the vast amount of work now being undertaken in laser physics and applications in micro- and nano-systems. We would like to give a special thank to the paper reviewers for their important role in the paper selection process and all the journal staff for their very professional support, dedication and energy, which made this special issue feasible.

  3. A highly efficient thermo-optic microring modulator assisted by graphene.

    PubMed

    Gan, Sheng; Cheng, Chuantong; Zhan, Yaohui; Huang, Beiju; Gan, Xuetao; Li, Shaojuan; Lin, Shenghuang; Li, Xiaofeng; Zhao, Jianlin; Chen, Hongda; Bao, Qiaoliang

    2015-12-21

    Graphene's remarkable electrical and optical properties afford great potential for constructing various optoelectronic devices, including modulators, photodetectors and pulse lasers. In particular, graphene-based optical modulators were demonstrated to be featured with a broadband response, small footprint, ultrafast speed and CMOS-compatibility, which may provide an alternative architecture for light-modulation in integrated photonic circuits. While on-chip graphene modulators have been studied in various structures, most of them are based on a capacitance-like configuration subjected to complicated fabrication processes and providing a low yield of working devices. Here, we experimentally demonstrate a new type of graphene modulator by employing graphene's electrical and thermal properties, which can be achieved with a simple fabrication flow. On a graphene-coated microring resonator with a small active area of 10 μm(2), we have obtained an effective optical modulation via thermal energy electrically generated in a graphene layer. The resonant wavelength of the ring resonator shifts by 2.9 nm under an electrical power of 28 mW, which enables a large modulation depth of 7 dB and a broad operating wavelength range of 6.2 nm with 3 dB modulation. Due to the extremely high electrical and thermal conductivity in graphene, the graphene thermo-optical modulator operates at a very fast switching rate compared with the conventional silicon thermo-optic modulator, i.e. 10%-90% rise (90%-10% fall) time of 750 ns (800 ns). The results promise a novel architecture for massive on-chip modulation of optical interconnects compatible with CMOS technology. PMID:26581024

  4. A highly efficient thermo-optic microring modulator assisted by graphene

    NASA Astrophysics Data System (ADS)

    Gan, Sheng; Cheng, Chuantong; Zhan, Yaohui; Huang, Beiju; Gan, Xuetao; Li, Shaojuan; Lin, Shenghuang; Li, Xiaofeng; Zhao, Jianlin; Chen, Hongda; Bao, Qiaoliang

    2015-11-01

    Graphene's remarkable electrical and optical properties afford great potential for constructing various optoelectronic devices, including modulators, photodetectors and pulse lasers. In particular, graphene-based optical modulators were demonstrated to be featured with a broadband response, small footprint, ultrafast speed and CMOS-compatibility, which may provide an alternative architecture for light-modulation in integrated photonic circuits. While on-chip graphene modulators have been studied in various structures, most of them are based on a capacitance-like configuration subjected to complicated fabrication processes and providing a low yield of working devices. Here, we experimentally demonstrate a new type of graphene modulator by employing graphene's electrical and thermal properties, which can be achieved with a simple fabrication flow. On a graphene-coated microring resonator with a small active area of 10 μm2, we have obtained an effective optical modulation via thermal energy electrically generated in a graphene layer. The resonant wavelength of the ring resonator shifts by 2.9 nm under an electrical power of 28 mW, which enables a large modulation depth of 7 dB and a broad operating wavelength range of 6.2 nm with 3 dB modulation. Due to the extremely high electrical and thermal conductivity in graphene, the graphene thermo-optical modulator operates at a very fast switching rate compared with the conventional silicon thermo-optic modulator, i.e. 10%-90% rise (90%-10% fall) time of 750 ns (800 ns). The results promise a novel architecture for massive on-chip modulation of optical interconnects compatible with CMOS technology.

  5. Beam Optics Analysis - An Advanced 3D Trajectory Code

    SciTech Connect

    Ives, R. Lawrence; Bui, Thuc; Vogler, William; Neilson, Jeff; Read, Mike; Shephard, Mark; Bauer, Andrew; Datta, Dibyendu; Beal, Mark

    2006-01-03

    Calabazas Creek Research, Inc. has completed initial development of an advanced, 3D program for modeling electron trajectories in electromagnetic fields. The code is being used to design complex guns and collectors. Beam Optics Analysis (BOA) is a fully relativistic, charged particle code using adaptive, finite element meshing. Geometrical input is imported from CAD programs generating ACIS-formatted files. Parametric data is inputted using an intuitive, graphical user interface (GUI), which also provides control of convergence, accuracy, and post processing. The program includes a magnetic field solver, and magnetic information can be imported from Maxwell 2D/3D and other programs. The program supports thermionic emission and injected beams. Secondary electron emission is also supported, including multiple generations. Work on field emission is in progress as well as implementation of computer optimization of both the geometry and operating parameters. The principle features of the program and its capabilities are presented.

  6. Advanced optical position sensors for magnetically suspended wind tunnel models

    NASA Technical Reports Server (NTRS)

    Lafleur, S.

    1985-01-01

    A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

  7. Beam Optics Analysis — An Advanced 3D Trajectory Code

    NASA Astrophysics Data System (ADS)

    Ives, R. Lawrence; Bui, Thuc; Vogler, William; Neilson, Jeff; Read, Mike; Shephard, Mark; Bauer, Andrew; Datta, Dibyendu; Beal, Mark

    2006-01-01

    Calabazas Creek Research, Inc. has completed initial development of an advanced, 3D program for modeling electron trajectories in electromagnetic fields. The code is being used to design complex guns and collectors. Beam Optics Analysis (BOA) is a fully relativistic, charged particle code using adaptive, finite element meshing. Geometrical input is imported from CAD programs generating ACIS-formatted files. Parametric data is inputted using an intuitive, graphical user interface (GUI), which also provides control of convergence, accuracy, and post processing. The program includes a magnetic field solver, and magnetic information can be imported from Maxwell 2D/3D and other programs. The program supports thermionic emission and injected beams. Secondary electron emission is also supported, including multiple generations. Work on field emission is in progress as well as implementation of computer optimization of both the geometry and operating parameters. The principle features of the program and its capabilities are presented.

  8. Advanced optical position sensors for magnetically suspended wind tunnel models

    NASA Astrophysics Data System (ADS)

    Lafleur, S.

    A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

  9. Advances in measuring ocean salinity with an optical sensor

    NASA Astrophysics Data System (ADS)

    Le Menn, M.; de Bougrenet de la Tocnaye, J. L.; Grosso, P.; Delauney, L.; Podeur, C.; Brault, P.; Guillerme, O.

    2011-11-01

    Absolute salinity measurement of seawater has become a key issue in thermodynamic models of the oceans. One of the most direct ways is to measure the seawater refractive index which is related to density and can therefore be related to the absolute salinity. Recent advances in high resolution position sensitive devices enable us to take advantage of small beam deviation measurements using refractometers. This paper assesses the advantages of such technology with respect to the current state-of-the-art technology. In particular, we present the resolution dependence on refractive index variations and derive the limits of such a solution for designing seawater sensors well suited for coastal and deep-sea applications. Particular attention has been paid to investigate the impact of environmental parameters, such as temperature and pressure, on an optical sensor, and ways to mitigate or compensate them have been suggested here. The sensor has been successfully tested in a pressure tank and in open oceans 2000 m deep.

  10. Few layers graphene as thermally activated optical modulator in the visible-near IR spectral range.

    PubMed

    Benítez, J L; Hernández-Cordero, Juan; Muhl, S; Mendoza, D

    2016-01-01

    We report the temperature modulation of the optical transmittance of a few layers of graphene (FLG). The FLG was heated either by the Joule effect of the current flowing between coplanar electrodes or by the absorption of a continuous-wave 532 nm laser. The optical signals used to evaluate the modulation of the FLG were at 633, 975, and 1550 nm; the last wavelengths are commonly used in optical communications. We also evaluated the effect of the substrate on the modulation effect by comparing the performance of a freely suspended FLG sample with one mounted on a glass substrate. Our results show that the modulation of the optical transmittance of FLG can be from millihertz to kilohertz. PMID:26696185

  11. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Mok; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong

    2013-12-01

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  12. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    SciTech Connect

    Kim, Jin-Mok Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong

    2013-12-15

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  13. Analysis of thermo-optic effect-based refractive index dynamic modulation in microspherical resonator.

    PubMed

    Wang, Yue; Wang, Quan-Long; Zhou, Song; Wu, Jun-Feng; Wu, Yi-Hui

    2015-10-01

    The thermo-optic effect has been utilized to modulate the refractive index dynamically within a whispering gallery mode resonator. Modulation with a large tuning range is mostly performed for mode locking and dynamic control of the optical path at a modulation frequency as low as several hertz, while high-frequency modulation up to megahertz is mainly exploited in optical switching devices with small tuning range. Here, we introduce the response functions theoretically to describe the dynamic response of temperature changes in the mode volume and the resonator body, respectively. This result is verified experimentally in silica microspherical resonators. The dependence of the tuning range on the modulation frequency is achieved. This knowledge could pave the way toward more practical control of refractive index in microresonators. PMID:26479610

  14. Optical control of the Advanced Technology Solar Telescope.

    PubMed

    Upton, Robert

    2006-08-10

    The Advanced Technology Solar Telescope (ATST) is an off-axis Gregorian astronomical telescope design. The ATST is expected to be subject to thermal and gravitational effects that result in misalignments of its mirrors and warping of its primary mirror. These effects require active, closed-loop correction to maintain its as-designed diffraction-limited optical performance. The simulation and modeling of the ATST with a closed-loop correction strategy are presented. The correction strategy is derived from the linear mathematical properties of two Jacobian, or influence, matrices that map the ATST rigid-body (RB) misalignments and primary mirror figure errors to wavefront sensor (WFS) measurements. The two Jacobian matrices also quantify the sensitivities of the ATST to RB and primary mirror figure perturbations. The modeled active correction strategy results in a decrease of the rms wavefront error averaged over the field of view (FOV) from 500 to 19 nm, subject to 10 nm rms WFS noise. This result is obtained utilizing nine WFSs distributed in the FOV with a 300 nm rms astigmatism figure error on the primary mirror. Correction of the ATST RB perturbations is demonstrated for an optimum subset of three WFSs with corrections improving the ATST rms wavefront error from 340 to 17.8 nm. In addition to the active correction of the ATST, an analytically robust sensitivity analysis that can be generally extended to a wider class of optical systems is presented. PMID:16926876

  15. Optical control of the Advanced Technology Solar Telescope.

    PubMed

    Upton, Robert

    2006-08-10

    The Advanced Technology Solar Telescope (ATST) is an off-axis Gregorian astronomical telescope design. The ATST is expected to be subject to thermal and gravitational effects that result in misalignments of its mirrors and warping of its primary mirror. These effects require active, closed-loop correction to maintain its as-designed diffraction-limited optical performance. The simulation and modeling of the ATST with a closed-loop correction strategy are presented. The correction strategy is derived from the linear mathematical properties of two Jacobian, or influence, matrices that map the ATST rigid-body (RB) misalignments and primary mirror figure errors to wavefront sensor (WFS) measurements. The two Jacobian matrices also quantify the sensitivities of the ATST to RB and primary mirror figure perturbations. The modeled active correction strategy results in a decrease of the rms wavefront error averaged over the field of view (FOV) from 500 to 19 nm, subject to 10 nm rms WFS noise. This result is obtained utilizing nine WFSs distributed in the FOV with a 300 nm rms astigmatism figure error on the primary mirror. Correction of the ATST RB perturbations is demonstrated for an optimum subset of three WFSs with corrections improving the ATST rms wavefront error from 340 to 17.8 nm. In addition to the active correction of the ATST, an analytically robust sensitivity analysis that can be generally extended to a wider class of optical systems is presented.

  16. Transport and handling of National Ignition Facility beamline optic modules

    SciTech Connect

    Yakuma, S.C.; Grasz, E.L.; Rowe, A.W.; Yourchenko, G.; Swan, D.A.; Robles, G.M.

    1997-12-23

    Installing the thousands of optics that make up the laser for the National Ignition Facility (NIF) is a complex operation. This paper introduces the Optical Transport and Material Handling designs that will be used to deliver the optics. The transport and handling hardware is being designed to allow autonomous, semiautonomous, and manual operations.

  17. Programmable generation of ultrafast optical waveforms: Recent advances in theory and technology

    SciTech Connect

    Wefers, M.M.; Nelson, K.A.

    1995-11-01

    Recent advances in the shaping of ultrafast optical waveforms using liquid crystal (LC) spatial light modulators (SLM) are presented. Two LC SLMs are used in a novel arrangement to produce programmable waveforms with specified time-dependent amplitude and temporal phase profiles with the greatest fidelity and complexity to date. The apparatus is also used to demonstrate the generation of an ultrafast waveform with a programmable time-dependent polarization profile. A general theoretical result that describes the space-time electric field profile of waveforms shaped by the spectral filtering of spatially separated frequency components is also presented. The main result is that diffraction gives rise to a translational spatial shift in the electric field profile that varies linearly with time along the shaped waveform.

  18. Analytical model and experimental verification of the critical power for modulation instability in optical fibers.

    PubMed

    Alem, Mehdi; Soto, Marcelo A; Thévenaz, Luc

    2015-11-16

    Modulation instability is thoroughly investigated and a simple analytical model for its power critically modifying the wave properties in terms of system parameters is derived and experimentally validated. The differences on the modulation instability gain spectrum in lossless and lossy optical fibers are analyzed based on theoretical models and numerical simulations. In particular the impact of background noise on the behavior of modulation instability is studied analytically and verified by measurements and simulations. The proposed analytical model is experimentally validated by monitoring the wave propagation along an optical fiber using a Brillouin optical time-domain analyzer. This way, the evolution of the optical signal traveling through optical fibers, especially, the pump depletion and the recurrence phenomenon are investigated. PMID:26698435

  19. Acousto-optic modulation of a photonic crystal nanocavity with Lamb waves in microwave K band

    SciTech Connect

    Tadesse, Semere A.; Li, Huan; Liu, Qiyu; Li, Mo

    2015-11-16

    Integrating nanoscale electromechanical transducers and nanophotonic devices potentially can enable acousto-optic devices to reach unprecedented high frequencies and modulation efficiency. Here, we demonstrate acousto-optic modulation of a photonic crystal nanocavity using Lamb waves with frequency up to 19 GHz, reaching the microwave K band. The devices are fabricated in suspended aluminum nitride membrane. Excitation of acoustic waves is achieved with interdigital transducers with period as small as 300 nm. Confining both acoustic wave and optical wave within the thickness of the membrane leads to improved acousto-optic modulation efficiency in these devices than that obtained in previous surface acoustic wave devices. Our system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.

  20. Electro-optic force measurement application using phase-modulated optical polarimetry

    NASA Astrophysics Data System (ADS)

    Mackey, Jeffrey R.; Salari, Ezzatollah; Spiegelberg, Stephen H.

    2002-02-01

    In this paper, we describe the design and development of a high sensitivity, large dynamic range force transducer capable of measuring transient force changes in tension and compression. Conventional force transducers typically rely on the deformation of strain gauges, or on servo-mechanical load cells. While strain gauge transducers exhibit a rapid response time, they are subject to electrical noise, and typically have a minimum useful limit of approximately 10-5 N. Servo-mechanical transducers have poor response times and exhibit compliance in the axis of deformation that is unacceptable for many applications. The research objective is to develop a novel force transducer based on the change in optical properties with loading of a pre-stressed polymer. The concept utilizes a pre-stressed polymer material as a linkage to which a force would be applied either in compression or tension. The molecular deformation of the polymer linkage will be analyzed using miniature optical components arranged as a phase-modulated polarimeter capable of birefringence measurements on the order of 10-9. Calibration of the measured birefringence with known loads provides the necessary calibration parameters. The instrument is capable of directional force measurements and is extremely accurate for measuring low-level forces. Since the force transducer is based on optical techniques, it would be resistant to electronic noise, and would allow measurement of rapidly changing loads. The best available force transducers capable of measuring transient responses have a lower resolution of approximately 10-5 N. Research with the rheology of fluids, transient flows of pharmaceuticals in combinatorial research, biological tissue response, and biomimetic adhesive research often require force measurements below this range. Although ultra-microbalances exist that have sensitivities well below this range, the averaging techniques employed that allow these measurements make them unsuitable for

  1. Light emitters and modulators on SOI for optical interconnects

    NASA Astrophysics Data System (ADS)

    Su, Yikai; Qiu, Ciyuan; Zhang, Yong; Liu, Ruili

    2016-03-01

    We discuss light emitters and modulators in silicon photonic interconnects. In particular, we experimentally demonstrate resonant luminescence from Ge quantum dots embedded in a photonic crystal ring resonator (PCRR) at room temperature. Six sharp resonant peaks are observed, which correspond to the resonant modes supported by the PCRR. We further study a high speed silicon-graphene nanobeam modulator, and a silicon spatial light modulator. These devices show great potential in future high density and high capacity interconnection systems.

  2. Electro-Optic Modulator Based on Organic Planar Waveguide Integrated with Prism Coupler

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S.

    2002-01-01

    The objectives of the project, as they were formulated in the proposal, are the following: (1) Design and development of novel electro-optic modulator using single crystalline film of highly efficient electro-optic organic material integrated with prism coupler; (2) Experimental characterization of the figures-of-merit of the modulator. It is expected to perform with an extinction ratio of 10 dB at a driving signal of 5 V; (3) Conclusions on feasibility of the modulator as an element of data communication systems of future generations. The accomplishments of the project are the following: (1) The design of the electro-optic modulator based on a single crystalline film of organic material NPP has been explored; (2) The evaluation of the figures-of-merit of the electro-optic modulator has been performed; (3) Based on the results of characterization of the figures-of-merit, the conclusion was made that the modulator based on a thin film of NPP is feasible and has a great potential of being used in optic communication with a modulation bandwidth of up to 100 GHz and a driving voltage of the order of 3 to 5 V.

  3. Optically tuned terahertz modulator based on annealed multilayer MoS2

    NASA Astrophysics Data System (ADS)

    Cao, Yapeng; Gan, Sheng; Geng, Zhaoxin; Liu, Jian; Yang, Yuping; Bao, Qiaoling; Chen, Hongda

    2016-03-01

    Controlling the propagation properties of terahertz waves is very important in terahertz technologies applied in high-speed communication. Therefore a new-type optically tuned terahertz modulator based on multilayer-MoS2 and silicon is experimentally demonstrated. The terahertz transmission could be significantly modulated by changing the power of the pumping laser. With an annealing treatment as a p-doping method, MoS2 on silicon demonstrates a triple enhancement of terahertz modulation depth compared with the bare silicon. This MoS2-based device even exhibited much higher modulation efficiency than the graphene-based device. We also analyzed the mechanism of the modulation enhancement originated from annealed MoS2, and found that it is different from that of graphene-based device. The unique optical modulating properties of the device exhibit tremendous promise for applications in terahertz switch.

  4. Optically tuned terahertz modulator based on annealed multilayer MoS2

    PubMed Central

    Cao, Yapeng; Gan, Sheng; Geng, Zhaoxin; Liu, Jian; Yang, Yuping; Bao, Qiaoling; Chen, Hongda

    2016-01-01

    Controlling the propagation properties of terahertz waves is very important in terahertz technologies applied in high-speed communication. Therefore a new-type optically tuned terahertz modulator based on multilayer-MoS2 and silicon is experimentally demonstrated. The terahertz transmission could be significantly modulated by changing the power of the pumping laser. With an annealing treatment as a p-doping method, MoS2 on silicon demonstrates a triple enhancement of terahertz modulation depth compared with the bare silicon. This MoS2-based device even exhibited much higher modulation efficiency than the graphene-based device. We also analyzed the mechanism of the modulation enhancement originated from annealed MoS2, and found that it is different from that of graphene-based device. The unique optical modulating properties of the device exhibit tremendous promise for applications in terahertz switch. PMID:26953153

  5. Optically tuned terahertz modulator based on annealed multilayer MoS2.

    PubMed

    Cao, Yapeng; Gan, Sheng; Geng, Zhaoxin; Liu, Jian; Yang, Yuping; Bao, Qiaoling; Chen, Hongda

    2016-01-01

    Controlling the propagation properties of terahertz waves is very important in terahertz technologies applied in high-speed communication. Therefore a new-type optically tuned terahertz modulator based on multilayer-MoS2 and silicon is experimentally demonstrated. The terahertz transmission could be significantly modulated by changing the power of the pumping laser. With an annealing treatment as a p-doping method, MoS2 on silicon demonstrates a triple enhancement of terahertz modulation depth compared with the bare silicon. This MoS2-based device even exhibited much higher modulation efficiency than the graphene-based device. We also analyzed the mechanism of the modulation enhancement originated from annealed MoS2, and found that it is different from that of graphene-based device. The unique optical modulating properties of the device exhibit tremendous promise for applications in terahertz switch. PMID:26953153

  6. Advanced optical smoke meters for jet engine exhaust measurement

    NASA Technical Reports Server (NTRS)

    Pitz, R. W.

    1986-01-01

    Smoke meters with increased sensitivity, improved accuracy, and rapid response are needed to measure the smoke levels emitted by modern jet engines. The standard soiled tape meter in current use is based on filtering, which yields long term averages and is insensitive to low smoke levels. Two new optical smoke meter techniques that promise to overcome these difficulties have been experimentally evaluated: modulated transmission (MODTRAN) and photothermal deflection spectroscopy (PDS). Both techniques are based on light absorption by smoke, which is closely related to smoke density. They are variations on direct transmission measurements which produce a modulated signal that can be easily measured with phase sensitive detection. The MODTRAN and PDS techniques were tested on low levels of smoke and diluted samples of NO2 in nitrogen, simulating light adsorption due to smoke. The results are evaluated against a set of ideal smoke meter criteria that include a desired smoke measurement range of 0.1 to 12 mg cu.m. (smoke numbers of 1 to 50) and a frequency response of 1 per second. The MODTRAN instrument is found to be inaccurate for smoke levels below 3 mg/cu.m. and is able to make a only about once every 20 seconds because of its large sample cell. The PDS instrument meets nearly all the characteristics of an ideal smoke meter: it has excellent sensitivity over a range of smoke levels from 0.1 to 20 mg/cu.m. (smoke numbers of 1 to 60) and good frequency response (1 per second).

  7. Plasmonics-enhanced and optically modulated delivery of gold nanostars into brain tumor

    PubMed Central

    Yuan, Hsiangkuo; Wilson, Christy M.; Xia, Jun; Doyle, Sarah L.; Li, Shuqin; Fales, Andrew M; Liu, Yang; Ozaki, Ema; Mulfaul, Kelly; Hanna, Gabi; Palmer, Gregory M.; Wang, Lihong V.; Grant, Gerald A.

    2014-01-01

    Plasmonics-active gold nanostars exhibiting strong imaging contrast and efficient photothermal transduction were synthesized for a novel pulsed laser-modulated plasmonics-enhanced brain tumor microvascular permeabilization. We demonstrate a selective, optically modulated delivery of nanoprobes into the tumor parenchyma with minimal off-target distribution. PMID:24619405

  8. The Hands-On Optics Project: a demonstration of module 3-magnificent magnifications

    NASA Astrophysics Data System (ADS)

    Pompea, Stephen M.; Sparks, Robert T.; Walker, Constance E.

    2014-07-01

    The Hands-On Optics project offers an example of a set of instructional modules that foster active prolonged engagement. Developed by SPIE, OSA, and NOAO through funding from the U.S. National Science Foundation, the modules were originally designed for afterschool settings and museums. However, because they were based on national standards in mathematics, science, and technology, they were easily adapted for use in classrooms. The philosophy and implementation strategies of the six modules will be described as well as lessons learned in training educators. The modules were implementing with the help of optics industry professionals who served as expert volunteers to assist educators. A key element of the modules was that they were developed around an understanding of optics misconceptions and used culminating activities in each module as a form of authentic assessment. Thus student achievement could be measured by evaluating the actual product created by each student in applying key concepts, tools, and applications together at the end of each module. The program used a progression of disciplinary core concepts to build an integrated sequence and crosscutting ideas and practices to infuse the principles of the modern electro-optical field into the modules. Whenever possible, students were encouraged to experiment and to create, and to pursue inquiry-based approaches. The result was a program that had high appeal to regular as well as gifted students.

  9. Acousto-optic modulator as an electronically selectable unidirectional device in a ring laser

    SciTech Connect

    Roy, R.; Schulz, P.A.; Walther, A.

    1987-09-01

    An acousto-optic modulator causes undirectional operation of dye and Ti:sapphire ring lasers. The modulator has a low insertion loss in the cavity and can be used to switch the direction of the beam electronically. The ring laser performance is characterized, and experiments to probe the origin of the unidirectional operation are described.

  10. Plasmonics-enhanced and optically modulated delivery of gold nanostars into brain tumor.

    PubMed

    Yuan, Hsiangkuo; Wilson, Christy M; Xia, Jun; Doyle, Sarah L; Li, Shuqin; Fales, Andrew M; Liu, Yang; Ozaki, Ema; Mulfaul, Kelly; Hanna, Gabi; Palmer, Gregory M; Wang, Lihong V; Grant, Gerald A; Vo-Dinh, Tuan

    2014-04-21

    Plasmonics-active gold nanostars exhibiting strong imaging contrast and efficient photothermal transduction were synthesized for a novel pulsed laser-modulated plasmonics-enhanced brain tumor microvascular permeabilization. We demonstrate a selective, optically modulated delivery of nanoprobes into the tumor parenchyma with minimal off-target distribution.

  11. Sol-Gel Material-Enabled Electro-Optic Polymer Modulators.

    PubMed

    Himmelhuber, Roland; Norwood, Robert A; Enami, Yasufumi; Peyghambarian, Nasser

    2015-01-01

    Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed. PMID:26225971

  12. Sol-Gel Material-Enabled Electro-Optic Polymer Modulators.

    PubMed

    Himmelhuber, Roland; Norwood, Robert A; Enami, Yasufumi; Peyghambarian, Nasser

    2015-07-27

    Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed.

  13. Sol-Gel Material-Enabled Electro-Optic Polymer Modulators

    PubMed Central

    Himmelhuber, Roland; Norwood, Robert A.; Enami, Yasufumi; Peyghambarian, Nasser

    2015-01-01

    Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed. PMID:26225971

  14. High-performance GaAs/AlGaAs optical phase modulators for microwave photonic integrated circuits

    SciTech Connect

    Hietala, V.M.; Kravitz, S.H.; Armendariz, M.G.; Vawter, G.A.; Carson, R.F.

    1994-03-01

    A high-performance high-speed optical phase modulator for photonic integrated circuit (PIC) use is described. Integration of these optical phase modulators into a real system (compass) is also discussed. The optical phase modulators are based on depletion-edge translation and have experimentally provided optical phase shifts in excess of 60{degrees}/V{center_dot}mm with approximately 4 dB/cm loss while simultaneously demonstrating bandwidths in excess of 10 GHz.

  15. Minimizing inter-channel cross-phase modulation with optical phase conjugation in asymmetric fibre links.

    PubMed

    Hesketh, Graham D; Petropoulos, Periklis

    2016-09-01

    Using analytic and numerical modelling of fibre transmission systems that employ optical phase conjugation (OPC), we show inter-channel cross-phase modulation depends on the integrated square error between nonlinear profiles before and after OPC and that arranging amplifiers and tuning power levels is crucial to minimizing noise. We derive modulation transparent formulas for phase noise and optimal power settings. Examples are shown for 16 and 64 quadrature amplitude modulation. PMID:27607633

  16. Performance Analysis of Different Modulation Formats in Optical Communication

    NASA Astrophysics Data System (ADS)

    Singh, Kulwinder; Singh, Maninder; Bhatia, Kamaljit Singh; Ryait, Hardeep Singh

    2016-06-01

    In this paper, we demonstrated the variation of different parameters with quadrature amplitude modulation (QAM) and differential phase shift key (DPSK) sequence generator, which generates modulated signals, in data transmission for communication and analysed that how the difference of these sequence generators effect its resonant frequency (RF) value, eye diagram and electrical constellation representation of the system.

  17. Generation of the "perfect" optical vortex using a liquid-crystal spatial light modulator.

    PubMed

    Ostrovsky, Andrey S; Rickenstorff-Parrao, Carolina; Arrizón, Víctor

    2013-02-15

    We introduce the concept of the perfect optical vortex whose dark hollow radius does not depend on the topological charge. It is shown analytically and experimentally that such a vortex can be approximately generated in the Fourier transforming optical system with a computer-controlled liquid-crystal spatial light modulator.

  18. Monolithically integrated quantum dot optical gain modulator with semiconductor optical amplifier for 10-Gb/s photonic transmission

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

    2015-03-01

    Short-range interconnection and/or data center networks require high capacity and a large number of channels in order to support numerous connections. Solutions employed to meet these requirements involve the use of alternative wavebands to increase the usable optical frequency range. We recently proposed the use of the T- and O-bands (Thousand band: 1000-1260 nm, Original band: 1260-1360 nm) as alternative wavebands because large optical frequency resources (>60 THz) can be easily employed. In addition, a simple and compact Gb/s-order high-speed optical modulator is a critical photonic device for short-range communications. Therefore, to develop an optical modulator that acts as a highfunctional photonic device, we focused on the use of self-assembled quantum dots (QDs) as a three-dimensional (3D) confined structure because QD structures are highly suitable for realizing broadband optical gain media in the T+O bands. In this study, we use the high-quality broadband QD optical gain to develop a monolithically integrated QD optical gain modulator (QD-OGM) device that has a semiconductor optical amplifier (QD-SOA) for Gb/s-order highspeed optical data generation in the 1.3-μm waveband. The insertion loss of the device can be compensated through the SOA, and we obtained an optical gain change of up to ~7 dB in the OGM section. Further, we successfully demonstrate a 10-Gb/s clear eye opening using the QD-OGM/SOA device with a clock-data recovery sequence at the receiver end. These results suggest that the monolithic QD-EOM/SOA is suitable for increasing the number of wavelength channels for smart short-range communications.

  19. Broadband energy-efficient optical modulation by hybrid integration of silicon nanophotonics and organic electro-optic polymer

    NASA Astrophysics Data System (ADS)

    Zhang, Xingyu; Hosseini, Amir; Subbaraman, Harish; Luo, Jingdong; Jen, Alex K.-Y.; Chung, Chi-jui; Yan, Hai; Pan, Zeyu; Nelson, Robert L.; Chen, Ray T.

    2015-03-01

    Silicon-organic hybrid integrated devices have emerging applications ranging from high-speed optical interconnects to photonic electromagnetic-field sensors. Silicon slot photonic crystal waveguides (PCWs) filled with electro-optic (EO) polymers combine the slow-light effect in PCWs with the high polarizability of EO polymers, which promises the realization of high-performance optical modulators. In this paper, a broadband, power-efficient, low-dispersion, and compact optical modulator based on an EO polymer filled silicon slot PCW is presented. A small voltage-length product of Vπ×L=0.282V×mm is achieved, corresponding to an unprecedented record-high effective in-device EO coefficient (r33) of 1230pm/V. Assisted by a backside gate voltage, the modulation response up to 50GHz is observed, with a 3-dB bandwidth of 15GHz, and the estimated energy consumption is 94.4fJ/bit at 10Gbit/s. Furthermore, lattice-shifted PCWs are utilized to enhance the optical bandwidth by a factor of ~10X over other modulators based on non-band-engineered PCWs and ring-resonators.

  20. Advanced photovoltaic concentrator system low-cost prototype module

    SciTech Connect

    Kaminar, N.R.; McEntee, J.; Curchod, D. )

    1991-09-01

    This report describes the continued development of an extruded lens and the development of a PV receiver, both of which will be used in the Solar Engineering Applications Corporation (SEA) 10X concentrator. These efforts were pare of a pre-Concentrator Initiative Program. The 10X concentrator consists of an inexpensive, extruded linear Fresnel lens which focuses on one-sun cells which are adhesive-bonded to an anodized aluminum heat sink. Module sides are planned to be molded along with the lens and are internally reflective for improved on- and off-track performance. End caps with molded-in bearings complete the module. Ten modules are mounted in a stationary frame for simple, single-axis tracking in the east-west direction. This configuration an array, is shipped completely assembled and requires only setting on a reasonably flat surface, installing 4 fasteners, and hooking up the wires. Development of the 10-inch wide extruded lens involved one new extrusion die and a series of modifications to this die. Over 76% lens transmission was measured which surpassed the program goal of 75%. One-foot long receiver sections were assembled and subjected to evaluation tests at Sandia National Laboratories. A first group had some problem with cell delamination and voids but a second group performed very well, indicating that a full size receiver would pass the full qualification test. Cost information was updated and presented in the report. The cost study indicated that the Solar Engineering Applications Corporation concentrator system can exceed the DOE electricity cost goals of less than 6cents per KW-hr. 33 figs., 11 tabs.

  1. Advances in targeting cell surface signalling molecules for immune modulation

    PubMed Central

    Yao, Sheng; Zhu, Yuwen; Chen, Lieping

    2013-01-01

    The past decade has witnessed a surge in the development of immunomodulatory approaches to combat a broad range of human diseases, including cancer, viral infections, autoimmunity and inflammation as well as in the prevention of transplant rejection. Immunomodulatory approaches mostly involve the use of monoclonal antibodies or recombinant fusion proteins that target cell surface signalling molecules on immune cells to drive immune responses towards the desired direction. Advances in our understanding of the human immune system, along with valuable lessons learned from the first generation of therapeutic biologics, are aiding the design of the next generation of immunomodulatory biologics with better therapeutic efficacy, minimized adverse effects and long-lasting clinical benefit. The recent encouraging results from antibodies targeting programmed cell death protein 1 (PD1) and B7 homolog 1 (B7H1; also known as PDL1) for the treatment of various advanced human cancers show that immunomodulatory therapy has come of age. PMID:23370250

  2. Advances in Mismatch Identification and Power Loss Evaluation of Concentrating Photovoltaic Multijunction Module

    NASA Astrophysics Data System (ADS)

    Minuto, A.; Timò, G.; Groppelli, P.

    2011-12-01

    The outdoor I-V curve of a concentrating photovoltaic (CPV) Multi-junction (MJ) module is affected by temperature, series resistance, electro-optical mismatches among receivers mainly due to soiling effects, tracker misalignment and a particular spectral solar content. Starting from the previous works [1] and [2] and considering CPV MJ modules of only-one string with series-connected receivers, an original algorithm is developed to identify the photovoltaic current and the operating junction temperature of each receiver. Power losses due to the temperature, the series resistance and the electro-optical mismatches can be separately identified as well.

  3. An optically controlled phased array antenna based on single sideband polarization modulation.

    PubMed

    Zhang, Yamei; Wu, Huan; Zhu, Dan; Pan, Shilong

    2014-02-24

    A novel optically controlled phased array antenna consisting a simple optical beamforming network and an N element linear patch antenna array is proposed and demonstrated. The optical beamforming network is realized by N independent phase shifters using a shared optical single sideband (OSSB) polarization modulator together with N polarization controllers (PCs), N polarization beam splitters (PBSs) and N photodetectors (PDs). An experiment is carried out. A 4-element linear patch antenna array operating at 14 GHz and a 1 × 4 optical beamforming network (OBFN) is employed to realize the phased array antenna. The radiation patterns of the phased array antenna at -30°, 0° and 30° are achieved.

  4. Final report on LDRD project : advanced optical trigger systems.

    SciTech Connect

    Roose, Lars D.; Hadley, G. Ronald; Mar, Alan; Serkland, Darwin Keith; Geib, Kent Martin; Sullivan, Charles Thomas; Keeler, Gordon Arthur; Bauer, Thomas M.; Peake, Gregory Merwin; Loubriel, Guillermo Manuel; Montano, Victoria A.

    2008-09-01

    Advanced optically-activated solid-state electrical switch development at Sandia has demonstrated multi-kA/kV switching and the path for scalability to even higher current/power. Realization of this potential requires development of new optical sources/switches based on key Sandia photonic device technologies: vertical-cavity surface-emitting lasers (VCSELs) and photoconductive semiconductor switch (PCSS) devices. The key to increasing the switching capacity of PCSS devices to 5kV/5kA and higher is to distribute the current in multiple parallel line filaments triggered by an array of high-brightness line-shaped illuminators. Commercial mechanically-stacked edge-emitting lasers have been used to trigger multiple filaments, but they are difficult to scale and manufacture with the required uniformity. In VCSEL arrays, adjacent lasers utilize identical semiconductor material and are lithographically patterned to the required dimensions. We have demonstrated multiple-line filament triggering using VCSEL arrays to approximate line generation. These arrays of uncoupled circular-aperture VCSELs have fill factors ranging from 2% to 30%. Using these arrays, we have developed a better understanding of the illumination requirements for stable triggering of multiple-filament PCSS devices. Photoconductive semiconductor switch (PCSS) devices offer advantages of high voltage operation (multi-kV), optical isolation, triggering with laser pulses that cannot occur accidentally in nature, low cost, high speed, small size, and radiation hardness. PCSS devices are candidates for an assortment of potential applications that require multi-kA switching of current. The key to increasing the switching capacity of PCSS devices to 5kV/5kA and higher is to distribute the current in multiple parallel line filaments triggered by an array of high-brightness line-shaped illuminators. Commercial mechanically-stacked edge-emitting lasers have been demonstrated to trigger multiple filaments, but they

  5. Electro-optic phase modulation by polymer dispersed liquid crystals

    NASA Astrophysics Data System (ADS)

    Vicari, L.

    1997-05-01

    We present a mathematical model to describe the optical phase shift induced by polymer dispersed liquid crystals (PDLCs) on light impinging transversely on the sample. PDLCs are dispersions of liquid crystal microdroplets in a polymeric binder. Droplets appear as optically uniaxial spheres randomly oriented so that the material is optically isotropic. The application of an external electric field results in a reorientation of the liquid crystal and therefore in an electrically controllable optical uniaxicity of the material. The model is discussed by comparison with experimental data and with previous theory [F. Basile, F. Bloisi, L. Vicari, and F. Simoni, Phys. Rev. E 48, 432 (1993)].

  6. Modulated-splitting-ratio fiber-optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter A.

    1988-01-01

    A fiber-optic temperature sensor is described, which uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

  7. Organic-based electro-optic modulators for microwave photonic applications

    NASA Astrophysics Data System (ADS)

    Eng, David

    As cutting-edge microwave photonic systems with higher complexity and stringent device requirement are being developed, the demand higher performance modulators with lower drive voltages and higher bandwidth is beginning to overtake the physical limitations of existing modulators based in LiNbO3. To address this growing demand, groundbreaking work in the field of organic electro-optic materials has been achieved over the past 10--15 years that has resulted in materials with electro-optic coefficients up to 10 times that of LiNbO3 and with demonstrated response times into the THz regime. This dissertation details work towards developing low drive-voltage, high bandwidth organic-based electro-optic modulators to support next generation microwave photonic systems. Initial efforts were focused on designing an organic electro-optic material based low frequency phase modulator and developing a fabrication procedure that successfully integrates the material without compromising its electro optic activity. Additionally a procedure for inducing the high electro-optic activity in the waveguide core through a process known as 'poling' was developed. The phase modulators were then characterized to confirm the expected high electro-optic activity and correspondingly low drive voltages. To transition from low frequency modulation to broadband operation it was necessary to gather some dielectric information of the waveguide materials for RF design. Because traditional RF dielectric constant measurements assume thick substrates on the order of 100s of microns, a modified microstrip ring resonator technique was developed to measure the dielectric constant of thin, polymer waveguide films on the order of 10 mum out to 110 GHz. A high frequency traveling wave microstrip modulator was then designed and optimized for operation up to 50 GHz, and efforts were turned towards RF packaging of the microstrip modulators for practical utilization and integration. To feed the RF signals a

  8. Intensity-modulated optical fiber sensors based on chirped-fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Dong, Xinyong

    2011-09-01

    Intensity-modulated fiber Bragg grating (FBG) sensors, compared with normal wavelength-encoding FBG sensors, can reduce the cost of sensor system significantly by using cost-efficient optical power detection devices, instead of expensive wavelength measurement instruments. Chirped-FBG (CFBG) based intensity-modulated sensors show potential applications in various sensing areas due to their many advantages, including inherent independence of temperature, high measurement speed, and low cost, in addition to the merits of all fiber-optic sensors. This paper theoretically studies the sensing principle of CFBG-based intensity-modulated sensors and briefly reviews their recent progress in measurement of displacement, acceleration, and tilt angle.

  9. Design of Mach-Zehnder interference modulators composed of enhanced electro-optic active polymers

    NASA Astrophysics Data System (ADS)

    Xu, Guangming; Liu, Jialei; Ren, Haohui; Fan, Guofang; Zhen, Zhen; Liu, Xinhou

    2014-03-01

    Organic electro-optic polymer has low dielectric constant and high electro-optic coefficient, which is one of the perfect materials for making modulators with low loss and high bandwidth. In this paper, we synthesized a novel chromophore based on the 4-(diethylamino) salicylaldehyde electron donor and the rigid isolated benzyl group. Based on the innovative chormophore, we designed low loss Mach-Zehnder interference modulators with 3dB bandwidth 50GHz using tapered waveguides and coplanar waveguide electrodes as well as micro-strip electrodes. Performance parameters of the modulators were detailed analyzed and two microwave driven electrodes were compared.

  10. New-generation concentrator modules based on cascade solar cells: Design and optical and thermal properties

    NASA Astrophysics Data System (ADS)

    Andreev, V. M.; Davidyuk, N. Yu.; Malevski, D. A.; Pan'chak, A. N.; Rumyantsev, V. D.; Sadchikov, N. A.; Chekalin, A. V.; Luque, A.

    2014-11-01

    New-generation concentrator modules use III-V nanoheterostructure cascade solar cells the efficiency of which can be raised to 50% for the number of cascades exceeding three. To obtain a high overall efficiency of photovoltaic conversion in power plants and extend their service time, it is necessary that the design of the modules be optimal in terms of optics and thermal engineering. In this work, main challenges in designing solar modules, such as optical concentration of radiation and residual heat removal, are considered. The results of pilot works that have been recently done in the Ioffe Physical Technical Institute are primarily reported.

  11. Advanced Gate Drive for the SNS High Voltage Converter Modulator

    SciTech Connect

    Nguyen, M.N.; Burkhart, C.; Kemp, M.A.; Anderson, D.E.; /Oak Ridge

    2009-05-07

    SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate [1], a critical component of the SNS High Voltage Converter Modulator [2]. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned driver improves upon the existing gate drive in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of dI/dt and Vce(sat) for fast over-current detection and suppression, and redundant power isolation are some of the added features. In addition, triggering insertion delay is reduced by a factor of four compared to the existing driver. This paper details the design and performance of the new IGBT gate driver. A simplified schematic and description of the construction are included. The operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention circuitry, and control power isolation breakdown detection circuit are discussed.

  12. Optical design of MOEMS-based micro-mechatronic modules for applications in spectroscopy

    NASA Astrophysics Data System (ADS)

    Tortschanoff, A.; Kremer, M.; Sandner, T.; Kenda, A.

    2014-05-01

    One of the important challenges for widespread application of MOEMS devices is to provide a modular interface for easy handling and accurate driving of the MOEMS elements, in order to enable seamless integration in larger spectroscopic system solutions. In this contribution we present in much detail the optical design of MOEMS driver modules comprising optical position sensing together with driver electronics, which can actively control different electrostatically driven MOEMS. Furthermore we will present concepts for compact spectroscopic devices, based on different MOEMS scanner modules with lD and 2D optical elements.

  13. Optical-data-processing properties of a liquid-crystal television spatial light modulator

    NASA Technical Reports Server (NTRS)

    Liu, H.-K.; Davis, J. A.; Lilly, R. A.

    1985-01-01

    The potential of an extremely inexpensive liquid-crystal television (LCTV) as a two-dimensional spatial light modulator has been investigated. The LCTV modulates the transmission of coherent or incoherent light and can either be electronically addressed through a microcomputer or optically addressed with a TV camera. The transmission characteristics of the device have been measured, its diffraction pattern is examined, and its use as an input device for an optical correlator is tested. It is discovered that, with proper modifications, it has potential for optical-data-processing applications.

  14. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns.

    PubMed

    Resink, S G; Steenbergen, W

    2015-06-01

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical phase modulation, the fraction of light that is tagged by ultrasound, speckle contrast, mean square difference of speckle patterns and the contrast of the summation of speckle patterns acquired at different ultrasound phases. We derive the important relations from basic assumptions and definitions, and then validate them with simulations. For ultrasound-generated phase modulation angles below 0.7 rad (assuming uniform modulation), we are now able to relate speckle pattern statistics to the acousto-optic phase modulation. Hence our theory allows quantifying speckle observations in terms of ultrasonically tagged fractions of light for near-unity-contrast speckle patterns.

  15. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns.

    PubMed

    Resink, S G; Steenbergen, W

    2015-06-01

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical phase modulation, the fraction of light that is tagged by ultrasound, speckle contrast, mean square difference of speckle patterns and the contrast of the summation of speckle patterns acquired at different ultrasound phases. We derive the important relations from basic assumptions and definitions, and then validate them with simulations. For ultrasound-generated phase modulation angles below 0.7 rad (assuming uniform modulation), we are now able to relate speckle pattern statistics to the acousto-optic phase modulation. Hence our theory allows quantifying speckle observations in terms of ultrasonically tagged fractions of light for near-unity-contrast speckle patterns. PMID:25985079

  16. Silicon electro-optic modulator based on an ITO-integrated tunable directional coupler

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Soo; Kim, Jin Tae

    2016-02-01

    Indium-tin-oxide (ITO) has attracted great attention because of its electrically-induced epsilon-near-zero (ENZ) characteristics, which has allowed us to develop electro-absorption optical modulators. As an extended application of ITO in a silicon optical modulator, we propose a silicon electro-optic modulator based on an ITO-integrated tunable directional coupler. An ITO block placed at the center of the two-core silicon directional coupler plays a key role in attenuating the optical power of the guided modes. Strong confinement of the optical field at the ENZ layer of ITO with the nonzero imaginary part of ITO’s permittivity let the guiding light experience high absorption as it propagates along the directional coupler. Numerical simulations reveal that the highest modulation depth of 5 dB is achievable at the ENZ region of ITO at a 1.55 μm wavelength. We can modulate the optical signals on an entire C-band ranging from a 1.530 to 1.565 μm wavelength with an on/off extinction ratio of larger than 4.6 dB.

  17. Advanced photovoltaic power systems using tandem GaAs/GaSb concentrator modules

    NASA Technical Reports Server (NTRS)

    Fraas, L. M.; Kuryla, M. S.; Pietila, D. A.; Sundaram, V. S.; Gruenbaum, P. E.; Avery, J. E.; Dihn, V.; Ballantyne, R.; Samuel, C.

    1992-01-01

    In 1989, Boeing announced the fabrication of a tandem gallium concentrator solar cell with an energy conversion efficiency of 30 percent. This research breakthrough has now led to panels which are significantly smaller, lighter, more radiation resistant, and potentially less expensive than the traditional silicon flat plate electric power supply. The new Boeing tandem concentrator (BTC) module uses an array of lightweight silicone Fresnel lenses mounted on the front side of a light weight aluminum honeycomb structure to focus sunlight onto small area solar cells mounted on a thin back plane. This module design is shown schematically. The tandem solar cell in this new module consists of a gallium arsenide light sensitive cell with a 24 percent energy conversion efficiency stacked on top of a gallium antimonide infrared sensitive cell with a conversion efficiency of 6 percent. This gives a total efficiency 30 percent for the cell-stack. The lens optical efficiency is typically 85 percent. Discounting for efficiency losses associated with lens packing, cell wiring, and cell operating temperature still allows for a module efficiency of 22 percent which leads to a module power density of 300 Watts/sq. m. This performance provides more than twice the power density available from a single crystal silicon flat plate module and at least four times the power density available from amorphous silicon modules. The fact that the lenses are only 0.010 ft. thick and the aluminum foil back plane is only 0.003 ft. thick leads to a very lightweight module. Although the cells are an easy to handle thickness of 0.020 ft., the fact that they are small, occupying one-twenty-fifth of the module area, means that they add little to the module weight. After summing all the module weights and given the high module power, we find that we are able to fabricate BTC modules with specific power of 100 watts/kg.

  18. A band-modulation device in advanced FDSOI technology: Sharp switching characteristics

    NASA Astrophysics Data System (ADS)

    El Dirani, Hassan; Solaro, Yohann; Fonteneau, Pascal; Legrand, Charles-Alex; Marin-Cudraz, David; Golanski, Dominique; Ferrari, Philippe; Cristoloveanu, Sorin

    2016-11-01

    A band-modulation device is demonstrated experimentally in advanced FDSOI (Fully Depleted SOI). The Z2-FET (Zero Impact Ionization and Zero Subthreshold Slope FET) is a very recent sharp switching device which achieves remarkable performance in terms of leakage current and triggering control. The device is fabricated with Ultra-Thin Body and Buried Oxide (UTBB) Silicon-On-Insulator (SOI) technology, features an extremely sharp on-switch, low leakage and an adjustable triggering voltage (VON). The Z2-FET operation relies on the modulation of electrons and holes injection barriers. In this paper, we show, for the first time, experimental data obtained with the most advanced FDSOI node.

  19. Fast optical frequency sweeping using voltage controlled oscillator driven single sideband modulation combined with injection locking.

    PubMed

    Wang, Jian; Chen, Dijun; Cai, Haiwen; Wei, Fang; Qu, Ronghui

    2015-03-23

    An ultrafast optical frequency sweeping technique for narrow linewidth lasers is reported. This technique exploits the large frequency modulation bandwidth of a wideband voltage controlled oscillator (VCO) and a high speed electro-optic dual parallel Mach-Zehnder modulator (DPMZM) which works on the state of carrier suppressed single sideband modulation(CS-SSB). Optical frequency sweeping of a narrow linewidth fiber laser with 3.85 GHz sweeping range and 80 GHz/μs tuning speed is demonstrated, which is an extremely high tuning speed for frequency sweeping of narrow linewidth lasers. In addition, injection locking technique is adopted to improve the sweeper's low optical power output and small side-mode suppression ratio (SMSR). PMID:25837048

  20. Direct Conversion of Free Space Millimeter Waves to Optical Domain by Plasmonic Modulator Antenna.

    PubMed

    Salamin, Yannick; Heni, Wolfgang; Haffner, Christian; Fedoryshyn, Yuriy; Hoessbacher, Claudia; Bonjour, Romain; Zahner, Marco; Hillerkuss, David; Leuchtmann, Pascal; Elder, Delwin L; Dalton, Larry R; Hafner, Christian; Leuthold, Juerg

    2015-12-01

    A scheme for the direct conversion of millimeter and THz waves to optical signals is introduced. The compact device consists of a plasmonic phase modulator that is seamlessly cointegrated with an antenna. Neither high-speed electronics nor electronic amplification is required to drive the modulator. A built-in enhancement of the electric field by a factor of 35,000 enables the direct conversion of millimeter-wave signals to the optical domain. This high enhancement is obtained via a resonant antenna that is directly coupled to an optical field by means of a plasmonic modulator. The suggested concept provides a simple and cost-efficient alternative solution to conventional schemes where millimeter-wave signals are first converted to the electrical domain before being up-converted to the optical domain.

  1. Optical-biased modulator employing a single silicon micro-ring resonator

    NASA Astrophysics Data System (ADS)

    Yan, Siqi; Dong, Jianji; Zheng, Aoling; Yu, Yuan

    2016-06-01

    We propose and experimentally demonstrate an optical-biased modulator employing a single silicon micro-ring resonator. By adjusting optical bias, the micro-ring modulator is capable of generating several modulation formats, namely, on-off keying, binary phase shift keying and reversed on-off keying, at the speed of 0.4 Gbit/s with extinction ratio higher than 5 dB. Compared to the previous reported bias control approaches, the optical bias proposed in this study is a novel mechanism, which can be easily conducted without complicated integrated structures or redundant electrical devices. Meanwhile, optical bias can also effectively protect the vulnerable integrated silicon devices from possible damage induced by high direct current voltage.

  2. Note: Laser frequency shifting by using two novel triple-pass acousto-optic modulator configurations

    SciTech Connect

    Carlos-Lopez, E. de; Lopez, J. M.; Lopez, S.; Espinosa, M. G.; Lizama, L. A.

    2012-11-15

    We report the design of two novel triple-pass acousto-optic modulator systems. These designs are extensions of the well known acousto-optic modulator (AOM) double-pass configuration, which eliminates the angle dependence of the diffracted beam with respect to the modulation frequency. In a triple-pass system, however, the frequency dependence of the angle does not disappear but the frequency shift is larger, spanning 3 times the AOM central frequency. In some applications, such as optically pumped Cesium-beam frequency standards, the frequencies of the two laser beams remain fixed and a triple-pass optical system can be used to reduce to one the number of lasers used in such atomic clocks. The two triple-pass configurations use either a retro-reflecting mirror, or a right angle prism to pass for third time the laser beam through the AOM, obtaining diffraction efficiencies of about 27% and 44%, respectively.

  3. Note: laser frequency shifting by using two novel triple-pass acousto-optic modulator configurations.

    PubMed

    de Carlos-López, E; López, J M; López, S; Espinosa, M G; Lizama, L A

    2012-11-01

    We report the design of two novel triple-pass acousto-optic modulator systems. These designs are extensions of the well known acousto-optic modulator (AOM) double-pass configuration, which eliminates the angle dependence of the diffracted beam with respect to the modulation frequency. In a triple-pass system, however, the frequency dependence of the angle does not disappear but the frequency shift is larger, spanning 3 times the AOM central frequency. In some applications, such as optically pumped Cesium-beam frequency standards, the frequencies of the two laser beams remain fixed and a triple-pass optical system can be used to reduce to one the number of lasers used in such atomic clocks. The two triple-pass configurations use either a retro-reflecting mirror, or a right angle prism to pass for third time the laser beam through the AOM, obtaining diffraction efficiencies of about 27% and 44%, respectively. PMID:23206109

  4. Direct Conversion of Free Space Millimeter Waves to Optical Domain by Plasmonic Modulator Antenna

    PubMed Central

    2015-01-01

    A scheme for the direct conversion of millimeter and THz waves to optical signals is introduced. The compact device consists of a plasmonic phase modulator that is seamlessly cointegrated with an antenna. Neither high-speed electronics nor electronic amplification is required to drive the modulator. A built-in enhancement of the electric field by a factor of 35 000 enables the direct conversion of millimeter-wave signals to the optical domain. This high enhancement is obtained via a resonant antenna that is directly coupled to an optical field by means of a plasmonic modulator. The suggested concept provides a simple and cost-efficient alternative solution to conventional schemes where millimeter-wave signals are first converted to the electrical domain before being up-converted to the optical domain. PMID:26570995

  5. Actively mode-locked fiber ring laser by intermodal acousto-optic modulation.

    PubMed

    Bello-Jiménez, M; Cuadrado-Laborde, C; Sáez-Rodríguez, D; Diez, A; Cruz, J L; Andrés, M V

    2010-11-15

    We report an actively mode-locked fiber ring laser. A simple and low-insertion-loss acousto-optic modulator driven by standing flexural waves, which couples core-to-cladding modes in a standard single-mode optical fiber, is used as an active mechanism for mode locking. Among the remarkable features of the modulator, we mention its high modulation depth (72%), broad bandwidth (187 GHz), easy tunability in the optical wavelength, and low insertion losses (0.7 dB). The narrowest optical pulses obtained were of 95 ps time width, 21 mW peak power, repetition rate of 4.758 MHz, and 110 mW of pump power.

  6. Electrically tunable metasurface perfect absorbers for ultrathin mid-infrared optical modulators.

    PubMed

    Yao, Yu; Shankar, Raji; Kats, Mikhail A; Song, Yi; Kong, Jing; Loncar, Marko; Capasso, Federico

    2014-11-12

    Dynamically reconfigurable metasurfaces open up unprecedented opportunities in applications such as high capacity communications, dynamic beam shaping, hyperspectral imaging, and adaptive optics. The realization of high performance metasurface-based devices remains a great challenge due to very limited tuning ranges and modulation depths. Here we show that a widely tunable metasurface composed of optical antennas on graphene can be incorporated into a subwavelength-thick optical cavity to create an electrically tunable perfect absorber. By switching the absorber in and out of the critical coupling condition via the gate voltage applied on graphene, a modulation depth of up to 100% can be achieved. In particular, we demonstrated ultrathin (thickness < λ0/10) high speed (up to 20 GHz) optical modulators over a broad wavelength range (5-7 μm). The operating wavelength can be scaled from the near-infrared to the terahertz by simply tailoring the metasurface and cavity dimensions. PMID:25310847

  7. UWB doublet signal generation and modulation based on DFB laser under optical pulses injection

    NASA Astrophysics Data System (ADS)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Zhou, Hua; Zhao, Jiyong; Huang, Long; Zhu, Huatao; Wang, Peng

    2016-05-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) doublet signals based on the cross-gain modulation (XGM) effect in the DFB lasers is proposed and experimentally demonstrated, the modulation and transmission of the generated UWB doublet signals are also researched. In the proposed system, a gain-switched laser (GSL) is used as a master laser (ML) and the optical pulses from the ML are optically injected into two paralleled DFB lasers, which are used as slave lasers (SL). Then the outputs from the SLs are detected by a balanced photodiode (BPD) to generate the Bi-phased UWB signals. By properly setting the system parameters, UWB signals with various modulation formats such as on-off keying (OOK), pulse amplitude modulation (PAM) as well as the phase-shift keying (PSK) can be generated. In addition, fiber transmission of the modulated UWB signals is also experimentally investigated.

  8. 200Gb/s 10-channel miniature optical interconnect transmitter module for high-performance computing (HPC)

    NASA Astrophysics Data System (ADS)

    Mohammed, Edris; Au, Hinmeng

    2010-02-01

    A major breakthrough to alleviating the interconnect bottleneck in intra cabinet system in HPC may happen by bringing optics directly to the processor package. In order to do so efficient and compact optical interconnect subassembly modules that utilize simple optical and electrical interfacing schemes are needed. In our current work the development of a novel 10-channel, miniature 7mm(W)x1.8mm(L)x3mm(H), optical interconnect transmitter subassembly module is described. The module consists of a high precision molded optical alignment unit with integrated microlens arrays, highspeed coplanar waveguide (CPW) electrical interfaces and a VCSEL (Vertical Cavity Surface Emitting Laser) array chip which is flip chip mounted. The module is designed to uniquely interface vertically with high-speed electrical I/O lines on a microprocessor style package or a motherboard to convert electrical signals to optical for transmission to other similar units using a standard (Multi-Terminal) MT style optical connector. We report on optical coupling efficiency, misalignment tolerance and high-speed electrical and optical measurements of the module. We have measured 40Gb/s electrical eye for the CPW interfaces on the module and 20Gb/s clear optical eyes for VCSEL assembled module from all the 10 channels to produce an aggregate transmitter bandwidth of 200Gb/s. We also measured 30Gb/s electrical and 20Gb/s optical eyes for the optical subassembly module that is bonded onto a microprocessor style package substrate.

  9. Inside Single Cells: Quantitative Analysis with Advanced Optics and Nanomaterials

    PubMed Central

    Cui, Yi; Irudayaraj, Joseph

    2014-01-01

    Single cell explorations offer a unique window to inspect molecules and events relevant to mechanisms and heterogeneity constituting the central dogma of biology. A large number of nucleic acids, proteins, metabolites and small molecules are involved in determining and fine-tuning the state and function of a single cell at a given time point. Advanced optical platforms and nanotools provide tremendous opportunities to probe intracellular components with single-molecule accuracy, as well as promising tools to adjust single cell activity. In order to obtain quantitative information (e.g. molecular quantity, kinetics and stoichiometry) within an intact cell, achieving the observation with comparable spatiotemporal resolution is a challenge. For single cell studies both the method of detection and the biocompatibility are critical factors as they determine the feasibility, especially when considering live cell analysis. Although a considerable proportion of single cell methodologies depend on specialized expertise and expensive instruments, it is our expectation that the information content and implication will outweigh the costs given the impact on life science enabled by single cell analysis. PMID:25430077

  10. DSA hole defectivity analysis using advanced optical inspection tool

    NASA Astrophysics Data System (ADS)

    Harukawa, Ryota; Aoki, Masami; Cross, Andrew; Nagaswami, Venkat; Tomita, Tadatoshi; Nagahara, Seiji; Muramatsu, Makoto; Kawakami, Shinichiro; Kosugi, Hitoshi; Rathsack, Benjamen; Kitano, Takahiro; Sweis, Jason; Mokhberi, Ali

    2013-04-01

    This paper discusses the defect density detection and analysis methodology using advanced optical wafer inspection capability to enable accelerated development of a DSA process/process tools and the required inspection capability to monitor such a process. The defectivity inspection methodologies are optimized for grapho epitaxy directed self-assembly (DSA) contact holes with 25 nm sizes. A defect test reticle with programmed defects on guide patterns is designed for improved optimization of defectivity monitoring. Using this reticle, resist guide holes with a variety of sizes and shapes are patterned using an ArF immersion scanner. The negative tone development (NTD) type thermally stable resist guide is used for DSA of a polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymer (BCP). Using a variety of defects intentionally made by changing guide pattern sizes, the detection rates of each specific defectivity type has been analyzed. It is found in this work that to maximize sensitivity, a two pass scan with bright field (BF) and dark field (DF) modes provides the best overall defect type coverage and sensitivity. The performance of the two pass scan with BF and DF modes is also revealed by defect analysis for baseline defectivity on a wafer processed with nominal process conditions.

  11. Laterally vibrating resonator based elasto-optic modulation in aluminum nitride

    NASA Astrophysics Data System (ADS)

    Ghosh, Siddhartha; Piazza, Gianluca

    2016-06-01

    An integrated strain-based optical modulator driven by a piezoelectric laterally vibrating resonator is demonstrated. The composite structure consists of an acoustic Lamb wave resonator, in which a photonic racetrack resonator is internally embedded to enable overlap of the guided optical mode with the induced strain field. Both types of resonators are defined in an aluminum nitride (AlN) thin film, which rests upon a layer of silicon dioxide in order to simultaneously define optical waveguides, and the structure is released from a silicon substrate. Lateral vibrations produced by the acoustic resonator are transferred through a partially etched layer of AlN, producing a change in the effective index of the guided wave through the interaction of the strain components with the AlN elasto-optic (p) coefficients. Optical modulation through the elasto-optic effect is demonstrated at electromechanically actuated frequencies of 173 MHz and 843 MHz. This device geometry further enables the development of MEMS-based optical modulators in addition to studying elasto-optic interactions in suspended piezoelectric thin films.

  12. Smart adaptive optic systems using spatial light modulators.

    PubMed

    Clark, N; Banish, M; Ranganath, H S

    1999-01-01

    Many factors contribute to the aberrations induced in an optical system. Atmospheric turbulence between the object and the imaging system, physical or thermal perturbations in optical elements degrade the system's point spread function, and misaligned optics are the primary sources of aberrations that affect image quality. The design of a nonconventional real-time adaptive optic system using a micro-mirror device for wavefront correction is presented. The unconventional compensated imaging system presented offers advantages in speed, cost, power consumption, and weight. A pulsed-coupled neural network is used to as a preprocessor to enhance the performance of the wavefront sensor for low-light applications. Modeling results that characterize the system performance are presented. PMID:18252558

  13. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes.

    PubMed

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L; Chekulaev, Dimitri; Canham, Leigh T; Kaplan, Andre

    2016-01-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm(2)). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications. PMID:27440224

  14. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes.

    PubMed

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L; Chekulaev, Dimitri; Canham, Leigh T; Kaplan, Andre

    2016-07-21

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm(2)). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications.

  15. Atomic-layer molybdenum sulfide optical modulator for visible coherent light

    PubMed Central

    Zhang, Yuxia; Wang, Shuxian; Yu, Haohai; Zhang, Huaijin; Chen, Yanxue; Mei, Liangmo; Di Lieto, Alberto; Tonelli, Mauro; Wang, Jiyang

    2015-01-01

    Coherent light sources in the visible range are playing important roles in our daily life and modern technology, since about 50% of the capability of the our human brains is devoted to processing visual information. Visible lasers can be achieved by nonlinear optical process of infrared lasers and direct lasing of gain materials, and the latter has advantages in the aspects of compactness, efficiency, simplicity, etc. However, due to lack of visible optical modulators, the directly generated visible lasers with only a gain material are constrained in continuous-wave operation. Here, we demonstrated the fabrication of a visible optical modulator and pulsed visible lasers based on atomic-layer molybdenum sulfide (MoS2), a ultrathin two-dimensional material with about 9–10 layers. By employing the nonlinear absorption of the modulator, the pulsed orange, red and deep red lasers were directly generated. Besides, the present atomic-layer MoS2 optical modulator has broadband modulating properties and advantages in the simple preparation process. The present results experimentally verify the theoretical prediction for the low-dimensional optoelectronic modulating devices in the visible wavelength region and may open an attractive avenue for removing a stumbling block for the further development of pulsed visible lasers. PMID:26067821

  16. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes

    PubMed Central

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L.; Chekulaev, Dimitri; Canham, Leigh T.; Kaplan, Andre

    2016-01-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm2). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications. PMID:27440224

  17. All-optical modulation in Mid-Wavelength Infrared using porous Si membranes

    NASA Astrophysics Data System (ADS)

    Park, Sung Jin; Zakar, Ammar; Zerova, Vera L.; Chekulaev, Dimitri; Canham, Leigh T.; Kaplan, Andre

    2016-07-01

    We demonstrate for the first time the possibility of all-optical modulation of self-standing porous Silicon (pSi) membrane in the Mid-Wavelength Infrared (MWIR) range using femtosecond pump-probe techniques. To study optical modulation, we used pulses of an 800 nm, 60 femtosecond for pump and a MWIR tunable probe in the spectral range between 3.5 and 4.4 μm. We show that pSi possesses a natural transparency window centred around 4 μm. Yet, about 55% of modulation contrast can be achieved by means of optical excitation at the pump power of 60 mW (4.8 mJ/cm2). Our analysis shows that the main mechanism of the modulation is interaction of the MWIR signal with the free charge carrier excited by the pump. The time-resolved measurements showed a sub-picosecond rise time and a recovery time of about 66 ps, which suggests a modulation speed performance of ~15 GHz. This optical modulation of pSi membrane in MWIR can be applied to a variety of applications such as thermal imaging and free space communications.

  18. James Webb Space Telescope optical telescope element/integrated science instrument module (OTIS) status

    NASA Astrophysics Data System (ADS)

    Feinberg, Lee; Voyon, Mark; Lander, Juli; Keski-Kuha, Ritva; Matthews, Gary

    2016-07-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirror center of curvature optical tests, electrical and operational tests, acoustics and vibration testing at the Goddard Space Flight Center before being shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparation for the cryogenic optical testing, the JWST project has built a Pathfinder telescope and has completed two Optical Ground System Equipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize optical test results to date and status the final Pathfinder test and the OTIS integration and environmental test preparations.

  19. James Webb Space Telescope Optical Telescope Element/Integrated Science Instrument Module (OTIS) Status

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Voyton, Mark; Lander, Juli; Keski-Kuha, Ritva; Matthews, Gary

    2016-01-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirror center of curvature optical tests, electrical and operational tests, acoustics and vibration testing at the Goddard Space Flight Center before being shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparation for the cryogenic optical testing, the JWST project has built a Pathfinder telescope and has completed two Optical Ground System Equipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize optical test results to date and status the final Pathfinder test and the OTIS integration and environmental test preparations

  20. Laser modulation of optical absorption in ZnSe

    NASA Technical Reports Server (NTRS)

    Major, R. W.

    1971-01-01

    The possibility of producing and detecting laser induced modulation of absorption (LIMA) in ZnSe crystals using a moderate laser intensity of about 6 mw output was investigated. The modulation is smaller than that previously obtained with higher laser photon flux, but is not too difficult to detect. Modulation of the order of a few parts in 10 to the 5th power, up to one part in 10 to the 4th power appears typical at the present. LIMA pulse shapes were recorded with varying system resolutions at a half dozen wavelengths in the visible, from 4800 A to 6000 A. Detailed data were taken, particularly at 5000 A, for a range of time intervals following laser pulse turn-on. Quantitative study of the excitation and decay kinetics of these is underway, though analysis is not complete. Major features are discussed with attention centered upon the detailed measurements made most recently at 5000 A.

  1. Magneto-optic transmittance modulation observed in a hybrid graphene-split ring resonator terahertz metasurface

    NASA Astrophysics Data System (ADS)

    Zanotto, Simone; Lange, Christoph; Maag, Thomas; Pitanti, Alessandro; Miseikis, Vaidotas; Coletti, Camilla; Degl'Innocenti, Riccardo; Baldacci, Lorenzo; Huber, Rupert; Tredicucci, Alessandro

    2015-09-01

    By placing a material in close vicinity of a resonant optical element, its intrinsic optical response can be tuned, possibly to a wide extent. Here, we show that a graphene monolayer, spaced a few tenths of nanometers from a split ring resonator metasurface, exhibits a magneto-optical response which is strongly influenced by the presence of the metasurface itself. This hybrid system holds promises in view of thin optical modulators, polarization rotators, and nonreciprocal devices, in the technologically relevant terahertz spectral range. Moreover, it could be chosen as the playground for investigating the cavity electrodynamics of Dirac fermions in the quantum regime.

  2. Magneto-optic transmittance modulation observed in a hybrid graphene–split ring resonator terahertz metasurface

    SciTech Connect

    Zanotto, Simone; Pitanti, Alessandro; Lange, Christoph; Maag, Thomas; Huber, Rupert; Miseikis, Vaidotas; Coletti, Camilla; Degl'Innocenti, Riccardo; Baldacci, Lorenzo; Tredicucci, Alessandro

    2015-09-21

    By placing a material in close vicinity of a resonant optical element, its intrinsic optical response can be tuned, possibly to a wide extent. Here, we show that a graphene monolayer, spaced a few tenths of nanometers from a split ring resonator metasurface, exhibits a magneto-optical response which is strongly influenced by the presence of the metasurface itself. This hybrid system holds promises in view of thin optical modulators, polarization rotators, and nonreciprocal devices, in the technologically relevant terahertz spectral range. Moreover, it could be chosen as the playground for investigating the cavity electrodynamics of Dirac fermions in the quantum regime.

  3. Integration of Optical Manipulation and Electrophysiological Tools to Modulate and Record Activity in Neural Networks

    NASA Astrophysics Data System (ADS)

    Difato, F.; Schibalsky, L.; Benfenati, F.; Blau, A.

    2011-07-01

    We present an optical system that combines IR (1064 nm) holographic optical tweezers with a sub-nanosecond-pulsed UV (355 nm) laser microdissector for the optical manipulation of single neurons and entire networks both on transparent and non-transparent substrates in vitro. The phase-modulated laser beam can illuminate the sample concurrently or independently from above or below assuring compatibility with different types of microelectrode array and patch-clamp electrophysiology. By combining electrophysiological and optical tools, neural activity in response to localized stimuli or injury can be studied and quantified at sub-cellular, cellular, and network level.

  4. Dynamic photophoresis-based optical trapping using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Porfirev, Aleksey P.; Skidanov, Roman V.

    2016-04-01

    We investigate optical trapping light-absorbing particles in the air employing photophoretic forces with optical tweezers generated by a spatial light modulator (SLM). SLM gives us the opportunity to form optical tweezers for multiple trapping in several planes. We investigate the possibility of using lenses with various focal lengths for trapping light-absorbing microparticles with the SLM. We used lenses with a large focal length and a large depth of focus. The results shown in this paper could be useful in various applications of optics and biology.

  5. Parallel lensless optical correlator based on two phase-only spatial light modulators.

    PubMed

    Zeng, Xu; Inoue, Takashi; Fukuchi, Norihiro; Bai, Jian

    2011-06-20

    In this paper, we proposed a parallel phase-only lensless optical correlator based on two pieces of Liquid Crystal on Silicon Spatial Light Modulators. Phase Fresnel Lens Array and specialized grating are implemented to realize multi-channel and multiplexed LOC. Experimental results of Chinese characters' recognitions are given as demonstration of proposed technique. High uniformity of processing channels has been verified by autocorrelation process of four same Chinese characters. The technique is programmable and adjustment of optical path could be realized without changing of optical setup. The implementations could be performed on the same configuration as single channel optical correlator without mechanical alternation. PMID:21716500

  6. A low power electro-optic polymer clad Mach-Zehnder modulator for high speed optical interconnects

    NASA Astrophysics Data System (ADS)

    Block, Bruce; Liff, Shawna; Kobrinsky, Mauro; Reshotko, Miriam; Tseng, Ricky; Ban, Ibrahim; Chang, Peter

    2013-02-01

    Electro-optic (EO) polymer cladding modulators are an option for low-power high-speed optical interconnects on a silicon platform. EO polymers have inherently high switching speeds and have shown 40 Gb/s operation in EO polymer clad ring resonator modulators (RRM). In EO polymer clad RRM, the modulator's area is small enough to be treated as a lumped capacitor; the capacitance is sufficiently low that the modulation speed is limited by the bandwidth of the resonator. A high Q resonator is needed for low voltage operation, but this can limit the speed and/or require precise control of the resonator's wavelength, necessitating power consuming heaters to maintain optimal performance over a large temperature range. Mach Zehnder modulators (MZM), on the other hand, are not as sensitive to temperature fluctuations, but typically are relatively long and must employ power consuming terminated travelling wave electrodes. In this paper, a novel MZM design is presented using an EO polymer clad device. In this device, the electrodes are broken into short parallel segments and the waveguide folds around them. The segments of the electrode length are designed to provide good signal integrity up to 20 GHz without termination. The electrodes are driven by a single drive voltage and provide push-pull modulation. Modulators were designed and fabricated using silicon nitride waveguides on bulk silicon wafers and were demonstrated at high speed (20 GHz). A VπL as low as 1.7 Vcm is measured on initial devices. An optimized device could provide 40 Gb/s performance at 1 V drive voltages, ~100 fF total device capacitance and less than 2 dB optical insertion loss.

  7. Radio over fiber transceiver employing phase modulation of an optical broadband source.

    PubMed

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2010-10-11

    This paper proposes a low-cost RoF transceiver for multichannel SCM/WDM signal distribution suitable for future broadband access networks. The transceiver is based on the phase modulation of an optical broadband source centered at third transmission window. Prior to phase modulation the optical broadband source output signal is launched into a Mach-Zehnder interferometer structure, as key device enabling radio signals propagation over the optical link. Furthermore, an optical CWDM is employed to create a multichannel scenario by performing the spectral slicing of the modulated optical signal into a number of channels each one conveying the information from the central office to different base stations. The operation range is up to 20 GHz with a modulation bandwidth around of 500 MHz. Experimental results of the transmission of SCM QPSK and 64-QAM data through 20 Km of SMF exhibit good EVM results in the operative range determined by the phase-to-intensity conversion process. The proposed approach shows a great suitability for WDM networks based on RoF signal transport and also represents a cost-effective solution for passive optical networks. PMID:20941075

  8. Ex vivo blood vessel imaging using ultrasound-modulated optical microscopy

    PubMed Central

    Kothapalli, Sri-Rajasekhar; Wang, Lihong V.

    2009-01-01

    Recently we developed ultrasound-modulated optical microscopy (UOM) based on a long-cavity confocal Fabry-Perot interferometer (CFPI) [J. Biomed. Opt. 13(5), 0504046, (2008)]. This interferometer is used for real time detection of multiply scattered light modulated by high frequency (30 MHz to 75 MHz) ultrasound pulses propagating in an optically strongly scattering medium. In this article, we use this microscope to study the dependence of ultrasound-modulated optical signals on the optical absorption and scattering properties of objects embedded about 3 mm deep in tissue mimicking phantoms. These results demonstrate that UOM has the potential to map both optical absorption and scattering contrast. Most importantly, for the first time in the field of ultrasound-modulated optical imaging, we imaged blood vasculature in highly scattering tissue samples from a mouse and a rat. Therefore UOM could be a promising tool to study the morphology of blood vasculature and blood-associated functional parameters, such as oxygen saturation. PMID:19256703

  9. Development of optical modulators for measurements of solar magnetic fields

    NASA Technical Reports Server (NTRS)

    West, E. A.; Smith, J. E.

    1987-01-01

    The measurement of polarized light allows solar astronomers to infer the magnetic field on the Sun. The accuracy of these measurements is dependent on the stable retardation characteristics of the polarization modulators used to minimize the atmospheric effects seen in ground-based observations. This report describes the work by the Space Science Laboratory at Marshall Space Flight Center to improve two types of polarization modulators. As a result, the timing characteristics for both electrooptic crystals (KD*Ps) and liquid crystal devices (LCDs) have been studied and will be used to enhance the capabilities of the MSFC Vector Magnetograph.

  10. Travel and Tourism Module. An Advanced-Level Option For Distribution and Marketing.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Occupational Education Curriculum Development.

    Intended as an advanced option for distributive education students in the twelfth grade, this travel and tourism module is designed to cover a minimum of ten weeks or a maximum of twenty weeks. Introductory material includes information on employment demands, administrative considerations, course format, teaching suggestions, expected outcomes,…

  11. Project T.E.A.M. (Technical Education Advancement Modules). Introduction to Computers.

    ERIC Educational Resources Information Center

    Ellis, Brenda

    This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 3-hour introduction to computers. The purpose is to develop the following competencies: (1) orientation to data processing; (2) use of data entry devices; (3) use of computer menus; and (4) entry of data with accuracy and…

  12. Project T.E.A.M. (Technical Education Advancement Modules). Introduction to Industrial Physics.

    ERIC Educational Resources Information Center

    Whisenhunt, James E.

    This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 20-hour introduction to industrial physics that explains and demonstrates to industrial maintenance mechanics the direct relationship of physics to machinery. Project TEAM is intended to upgrade basic technical competencies of…

  13. Alignment and integration of thin, lightweight x-ray optics into modules

    NASA Astrophysics Data System (ADS)

    Biskach, Michael P.; Chan, Kai-Wing; Mazzarella, James R.; McClelland, Ryan S.; Saha, Timo T.; Schofield, Mark J.; Zhang, William W.

    2014-07-01

    Future X-ray telescopes with high angular resolution and high throughput optics will help enable new high energy observations. X-ray optics in development at NASA Goddard Space Flight Center by the Next Generation X-ray Optics (NGXO) group utilizes a Flight Mirror Assembly (FMA) comprised of dozens of mirror modules populated with mirror segments aligned to a common focus. Mirror segments are currently aligned and permanently fixed into a module one at a time with emphasis on preventing degradation of the overall module performance. To meet cost and schedule requirements, parallelization and automation of the module integration process must be implemented. Identification of critical mirror segment alignment factors in addition to the progress towards a robust and automated module integration process is presented. There is a fundamental need for a reliable mirror segment alignment and bonding process that will be performed on hundreds or thousands of mirror segments. Results from module X-ray performance verification tests are presented to confirm module performance meets requirements.

  14. Integrating the Advanced Human Eye Model (AHEM) and optical instrument models to model complete visual optical systems inclusive of the typical or atypical eye

    NASA Astrophysics Data System (ADS)

    Donnelly, William J., III

    2012-06-01

    PURPOSE: To present a commercially available optical modeling software tool to assist the development of optical instrumentation and systems that utilize and/or integrate with the human eye. METHODS: A commercially available flexible eye modeling system is presented, the Advanced Human Eye Model (AHEM). AHEM is a module that the engineer can use to perform rapid development and test scenarios on systems that integrate with the eye. Methods include merging modeled systems initially developed outside of AHEM and performing a series of wizard-type operations that relieve the user from requiring an optometric or ophthalmic background to produce a complete eye inclusive system. Scenarios consist of retinal imaging of targets and sources through integrated systems. Uses include, but are not limited to, optimization, telescopes, microscopes, spectacles, contact and intraocular lenses, ocular aberrations, cataract simulation and scattering, and twin eye model (binocular) systems. RESULTS: Metrics, graphical data, and exportable CAD geometry are generated from the various modeling scenarios.

  15. Modeling of Millimeter-Wave Modulation Characteristics of Semiconductor Lasers under Strong Optical Feedback

    PubMed Central

    Bakry, Ahmed

    2014-01-01

    This paper presents modeling and simulation on the characteristics of semiconductor laser modulated within a strong optical feedback (OFB-)induced photon-photon resonance over a passband of millimeter (mm) frequencies. Continuous wave (CW) operation of the laser under strong OFB is required to achieve the photon-photon resonance in the mm-wave band. The simulated time-domain characteristics of modulation include the waveforms of the intensity and frequency chirp as well as the associated distortions of the modulated mm-wave signal. The frequency domain characteristics include the intensity modulation (IM) and frequency modulation (FM) responses in addition to the associated relative intensity noise (RIN). The signal characteristics under modulations with both single and two mm-frequencies are considered. The harmonic distortion and the third order intermodulation distortion (IMD3) are examined and the spurious free dynamic range (SFDR) is calculated. PMID:25383381

  16. Impact of modulator chirp in 100 Gbps class optical discrete multi-tone transmission system

    NASA Astrophysics Data System (ADS)

    Nishihara, Masato; Tanaka, Toshiki; Takahara, Tomoo; Li, Lei; Tao, Zhenning; Rasmussen, Jens C.

    2012-12-01

    Discrete multi-tone (DMT) technology is an attractive modulation technique for short reach optical transmission system. One of the main factors that limit the performance of the 1.5-μm band DMT system is the interplay between the chromatic dispersion of the transmission fiber and the chirp characteristic of the transmitter. We experimentally measured and compared the chirp characteristics of various modulator configurations, which are lithium-niobate Mach-Zehnder modulator, directly modulated laser, and electro-absorption modulator, by the frequency discriminator method using MZ interferometer. We also measured and compared the transmission characteristics of the transmitters using above-mentioned modulators and discuss the suitable transmitter configuration for DMT technology.

  17. Two-tone intensity-modulated optical stimulus for self-referencing microwave characterization of high-speed photodetectors

    NASA Astrophysics Data System (ADS)

    Wang, Heng; Zhang, Shangjian; Zou, Xinhai; Zhang, Yali; Lu, Rongguo; Zhang, Zhiyao; Zhang, Xiaoxia; Liu, Yong

    2016-08-01

    The two-tone intensity modulated optical stimulus is proposed and demonstrated for measuring the high-frequency response of photodetectors. The method provides a narrow linewidth and wide bandwidth optical stimulus based on the two-tone modulation of a Mach-Zehnder electro-optical intensity modulator, and achieves the self-referenced measurement of photodetectors without the need for correcting the power variation of optical stimulus. Moreover, the two-tone intensity modulation method allows bias-independent measurement with doubled measuring frequency range. In the experiment, the consistency between our method and the conventional methods verifies the simple but accurate measurement.

  18. Experimental characterization, evaluation, and diagnosis of advanced hybrid infrared focal plane array electro-optical performance

    NASA Astrophysics Data System (ADS)

    Lomheim, Terrence S.; Schumann, Lee W.; Kohn, Stanley E.

    1998-07-01

    High performance scanning time-delay-and-integration and staring hybrid focal plane devices with very large formats, small pixel sizes, formidable frame and line rates, on-chip digital programmability, and high dynamic ranges, are being developed for a myriad of defense, civil, and commercial applications that span the spectral range from shortwave infrared (SWIR) to longwave infrared (LWIR). An essential part in the development of such new advanced hybrid infrared focal planes is empirical validation of their electro-optical (EO) performance. Many high-reliability, high-performance applications demand stringent and near flawless EO performance over a wide variety of operating conditions and environments. Verification of focal plane performance compliance over this wide range of parametric conditions requires the development and use of accurate, flexible, and statistically complete test methods and associated equipment. In this paper we review typical focal plane requirements, the ensuing measurement requirements (quantity, accuracy, repeatability, etc.), test methodologies, test equipment requirements, electronics and computer-based data acquisition requirements, statistical data analysis and display requirements, and associated issues. We also discuss special test requirements for verifying the performance of panchromatic thermal and multispectral imaging focal planes where characterization of dynamic modulation transfer function (MTF), and point-image response and optical overload is generally required. We briefly overview focal plane radiation testing. We conclude with a discussion of the technical challenges of characterizing future advanced hybrid focal plane testing where it is anticipated that analog-to- digital conversion will be included directly on focal plane devices, thus creating the scenario of 'photons-in-to-bits- out' within the focal plane itself.

  19. Ultrafast Radiation Detection by Modulation of an Optical Probe Beam

    SciTech Connect

    Vernon, S P; Lowry, M E

    2006-02-22

    We describe a new class of radiation sensor that utilizes optical interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor sensor medium. Radiation absorption in the sensor material produces a transient, non-equilibrium, electron-hole pair distribution that locally modifies the complex, optical refractive index of the sensor medium. Changes in the real (imaginary) part of the local refractive index produce a differential phase shift (absorption) of an optical probe used to interrogate the sensor material. In contrast to conventional radiation detectors where signal levels are proportional to the incident energy, signal levels in these optical sensors are proportional to the incident radiation energy flux. This allows for reduction of the sensor form factor with no degradation in detection sensitivity. Furthermore, since the radiation induced, non-equilibrium electron-hole pair distribution is effectively measured ''in place'' there is no requirement to spatially separate and collect the generated charges; consequently, the sensor risetime is of the order of the hot-electron thermalization time {le} 10 fs and the duration of the index perturbation is determined by the carrier recombination time which is of order {approx} 600 fs in, direct-bandgap semiconductors, with a high density of recombination defects; consequently, the optical sensors can be engineered with sub-ps temporal response. A series of detectors were designed, and incorporated into Mach Zehnder and Fabry-Perot interferometer-based detection systems: proof of concept, lower detection sensitivity, Mach-Zehnder detectors were characterized at beamline 6.3 at SSRL; three generations of high sensitivity single element and imaging Fabry-Perot detectors were measured at the LLNL Europa facility. Our results indicate that this technology can be used to provide x-ray detectors and x-ray imaging systems with single x-ray sensitivity and S/N {approx} 30 at x

  20. Potential roles of optical interconnections within broadband switching modules

    NASA Astrophysics Data System (ADS)

    Lalk, Gail R.; Habiby, Sarry F.; Hartman, Davis H.; Krchnavek, Robert R.; Wilson, Donald K.; Young, Kenneth C., Jr.

    1991-04-01

    An investigation of potential physical design bottlenecks in future broadband telecommunication switches has led to the identification of several areas where optical interconnections may play a role in the practical realization of required system performance. In the model used the speed and interconnection densities as well as requirements for ease-of-access and efficient power utilization challenge conventional partitioning and packaging strategies. Potential areas where optical interconnections may relieve some of the physical design bottlenecks include fiber management at the customer interface to the switch routing and distribution of high-density interconnections within the fabric of the switch and backplane interconnections to increase system throughput.

  1. Advanced Screencasting With Embedded Assessments in Pathophysiology and Therapeutics Course Modules

    PubMed Central

    Jensen, Megan; Loeffler, William; Avery, Lisa

    2014-01-01

    Objective. To implement and assess the effectiveness of a hybrid learning model using advanced screencasting with embedded assessments in pathophysiology and therapeutics modules. Design. Two pathophysiology and therapeutics course modules on viral hepatitis and the clinical pharmacokinetics of aminoglycosides were chosen for study. The preclass portion of the hybrid model involved student completion of interactive e-lectures that were created with the use of advanced screencasting and included embedded assessments. Students viewed the e-lectures and completed the assessment questions prior to in-class lecture. Assessment. Preimplementation and postimplementation test scores were compared and student survey data were analyzed. Test scores improved significantly and students’ perceptions of the learning method were favorable. Test scores improved most significantly on higher-level Bloom’s taxonomy questions. Conclusion. A hybrid model that used advanced screencasting with embedded assessments offered a novel method to afford students active-learning opportunities to progress to higher cognitive domains of learning. PMID:25147400

  2. Plasmonic/Nonlinear Optical Material Core/Shell Nanorods as Nanoscale Plasmon Modulators and Optical Voltage Sensors.

    PubMed

    Yin, Anxiang; He, Qiyuan; Lin, Zhaoyang; Luo, Liang; Liu, Yuan; Yang, Sen; Wu, Hao; Ding, Mengning; Huang, Yu; Duan, Xiangfeng

    2016-01-11

    Herein, we report the design and synthesis of plasmonic/non-linear optical (NLO) material core/shell nanostructures that can allow dynamic manipulation of light signals using an external electrical field and enable a new generation of nanoscale optical voltage sensors. We show that gold nanorods (Au NRs) can be synthesized with tunable plasmonic properties and function as the nucleation seeds for continued growth of a shell of NLO materials (such as polyaniline, PANI) with variable thickness. The formation of a PANI nanoshell allows dynamic modulation of the dielectric environment of the plasmonic Au NRs, and therefore the plasmonic resonance characteristics, by an external electrical field. The finite element simulation confirms that such modulation is originated from the field-induced modulation of the dielectric constant of the NLO shell. This approach is general, and the coating of the Au NRs with other NLO materials (such as barium titanate, BTO) is found to produce a similar effect. These findings can not only open a new pathway to active modulation of plasmonic resonance at the sub-wavelength scale but also enable the creation of a new generation of nanoscale optical voltage sensors (NOVS). PMID:26783058

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  4. Tunable Electro-optic modulators for lidar systems and atmospheric applications

    NASA Technical Reports Server (NTRS)

    Eng, R. S.; Harris, N. W.; Summers, C. L.; Lax, B.

    1992-01-01

    In global sensing applications using different types of lidars, the spectral range and fine frequency coverages are often limited because of the finite tunabilities of molecular lasers and the number of molecular species that are available. To overcome the above obstacle, we have proposed new broadband frequency tunable electro-optic (EO) modulators that can cover a wide range from the mid-infrared to the visible as lidar sources in atmospheric sensing applications such as high resolution atmospheric molecular spectroscopy, Differential Absorption Lidar (DIAL), and laser radar imaging. The configuration of the proposed new tunable EO modulators includes an electro-optic active crystal element surrounded by a ferrite tuning element which is placed inside a microwave waveguide. The tuning is provided by an external magnetic field, which is either longitudinal or transverse, and the modulator can be either single sideband type or a double sideband type depending on the application required for the spectral purity of the modulator output.

  5. Mode locking of an all-fiber laser by acousto-optic superlattice modulation.

    PubMed

    Cuadrado-Laborde, C; Diez, A; Delgado-Pinar, M; Cruz, J L; Andrés, M V

    2009-04-01

    Active mode locking of an erbium-doped all-fiber laser with a Bragg-grating-based acousto-optic modulator is demonstrated. The fiber Bragg grating was acoustically modulated by a standing longitudinal elastic wave, which periodically modulates the sidebands at twice the acoustic frequency. The laser has a Fabry-Perot configuration in which cavity loss modulation is achieved by tuning the output fiber Bragg grating to one of the acoustically induced sidebands. Optical pulses at 9 MHz repetition rate, 120 mW peak power, and 780 ps temporal width were obtained. The output results to be stable and has a timing jitter below 40 ps. The measured linewidth, 2.8 pm, demonstrates that these pulses are transform limited.

  6. Optical transfer cavity stabilization using current-modulated injection-locked diode lasers

    SciTech Connect

    Bohlouli-Zanjani, P.; Afrousheh, K.; Martin, J. D. D.

    2006-09-15

    It is demonstrated that rf current modulation of a frequency stabilized injection-locked diode laser allows the stabilization of an optical cavity to adjustable lengths, by variation of the rf frequency. This transfer cavity may be used to stabilize another laser at an arbitrary wavelength, in the absence of atomic or molecular transitions suitable for stabilization. Implementation involves equipment and techniques commonly used in laser cooling and trapping laboratories and does not require electro- or acousto-optic modulators. With this technique we stabilize a transfer cavity using a rf current-modulated diode laser which is injection locked to a 780 nm reference diode laser. The reference laser is stabilized using polarization spectroscopy in a Rb cell. A Ti:sapphire ring laser at 960 nm is locked to this transfer cavity and may be precisely scanned by varying the rf modulation frequency. We demonstrate the suitability of this system for the excitation of laser cooled Rb atoms to Rydberg states.

  7. Short optical pulse generation at 40 GHz with a bulk electro-absorption modulator packaged device

    NASA Astrophysics Data System (ADS)

    Langlois, Patrick; Moore, Ronald; Prosyk, Kelvin; O'Keefe, Sean; Oosterom, Jill A.; Betty, Ian; Foster, Robert; Greenspan, Jonathan; Singh, Priti

    2003-12-01

    Short optical pulse generation at 40GHz and 1540nm wavelength is achieved using fully packaged bulk quaternary electro-absorption modulator modules. Experimental results obtained with broadband and narrowband optimized packaged modules are presented and compared against empirical model predictions. Pulse duty cycle, extinction ratio and chirp are studied as a function of sinusoidal drive voltage and detuning between operating wavelength and modulator absorption band edge. Design rules and performance trade-offs are discussed. Low-chirp pulses with a FWHM of ~12ps and sub-4ps at a rate of 40GHz are demonstrated. Optical time-domain demultiplexing of a 40GHz to a 10GHz pulse train is also demonstrated with better than 20dB extinction ratio.

  8. Method And Apparatus For Coupling Optical Elements To Optoelectronic Devices For Manufacturing Optical Transceiver Modules

    SciTech Connect

    Anderson, Gene R.; Armendariz, Marcelino G.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; Giunta, Rachel Knudsen; Mitchell, Robert T.; McCormick, Frederick B.; Peterson, David W.; Rising, Merideth A.; Reber, Cathleen A.; Reysen, Bill H.

    2005-06-14

    A process is provided for aligning and connecting at least one optical fiber to at least one optoelectronic device so as to couple light between at least one optical fiber and at least one optoelectronic device. One embodiment of this process comprises the following steps: (1) holding at least one optical element close to at least one optoelectronic device, at least one optical element having at least a first end; (2) aligning at least one optical element with at least one optoelectronic device; (3) depositing a first non-opaque material on a first end of at least one optoelectronic device; and (4) bringing the first end of at least one optical element proximate to the first end of at least one optoelectronic device in such a manner that the first non-opaque material contacts the first end of at least one optoelectronic device and the first end of at least one optical element. The optical element may be an optical fiber, and the optoelectronic device may be a vertical cavity surface emitting laser. The first non-opaque material may be a UV optical adhesive that provides an optical path and mechanical stability. In another embodiment of the alignment process, the first end of at least one optical element is brought proximate to the first end of at least one optoelectronic device in such a manner that an interstitial space exists between the first end of at least one optoelectronic device and the first end of at least one optical element.

  9. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  10. Silicon rib waveguide electro-absorption optical modulator using transparent conductive oxide bilayer

    NASA Astrophysics Data System (ADS)

    Ayata, Masafumi; Nakano, Yoshiaki; Tanemura, Takuo

    2016-04-01

    We propose a novel ultra compact electro-absorption optical modulator based on a silicon rib waveguide and numerically demonstrate its performance. The proposed design employs two types of transparent conductive oxide (TCO) layers with different carrier densities to achieve both high modulation efficiency and low optical insertion loss. The thin TCO layer with high carrier density enables efficient modulation through the metal-oxide-semiconductor structure. On the other hand, the upper TCO layer with low carrier density allows low-resistance electrical contact for the top electrode without large optical loss. Using an indium tin oxide bilayer with optimized carrier densities, we numerically demonstrate a 4.3 dB extinction ratio and a 2.6 dB optical insertion loss with 1 µm device length. We estimate that the modulator operates under a low driving voltage of 1.3 V, exhibiting an ultra low energy consumption of 22.5 fJ/bit and a broad RC modulation bandwidth of over 40 GHz.

  11. Optically addressed and submillisecond response phase only liquid crystal spatial light modulator

    NASA Astrophysics Data System (ADS)

    Zhao, Xiangjie; Duan, Jiazhu; Zhang, Dayong; Luo, Yongquan

    2014-10-01

    Liquid crystal based phase only spatial light modulator has attracted many research interests since last decades because of its superior advantage. Until now the liquid crystal spatial light modulator has been applied in many fields, but the response speed of nematic LC limited its further application. In this paper, an optically addressed phase only LC spatial light modulator was proposed based on polymer network liquid crystal. Morphology effect on the light scattering of PNLC was studied, which was mainly consisted of fiber and fiber bundles. The morphology nearly determined the light scattering and electro-optical property. Due to the high threshold voltage, to address the PNLC phase modulator was also concerned. Optical addressing method was proposed, in which BSO crystal was selected to replace one of the glass substrate. The response speed of PNLC was so fast that the reorientation of liquid crystal director will follow the change of effective voltage applied on LC layer, which was related with the voltage signal and especially with electron transport of photo-induced carriers due to diffusion and drift. The on state dynamic response of phase change was investigated. Based on this device, beam steering was also achieved by loading 488nm laser strip on the optical addressed phase only spatial light modulator.

  12. Efficiency of various modulation types in Step Index Polymer Optical Fiber

    NASA Astrophysics Data System (ADS)

    Siuzdak, Jerzy; Stepniak, Grzegorz

    2014-11-01

    Efficiency of PAM, CAP/QAM and OFDM/DMT modulation for Step Index Polymer Optical Fiber channel is analyzed theoretically. It is shown that for the same transmitted optical power and same BER they offer similar data throughputs. However, when the light source has limited dynamics the crucial factor is the peak to average power ratio of the modulating signal. This is the greatest for OFDM/DMT and smaller for CAP and PAM. Consequently, the efficiency for PAM and CAP should be comparable whereas that of DMT - inferior. This conclusion was confirmed by experimental results.

  13. Response to dynamical modulation of the optical lattice for fermions in the Hubbard model

    SciTech Connect

    Xu Zhaoxin; Yang Shuxiang; Sheehy, Daniel E.; Moreno, Juana; Jarrell, Mark; Chiesa, Simone; Su Shiquan; Scalettar, Richard T.

    2011-08-15

    Fermionic atoms in a periodic optical lattice provide a realization of the single-band Hubbard model. Using quantum Monte Carlo simulations along with the maximum-entropy method, we evaluate the effect of a time-dependent perturbative modulation of the optical lattice amplitude on atomic correlations, revealed in the fraction of doubly occupied sites. We find that the effect of modulation depends strongly on the filling--the response of the double occupation is significantly different in the half-filled Mott insulator from that in the doped Fermi liquid region.

  14. Multiplexing of optical fiber sensors using a frequency-modulated source and gated output

    NASA Astrophysics Data System (ADS)

    Sakai, I.; Youngquist, R. C.; Parry, G.

    1987-07-01

    A novel method is proposed and demonstrated for multiplexing fiber-optic interferometric sensors using the FM CW technique. The method uses a gas laser whose optical frequency is modulated sinusoidally by an external modulator. The use of gating and appropriate signal processing can achieve low crosstalk between sensors. Experiments on two and three sensor systems are reported. The minimum detectable signal measured is 1 mrad/sq root Hz and the crosstalk factor achieved is -35 dB. The major causes of crosstalk are also analyzed.

  15. Amplification of frequency-modulated soliton-like pulses in inhomogeneous optical waveguides with normal dispersion

    NASA Astrophysics Data System (ADS)

    Zolotovskii, I. O.; Novikov, S. G.; Okhotnikov, O. G.; Sementsov, D. I.; Yavtushenko, I. O.; Yavtushenko, M. S.

    2012-06-01

    The possibility of effective amplification of self-similar frequency-modulated pulses (FMPs) in longitudinally inhomogeneous active optical waveguides is studied. Peculiarities of the dynamics of parabolic pulses with a constant frequency modulation rate are considered. An optimal profile of variation of the group velocity dispersion was obtained in correspondence with optimal amplification of a similariton-like pulse. The use of FMPs in amplifying and longitudinally inhomogeneous optical waveguides with a correspondingly matched profile of normal dispersion of group velocities is shown to be capable of providing for an amplification of subpicosecond pulses up to energies above 1 nJ.

  16. Performance characterization of an internsity-modulated fiber optic displacement sensor

    SciTech Connect

    Moro, Erik Allan; Todd, Michael D; Puckett, Santhony D

    2010-09-30

    A testbed simulating an intensity-modulated fiber optic displacement sensor is experimentally characterized, and the implications regarding sensor design are discussed. Of interest are the intensity distribution of the transmitted optical signal and the relationships between sensor architecture and performance. Particularly, an intensity-modulated sensor's sensitivity, linearity, displacement range, and resolution are functions of the relative positioning of its transmitting and receiving fibers. In this paper, sensor architectures with various combinations of these performance metrics are discussed. A sensor capable of micrometer resolution is reported, and it is concluded that this work could lead to an improved methodology for sensor design.

  17. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels.

    PubMed

    Jaramillo-Ochoa, Liliana; Ramirez-Gutierrez, Cristian F; Sánchez-Moguel, Alonso; Acosta-Osorio, Andrés; Rodriguez-Garcia, Mario E

    2015-01-01

    This work is focused in the development of a modulated optical transmission system with temperature control to determine the thermal properties of biodiesels such as the cloud and freezing points. This system is able to determine these properties in real time without relying on the operator skills as indicated in the American Society for Testing Materials (ASTM) norms. Thanks to the modulation of the incident laser, the noise of the signal is reduced and two information channels are generated: amplitude and phase. Lasers with different wavelengths can be used in this system but the sample under study must have optical absorption at the wavelength of the laser.

  18. Tailoring Cyanine Dark States for Improved Optically Modulated Fluorescence Recovery

    PubMed Central

    Mahoney, Daniel P.; Owens, Eric A.; Fan, Chaoyang; Hsiang, Jung-Cheng; Henary, Maged M.; Dickson, Robert M.

    2016-01-01

    Cyanine dyes are well known for their bright fluorescence and utility in biological imaging. Yet, cyanines also readily photoisomerize to produce non-emissive dark states. Co-illumination with a secondary, red-shifted light source on-resonance with the longer wavelength absorbing dark state reverses the photoisomerization and returns the cyanine dye to the fluorescent manifold, increasing steady-state fluorescence intensity. Modulation of this secondary light source dynamically alters emission intensity, drastically improving detection sensitivity and facilitating fluorescence signals to be recovered from otherwise overwhelming background. Red and near-IR emitting cyanine derivatives have been synthesized with varying alkyl chain lengths and halogen substituents to alter dual-laser fluorescence enhancement. Photophysical properties and enhancement with dual laser modulation were coupled with density functional calculations to characterize substituent effects on dark state photophysics, potentially improving detection in high background biological environments. PMID:25763888

  19. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    NASA Astrophysics Data System (ADS)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  20. Research of AGC technology in a digital optical fiber sensing system with PGC modulation and demodulation

    NASA Astrophysics Data System (ADS)

    Tang, Jianfeng; Xiong, Shuidong; Zhang, Yan

    2014-11-01

    The magnitude of light intensity on the photo-to-electric detector fluctuates all the time in an optic fiber sensing system, because of the influence of various factors in the fiber optic sensing system and from the external environment. As a result of the excessive intensity, the electric signal will be overload after the amplifier circuit with constant enlargement factor, and when the light intensity becames too small, it will reduce the signal-to-noise ratio of the electric signal. Therefore, it is necessary to introduce an automatic gain control (AGC) module into the system, which can insure the electric signal in a reasonable magnitude. In order to solve the problem of optic intensity fluctuating in the optical fiber sensing system with PGC modulation and demodulation, in this paper, firstly, it is analyzed that the impact of different magnitudes of interferential intensity to the PGC demodulation in theory. Secondly, a reasonable control method is put forward and an AGC module based on the AD602 chip is designed and produced. Finally, it is proved that the optic fiber sensor system with an AGC module has strong ability to resist fluctuation of light intensity within 40dB.

  1. Externally-Modulated Electro-Optically Coupled Detector Architecture for Nuclear Physics Instrumentation

    SciTech Connect

    Xi, Wenze; McKisson, John E.; Weisenberger, Andrew G.; Zhang, Shukui; Zorn, Carl J.

    2014-06-01

    A new laser-based externally-modulated electro-optically coupled detector (EOCD) architecture is being developed to enable high-density readout for radiation detectors with accurate analog radiation pulse shape and timing preservation. Unlike digital conversion before electro-optical modulation, the EOCD implements complete analog optical signal modulation and multiplexing in its detector front-end. The result is a compact, high performance detector readout that can be both radiation tolerant and immune to magnetic fields. In this work, the feasibility of EOCD was explored by constructing a two-wavelength laser-based externally-modulated EOCD, and testing analog pulse shape preservation and wavelength-division multiplexing (WDM) crosstalk. Comparisons were first made between the corresponding initial pulses and the electro-optically coupled analog pulses. This confirmed an excellent analog pulse preservation over $ sim {hbox {29}}% $ of the modulator’s switching voltage range. Optical spectrum analysis revealed less than $-{hbox {14}}~hbox{dB}$ crosstalk with 1.2 nm WDM wavelength bandgap, and provided insight on experimental conditions that could lead to increased inter-wavelength crosstalk. Further discussions and previous research on the radiation tolerance and magnetic field immunity of the candidate materials were also given, and quantitative device testing is proposed in the future.

  2. Reconfigurable optical interleaver modules with tunable wavelength transfer matrix function using polymer photonics lightwave circuits.

    PubMed

    Chen, Changming; Niu, Xiaoyan; Han, Chao; Shi, Zuosen; Wang, Xinbin; Sun, Xiaoqiang; Wang, Fei; Cui, Zhanchen; Zhang, Daming

    2014-08-25

    A transparent reconfigurable optical interleaver module composed of cascaded AWGs-based wavelength-channel-selector/interleaver monolithically integrated with multimode interference (MMI) variable optical attenuators (VOAs) and Mach-Zehnder interferometer (MZI) switch arrays was designed and fabricated using polymer photonic lightwave circuits. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and caldding, respectively. Thermo-optic (TO) tunable wavelength transfer matrix (WTM) function of the module can be achieved for optical routing network. The one-chip transmission loss is ~ 6 dB and crosstalk is less than ~25 dB for transverse-magnetic (TM) mode. The crosstalk and extinction ratio of the MMI VOAs were measured as -15.2 dB and 17.5 dB with driving current 8 mA, respectively. The modulation depth of the TO switches is obtained as ~18.2 dB with 2.2 V bias. Proposed novel interleaver module could be well suited for DWDM optical communication systems.

  3. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    SciTech Connect

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-10-18

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm{sup 2} and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO{sub 2} lasers.

  4. Modulated-alignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues

    PubMed Central

    Leigh, Steven Y.; Chen, Ye; Liu, Jonathan T.C.

    2014-01-01

    A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively ‘labels’ in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues. PMID:24940534

  5. Bidirectional optical subassembly-shaped 20-Gbit/s compact single-mode four-channel wavelength-division multiplexing optical modules for optical multimedia interfaces

    NASA Astrophysics Data System (ADS)

    Lim, Kwon-Seob; Yu, Hong-Yeon; Park, Hyoung-Jun; Kang, Hyun Seo; Jang, Jae-Hyung

    2016-06-01

    Low-cost single-mode four-channel optical transmitter and receiver modules using the wavelength-division multiplexing (WDM) method have been developed for long-reach fiber optic applications. The single-mode four-channel WDM optical transmitter and receiver modules consist of two dual-wavelength optical transmitter and receiver submodules, respectively. The integration of two channels in a glass-sealed transistor outline-can package is an effective way to reduce cost and size and to extend the number of channels. The clear eye diagrams with more than about 6 dB of the extinction ratio and the minimum receiver sensitivity of lower than -16 dBm at a bit error rate of 10-12 have been obtained for the transmitter and receiver modules, respectively, at 5 Gbps/channel. The 4K ultrahigh definition contents have been transmitted over a 1-km-long single-mode fiber using a pair of proposed four-channel transmitter optical subassembly and receiver optical subassembly.

  6. Low loss and high speed silicon optical modulator based on a lateral carrier depletion structure.

    PubMed

    Marris-Morini, Delphine; Vivien, Laurent; Fédéli, Jean Marc; Cassan, Eric; Lyan, Philippe; Laval, Suzanne

    2008-01-01

    A high speed and low loss silicon optical modulator based on carrier depletion has been made using an original structure consisting of a p-doped slit embedded in the intrinsic region of a lateral pin diode. This design allows a good overlap between the optical mode and carrier density variations. Insertion loss of 5 dB has been measured with a contrast ratio of 14 dB for a 3 dB bandwidth of 10 GHz.

  7. Chaos in coherence modulation: bifurcations of an oscillator generating optical delay fluctuations

    SciTech Connect

    Larger, Laurent; Lee, Min Won; Goedgebuer, Jean-Pierre; Elflein, Wilhelm; Erneux, Thomas

    2001-08-01

    A new chaos generator is described that produces chaotic fluctuations of the optical-path difference in a coherence modulator driven electrically by a nonlinear delayed-feedback loop. Numerical simulations and experimental results are reported. A closed branch of periodic solutions bounded by a forward and a reverse Hopf bifurcation is observed for the first time, to our knowledge, for this type of nonlinear dynamical system. {copyright} 2001 Optical Society of America

  8. Low loss and high speed silicon optical modulator based on a lateral carrier depletion structure.

    PubMed

    Marris-Morini, Delphine; Vivien, Laurent; Fédéli, Jean Marc; Cassan, Eric; Lyan, Philippe; Laval, Suzanne

    2008-01-01

    A high speed and low loss silicon optical modulator based on carrier depletion has been made using an original structure consisting of a p-doped slit embedded in the intrinsic region of a lateral pin diode. This design allows a good overlap between the optical mode and carrier density variations. Insertion loss of 5 dB has been measured with a contrast ratio of 14 dB for a 3 dB bandwidth of 10 GHz. PMID:18521165

  9. Liquid crystal modulated optical amplifier for night vision imaging

    NASA Astrophysics Data System (ADS)

    Parfenov, Alexander; Xia, X. Winston; Tengara, Indra; Win, Tin; Holmstedt, Jason; Rakuljic, Neven; Aye, Tin M.; Swinney, Mathew W.; Marasco, Peter L.

    2008-08-01

    Image intensifier tubes, as part of night vision devices, have been the primary devices for the detection and amplification of near infrared light for night vision operations. In this paper, we demonstrate a novel all-optical night vision amplifier device with a potential to replace the image intensifier tube in night vision goggles. This image amplifier is based on a novel structure of semiconductor and spectrally tunable liquid crystal (LC) materials within a thin cell. The LC reacts to near-infrared (NIR) radiation but is unaffected by visible light, allowing see-through capability including visible-wavelength cockpit light. The technology is made very attractive by its high sensitivity, spatial resolution, and contrast without expensive, bulky, and heavy optics or high-voltage components.

  10. Thermal dissipation modeling in optical components modules for electrical power consumption optimization

    NASA Astrophysics Data System (ADS)

    Sabot, Germain; Chaudenson, Julien; Raulin, Franck; Jacquet, Jo"l.

    2010-02-01

    In a semi-conductor optical amplifier (SOA) as in any other optical devices, the performances that can be reached is strongly dependent on the chip temperature. For example, the optical output power of a laser or the optical gain in a SOA is reduced when the temperature of the junction increases. This latter can be controlled or monitored thanks to a thermo-electronic cooler (or a Peltier element) and a thermistor. In this paper, we first have calculated the thermal resistance of various semiconductor structures such as buried or ridge waveguides lasers. We then calculate the Peltier consumption necessary to maintain a given temperature. The influence of the thermistor position as well as the module conception have been investigated in these calculation. The size of the different mechanical elements, the nature and thermal properties of the material use for the module fabrication have been found to play an important role in the thermal performance of the optical modules. The Peltier size is defined by maximizing its efficiency. It depends on the power to be dissipated as well as the temperature operation of the device. The latter depends on the performance expected by the optical devices. We discussed the optimization of the device structure associated to its packaging to find the best compromise between performance and electrical consumption. The trade-off found depends on the temperature at which the device operates as well as on the thermal power to be dissipated.

  11. Modulation and coding for throughput-efficient optical free-space links

    NASA Technical Reports Server (NTRS)

    Georghiades, Costas N.

    1993-01-01

    Optical direct-detection systems are currently being considered for some high-speed inter-satellite links, where data-rates of a few hundred megabits per second are evisioned under power and pulsewidth constraints. In this paper we investigate the capacity, cutoff-rate and error-probability performance of uncoded and trellis-coded systems for various modulation schemes and under various throughput and power constraints. Modulation schemes considered are on-off keying (OOK), pulse-position modulation (PPM), overlapping PPM (OPPM) and multi-pulse (combinatorial) PPM (MPPM).

  12. Flexible generation of optical nonuniform bit-mapping signal based on InP transmitter module.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Liu, Lei

    2014-01-15

    Flexible generation of an optical nonuniform bit-mapping signal based on an InP transmitter module is demonstrated. It can realize flexible bit mapping through the photonic modulation method, which can break the limitations of an electrical digital-to-analog convertor and field-programmable gate array. This module has potential to easily increase the signal rate or refine the granularity without electronics, which indicates it may be a future application to replace the traditional transmitter. The feasibility and performance of the proposed scheme are demonstrated in the experiment.

  13. Generation of Optical Millimeter Wave Using Two Cascaded Polarization Modulators Based on Frequency Octupling Without Filtering

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Ma, Jianxin; Zhang, Ruijiao; Xin, Xiangjun; Zhang, Junyi

    2015-11-01

    An approach to generate an optical millimeter wave is introduced with frequency octupling using two cascaded polarization modulators followed by polarizers, respectively. By adjusting the modulation indexes of polarization modulators, only the ±4th-order sidebands are generated with a pure spectrum. Since no filter is needed, the proposed technique can be used to generate a frequency-tunable millimeter wave with a large frequency-tunable range. To prove the feasibility of the proposed approach, a simulation is conducted to generate an 80-GHz millimeter wave, and then its transmission performance is checked.

  14. Structure modulations in nonlinear optical (NLO) materials Cs(2)TB4O9 (T = Ge, Si).

    PubMed

    Zhou, Zhengyang; Xu, Xiang; Fei, Rao; Mao, Jianggao; Sun, Junliang

    2016-04-01

    Incommensurately modulated borate structures of a new type were studied in detail in the nonlinear optical (NLO) materials Cs(2)TB4O9 (T = Ge, Si) using single-crystal X-ray diffraction techniques. The structures were solved by the charge-flipping algorithm in the superspace group I2(αβ0)0. The refinement results strongly suggest that the main structure modulation feature of Cs(2)TB4O9 is the ordering of the O atoms. With these modulated structure models, the unreasonable B-O distances in the average structures were explained as the ordering of BO4 and BO3.

  15. Structure modulations in nonlinear optical (NLO) materials Cs(2)TB4O9 (T = Ge, Si).

    PubMed

    Zhou, Zhengyang; Xu, Xiang; Fei, Rao; Mao, Jianggao; Sun, Junliang

    2016-04-01

    Incommensurately modulated borate structures of a new type were studied in detail in the nonlinear optical (NLO) materials Cs(2)TB4O9 (T = Ge, Si) using single-crystal X-ray diffraction techniques. The structures were solved by the charge-flipping algorithm in the superspace group I2(αβ0)0. The refinement results strongly suggest that the main structure modulation feature of Cs(2)TB4O9 is the ordering of the O atoms. With these modulated structure models, the unreasonable B-O distances in the average structures were explained as the ordering of BO4 and BO3. PMID:27048721

  16. Precision 3-D microscopy with intensity modulated fibre optic scanners

    NASA Astrophysics Data System (ADS)

    Olmos, P.

    2016-01-01

    Optical 3-D imagers constitute a family of precision and useful instruments, easily available on the market in a wide variety of configurations and performances. However, besides their cost they usually provide an image of the object (i.e. a more or less faithful representation of the reality) instead of a truly object's reconstruction. Depending on the detailed working principles of the equipment, this reconstruction may become a challenging task. Here a very simple yet reliable device is described; it is able to form images of opaque objects by illuminating them with an optical fibre and collecting the reflected light with another fibre. Its 3-D capability comes from the spatial filtering imposed by the fibres together with their movement (scanning) along the three directions: transversal (surface) and vertical. This unsophisticated approach allows one to model accurately the entire optical process and to perform the desired reconstruction, finding that information about the surface which is of interest: its profile and its reflectance, ultimately related to the type of material.

  17. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    NASA Astrophysics Data System (ADS)

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-09-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals.

  18. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    PubMed Central

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-01-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals. PMID:27682836

  19. Optically pumped terahertz wave modulation in MoS2-Si heterostructure metasurface

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Fan, Fei; Chen, Meng; Chen, Sai; Chang, Sheng-Jiang

    2016-07-01

    An optically pumped terahertz (THz) modulator based on a MoS2-Si heterostructure metasurface are fabricated and investigated in this paper. The THz wave modulation in MoS2 metasurface has been demonstrated by THz time domain spectroscopy experiment and numerical simulation, which can reach over 90% under the continuous wave laser pumping of 4W/cm2 power density. Importantly, the catalysis of photocarrier generation in MoS2-Si heterostructure has been proved by the comparsion between the modulation depth of metasurface with and without MoS2 nanosheet under the same pumping power, and we found that the strcuture of metasurface and polariztion direction can also influence the photocarrier density in MoS2 metasurface. This novel THz modulator based on 2D material has a high effective modulation on THz waves under a low pumping power, which has a bright potential in THz applications.

  20. Electrically modulated transparent liquid crystal -optical grating projection.

    PubMed

    Buss, Thomas; Smith, Cameron L C; Kristensen, Anders

    2013-01-28

    A transparent, fully integrated electrically modulated projection technique is presented based on light guiding through a thin liquid crystal layer covering sub-wavelength gratings. The reported device operates at 10 V with response times of 4.5 ms. Analysis of the liquid crystal alignment shows that director-reorientation occurs over timescales on the order of 90 µs close to the grating surface. The technology is suitable for next generation heads-up-displays and reconfigurable multilayer photonic integrated circuits. PMID:23389166

  1. Development of Advanced Seed Laser Modules for Lidar and Spectroscopy Applications

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.; Rosiewicz, Alex; Coleman, Steven M.

    2013-01-01

    We report on recent progress made in the development of highly compact, single mode, distributed feedback laser (DFB) seed laser modules for lidar and spectroscopy applications from space based platforms. One of the intended application of this technology is in the NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The DFB laser modules operating at 1571 nm and 1262 nm have advanced current and temperature drivers built into them. A combination of temperature and current tuning allows coarse and fine adjustment of the diode wavelengths.

  2. Recent advance in application of acousto-optic tunable filters

    NASA Astrophysics Data System (ADS)

    Khansuvarov, Ruslan A.; Shakin, Oleg V.; Vaganov, Mikhail A.; Zhdanov, Arseniy Y.; Prokashev, Vadim N.

    2014-09-01

    This paper aims to inform those interested in the scientific work of a large group of scientists: workers of the Department of Electronics and Optical communications of St. Petersburg State University of Aerospace Instrumentation in collaboration with workers of the Department of Quantum Electronics of St. Petersburg State Technical University in the area of researches and development of acousto-optic tunable filters (AOTF). Paper discusses the important features of the AOTF structure and their parameters that affect its work, such as: spectral range of optical radiation, spectral resolution, active aperture of the optical radiation, optical transmission of the working spectral range, optical radiation polarization (linear, circular or arbitrary) , diffraction efficiency, contrast, distortion of the optical radiation's front, frequency range of elastic waves, switching time, maximum electric control power, impedance. Also the AOTF using is considered: AOTF's implications for control of laser radiation, AOTF's application to determine the counterfeit money. The last part of the report focuses on materials that act as antireflection thin films. Spectral characteristics of "clean" and enlightened substrates of ZnSe and Ge are shown. As seen from the examples in the report, antireflection thin films increase transmittance of optical elements.

  3. Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Poppel, G. L.; Glasheen, W. M.

    1989-01-01

    A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface.

  4. NASA SBIR Subtopic S2.04 "Advanced Optical Components"

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2009-01-01

    The primary purpose of this subtopic is to develop and demonstrate technologies to manufacture ultra-low-cost precision optical systems for very large x-ray, UV/optical or infrared telescopes. Potential solutions include but are not limited to direct precision machining, rapid optical fabrication, slumping or replication technologies to manufacture 1 to 2 meter (or larger) precision quality mirror or lens segments (either normal incidence for uv/optical/infrared or grazing incidence for x-ray). An additional key enabling technology for UV/optical telescopes is a broadband (from 100 nm to 2500 nm) high-reflectivity mirror coating with extremely uniform amplitude and polarization properties which can be deposited on 1 to 3 meter class mirror.

  5. Phase-Array Approach to Optical Whispering Gallery Modulators

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry

    2010-01-01

    This technology leverages the well-defined orbital number of a whispering gallery modulator (WGM) to expand the range of applications for such resonators. This property rigidly connects the phase variation of the field in this mode with the azimuthal angle between the coupling locations. A WGM with orbital momentum L has exactly L instant nodes around the circumference of the WGM resonator supporting such a mode. Therefore, in two locations separated by the arc alpha, the phase difference of such a field will be equal to phi= alpha L. Coupling the field out of such locations, and into a balanced interferometer, once can observe a complete constructive or distractive interference (or have any situation in between) depending on the angle alpha. Similarly, a mode L + delta L will pick up the phase phi + alpha delta L. In all applications of a WGM resonator as a modulator, the orbital numbers for the carrier and sidebands are different, and their differences delta L are known (usually, but not necessarily, delta L = 1). Therefore, the choice of the angle alpha, and of the interferometer arms difference, allows one to control the relative phase between different modes and to perform the conversion, separation, and filtering tasks necessary.

  6. Phase and gain control of GaAs MMIC transmit-receive modules by optical means

    NASA Astrophysics Data System (ADS)

    Herczfeld, P. R.; Daryoush, A.; Jemison, W.; Rosen, Arye; Paolella, A.

    The authors report on the optical phase and gain control of GaAs microwave monolithic integrated-circuit (MMIC) transmit-receive modules with applications for active phased-array antennas. Phase shifts of 45 degrees were obtained with 50 mW of optical power, and amplifier gain was controlled 15 dB with 250 mW of light intensity. It is concluded that this approach can be extended to the millimeter wave range, is compatible with GaAs MMICs, has potential for fast response, is cost effective, and is compatible with parallel optical processing.

  7. Detection of radio-frequency modulated optical signals by two and three terminal microwave devices

    NASA Technical Reports Server (NTRS)

    Bhasin, K. B.; Simons, R. N.; Wojtczuk, S.

    1987-01-01

    An interdigitated photoconductor (two terminal device) on GaAlAs/GaAs heterostructure was fabricated and tested by an electro-optical sampling technique. Further, the photoresponse of GaAlAs/GaAs HEMT (three terminal device) was obtained by illuminating the device with an optical signal modulated up to 8 GHz. Gain-bandwidth product, response time, and noise properties of photoconductor and HEMT devices were obtained. Monolithic integration of these photodetectors with GaAs microwave devices for optically controlled phased array antenna applications is discussed.

  8. Advanced modulation technology development for earth station demodulator applications. Coded modulation system development

    NASA Technical Reports Server (NTRS)

    Miller, Susan P.; Kappes, J. Mark; Layer, David H.; Johnson, Peter N.

    1990-01-01

    A jointly optimized coded modulation system is described which was designed, built, and tested by COMSAT Laboratories for NASA LeRC which provides a bandwidth efficiency of 2 bits/s/Hz at an information rate of 160 Mbit/s. A high speed rate 8/9 encoder with a Viterbi decoder and an Octal PSK modem are used to achieve this. The BER performance is approximately 1 dB from the theoretically calculated value for this system at a BER of 5 E-7 under nominal conditions. The system operates in burst mode for downlink applications and tests have demonstrated very little degradation in performance with frequency and level offset. Unique word miss rate measurements were conducted which demonstrate reliable acquisition at low values of Eb/No. Codec self tests have verified the performance of this subsystem in a stand alone mode. The codec is capable of operation at a 200 Mbit/s information rate as demonstrated using a codec test set which introduces noise digitally. The measured performance is within 0.2 dB of the computer simulated predictions. A gate array implementation of the most time critical element of the high speed Viterbi decoder was completed. This gate array add-compare-select chip significantly reduces the power consumption and improves the manufacturability of the decoder. This chip has general application in the implementation of high speed Viterbi decoders.

  9. Advanced modulation technology development for earth station demodulator applications. Coded modulation system development

    NASA Astrophysics Data System (ADS)

    Miller, Susan P.; Kappes, J. Mark; Layer, David H.; Johnson, Peter N.

    1990-04-01

    A jointly optimized coded modulation system is described which was designed, built, and tested by COMSAT Laboratories for NASA LeRC which provides a bandwidth efficiency of 2 bits/s/Hz at an information rate of 160 Mbit/s. A high speed rate 8/9 encoder with a Viterbi decoder and an Octal PSK modem are used to achieve this. The BER performance is approximately 1 dB from the theoretically calculated value for this system at a BER of 5 E-7 under nominal conditions. The system operates in burst mode for downlink applications and tests have demonstrated very little degradation in performance with frequency and level offset. Unique word miss rate measurements were conducted which demonstrate reliable acquisition at low values of Eb/No. Codec self tests have verified the performance of this subsystem in a stand alone mode. The codec is capable of operation at a 200 Mbit/s information rate as demonstrated using a codec test set which introduces noise digitally. The measured performance is within 0.2 dB of the computer simulated predictions. A gate array implementation of the most time critical element of the high speed Viterbi decoder was completed. This gate array add-compare-select chip significantly reduces the power consumption and improves the manufacturability of the decoder. This chip has general application in the implementation of high speed Viterbi decoders.

  10. Advances in hybrid optics physical sensors for extreme environments

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.

    2010-04-01

    Highlighted are novel innovations in hybrid optical design physical sensors for extreme environments. Various hybrid design compositions are proposed that are suited for a particular sensor application. Examples includes combining freespace (wireless) and fiber-optics (wired) for gas turbine sensing and combining single crystal and sintered Silicon Carbide (SiC) materials for robust extreme environment Coefficent of Thermal Expansion (CTE) matched frontend probe design. Sensor signal processing also includes the hybrid theme where for example Black-Body radiation thermometry (pyrometry) is combined with laser interferometry to provide extreme temperature measurements. The hybrid theme also operates on the optical device level where a digital optical device such as a Digital Micromirror Device (DMD) is combined with an analog optical device such as an Electronically Controlled Variable Focal Length Lens (ECVFL) to deliver a smart and compressive Three Dimensional (3-D) imaging sensor for remote scene and object shape capture including both ambient light (passive) mode and active laser targeting and receive processing. Within a device level, the hybrid theme also operates via combined analog and digital control such as within a wavelength-coded variable optical delay line. These powerful hybrid design optical sensors have numerous applications in engineering and science applications from the military to the commercial/industrial sectors.

  11. Photonic and plasmonic modulators based on optical switching in VO2

    NASA Astrophysics Data System (ADS)

    Haglund, Richard F.; Weiss, Sharon M.; Appavoo, Kannatassen

    2015-01-01

    Researchers all over the world are competing in a technology-driven quest to develop the next generation of ultrasmall, low-power photonic and plasmonic devices. One route to this objective involves hybrid structures that incorporate a phase-changing material into the structure, creating a nanocomposite material in which the optical response of a plasmonic or photonic structure is modulated by a change in phase, crystallinity or dielectric function induced by thermal, optical or electrical stimulus. Vanadium dioxide (VO2) has been considered as a potential electro-optic switching material for electronic and photonic applications ever since its semiconductor-to-metal transition (SMT) was first described half a century ago. This review describes the application of vanadium dioxide as the switching element in (i) a hybrid silicon ring resonator and (ii) a polarization-sensitive, multifunctional plasmonic modulator in the form of a nanoscale heterodimer. As is now widely known, the SMT in VO2 is also accompanied by a structural phase transition (SPT) from the M1 (monoclinic) to a rutile (tetragonal, R) crystalline form that was believed to prevent a fast recovery after switching. However, recent research has shown that this picture is oversimplified, and that there is a monoclinic metallic state that enables true ultrafast switching. That understanding, in turn, is leading to new concepts in developing hybrid nanocomposites that incorporate VO2 in silicon photonics and plasmonic modulators, enabling the construction of ultrafast optical switches, modulators and memory elements.

  12. Magnetic field topographical survey by magneto-optical space-time light modulators

    NASA Astrophysics Data System (ADS)

    Levy, Sergey V.; Ostrovsky, Andrey S.; Agalidy, Yu. S.

    1993-12-01

    Utilization of magneto-optical spacing light modulators based on Bi-substituted monocrystalline ferrite-garnet films for spatially distributed magnetic field measurements is discussed. Numerous variants of magnetic field topographical survey for different types (audio & video ...) of magnetic signalogramms geometrical parameters control are described. Special usages for magnetic signalogramms criminalistics examination and faint amplitude signalogramms visualization are described too.

  13. Four-wave mixing for clock recovery of phase modulated optical OFDM superchannel.

    PubMed

    Power, Mark J; Jia, Wei; Webb, Roderick P; Manning, Robert J; Gunning, Fatima C Garcia

    2014-03-24

    We simulate and experimentally demonstrate a novel all-optical clock recovery technique for a BPSK OFDM superchannel. Four-wave mixing in SOAs is used to strip the modulation from the superchannel sub-carriers, two of which are filtered and beat together in a photodiode to recover the clock.

  14. Intensity-based fibre-optic sensing system using contrast modulation of subcarrier interference pattern

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.; Sherer, T. N.; Maitland, D. J.

    1989-01-01

    A novel technique to compensate for unwanted intensity losses in a fiber-optic sensing system is described. The technique involves a continuous sinusoidal modulation of the light source intensity at radio frequencies and an intensity sensor placed in an unbalanced interferometer. The system shows high sensitivity and stability.

  15. Advancing clinical development pathways for new CFTR modulators in cystic fibrosis

    PubMed Central

    Mayer-Hamblett, Nicole; Boyle, Michael; VanDevanter, Donald

    2016-01-01

    Cystic fibrosis (CF) is a life-shortening genetic disease affecting approximately 70 000 individuals worldwide. Until recently, drug development efforts have emphasised therapies treating downstream signs and symptoms resulting from the underlying CF biological defect: reduced function of the CF transmembrane conductance regulator (CFTR) protein. The current CF drug development landscape has expanded to include therapies that enhance CFTR function by either restoring wild-type CFTR protein expression or increasing (modulating) the function of mutant CFTR proteins in cells. To date, two systemic small-molecule CFTR modulators have been evaluated in pivotal clinical trials in individuals with CF and specific mutant CFTR genotypes that have led to regulatory review and/or approval. Advances in the discovery of CFTR modulators as a promising new class of therapies have been impressive, yet work remains to develop highly effective, disease-modifying modulators for individuals of all CF genotypes. The objectives of this review are to outline the challenges and opportunities in drug development created by systemic genotype-specific CFTR modulators, highlight the advantages of sweat chloride as an established biomarker of CFTR activity to streamline early-phase development and summarise options for later phase clinical trial designs that respond to the adoption of approved genotype-specific modulators into standard of care. An optimal development framework will be needed to move the most promising therapies efficiently through the drug development pipeline and ultimately deliver efficacious and safe therapies to all individuals with CF. PMID:26903594

  16. Advancing clinical development pathways for new CFTR modulators in cystic fibrosis.

    PubMed

    Mayer-Hamblett, Nicole; Boyle, Michael; VanDevanter, Donald

    2016-05-01

    Cystic fibrosis (CF) is a life-shortening genetic disease affecting approximately 70,000 individuals worldwide. Until recently, drug development efforts have emphasised therapies treating downstream signs and symptoms resulting from the underlying CF biological defect: reduced function of the CF transmembrane conductance regulator (CFTR) protein. The current CF drug development landscape has expanded to include therapies that enhance CFTR function by either restoring wild-type CFTR protein expression or increasing (modulating) the function of mutant CFTR proteins in cells. To date, two systemic small-molecule CFTR modulators have been evaluated in pivotal clinical trials in individuals with CF and specific mutant CFTR genotypes that have led to regulatory review and/or approval. Advances in the discovery of CFTR modulators as a promising new class of therapies have been impressive, yet work remains to develop highly effective, disease-modifying modulators for individuals of all CF genotypes. The objectives of this review are to outline the challenges and opportunities in drug development created by systemic genotype-specific CFTR modulators, highlight the advantages of sweat chloride as an established biomarker of CFTR activity to streamline early-phase development and summarise options for later phase clinical trial designs that respond to the adoption of approved genotype-specific modulators into standard of care. An optimal development framework will be needed to move the most promising therapies efficiently through the drug development pipeline and ultimately deliver efficacious and safe therapies to all individuals with CF. PMID:26903594

  17. Advancing clinical development pathways for new CFTR modulators in cystic fibrosis.

    PubMed

    Mayer-Hamblett, Nicole; Boyle, Michael; VanDevanter, Donald

    2016-05-01

    Cystic fibrosis (CF) is a life-shortening genetic disease affecting approximately 70,000 individuals worldwide. Until recently, drug development efforts have emphasised therapies treating downstream signs and symptoms resulting from the underlying CF biological defect: reduced function of the CF transmembrane conductance regulator (CFTR) protein. The current CF drug development landscape has expanded to include therapies that enhance CFTR function by either restoring wild-type CFTR protein expression or increasing (modulating) the function of mutant CFTR proteins in cells. To date, two systemic small-molecule CFTR modulators have been evaluated in pivotal clinical trials in individuals with CF and specific mutant CFTR genotypes that have led to regulatory review and/or approval. Advances in the discovery of CFTR modulators as a promising new class of therapies have been impressive, yet work remains to develop highly effective, disease-modifying modulators for individuals of all CF genotypes. The objectives of this review are to outline the challenges and opportunities in drug development created by systemic genotype-specific CFTR modulators, highlight the advantages of sweat chloride as an established biomarker of CFTR activity to streamline early-phase development and summarise options for later phase clinical trial designs that respond to the adoption of approved genotype-specific modulators into standard of care. An optimal development framework will be needed to move the most promising therapies efficiently through the drug development pipeline and ultimately deliver efficacious and safe therapies to all individuals with CF.

  18. Aerodynamics of the advanced launch system (ALS) propulsion and avionics (P/A) module

    NASA Technical Reports Server (NTRS)

    Ferguson, Stan; Savage, Dick

    1992-01-01

    This paper discusses the design and testing of candidate Advanced Launch System (ALS) Propulsion and Avionics (P/A) Module configurations. The P/A Module is a key element of future launch systems because it is essential to the recovery and reuse of high-value propulsion and avionics hardware. The ALS approach involves landing of first stage (booster) and/or second stage (core) P/A modules near the launch site to minimize logistics and refurbishment cost. The key issue addressed herein is the aerodynamic design of the P/A module, including the stability characteristics and the lift-to-drag (L/D) performance required to achieve the necessary landing guidance accuracy. The reference P/A module configuration was found to be statically stable for the desired flight regime, to provide adequate L/D for targeting, and to have effective modulation of the L/D performance using a body flap. The hypersonic aerodynamic trends for nose corner radius, boattail angle and body flap deflections were consistent with pretest predictions. However, the levels for the L/D and axial force for hypersonic Mach numbers were overpredicted by impact theories.

  19. Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

    NASA Technical Reports Server (NTRS)

    Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

    1986-01-01

    A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

  20. Tailoring the Optical Properties of Silicon with Ion Beam Created Nanostructures for Advanced Photonics Applications

    NASA Astrophysics Data System (ADS)

    Akhter, Perveen

    light trapping in poly-Si thin films using ion implantation induced surface texturing. In addition to surface texturing produced by H and Ar ion implantations, metal nanostructures are also added to the surface to further suppress light reflection at the plasmonic resonance of metal nanostructures. Remarkable suppression has been achieved resulting in reflection from the air/Si interface to below ˜5%. In the second part, optical properties of embedded metal nanostructures in silicon matrix gettered into the ion implantation created nanocavities are studied. Embedded nanostructures can have a huge impact in future photonics applications by replacing the existing electronic and photonic components such as interconnects, waveguides, modulators and amplifiers with their plasmonic counterparts. This new method of encapsulating metal nanostructures in silicon is cost-effective and compatible with silicon fabrication technology. Spectroscopic ellipsometry is used to study the dielectric properties of silicon with embedded silver nanostructures. High absorption regions around 900 nm, corresponding to plasmonic absorption of Ag nanoparticles in Si, have been observed and compared to theoretical calculations and simulation results. The possibility of modifying the dielectric function of Si with metal nanostructures can lay the foundation for functional base structures for advanced applications in silicon photonics, photovoltaics and plasmonics.

  1. Non-invasive optical modulation of local vascular permeability

    NASA Astrophysics Data System (ADS)

    Choi, Myunghwan; Choi, Chulhee

    2011-03-01

    For a systemically administered drug to act, it first needs to cross the vascular wall. This step represents a bottleneck for drug development, especially in the brain or retina, where tight junctions between endothelial cells form physiological barriers. Here, we demonstrate that femtosecond pulsed laser irradiation focused on the blood vessel wall induces transient permeabilization of plasma. Nonlinear absorption of the pulsed laser enabled the noninvasive modulation of vascular permeability with high spatial selectivity in three dimensions. By combining this method with systemic injection, we could locally deliver molecular probes in various tissues, such as brain cortex, meninges, ear, striated muscle, and bone. We suggest this method as a novel delivery tool for molecular probes or drugs.

  2. Gain compression effect on the modulation dynamics of an optically injection-locked semiconductor laser using gain lever

    NASA Astrophysics Data System (ADS)

    Sarraute, J.-M.; Schires, K.; LaRochelle, S.; Grillot, F.

    2016-03-01

    The modulation response of an optically-injected gain lever semiconductor laser is studied and calculations show that a gain-lever laser operating under medium to strong optical injection provides a unique and robust configuration for ultra large bandwidth enhancement. Modulation bandwidths above nine times the relaxation oscillation frequency of the free-running laser can be reached using injection-locking conditions that are reasonable for practical applications. The impact of the gain compression on the modulation dynamic is discussed for the first time. This work is of prime importance for the development of directly-modulated broadband optical sources for high-speed operation at 40 Gbps and beyond.

  3. Silicon-Based Optical Waveguide Modulators and Mode-Locked TITANIUM:SAPPHIRE Laser Dynamics.

    NASA Astrophysics Data System (ADS)

    Liu, Yanming

    Single-mode deeply-etched silicon-germanium/silicon (SiGe/Si) rib waveguides have been fabricated and characterized with low propagation losses and strong guiding. Such a waveguide structure is suitable for bent waveguide devices and provides efficient field overlapping, which is needed for devices requiring strong nonlinear coupling. Using the deeply-etched waveguide technique, we have fabricated Si/SiGe/Si Mach-Zehnder modulators, which show strong single-mode waveguiding but only small electro -optic modulation has been observed so far. Another Si modulator is a Fabry-Perot interferometer. We have demonstrated all-optical modulation at 1.3 μm and 1.5 μm in the reflection mode of the asymmetric Si Fabry-Perot interferometer by a control light beam at 0.85 mum. Both switching -on and switching-off operations are demonstrated by transversely moving the etalon. In addition, we have analyzed that silicon carbide (SiC) waveguides exhibit low loss for fundamental modes and high loss for higher-order modes at wavelengths from 0.6 to 1.6 mum. Electro-optic modulation is analyzed with a SiC-on-SiO_2 waveguide structure. Such modulators are potential candidates for high-speed electro-optic modulation for silicon-based optoelectronic devices. Furthermore, we studied the dynamics of a Kerr -lens self-mode-locked Ti:sapphire laser, generating 40 -fs pulses and tunable from 750 nm to 920 nm. A moving mirror was first proposed as a starting mechanism for self -mode locking and the starting dynamics is studied in detail. In addition, periodic pulse-train amplitude modulations have been observed and studied. The observation of the amplitude modulation further confirms the dynamic Kerr-lens self -focusing model of self-mode locking in Ti:sapphire lasers and helps us better understand the laser performance. Furthermore, dual-wavelength mode locking is observed over a broad tuning range, which would be very useful for two-wavelength subpicosecond optical sampling, such as pump

  4. Dynamics of a periodically modulated optical parametric oscillator near lasing threshold

    NASA Astrophysics Data System (ADS)

    Brazhnyi, V. A.; Konotop, V. V.; Taki, M.

    2009-10-01

    We present analytical investigation of the nonlinear dynamics of a degenerate optical parametric oscillator with periodic modulation of transverse refraction index. By a proper choice of the injected external field that must compensate for losses and match with the modulation period, nonlinear optical cavities can exhibit dissipative Bloch waves which are attracting solutions of nonequilibrium system. This allows us to propose method of experimental visualization of the band structure of the cavity medium. Using multiple-scale expansion near the leasing threshold, we obtain the equation of evolution of the small-amplitude envelop of the signal field which appears strongly affected by the periodic modulation of the refractive index. We discuss the physical meaning of the obtained equation.

  5. Deep sea tests of a prototype of the KM3NeT digital optical module

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Ageron, M.; Aharonian, F.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; de Asmundis, R.; Balasi, K.; Band, H.; Barbarino, G.; Barbarito, E.; Barbato, F.; Baret, B.; Baron, S.; Belias, A.; Berbee, E.; van den Berg, A. M.; Berkien, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Bianucci, S.; Billault, M.; Birbas, A.; Boer Rookhuizen, H.; Bormuth, R.; Bouché, V.; Bouhadef, B.; Bourlis, G.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Caruso, F.; Cecchini, S.; Ceres, A.; Cereseto, R.; Champion, C.; Château, F.; Chiarusi, T.; Christopoulou, B.; Circella, M.; Classen, L.; Cocimano, R.; Colonges, S.; Coniglione, R.; Cosquer, A.; Costa, M.; Coyle, P.; Creusot, A.; Curtil, C.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Rosa, G.; Deniskina, N.; Destelle, J.-J.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Drury, L.; Durand, D.; Eberl, T.; Eleftheriadis, C.; Elsaesser, D.; Enzenhöfer, A.; Fermani, P.; Fusco, L. A.; Gajana, D.; Gal, T.; Galatà, S.; Gallo, F.; Garufi, F.; Gebyehu, M.; Giordano, V.; Gizani, N.; Gracia Ruiz, R.; Graf, K.; Grasso, R.; Grella, G.; Grmek, A.; Habel, R.; van Haren, H.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Herold, B.; Hevinga, M. A.; van der Hoek, M.; Hofestädt, J.; Hogenbirk, J.; Hugon, C.; Hößl, J.; Imbesi, M.; James, C.; Jansweijer, P.; Jochum, J.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Kappos, E.; Katz, U.; Kavatsyuk, O.; Keller, P.; Kieft, G.; Koffeman, E.; Kok, H.; Kooijman, P.; Koopstra, J.; Korporaal, A.; Kouchner, A.; Koutsoukos, S.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Le Provost, H.; Leisos, A.; Lenis, D.; Leonora, E.; Lindsey Clark, M.; Liolios, A.; Llorens Alvarez, C. D.; Löhner, H.; Lo Presti, D.; Louis, F.; Maccioni, E.; Mannheim, K.; Manolopoulos, K.; Margiotta, A.; Mariş, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Masullo, R.; Michael, T.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C.; Mongelli, M.; Morganti, M.; Mos, S.; Moudden, Y.; Musico, P.; Musumeci, M.; Nicolaou, C.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papageorgiou, K.; Papaikonomou, A.; Papaleo, R.; Păvălaş, G. E.; Peek, H.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Petridou, C.; Piattelli, P.; Pikounis, K.; Popa, V.; Pradier, Th.; Priede, M.; Pühlhofer, G.; Pulvirenti, S.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rapidis, P. A.; Razis, P.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rovelli, A.; Royon, J.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Savvidis, I.; Schmelling, J.; Schnabel, J.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Siotis, I.; Sipala, V.; Solazzo, M.; Spitaleri, A.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stolarczyk, T.; Stransky, D.; Taiuti, M.; Terreni, G.; Tézier, D.; Théraube, S.; Thompson, L. F.; Timmer, P.; Trapierakis, H. I.; Trasatti, L.; Trovato, A.; Tselengidou, M.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Vernin, P.; Viola, S.; Vivolo, D.; Werneke, P.; Wiggers, L.; Wilms, J.; de Wolf, E.; van Wooning, R. H. L.; Yatkin, K.; Zachariadou, K.; Zonca, E.; Zornoza, J. D.; Zúñiga, J.; Zwart, A.

    2014-09-01

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same $^{40}$K decay and the localization bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions.

  6. Electro-optic modulation for high-speed characterization of entangled photon pairs

    SciTech Connect

    Lukens, Joseph M.; Odele, Ogaga D.; Leaird, Daniel E.; Weiner, Andrew M.

    2015-11-10

    In this study, we demonstrate a new biphoton manipulation and characterization technique based on electro-optic intensity modulation and time shifting. By applying fast modulation signals with a sharply peaked cross-correlation to each photon from an entangled pair, it is possible to measure temporal correlations with significantly higher precision than that attainable using standard single-photon detection. Low-duty-cycle pulses and maximal-length sequences are considered as modulation functions, reducing the time spread in our correlation measurement by a factor of five compared to our detector jitter. With state-of-the-art electro-optic components, we expect the potential to surpass the speed of any single-photon detectors currently available.

  7. Electro-optic modulation for high-speed characterization of entangled photon pairs

    DOE PAGES

    Lukens, Joseph M.; Odele, Ogaga D.; Leaird, Daniel E.; Weiner, Andrew M.

    2015-11-10

    In this study, we demonstrate a new biphoton manipulation and characterization technique based on electro-optic intensity modulation and time shifting. By applying fast modulation signals with a sharply peaked cross-correlation to each photon from an entangled pair, it is possible to measure temporal correlations with significantly higher precision than that attainable using standard single-photon detection. Low-duty-cycle pulses and maximal-length sequences are considered as modulation functions, reducing the time spread in our correlation measurement by a factor of five compared to our detector jitter. With state-of-the-art electro-optic components, we expect the potential to surpass the speed of any single-photon detectors currentlymore » available.« less

  8. [Improving the signal to noise ratio of spectroscopy for tongue inspection by optical modulation].

    PubMed

    Li, Gang; Zhao, Jing; Lin, Ling; Wu, Xiao-rong

    2012-01-01

    In order to solve the problem that the collected spectrum was influenced seriously by the environment light, optical modulation was used to improve the signal to noise ratio of spectroscopy-tongue inspection for the first time. First, reference light was modulated by reticle in this system; second, the reflect spectrum of the same measured object was collected under the condition that it was influenced by green, purple, red laser and environment light respectively; thirdly, the DFT was used to demodulate the collected spectrum data; the maximum harmonic components were extracted and normalized, then the spectral curve was drawn; by comparison, the spectral curves of the same measured object under different condition were almost the same. The experiment result showed that the optical modulation can remove the influence of the environment light; and this method can provide a new way to improve the signal to noise ratio of spectroscopy for tongue inspection. PMID:22497157

  9. Development of a multi-PMT optical module prototype for PINGU

    SciTech Connect

    Classen, Lew; Collaboration: IceCube-PINGU Collaboration

    2014-11-18

    The multi-PMT digital optical module (mDOM) contains 41 three-inch{sup 2} PMTs in a cylindrical glass vessel. The design is based on the KM3NeT DOM. Among other advantages, this approach offers a significant increase of photocathode area per module and also per string length. As an R and D activity targeted at potential future extensions, this new type of optical modules will be tested in the framework of the PINGU project (Precision IceCube Next Generation Upgrade). PINGU will add denser instrumentation to the IceCube/DeepCore sub-volume aiming at a further decrease of the neutrino energy threshold (to a few GeV). The current status of the development and the prototype construction is presented.

  10. A dynamic plasmonic manipulation technique assisted by phase modulation of an incident optical vortex beam.

    PubMed

    Yuan, G H; Wang, Q; Tan, P S; Lin, J; Yuan, X-C

    2012-09-28

    A novel phase modulation method for dynamic manipulation of surface plasmon polaritons (SPPs) with a phase engineered optical vortex (OV) beam illuminating on nanoslits is experimentally demonstrated. Because of the unique helical phase carried by an OV beam, dynamic control of SPP multiple focusing and standing wave generation is realized by changing the OV beam's topological charge constituent with the help of a liquid-crystal spatial light modulator. Measurement of SPP distributions with near-field scanning optical microscopy showed an excellent agreement with numerical predictions. The proposed phase modulation technique for manipulating SPPs features has seemingly dynamic and reconfigurable advantages, with profound potential for development of SPP coupling, routing, multiplexing and high-resolution imaging devices on plasmonic chips. PMID:22948098

  11. An all-optical modulation method in sub-micron scale

    PubMed Central

    Yang, Longzhi; Pei, Chongyang; Shen, Ao; Zhao, Changyun; Li, Yan; Li, Xia; Yu, Hui; Li, Yubo; Jiang, Xiaoqing; Yang, Jianyi

    2015-01-01

    We report a theoretical study showing that by utilizing the illumination of an external laser, the Surface Plasmon Polaritons (SPP) signals on the graphene sheet can be modulated in the sub-micron scale. The SPP wave can propagate along the graphene in the middle infrared range when the graphene is properly doped. Graphene's carrier density can be modified by a visible laser when the graphene sheet is exfoliated on the hydrophilic SiO2/Si substrate, which yields an all-optical way to control the graphene's doping level. Consequently, the external laser beam can control the propagation of the graphene SPP between the ON and OFF status. This all-optical modulation effect is still obvious when the spot size of the external laser is reduced to 400 nm while the modulation depth is as high as 114.7 dB/μm. PMID:25777581

  12. An all-optical modulation method in sub-micron scale.

    PubMed

    Yang, Longzhi; Pei, Chongyang; Shen, Ao; Zhao, Changyun; Li, Yan; Li, Xia; Yu, Hui; Li, Yubo; Jiang, Xiaoqing; Yang, Jianyi

    2015-01-01

    We report a theoretical study showing that by utilizing the illumination of an external laser, the Surface Plasmon Polaritons (SPP) signals on the graphene sheet can be modulated in the sub-micron scale. The SPP wave can propagate along the graphene in the middle infrared range when the graphene is properly doped. Graphene's carrier density can be modified by a visible laser when the graphene sheet is exfoliated on the hydrophilic SiO2/Si substrate, which yields an all-optical way to control the graphene's doping level. Consequently, the external laser beam can control the propagation of the graphene SPP between the ON and OFF status. This all-optical modulation effect is still obvious when the spot size of the external laser is reduced to 400 nm while the modulation depth is as high as 114.7 dB/μm. PMID:25777581

  13. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    PubMed

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules. PMID:27410896

  14. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    PubMed

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules.

  15. Fiber optic (flight quality) sensors for advanced aircraft propulsion

    NASA Technical Reports Server (NTRS)

    Poppel, Gary L.

    1994-01-01

    Development of flight prototype, fiber-optic sensing system components for measuring nine sensed parameters (three temperatures, two speeds, three positions, and one flame) on an F404-400 aircraft engine is described. Details of each sensor's design, functionality, and environmental testing, and the electro-optics architecture for sensor signal conditioning are presented. Eight different optical sensing techniques were utilized. Design, assembly, and environmental testing of an engine-mounted, electro-optics chassis unit (EOU), providing MIL-C-1553 data output, are related. Interconnection cables and connectors between the EOU and the sensors are identified. Results of sensor/cable/circuitry integrated testing, and installation and ground testing of the sensor system on an engine in October 1993 and April 1994 are given, including comparisons with the engine control system's electrical sensors. Lessons learned about the design, fabrication, testing, and integration of the sensor system components are included.

  16. Recent advances in reaction bonded silicon carbide optics and optical systems

    NASA Astrophysics Data System (ADS)

    Robichaud, Joseph; Schwartz, Jay; Landry, David; Glenn, William; Rider, Brian; Chung, Michael

    2005-08-01

    SSG Precision Optronics, Inc. (SSG) has recently developed a number of Reaction Bonded (RB) Silicon Carbide (SiC) optical systems for space-based remote sensing and astronomical observing applications. RB SiC's superior material properties make it uniquely well suited to meet the image quality and long term dimensional stability requirements associated with these applications. An overview of the RB SiC manufacturing process is presented, along with a summary description of recently delivered RB SiC flight hardware. This hardware includes an RB SiC telescope and Pointing Mirror Assembly (PMA) for the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) mission and an imaging telescope for the Long-Range Reconnaissance Imager (LORRI) mission. SSG continues to advance the state-of-the-technology with SiC materials and systems. A summary of development activities related to a low-cost, fracture tough, fiber reinforced RB SiC material formulation, novel tooling to produce monolithic, partially closed back mirror geometries, and extension of the technology to large aspheric mirrors is also provided.

  17. Chiral, J-Aggregate-Forming Dyes for Alternative Signal Modulation Mechanisms in Self-Immolative Enzyme-Activatable Optical Probes.

    PubMed

    Sloniec-Myszk, Jagoda; Resch-Genger, Ute; Hennig, Andreas

    2016-02-11

    Enzyme-activatable optical probes are important for future advances in cancer imaging, but may easily suffer from low signal-to-background ratios unless not optimized. To address this shortcoming, numerous mechanisms to modulate the fluorescence signal have been explored. We report herein newly synthesized probes based on self-immolative linkers containing chiral J-aggregate-forming dyes. Signal modulation by formation of chiral J-aggregates is yet unexplored in optical enzyme probe design. The comprehensive characterization of the probes by absorption, CD, fluorescence, and time-resolved fluorescence spectroscopy revealed dye-dye interactions not observed for the free dyes in solution as well as dye-protein interactions with the enzyme. This suggested that J-aggregate formation is challenging to achieve with current probe design and that interactions of the dyes with the enzyme may interfere with achieving high signal-to-background ratios. The detailed understanding of the interactions provided herein provides valuable guidelines for the future design of similar probes.

  18. Crystalline/amorphous tungsten oxide core/shell hierarchical structures and their synergistic effect for optical modulation.

    PubMed

    Zhou, D; Xie, D; Shi, F; Wang, D H; Ge, X; Xia, X H; Wang, X L; Gu, C D; Tu, J P

    2015-12-15

    High-performance electrochromic films with large color contrast and fast switching speed are of great importance for developing advanced smart windows. In this work, crystalline/amorphous WO3 core/shell (c-WO3@a-WO3) nanowire arrays rationally are synthesized by combining hydrothermal and electrodeposition methods. The 1D c-WO3@a-WO3 core/shell hierarchical structures show a synergistic effect for the enhancement of optical modulation, especially in the infrared (IR) region. By optimizing the electrodeposition time of 400s, the core/shell array exhibits a significant optical modulation (70.3% at 750nm, 42.0% at 2000nm and 51.4% at 10μm), fast switching speed (3.5s and 4.8s), high coloration efficiency (43.2cm(2)C(-1) at 750nm) and excellent cycling performance (68.5% after 3000 cycles). The crystalline/amorphous nanostructured film can provide an alternative way for developing high-performance electrochromic materials. PMID:26321573

  19. Advances and problems in plasma-optical mass-separation

    SciTech Connect

    Bardakov, V. M.; Ivanov, S. D.; Strokin, N. A.

    2014-03-15

    This paper presents a short review of plasma-optical mass-separation and defines the fields for its possible application. During theoretical studies, numerical simulations, and experiments, the effect of the azimuthator finite size and of the vacuum conditions on the mass separator characteristics was revealed, as well as the quality of different-mass ion separation. The problems, solving which may lead to a successful end of the mass-separation plasma-optical technique implementation, were specified.

  20. Advances in fiber optic sensors for in-vivo monitoring

    NASA Astrophysics Data System (ADS)

    Baldini, Francesco; Mignani, Anna G.

    1995-09-01

    Biomedical fiber-optic sensors are attractive for the measurement of both physical and chemical parameters as well as for spectral measurements directly performed on the patient. An overview of fiber-optic sensors for in vivo monitoring is given, with particular attention to the advantages that these sensors are able to offer in different fields of application such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology, and dentistry.