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Sample records for synchronic optical transmission

  1. New low-complexity and robust time synchronization technique for optical IMDD OFDM transmissions.

    PubMed

    Truong, Tuan-Anh; Arzel, Matthieu; Lin, Hao; Jahan, Bruno; Jezequel, Michel

    2014-06-16

    This paper provides an analysis of the performance of conventional preamble-based time synchronization techniques, which have been proposed for Orthogonal Frequency Division Multiplexing (OFDM) radio transmissions, in the context of optical Intensity Modulated and Direct Detected (IMDD) OFDM transmissions over single-mode fiber. A novel preamble structure along with a two-stage synchronization algorithm is proposed. Thanks to the particular structure of the preamble, a first coarse synchronization metric does not present minor peaks. In addition, without the knowledge of the preamble waveform the receiver can perform both coarse and fine synchronization steps. As maximal delay in arrival time between different frequency components of a signal depends on chromatic dispersion and the signal bandwidth, it is also observed that a slowly time-varying preamble is more robust than a fast time-varying one. By means of numerical simulations, the proposed method is shown to provide better performance when compared to other conventional methods in terms of timing offset variance with reduced receiver complexity. In unamplified transmissions the proposed technique guarantees a quasi-optimal transmission capacity even with a short cyclic prefix. PMID:24977530

  2. Carrier Synchronization for 3-and 4-bit-per-Symbol Optical Transmission

    NASA Astrophysics Data System (ADS)

    Ip, Ezra; Kahn, Joseph M.

    2005-12-01

    We investigate carrier synchronization for coherent detection of optical signals encoding 3 and 4 bits/symbol. We consider the effects of laser phase noise and of additive white Gaussian noise (AWGN), which can arise from local oscillator (LO) shot noise or LO-spontaneous beat noise. We identify 8-and 16-ary quadrature amplitude modulation (QAM) schemes that perform well when the receiver phase-locked loop (PLL) tracks the instantaneous signal phase with moderate phase error. We propose implementations of 8-and 16-QAM transmitters using Mach-Zehnder (MZ) modulators. We outline a numerical method for computing the bit error rate (BER) of 8-and 16-QAM in the presence of AWGN and phase error. It is found that these schemes can tolerate phase-error standard deviations of 2.48° and 1.24°, respectively, for a power penalty of 0.5 dB at a BER of 10-9. We propose a suitable PLL design and analyze its performance, taking account of laser phase noise, AWGN, and propagation delay within the PLL. Our analysis shows that the phase error depends on the constellation penalty, which is the mean power of constellation symbols times the mean inverse power. We establish a procedure for finding the optimal PLL natural frequency, and determine tolerable laser linewidths and PLL propagation delays. For zero propagation delay, 8-and 16-QAM can tolerate linewidth-to-bit-rate ratios of 1.8 × 10-5 and 1.4 × 10-6, respectively, assuming a total penalty of 1.0 dB.

  3. Robust hyperchaotic synchronization via analog transmission line

    NASA Astrophysics Data System (ADS)

    Sadoudi, S.; Tanougast, C.

    2016-02-01

    In this paper, a novel experimental chaotic synchronization technique via analog transmission is discussed. We demonstrate through Field-Programmable Gate Array (FPGA) implementation design the robust synchronization of two embedded hyperchaotic Lorenz generators interconnected with an analog transmission line. The basic idea of this work consists in combining a numerical generation of chaos and transmitting it with an analog signal. The numerical chaos allows to overcome the callback parameter mismatch problem and the analog transmission offers robust data security. As application, this technique can be applied to all families of chaotic systems including time-delayed chaotic systems.

  4. Synchronization of optically coupled resonant tunneling diode oscillators

    NASA Astrophysics Data System (ADS)

    Romeira, Bruno; Figueiredo, José M. L.; Ironside, Charles N.; Quintana, José M.

    2013-11-01

    We experimentally investigate the synchronous response of two fiber-optic coupled optoelectronic circuit oscillators based on resonant tunneling diodes (RTDs). The fiber-optic synchronization link employs injection of a periodic oscillating optical modulated signal generated by a master RTD-laser diode (LD) oscillator to a slave RTD-photodetector (PD) oscillator. The synchronous regimes were evaluated as a function of frequency detuning and optical injection strength. The results show the slave RTD-PD oscillator follows the frequency and noise characteristics of the master RTD-LD oscillator resulting in two oscillators with similar phase noise characteristics exhibiting single side band phase noise levels below -100 dBc/Hz at 1 MHz offset from the carrier frequency. Optical synchronization of RTD-based optoelectronic circuit oscillators have many applications spanning from sensing, to microwave generation, and data transmission.

  5. Spiking optical patterns and synchronization

    NASA Astrophysics Data System (ADS)

    Rosenbluh, Michael; Aviad, Yaara; Cohen, Elad; Khaykovich, Lev; Kinzel, Wolfgang; Kopelowitz, Evi; Yoskovits, Pinhas; Kanter, Ido

    2007-10-01

    We analyze the time resolved spike statistics of a solitary and two mutually interacting chaotic semiconductor lasers whose chaos is characterized by apparently random, short intensity spikes. Repulsion between two successive spikes is observed, resulting in a refractory period, which is largest at laser threshold. For time intervals between spikes greater than the refractory period, the distribution of the intervals follows a Poisson distribution. The spiking pattern is highly periodic over time windows corresponding to the optical length of the external cavity, with a slow change of the spiking pattern as time increases. When zero-lag synchronization between two lasers is established, the statistics of the nearly perfectly matched spikes are not altered. The similarity of these features to those found in complex interacting neural networks, suggests the use of laser systems as simpler physical models for neural networks.

  6. A Study of Synchronization Techniques for Optical Communication Systems

    NASA Technical Reports Server (NTRS)

    Gagliardi, R. M.

    1975-01-01

    The study of synchronization techniques and related topics in the design of high data rate, deep space, optical communication systems was reported. Data cover: (1) effects of timing errors in narrow pulsed digital optical systems, (2) accuracy of microwave timing systems operating in low powered optical systems, (3) development of improved tracking systems for the optical channel and determination of their tracking performance, (4) development of usable photodetector mathematical models for application to analysis and performance design in communication receivers, and (5) study application of multi-level block encoding to optical transmission of digital data.

  7. Synchronization using pulsed edge tracking in optical PPM communication system

    NASA Technical Reports Server (NTRS)

    Gagliardi, R.

    1972-01-01

    A pulse position modulated (PPM) optical communication system using narrow pulses of light for data transmission requires accurate time synchronization between transmitter and receiver. The presence of signal energy in the form of optical pulses suggests the use of a pulse edge tracking method of maintaining the necessary timing. The edge tracking operation in a binary PPM system is examined, taking into account the quantum nature of the optical transmissions. Consideration is given first to pure synchronization using a periodic pulsed intensity, then extended to the case where position modulation is present and auxiliary bit decisioning is needed to aid the tracking operation. Performance analysis is made in terms of timing error and its associated statistics. Timing error variances are shown as a function of system signal to noise ratio.

  8. Fiber optic data transmission

    NASA Technical Reports Server (NTRS)

    Shreve, Steven T.

    1987-01-01

    The Ohio University Avionics Engineering Center is currently developing a fiber optic data bus transmission and reception system that could eventually replace copper cable connections in airplanes. The original form of the system will transmit information from an encoder to a transponder via a fiber optic cable. An altimeter and an altitude display are connected to a fiber optic transmitter by copper cable. The transmitter converts the altimetry data from nine bit parallel to serial form and send these data through a fiber optic cable to a receiver. The receiver converts the data using a cable similar to that used between the altimeter and display. The transmitting and receiving ends also include a display readout. After completion and ground testing of the data bus, the system will be tested in an airborne environment.

  9. Bidirectional synchronization and hierarchical error correction for robust image transmission

    NASA Astrophysics Data System (ADS)

    Li, HongZhi; Chen, Chang W.

    1998-12-01

    In this paper, we present a novel joint source and channel image coding scheme for noisy channel transmission. The proposed scheme consists of two innovative components: (1) Intelligent bi-directional synchronization, and (2) Layered bit-plane error protection. The bi-directional synchronization is able to recover the coding synchronization when any single or even when two consecutive synchronization codes are corrupted by the channel noise. With synchronized partition, unequal error protection for each bit-plane can be designed to suit for a wide range of channel environments. The hierarchical error protection strategy is based on the analysis of bit-plane error sensitivity, aiming at achieving an optimal joint source and channel coding when the compressed image data are transmitted over noisy channels. Experimental results over extensive channel simulations show that the proposed scheme outperforms the approach proposed by Sherwood and Zeger who have reported the best numerical results in the literature.

  10. Data transmission optical link for RF-GUN project

    NASA Astrophysics Data System (ADS)

    Olowski, Krzysztof; Zielinski, Jerzy; Jalmuzna, Wojciech; Pozniak, Krzysztof; Romaniuk, Ryszard

    2005-09-01

    Today, the fast optical data transmission is one of the fundamentals of modern distributed control systems. The fibers are widely use as multi-gigabit data stream medium. For a short range transmission, the multimode fibers are in common use. The data rate for this kind of transmission exceeds 10 Gbps for 10 Gigabit Ethernet and 10G Fibre Channel protocols. The Field Programmable Gate Arrays are one of the opportunities of managing the optical transmission. This article is concerning a synchronous optical transmission system via a multimode fiber. The transmission is controlled by the FPGA of two manufacturers: Xilinx and Altera. This paper contains the newest technology overview and market device parameters. It also describes a board for the optical transmission, technical details of the transmission and optical transmission results.

  11. Dual-control nonlinear-optical loop mirrors for all-optical soliton synchronous modulation

    NASA Astrophysics Data System (ADS)

    Bigo, Sébastien; Desurvire, Emmanuel; Audouin, Olivier

    1996-09-01

    A novel dual-control configuration of nonlinear loop mirrors is used for all-optical soliton synchronous regeneration. Simulations show substantial improvement in transmission in this device compared with single-control devices, owing to chirp-free modulation. The absence of chirp is confirmed experimentally through a spectral analysis of the dual-control modulator.

  12. Investigation on the synchronized characteristics of the incoherent optical feedback chaotic system

    NASA Astrophysics Data System (ADS)

    Xu, Li; Wu, Zhengmao; Li, Linfu; Fan, Li; Fan, Yan; Xia, Guangqiong

    2007-11-01

    Based on the theoretical model of the synchronization system with incoherent optical feedback, the influence of the internal parameter mismatch on the synchronized characteristics of the chaotic system has been investigated. The result shows that the chaotic system with incoherent optical feedback can be realized more easily than the complete synchronized system, and has higher security than injection locking synchronization system. Using encoding of chaos shift keying, the message can be hidden efficiently during the transmission in the system and decoded easily in receiver.

  13. Stealth transmission of temporal phase en/decoded polarization-modulated-code-shift-keying optical-code-division multiple-access signal over synchronous digital hierarchy network with asynchronous detection

    NASA Astrophysics Data System (ADS)

    Chen, Yinfang; Wang, Rong; Fang, Tao; Pu, Tao; Xiang, Peng; Zhu, Huatao; Zheng, Jilin

    2014-06-01

    An innovative approach for security-enhanced optical stealth transmission in a synchronous digital hierarchy network is proposed and experimentally investigated. The security enhancement is achieved through a signal modulation format, so-called polarization-modulated-code-shift-keying, which is implemented with two superstructured fiber Bragg gratings-based optical-code-division multiple-access encoders and a polarization modulator. The proposed modulation format can provide a constant energy level for both bits 0's and 1's, which avoids secure vulnerability of single-stealth-user with on-off-keying modulation before coupling into the host channel and after the cascade of filters. Moreover, a self-made cost-effective gain-switched distributed feedback laser with relatively narrow spectrum is first employed as a stealth optical source, which greatly reduces the system cost and complexity. The stealth signal is recovered and detected asynchronously. The experimental results show high secure performance and robustness against eavesdropping, while keeping a bit error rate below forward error correction limit.

  14. All optical OFDM transmission systems

    NASA Astrophysics Data System (ADS)

    Rhee, June-Koo K.; Lim, Seong-Jin; Kserawi, Malaz

    2011-12-01

    All-optical OFDM data transmission opens up a new realm of advanced optical transmission at extreme data rates, as subcarriers are multiplexed and demultiplexed by all optical discrete Fourier transforms (DFT). This paper reviews the principles of all optical OFDM transmission and its system application techniques, providing the generic ideas and the practical implementation issues to achieve 100Gbps or higher data rates with a spectral efficiency of 1 bps/Hz or better. This paper also include discussions on all-optical OFDM implementation variants such as an AWG-based OFDM multiplexer and demultiplexer, a receiver design without optical sampling, a transmitter design with frequency-locked cw lasers, an OFDM cyclic prefix designs, and a chromatic dispersion mitigation technique.

  15. A fiber optic synchronization system for LUX

    SciTech Connect

    Wilcox, R.B.; Staples, J.W.; Doolittle, L.R.

    2004-06-30

    The LUX femtosecond light source concept would support pump-probe experiments that need to synchronize laser light pulses with electron-beam-generated X-ray pulses to less than 50 fs at the experimenter endstations. To synchronize multiple endstation lasers with the X-ray pulse, we are developing a fiber-distributed optical timing network. A high frequency clock signal is distributed via fiber to RF cavities (controlling X-ray probe pulse timing) and mode-locked lasers at endstations (controlling pump pulse timing). The superconducting cavities are actively locked to the optical clock phase. Most of the RF timing error is contained within a 10 kHz bandwidth, so these errors and any others affecting X-ray pulse timing (such as RF gun phase) can be detected and transmitted digitally to correct laser timing at the endstations. Time delay through the fibers will be stabilized by comparing a retro-reflected pulse from the experimenter endstation end with a reference pulse from the sending en d, and actively controlling the fiber length.

  16. Effects of unwanted feedback on synchronized chaotic optical communications

    NASA Astrophysics Data System (ADS)

    Li, Xiaofeng; Pan, Wei; Luo, Bin; Ma, Dong

    2006-04-01

    The effects of unwanted external optical feedback on synchronized chaotic optical communication systems are studied numerically. We consider an open-loop configuration consisting of a transmitter laser with double external optical feedbacks and a receiver laser with optical injection from the transmitter laser. First, including the effects of unwanted optical feedback, the synchronization performances of both the complete synchronization and the generalized synchronization are examined. Then the encoding and decoding performances of the generalized synchronization and the effects of the introduced feedback are investigated, respectively. Finally, we study the control of the unwanted feedback on the dynamics of the transmitter laser and briefly discuss the system security when the transmitter laser is driven to operate in a steady state or periodic oscillation state by the additional feedback.

  17. Method of joint frame synchronization and data-aided channel estimation for 100-Gb/s polarization-division multiplexing-single carrier frequency domain equalization coherent optical transmission systems

    NASA Astrophysics Data System (ADS)

    Cheng, Yun; Tan, Jun; Liu, Liu; He, Jing; Tang, Jin; Chen, Lin; Zhang, Jun; Li, Qiang; Xiao, Minlei

    2016-02-01

    To improve the performance of channel estimation (CE), a method of joint frame synchronization and data-aided CE using less training overhead is proposed. A 100-Gb/s polarization-division multiplexing coherent transmission system with quaternary phase-shift keying based on the proposed method is demonstrated by simulation. The simulation results show that the proposed method could achieve accurate timing offset and CE in the presence of strong amplified spontaneous emission noise.

  18. Transmission of radiometer data from the Synchronous Meteorological Satellite

    NASA Technical Reports Server (NTRS)

    Davies, R. S.

    1973-01-01

    The Synchronous Meteorological Satellite uses a spin scanner radiometer which generates eight visual signals and two infrared signals. These signals are multiplexed and converted into a 28-Mbps data stream. This signal is transmitted to ground by quadriphase modulation at 1686.1 MHz. On the ground, the digital signal is reconstructed to an analog signal. To conserve bandwidth, an analog-to-digital converter with a nonlinear transfer function was used for the visual signals. The size of the quantization step was made proportional to the noise output of the scanner photomultiplier tube which increases as the square root of incident light. The radiometer data transmission link was simulated on a digital computer to determine the transfer function. Some results of the simulation are shown.

  19. Performance of PLL synchronized optical PPM communication systems

    NASA Technical Reports Server (NTRS)

    Chen, C.-C.; Gardner, C. S.

    1986-01-01

    Receiver timing synchronization of an optical PPM communication system can be achieved using a phase-locked loop (PLL) if the photodetector output is properly processed. The synchronization performance is shown to improve with increasing signal power and decreasing loop bandwidth. The bit error rate performance of the PLL synchronized PPM system is analyzed and compared to that of the perfectly synchronized system. It is shown that the increase in signal power needed to compensate for the imperfect sychronization is small (less than 0.1 dB) for loop bandwidths less than 0.1 percent of the slot frequency.

  20. Dynamics and Synchronization of Semiconductor Lasers for Chaotic Optical Communications

    NASA Astrophysics Data System (ADS)

    Liu, Jia-Ming; Chen, How-Foo; Tang, Shuo

    The objective of this chapter is to provide a complete picture of the nonlinear dynamics and chaos synchronization of single-mode semiconductor lasers for chaotic optical communications. Basic concepts and theoretical framework are reviewed. Experimental results are presented to demonstrate the fundamental concepts. Numerical computations are employed for mapping the dynamical states and for illustrating certain detailed characteristics of the chaotic states. Three different semiconductor laser systems, namely, the optical injection system, the optical feedback system, and the optoelectronic feedback system, that are of most interest for high-bit-rate chaotic optical communications are considered. The optical injection system is a nonautonomous system that follows a period-doubling route to chaos. The optical feedback system is a phase-sensitive delayed-feedback autonomous system for which all three known routes, namely, period-doubling, quasiperiodicity, and intermittency, to chaos can be found. The optical feedback system is a phase-insensitive delayed-feedback autonomous system that follows a quasiperiodicity route to chaotic pulsing. Identical synchronization in unidirectionally coupled configurations is the focus of discussions for chaotic communications. For optical injection and optical feedback systems, the frequency, phase, and amplitude of the optical fields of both transmitter and receiver lasers are all locked in synchronism when complete synchronization is accomplished. For the optoelectronic feedback system, chaos synchronization involves neither the locking of the optical frequency nor the synchronization of the optical phase. For both optical feedback and optoelectronic feedback systems, where the transmitter is configured with a delayed feedback loop, anticipated and retarded synchronization can be observed as the difference between the feedback delay time and the propagation time from the transmitter laser to the receiver laser is varied. For a

  1. Synchronization of Distant Optical Clocks at the Femtosecond Level

    NASA Astrophysics Data System (ADS)

    Deschênes, Jean-Daniel; Sinclair, Laura C.; Giorgetta, Fabrizio R.; Swann, William C.; Baumann, Esther; Bergeron, Hugo; Cermak, Michael; Coddington, Ian; Newbury, Nathan R.

    2016-04-01

    The use of optical clocks or oscillators in future ultraprecise navigation, gravitational sensing, coherent arrays, and relativity experiments will require time comparison and synchronization over terrestrial or satellite free-space links. Here, we demonstrate full unambiguous synchronization of two optical time scales across a free-space link. The time deviation between synchronized time scales is below 1 fs over durations from 0.1 to 6500 s, despite atmospheric turbulence and kilometer-scale path length variations. Over 2 days, the time wander is 40 fs peak to peak. Our approach relies on the two-way reciprocity of a single-spatial-mode optical link, valid to below 225 attoseconds across a turbulent 4-km path. This femtosecond level of time-frequency transfer should enable optical networks using state-of-the-art optical clocks or oscillators.

  2. A synchronous phase detection system for an optical interferometric sensor

    NASA Astrophysics Data System (ADS)

    Bush, I. J.

    1982-05-01

    A system has been developed to accurately detect phase produced in optical interferometric sensors. The system employs optical heterodyning, and it synchronously detects optical phase by feeding an error signal back to a phase modulator in the reference leg of the interferometer. This system is seen to have properties similar to a phase-locked loop used for the demodulation of FM signals. The system model is second order and nonlinear, but a linear approximation serves to accurately describe the system in synchronous operation and is corroborated with well-matched empirical data. The complete model is simulated via computer techniques and is needed to describe the system's parameters that lead to loss and reacquisition of synchronization.

  3. Synchronization

    NASA Astrophysics Data System (ADS)

    Pikovsky, Arkady; Rosenblum, Michael; Kurths, Jürgen

    2003-04-01

    Preface; 1. Introduction; Part I. Synchronization Without Formulae: 2. Basic notions: the self-sustained oscillator and its phase; 3. Synchronization of a periodic oscillator by external force; 4. Synchronization of two and many oscillators; 5. Synchronization of chaotic systems; 6. Detecting synchronization in experiments; Part II. Phase Locking and Frequency Entrainment: 7. Synchronization of periodic oscillators by periodic external action; 8. Mutual synchronization of two interacting periodic oscillators; 9. Synchronization in the presence of noise; 10. Phase synchronization of chaotic systems; 11. Synchronization in oscillatory media; 12. Populations of globally coupled oscillators; Part III. Synchronization of Chaotic Systems: 13. Complete synchronization I: basic concepts; 14. Complete synchronization II: generalizations and complex systems; 15. Synchronization of complex dynamics by external forces; Appendix 1. Discovery of synchronization by Christiaan Huygens; Appendix 2. Instantaneous phase and frequency of a signal; References; Index.

  4. Efficient signal transmission by synchronization through compound chaotic signal

    NASA Astrophysics Data System (ADS)

    Murali, K.; Lakshmanan, M.

    1997-07-01

    The idea of synchronization of chaotic systems is further extended to the case where all the drive system variables are combined suitably to obtain a compound chaotic signal. An appropriate feedback loop is constructed in the response system to achieve synchronization among the variables of the drive and response systems. We apply this approach to transmit both analog and digital data signals in which the quality of the recovered signal is higher and the encoding is more secure.

  5. Inter-Symbol Guard Time for Synchronizing Optical PPM

    NASA Technical Reports Server (NTRS)

    Far, William; Gin, Jonathan; Srinivasan, Meera; Quirk, Kevin

    2009-01-01

    An inter-symbol guard time has been proposed as a means of synchronizing the symbol and slot clocks of an optical pulse-position modulation (PPM) receiver with the symbol and slot periods of an incoming optical PPM signal.The proposal is applicable to the low-flux case in which the receiver photodetector operates in a photon-counting mode and the count can include contributions from incidental light sources and dark current.

  6. Word and frame synchronization with verification for PPM optical communications

    NASA Technical Reports Server (NTRS)

    Marshall, William K.

    1986-01-01

    A method for obtaining word and frame synchronization in pulse position modulated optical communication systems is described. The method uses a short sync sequence inserted at the beginning of each data frame and a verification procedure to distinguish between inserted and randomly occurring sequences at the receiver. This results in an easy to implement sync system which provides reliable synchronization even at high symbol error rates. Results are given for the application of this approach to a highly energy efficient 256-ary PPM test system.

  7. 40 Gb/s dynamic wavelength-division-multiplexing/time-division-multiplexing hybrid access network with energy and data stream synchronized transmission.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Liu, Lei

    2013-09-15

    A dynamic wavelength-division-multiplexing/time-division-multiplexing hybrid access network with energy and data synchronized transmission is proposed to support flexible resource allocation. Dynamic scheduling of wavelength with different split ratio nodes is realized by the control model at the optical distribution network (ODN). All-optical amplification of the optical data signal and energy supply are also incorporated in the ODN. A proof-of-concept experiment is implemented to verify the feasibility of the proposal. PMID:24104799

  8. Photonic layer security in fiber-optic networks and optical OFDM transmission

    NASA Astrophysics Data System (ADS)

    Wang, Zhenxing

    Currently the Internet is experiencing an explosive growth in the world. Such growth leads to an increased data transmission rate demand in fiber-optical networks. Optical orthogonal frequency multiplexing (OFDM) is considered as a promising solution to achieve data rate beyond 100Gb/s per wavelength channel. In the meanwhile, because of extensive data transmission and sharing, data security has become an important problem and receives considerable attention in current research literature. This thesis focuses on data security issues at the physical layer of optical networks involving code-division multiple access (CDMA) systems and steganography methods. The thesis also covers several implementation issues in optical OFDM transmission. Optical CDMA is regarded as a good candidate to provide photonic layer security in multi-access channels. In this thesis we provide a systematic analysis of the security performance of incoherent optical CDMA codes. Based on the analysis, we proposed and experimentally demonstrated several methods to improve the security performance of the optical CDMA systems, such as applying all-optical encryption, and code hopping using nonlinear wavelength conversion. Moreover, we demonstrate that the use of wireless CDMA codes in optical systems can enhance the security in one single-user end-to-end optical channel. Optical steganography is another method to provide photonic data security and involves hiding the existence of data transmissions. In the thesis, we demonstrate that an optical steganography channel can exist in phase modulated public channels as well as traditional on-off-keying (OOK) modulated channels, without data synchronization. We also demonstrate an optical steganography system with enhanced security by utilizing temporal phase modulation techniques. Additionally, as one type of an overlay channel, the optical steganography technology can carry the sensor data collected by wireless sensor network on top of public optical

  9. Improved superimposed training sequence-based timing synchronization for space optical orthogonal frequency division multiplexing system

    NASA Astrophysics Data System (ADS)

    Wang, Ruyan; Wang, Xiaobing; Zhao, Hui

    2015-10-01

    This paper investigates the timing synchronization problem of a space optical orthogonal frequency division multiplexing (OOFDM) communication system. First, based on the good autocorrelation property of generalized chirp-like sequence, a training sequence is constructed to fit the non-negative light intensity signal requirement of the OOFDM system, of which the front and rear portions are cyclical and the whole is mirror-symmetric. No longer a periodic-repetition structure, the mirror-symmetric structure can effectively avoid the side lobe of objective function and reduce the complexity of correlation calculation, and thereby can improve the synchronization performance. Then, the constructed training sequence is superimposed on a complete data symbol for transmission to efficiently utilize transmitting power and spectrum resources of the communication system. At the receiver, the position of timing synchronization is estimated using maximum-likelihood algorithm and the correlation between the local sequence and the received signal. Simulation results show that, compared with several existing methods, the proposed timing synchronization method achieves better synchronization performances under both strong and weak atmospheric turbulence channels.

  10. Optical synchronization system for femtosecond X-ray sources

    DOEpatents

    Wilcox, Russell B.; Holzwarth, Ronald

    2011-12-13

    Femtosecond pump/probe experiments using short X-Ray and optical pulses require precise synchronization between 100 meter-10 km separated lasers in a various experiments. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1-10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with various implementations. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range two single-frequency lasers separated by several teraHertz will be lock to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.

  11. Synchronous Spin Exchange Optical Pumping for Precision NMR

    NASA Astrophysics Data System (ADS)

    Korver, Anna; Weber, Josh; Thrasher, Daniel; Walker, Thad

    2016-05-01

    We present the successful execution of synchronous spin exchange optical pumping for precision NMR. In this novel form of NMR, the bias field is applied as a sequence of alkali 2 π pulses; the resulting transverse alkali polarization is then modulated at the NMR frequency and spin exchange collisions build up a transverse precessing noble gas polarization. As compared to longitudinally pumped NMR, this method suppresses the alkali frequency shift by over a factor of 2500. We also discuss how we use synchronous spin exchange optical pumping to excite two noble gas species simultaneously. With dual species operation, we are able to use one species to lock the magnetic field while the other is left to detect nonmagnetic interactions. This method promises to achieve NMR frequency uncertainties of 100nHz/√{ Hz}. Research supported by the NSF and Northrop-Grumman Corp.

  12. Synchronous Spin-Exchange Optical Pumping.

    PubMed

    Korver, A; Thrasher, D; Bulatowicz, M; Walker, T G

    2015-12-18

    We demonstrate a new approach to precision NMR with hyperpolarized gases designed to mitigate NMR shifts due to the alkali spin-exchange field. The NMR bias field is implemented as a sequence of alkali (Rb) 2π pulses, allowing the Rb polarization to be optically pumped transverse to the bias field. When the Rb polarization is modulated at the noble-gas (Xe) NMR resonance, spin-exchange collisions buildup a precessing transverse Xe polarization. We study and mitigate novel NMR broadening effects due to the oscillating spin-exchange field. Spin-exchange frequency shifts are suppressed 2500×, and Rb magnetometer gain measurements project photon shot-noise limited NMR frequency uncertainties below 10  nHz/sqrt[Hz]. PMID:26722919

  13. Synchronous Spin-Exchange Optical Pumping

    NASA Astrophysics Data System (ADS)

    Korver, A.; Thrasher, D.; Bulatowicz, M.; Walker, T. G.

    2015-12-01

    We demonstrate a new approach to precision NMR with hyperpolarized gases designed to mitigate NMR shifts due to the alkali spin-exchange field. The NMR bias field is implemented as a sequence of alkali (Rb) 2 π pulses, allowing the Rb polarization to be optically pumped transverse to the bias field. When the Rb polarization is modulated at the noble-gas (Xe) NMR resonance, spin-exchange collisions buildup a precessing transverse Xe polarization. We study and mitigate novel NMR broadening effects due to the oscillating spin-exchange field. Spin-exchange frequency shifts are suppressed 2500 ×, and Rb magnetometer gain measurements project photon shot-noise limited NMR frequency uncertainties below 10 nHz /√{Hz } .

  14. Synchronization of laser oscillators, associative memory, and optical neurocomputing

    NASA Astrophysics Data System (ADS)

    Hoppensteadt, Frank C.; Izhikevich, Eugene M.

    2000-09-01

    We investigate here possible neurocomputational features of networks of laser oscillators. Our approach is similar to classical optical neurocomputing where artificial neurons are lasers and connection matrices are holographic media. However, we consider oscillatory neurons communicating via phases rather than amplitudes. Memorized patterns correspond to synchronized states where the neurons oscillate with equal frequencies and with prescribed phase relations. The mechanism of recognition is related to phase locking.

  15. Miniature rotating transmissive optical drum scanner

    NASA Technical Reports Server (NTRS)

    Lewis, Robert (Inventor); Parrington, Lawrence (Inventor); Rutberg, Michael (Inventor)

    2013-01-01

    A miniature rotating transmissive optical scanner system employs a drum of small size having an interior defined by a circumferential wall rotatable on a drum axis, an optical element positioned within the interior of the drum, and a light-transmissive lens aperture provided at an angular position in the circumferential wall of the drum for scanning a light beam to or from the optical element in the drum along a beam azimuth angle as the drum is rotated. The miniature optical drum scanner configuration obtains a wide scanning field-of-view (FOV) and large effective aperture is achieved within a physically small size.

  16. Optical Synchronization Systems for Femtosecond X-raySources

    SciTech Connect

    Wilcox, Russell; Staples, John W.; Holzwarth, Ronald

    2004-05-09

    In femtosecond pump/probe experiments using short X-Ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error over 100 meter of glass fiber. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1 10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with a piezoelectric phase modulator. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range we will lock two single-frequency lasers separated by several tera Hertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.

  17. Laser diode array and transmission optics

    NASA Technical Reports Server (NTRS)

    Kwon, Jin H.

    1989-01-01

    Information on laser diode array and transmission optics is given in viewgraph form. Information is given on coherent combining of laser diode arrays, amplification through a laser diode array, the far field pattern of a laser diode transmitter, and beam diameter at receiver vs. transmission distance.

  18. Remote atomic clock synchronization via satellites and optical fibers

    NASA Astrophysics Data System (ADS)

    Piester, D.; Rost, M.; Fujieda, M.; Feldmann, T.; Bauch, A.

    2011-07-01

    In the global network of institutions engaged with the realization of International Atomic Time (TAI), atomic clocks and time scales are compared by means of the Global Positioning System (GPS) and by employing telecommunication satellites for two-way satellite time and frequency transfer (TWSTFT). The frequencies of the state-of-the-art primary caesium fountain clocks can be compared at the level of 10-15 (relative, 1 day averaging) and time scales can be synchronized with an uncertainty of one nanosecond. Future improvements of worldwide clock comparisons will require also an improvement of the local signal distribution systems. For example, the future ACES (atomic clock ensemble in space) mission shall demonstrate remote time scale comparisons at the uncertainty level of 100 ps. To ensure that the ACES ground instrument will be synchronized to the local time scale at the Physikalisch-Technische Bundesanstalt (PTB) without a significant uncertainty contribution, we have developed a means for calibrated clock comparisons through optical fibers. An uncertainty below 40 ps over a distance of 2 km has been demonstrated on the campus of PTB. This technology is thus in general a promising candidate for synchronization of enhanced time transfer equipment with the local realizations of Coordinated Universal Time UTC. Based on these experiments we estimate the uncertainty level for calibrated time transfer through optical fibers over longer distances. These findings are compared with the current status and developments of satellite based time transfer systems, with a focus on the calibration techniques for operational systems.

  19. Power transmission by laser beam from lunar-synchronous satellite

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Deyoung, R. J.; Schuster, G. L.; Choi, S. H.; Dagle, J. E.; Coomes, E. P.; Antoniak, Z. I.; Bamberger, J. A.; Bates, J. M.; Chiu, M. A.

    1993-01-01

    The possibility of beaming power from synchronous lunar orbits (the L1 and L2 Lagrange points) to a manned long-range lunar rover is addressed. The rover and two versions of a satellite system (one powered by a nuclear reactor, the other by photovoltaics) are described in terms of their masses, geometries, power needs, missions, and technological capabilities. Laser beam power is generated by a laser diode array in the satellite and converted to 30 kW of electrical power at the rover. Present technological capabilities, with some extrapolation to near future capabilities, are used in the descriptions. The advantages of the two satellite/rover systems over other such systems and over rovers with onboard power are discussed along with the possibility of enabling other missions.

  20. Synchronization of optical photons for quantum information processing

    PubMed Central

    Makino, Kenzo; Hashimoto, Yosuke; Yoshikawa, Jun-ichi; Ohdan, Hideaki; Toyama, Takeshi; van Loock, Peter; Furusawa, Akira

    2016-01-01

    A fundamental element of quantum information processing with photonic qubits is the nonclassical quantum interference between two photons when they bunch together via the Hong-Ou-Mandel (HOM) effect. Ultimately, many such photons must be processed in complex interferometric networks. For this purpose, it is essential to synchronize the arrival times of the flying photons and to keep their purities high. On the basis of the recent experimental success of single-photon storage with high purity, we demonstrate for the first time the HOM interference of two heralded, nearly pure optical photons synchronized through two independent quantum memories. Controlled storage times of up to 1.8 μs for about 90 events per second were achieved with purities that were sufficiently high for a negative Wigner function confirmed with homodyne measurements. PMID:27386536

  1. Synchronization of optical photons for quantum information processing.

    PubMed

    Makino, Kenzo; Hashimoto, Yosuke; Yoshikawa, Jun-Ichi; Ohdan, Hideaki; Toyama, Takeshi; van Loock, Peter; Furusawa, Akira

    2016-05-01

    A fundamental element of quantum information processing with photonic qubits is the nonclassical quantum interference between two photons when they bunch together via the Hong-Ou-Mandel (HOM) effect. Ultimately, many such photons must be processed in complex interferometric networks. For this purpose, it is essential to synchronize the arrival times of the flying photons and to keep their purities high. On the basis of the recent experimental success of single-photon storage with high purity, we demonstrate for the first time the HOM interference of two heralded, nearly pure optical photons synchronized through two independent quantum memories. Controlled storage times of up to 1.8 μs for about 90 events per second were achieved with purities that were sufficiently high for a negative Wigner function confirmed with homodyne measurements. PMID:27386536

  2. A synchronous fiber optic ring local area network for multigigabit/s mixed-traffic communication

    NASA Technical Reports Server (NTRS)

    Bergman, L. A.; Eng, S. T.

    1985-01-01

    A synchronous-ring fiber optic local area network is reported that facilitates the simultaneous transmission of packet and real-time traffic at gigabit/s rates, minimizes the amount of high-speed logic, and simplifies the user interface to the network. The novelty of the technique is based on (1) suspending in transit around the ring's circumference an integral number of data frames and (2) achieving this condition by skewing the frame clock rate a small amount. Rather than use the whole data frame as one packet destined to a specific user, many individual channels are instead time-multiplexed into the data frame. This technique only becomes feasible for local networks as data rates approach the Gbit/s range. This departure from other synchronous rings results in several advantages both in terms of system performance and hardware simplicity.

  3. Computer controlled synchronous shifting of an automatic transmission

    DOEpatents

    Davis, Roy I.; Patil, Prabhakar B.

    1989-01-01

    A multiple forward speed automatic transmission produces its lowest forward speed ratio when a hydraulic clutch and hydraulic brake are disengaged and a one-way clutch connects a ring gear to the transmission casing. Second forward speed ratio results when the hydraulic clutch is engaged to connect the ring gear to the planetary carrier of a second gear set. Reverse drive and regenerative operation result when an hydraulic brake fixes the planetary and the direction of power flow is reversed. Various sensors produce signals representing the torque at the output of the transmission or drive wheels, the speed of the power source, and the hydraulic pressure applied to a clutch and brake. A control algorithm produces input data representing a commanded upshift, a commanded downshift, a commanded transmission output torque, and commanded power source speed. A microprocessor processes the inputs and produces a response to them in accordance with the execution of a control algorithm. Output or response signals cause selective engagement and disengagement of the clutch and brake at a rate that satisfies the requirements for a short gear ratio change and smooth torque transfer between the friction elements.

  4. Computer controllable synchronous shifting of an automatic transmission

    DOEpatents

    Davis, R.I.; Patil, P.B.

    1989-08-08

    A multiple forward speed automatic transmission produces its lowest forward speed ratio when a hydraulic clutch and hydraulic brake are disengaged and a one-way clutch connects a ring gear to the transmission casing. Second forward speed ratio results when the hydraulic clutch is engaged to connect the ring gear to the planetary carrier of a second gear set. Reverse drive and regenerative operation result when an hydraulic brake fixes the planetary and the direction of power flow is reversed. Various sensors produce signals representing the torque at the output of the transmission or drive wheels, the speed of the power source, and the hydraulic pressure applied to a clutch and brake. A control algorithm produces input data representing a commanded upshift, a commanded downshift, a commanded transmission output torque, and commanded power source speed. A microprocessor processes the inputs and produces a response to them in accordance with the execution of a control algorithm. Output or response signals cause selective engagement and disengagement of the clutch and brake at a rate that satisfies the requirements for a short gear ratio change and smooth torque transfer between the friction elements. 6 figs.

  5. Electrochromic variable transmission optical combiner

    NASA Astrophysics Data System (ADS)

    Draper, Russell S.; Wood, Michael V.; Radmard, Bijan; Mahmud, Ken; Schuler, Peter; Sotzing, Gregory A.; Seshadri, Venkataraman; Mino, Warren; Padilla, Javier; Otero, Tobibio F.

    2005-05-01

    Complementary coloring conducting polymer based electrochromic devices have been designed, fabricated and tested for possible application as a variable attenuation combiner element for a see-through head mounted display or a variable trasnsmissive sand wind dust goggle lens. Electrochromic cells fabricated on both glass and polycarbonate substrates have been demonstrated to meet closely the desired goals of low power consumption, wide transmission range, fast switching speeds and long lifetime. Photopic transmissions of 34% in colored state and 67% in bleached state were achieved in a reproducible manner. The measured switching times are 0.6 sec (colored to bleached state) and 1.9 sec (bleached to colored state). The life cycle testing showed stability up to 92,000 switches. The measured power consumption of the fabricated devices was < 1 mW/cm . The electrochromic technology design effort has identified processes for obtaining the optimum layer thickness and selecting polymers and gel electrolytes necessary to obtain the widest transmission range, fastest switching speed and longest lifetime. Early environmental testing has been performed by subjecting prototype electrochromic cells to temperatures varying from -30°C to + 40°C with the results reported herein. Follow on work includes further optimization of electronic drive schemes as well as field testing of electrochromic lens equipped sand, wind dust goggles.

  6. Synchronization of colloidal rotors through angular optical binding

    NASA Astrophysics Data System (ADS)

    Simpson, S. H.; Chvátal, L.; Zemánek, P.

    2016-02-01

    A mechanism for the synchronization of driven colloidal rotors via optical coupling torques is presented and analyzed. Following our recent experiments [Brzobohatý et al., Opt. Express 23, 7273 (2015)], 10.1364/OE.23.007273, we consider a counterpropagating optical beam trap that carries spin angular momentum, but no net linear momentum, operating in an aqueous solvent. The angular momentum carried by the beams causes the continuous low-Reynolds-number rotation of spheroidal colloids. Due to multiple scattering, the optical torques experienced by these particles depend on their relative orientations, while the effect of hydrodynamic interaction is negligible. This results in frequency pulling, which causes weakly dissimilar spheroids to synchronize their rotation rates and lock their relative phases. The effect is qualitatively captured by a coupled dipole model and quantitatively reproduced by T -matrix calculations. For pairs of rotors, the relative torque Δ τ is shown to vary with relative phase Δ ϕ according to Δ τ ≈A sin(2 Δ ϕ +δ )+B for constants A ,B ,δ , so the resulting motion is governed by the well-known Adler equation. We show that this behavior can be preserved for larger numbers of particles. The application of these phenomena to the inertial motion of particles in vacuum could provide a route to the sympathetic cooling of mesoscopic particles.

  7. Solar light transmission of polymer optical fibers

    SciTech Connect

    Tekelioglu, Murat; Wood, Byard D.

    2009-11-15

    Light transfer (10 m) has been shown in recent experiments that used large-core optical fibers. Theoretical models are not extensive, however, and a further correlation between the theory and experiments has not been given. In this paper, straight and bent fiber subsystem models are introduced with skew and meridional rays to predict the light transmission of POFs (plastic optical fibers). Such fibers have been realized, for example, in HSL (hybrid solar lighting) systems. The purpose of this paper is to combine the straight and bent fiber subsystems to estimate the light transmission of HSL systems. It is shown that meridional rays, for which the optical-loss parameters were estimated, better represent the experimental results compared to skew rays ({+-}5.3% vs {+-}24.7% of %-difference). Model predictions were compared with the results of a commercial software. Sensitivity analysis on the subsystems indicated the most-to-least significant parameters in light transmission. (author)

  8. Spectrally efficient polymer optical fiber transmission

    NASA Astrophysics Data System (ADS)

    Randel, Sebastian; Bunge, Christian-Alexander

    2011-01-01

    The step-index polymer optical fiber (SI-POF) is an attractive transmission medium for high speed communication links in automotive infotainment networks, in industrial automation, and in home networks. Growing demands for quality of service, e.g., for IPTV distribution in homes and for Ethernet based industrial control networks will necessitate Gigabit speeds in the near future. We present an overview on recent advances in the design of spectrally efficient and robust Gigabit-over-SI-POF transmission systems.

  9. Synchronized amplification of local information transmission by peripheral retinal input.

    PubMed

    Jadzinsky, Pablo D; Baccus, Stephen A

    2015-01-01

    Sensory stimuli have varying statistics influenced by both the environment and by active sensing behaviors that rapidly and globally change the sensory input. Consequently, sensory systems often adjust their neural code to the expected statistics of their sensory input to transmit novel sensory information. Here, we show that sudden peripheral motion amplifies and accelerates information transmission in salamander ganglion cells in a 50 ms time window. Underlying this gating of information is a transient increase in adaptation to contrast, enhancing sensitivity to a broader range of stimuli. Using a model and natural images, we show that this effect coincides with an expected increase in information in bipolar cells after a global image shift. Our findings reveal the dynamic allocation of energy resources to increase neural activity at times of expected high information content, a principle of adaptation that balances the competing requirements of conserving spikes and transmitting information. PMID:26568312

  10. 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.

  11. Transmission in Optically Transparent Core Networks

    NASA Astrophysics Data System (ADS)

    Kilper, Dan; Jensen, Rich; Petermann, Klaus; Karasek, Miroslav

    2007-03-01

    Call for Papers: Transmission in Optically Transparent Core Networks

    Guest Feature Editors

    Dan Kilper and Rich Jensen, Coordinating Associate Editors Klaus Petermann and Miroslav Karasek, Guest Feature Editors

    Submission deadline: 15 June 2007
    Optically transparent networks in which optical transport signals are routed uninterrupted through multiple nodes have long been viewed as an important evolutionary step in fiber optic communications. More than a decade of research and development on transparent network technologies together with the requisite traffic growth has culminated in the recent deployment of commercial optically transparent systems. Although many of the traditional research goals of optical transmission remain important, optical transparency introduces new challenges. Greater emphasis is placed on system efficiency and control. The goal of minimizing signal terminations, which has been pursued through increasing reach and channel capacity, also can be realized through wavelength routing techniques. Rather than bounding system operation by rigid engineering rules, the physical layer is controlled and managed by automation tools. Many static signal impairments become dynamic due to network reconfiguration and transient fault events. Recently new directions in transmission research have emerged to address transparent networking problems. This special issue of the Journal of Optical Networking will examine the technologies and theory underpinning transmission in optically transparent core networks, including both metropolitan and long haul systems.

    Scope of Submission

    The special issue editors are soliciting high-quality original research papers related to transmission in optically transparent core networks. Although this does not include edge networks such as access or enterprise networks, core networks that have access capabilities will be considered in scope as will topics

  12. Synchronized amplification of local information transmission by peripheral retinal input

    PubMed Central

    Jadzinsky, Pablo D; Baccus, Stephen A

    2015-01-01

    Sensory stimuli have varying statistics influenced by both the environment and by active sensing behaviors that rapidly and globally change the sensory input. Consequently, sensory systems often adjust their neural code to the expected statistics of their sensory input to transmit novel sensory information. Here, we show that sudden peripheral motion amplifies and accelerates information transmission in salamander ganglion cells in a 50 ms time window. Underlying this gating of information is a transient increase in adaptation to contrast, enhancing sensitivity to a broader range of stimuli. Using a model and natural images, we show that this effect coincides with an expected increase in information in bipolar cells after a global image shift. Our findings reveal the dynamic allocation of energy resources to increase neural activity at times of expected high information content, a principle of adaptation that balances the competing requirements of conserving spikes and transmitting information. DOI: http://dx.doi.org/10.7554/eLife.09266.001 PMID:26568312

  13. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, Wallace B.; DuBois, David H.

    1996-01-01

    A system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway.

  14. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, W.B.; DuBois, D.H.

    1996-12-03

    Disclosed is a system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway. 7 figs.

  15. Spike phase synchronization in delayed-coupled neural networks: Uniform vs. non-uniform transmission delay

    NASA Astrophysics Data System (ADS)

    Jalili, Mahdi

    2013-03-01

    In this paper, we investigated phase synchronization in delayed dynamical networks. Non-identical spiking Hindmarsh-Rose neurons were considered as individual dynamical systems and coupled through a number of network structures such as scale-free, Erdős-Rényi, and modular. The individual neurons were coupled through excitatory chemical synapses with uniform or distributed time delays. The profile of spike phase synchrony was different when the delay was uniform across the edges as compared to the case when it was distributed, i.e., different delays for the edges. When an identical transmission delay was considered, a quasi-periodic pattern was observed in the spike phase synchrony. There were specific values of delay where the phase synchronization reached to its peaks. The behavior of the phase synchronization in the networks with non-uniform delays was different with the former case, where the phase synchrony decreased as distributed delays introduced to the networks.

  16. Optical chaos synchronization and encrypted communications of VCSEL by direct optical injection

    NASA Astrophysics Data System (ADS)

    Hosomi, Naohito; Sasaki, Wakao

    2014-09-01

    In this work, we propose electro-optical nonlinear delayed feedback systems (NDFS) for optical secure communications using VCSEL for the first time. Its optical output can perform more sensitive chaotic dynamics by varying only a few mA of injection current range resulting in very significant charges of VCSEL's operation conditions from threshold to maximum rating. This enables us to vary chaotic output dynamically by a slight difference of initial values in NDFS. We have proposed a chaos synchronization system using two identical NDFS's of VCSEL, and realized chaos synchronization by optical injection. As a result of experiment the correlation coefficient up to about 0.88 was obtained. Moreover, by varying the delay time and feedback gain in the parameters of NDFSs, we have confirmed that the variations of these parameters may affect variations of correlation.

  17. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, Wallace B.; DuBois, David H.

    1998-08-11

    A digital system provides sending and receiving gateways for HIPPI interfaces. Electronic logic circuitry formats data signals and overhead signals in a data frame that is suitable for transmission over a connecting fiber optic link. Multiplexers route the data and overhead signals to a framer module. The framer module allocates the data and overhead signals to a plurality of 9-byte words that are arranged in a selected protocol. The formatted words are stored in a storage register for output through the gateway.

  18. Synchronously pumped femtosecond optical parametric oscillator with broadband chirped mirrors

    NASA Astrophysics Data System (ADS)

    Stankevičiūte, Karolina; Melnikas, Simas; Kičas, Simonas; Trišauskas, Lukas; Vengelis, Julius; Grigonis, Rimantas; Vengris, Mikas; Sirutkaitis, Valdas

    2015-05-01

    We present results obtained during investigation of synchronously pumped optical parametric oscillator (SPOPO) with broadband complementary chirped mirror pairs (CMP). The SPOPO based on β-BBO nonlinear crystal is pumped by second harmonic of femtosecond Yb:KGW laser and provides signal pulses tunable over spectral range from 625 to 980 nm. More than 500 mW are generated in the signal beam, giving up to 27 % pump power to signal power conversion efficiency. The plane SPOPO cavity mirror pairs were specially designed to provide 99 % reflection in broad spectral range corresponding to signal wavelength tuning (630-1030 nm) and to suppress group delay dispersion (GDD) oscillations down to +/-10 fs2. Dispersion properties of designed mirrors were tested with white light interferometer (WLI) and attributed to the SPOPO tuning behaviour.

  19. Regeneration in synchronous optical network/WDM rings

    NASA Astrophysics Data System (ADS)

    Sevian, Armen R.

    2003-06-01

    In today's WDM all-optical networks, a majority of existing virtual topology design algorithms have ignored link-performance limiting factors such as dispersion, amplified spontaneous emission (ASE), cross talk resulting from signal leakage in optical cross connects (OXCs), and fiber nonlinearities. All these factors result in bit-error-rate (BER) degradation at the receiving end. To maintain a BER below a certain level, some lightpaths in the network will require regeneration at the intermediate nodes, thus, setting up a lightpath in a multihop manner. In synchronous optical network (SONET) ring networks, the terminal equipment cost associated with electronic multiplexing is predominantly high. Wavelength add-drop multiplexers reduce the amount of SONET terminal equipment at each node by allowing certain wavelengths or bands to bypass the node optically without being electronically terminated. Most of the previous research in this area has focused on the virtual topology design and wavelength-routing algorithms to address the cost savings. Here we consider both unidirectional path-switched and bidirectional line-switched rings (UPSR, BLSR/2) with optical bypass. We analytically derive a relationship for the number of regenerators to support both single-hub and all-to-all situations for uniform and nonuniform traffic cases with an arbitrary internodal length distribution. We obtain lower and upper bounds for regeneration cost on a ring when nodes are randomly placed. Equivalency is established between UPSR and BLSR/2 networks in terms of regeneration cost for cases of single link failure. Regeneration cost advantage is shown for nonzero dispersion-shifted fiber (NZDSF) over standard single-mode fiber in dispersion-limited regimes.

  20. Effects of transmission on Gaussian optical states.

    PubMed

    McKinstrie, C J; Marshall, K; Weedbrook, C

    2015-04-20

    The noise properties of phase-insensitive and phase-sensitive optical transmission links are described in detail, for Gaussian input signals. Formulas are derived for the quadrature covariance matrices of the output signals, which allow one to quantify the noise figures of the links and the fidelities of transmission. Another formula is derived, which relates the density operator of an output signal, in the number-state representation, to its covariance matrix. This density matrix allows one to quantify the decrease in coherence and changes in photon-number probabilities associated with transmission. Based on the aforementioned performance metrics, links with distributed phase-sensitive amplification perform significantly better than other links. PMID:25969122

  1. Optical Transmission Properties of Dielectric Aperture Arrays

    NASA Astrophysics Data System (ADS)

    Yang, Tao

    Optical detection devices such as optical biosensors and optical spectrometers are widely used in many applications for the functions of measurements, inspections and analysis. Due to the large dimension of prisms and gratings, the traditional optical devices normally occupy a large space with complicated components. Since cheaper and smaller optical devices are always in demand, miniaturization has been kept going for years. Thanks to recent fabrication advances, nanophotonic devices such as semiconductor laser chips have been growing in number and diversity. However, the optical biosensor chips and the optical spectrometer chips are seldom reported in the literature. For the reason of improving system integration, the study of ultra-compact, low-cost, high-performance and easy-alignment optical biosensors and optical spectrometers are imperative. This thesis is an endeavor in these two subjects and will present our research work on studying the optical transmission properties of dielectric aperture arrays and developing new optical biosensors and optical spectrometers. The first half of the thesis demonstrates that the optical phase shift associated with the surface plasmon (SP) assisted extraordinary optical transmission (EOT) in nano-hole arrays fabricated in a metal film has a strong dependence on the material refractive index value in close proximity to the holes. A novel refractive index sensor based on detecting the EOT phase shift is proposed by building a model. This device readily provides a 2-D biosensor array platform for non-labeled real-time detection of a variety of organic and biological molecules in a sensor chip format, which leads to a high packing density, minimal analyte volumes, and a large number of parallel channels while facilitating high resolution imaging and supporting a large space-bandwidth product (SBP). Simulation (FDTD Solutions, Lumerical Solutions Inc) results indicate an achievable sensitivity limit of 4.37x10-9 refractive index

  2. Phase locked loop synchronization for direct detection optical PPM communication systems

    NASA Technical Reports Server (NTRS)

    Chen, C. C.; Gardner, C. S.

    1985-01-01

    Receiver timing synchronization of an optical pulse position modulation (PPM) communication system can be achieved using a phase locked loop (PLL) if the photodetector output is properly processed. The synchronization performance is shown to improve with increasing signal power and decreasing loop bandwidth. Bit error rate (BER) of the PLL synchronized PPM system is analyzed and compared to that for the perfectly synchronized system. It is shown that the increase in signal power needed to compensate for the imperfect synchronization is small (less than 0.1 dB) for loop bandwidths less than 0.1% of the slot frequency.

  3. Blind symbol synchronization for direct detection optical OFDM using a reduced number of virtual subcarriers.

    PubMed

    Bouziane, R; Killey, R I

    2015-03-01

    Symbol synchronization constitutes a major component in optical OFDM transceivers. In this paper, we propose reducing the complexity of a blind symbol synchronization technique for direct detection OFDM receivers based on virtual subcarriers by optimizing the number and location of the virtual subcarriers. Compared to the system design in our previous study, this new technique offers a reduction of 92% in the number of virtual subcarriers (from 26 to 2 in a system with 50 data carrying subchannels) resulting in significant savings in complexity with a minimal penalty. Moreover, it offers an increase in the system capacity as more subcarriers can be used to transmit data. The technique was assessed experimentally using a transmission system of direct detection 16-QAM optical OFDM operating at a data rate of 30.65 Gb/s over 23.3 km SSMF with BER of 10(-3). Negligible penalty was observed at high received powers. However, at low received powers, the number of averaging symbols had to be increased in order to improve the robustness of the method. PMID:25836864

  4. Nonlinear optical transmission of cyanobacteria-derived optical materials

    NASA Astrophysics Data System (ADS)

    Zhao, Edward H.; Watanabe, Fumiya; Zhao, Wei

    2015-08-01

    Cyanobacteria-derived optical materials for optical limiting applications have been studied in this work. Six samples have been prepared from cyanobacteria including cyanobacteria suspension in water, extracts in water, methanol, and N,N-dimethylformamide, and pyrolyzed cyanobacteria (PCYB) dispersed in dsDNA (sodium salt from salmon testes) solution and sodium dodecyl sulfate solution, respectively. The extracts contain phycocyanin, chlorophyll a, and carotenoids as measured by optical absorption spectroscopy, while the PCYB is a nanostructural composite composed of multi-walled carbon nanotubes, carbon nanoringes, and multilayer graphenes, as revealed by transmission electron microscopy. The optical limiting responses of the samples have been measured at 532 and 756 nm. The PCYB in dsDNA solution has the best limiting performance out of all the cyanobacteria-derived samples. It outperforms carbon black suspension standard at 532 nm and is a broadband limiter, which makes it attractive for optical limiting applications.

  5. Synchronous and asynchronous modes of synaptic transmission utilize different calcium sources.

    PubMed

    Wen, Hua; Hubbard, Jeffrey M; Rakela, Benjamin; Linhoff, Michael W; Mandel, Gail; Brehm, Paul

    2013-01-01

    Asynchronous transmission plays a prominent role at certain synapses but lacks the mechanistic insights of its synchronous counterpart. The current view posits that triggering of asynchronous release during repetitive stimulation involves expansion of the same calcium domains underlying synchronous transmission. In this study, live imaging and paired patch clamp recording at the zebrafish neuromuscular synapse reveal contributions by spatially distinct calcium sources. Synchronous release is tied to calcium entry into synaptic boutons via P/Q type calcium channels, whereas asynchronous release is boosted by a propagating intracellular calcium source initiated at off-synaptic locations in the axon and axonal branch points. This secondary calcium source fully accounts for the persistence following termination of the stimulus and sensitivity to slow calcium buffers reported for asynchronous release. The neuromuscular junction and CNS neurons share these features, raising the possibility that secondary calcium sources are common among synapses with prominent asynchronous release. DOI: http://dx.doi.org/10.7554/eLife.01206.001. PMID:24368731

  6. Chaotic synchronization in Bose-Einstein condensate of moving optical lattices via linear coupling

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Ying; Feng, Xiu-Qin; Yao, Zhi-Hai; Jia, Hong-Yang

    2015-11-01

    A systematic study of the chaotic synchronization of Bose-Einstein condensed body is performed using linear coupling method based on Lyapunov stability theory, Sylvester’s criterion, and Gerschgorin disc theorem. The chaotic synchronization of Bose-Einstein condensed body in moving optical lattices is realized by linear coupling. The relationship between the synchronization time and coupling coefficient is obtained. Both the single-variable coupling and double-variable coupling are effective. The results of numerical calculation prove that the chaotic synchronization of double-variable coupling is faster than that of single-variable coupling and small coupling coefficient can achieve the chaotic synchronization. Weak noise has little influence on synchronization effect, so the linear coupling technology is suitable for the chaotic synchronization of Bose-Einstein condensate. Project supported by the Industrial Technology Research and Development Special Project of Jilin Province, China (Grant No. 2013C46) and the Natural Science Foundation of Jilin Province, China (Grant No. 20101510).

  7. Optical scanning cryptography for secure wireless transmission

    NASA Astrophysics Data System (ADS)

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-01

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

  8. Optical scanning cryptography for secure wireless transmission.

    PubMed

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-10

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea. PMID:14650492

  9. SINR Analysis of Hexagonal Multicarrier Transmission Systems in the Presence of Insufficient Synchronization for Doubly Dispersive Channel

    NASA Astrophysics Data System (ADS)

    Xu, Kui; Xu, Youyun; Zhang, Dongmei

    2011-07-01

    This paper analyzes the effect of the insufficient synchronization (carrier frequency offset, timing offset) on hexagonal multicarrier transmission (HMT) systems for doubly dispersive channel. Exact SINR and demodulated symbol expressions for HMT systems in the presence of insufficient synchronization transmission conditions over doubly dispersive channel with exponential delay power profile and U-shape Doppler power spectrum and uniform delay power profile and uniform Doppler power spectrum are derived, respectively. Theoretical analysis shows that similar degradations on symbol amplitude and phase caused by insufficient synchronization are incurred as in traditional cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) transmission. HMT systems outperform traditional OFDM systems with respect to signal to interference-plus-noise-ratio (SINR) against inter-symbol interference (ISI) and inter-carrier interference (ICI) caused by insufficient synchronization and doubly dispersive(DD) channel. The BER performance of the HMT systems using Monte Carlo simulation match with the conclusion given by the proposed exact SINR expression.

  10. Energy efficiency of optical grooming of QAM optical transmission channels.

    PubMed

    Bhopalwala, Mariya; Rastegarfar, Houman; Kilper, Daniel C; Wang, Michael; Bergman, Keren

    2016-02-01

    Analysis of the energy use for optical grooming of quadrature amplitude modulated signals in optical transmission systems is used to determine the potential efficiency benefits. An energy model is developed for both optical and electronic grooming and used to study the relative efficiency for three different network scenarios. The energy efficiency is evaluated considering both coherent and direct detection transceivers including power management strategies. Results indicate efficiency improvements up to an order of magnitude may be possible for 100 GBaud rates and 25-30 GBaud is a critical point at which optical grooming becomes the more efficient approach. These results are further shown to apply for the case of projected efficiency improvements in the underlying device technologies. PMID:26906845

  11. Transmissive Diffractive Optical Element Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

    Solar-thermal-radiation concentrators in the form of transmissive diffractive optical elements (DOEs) have been proposed as alternatives to mirror-type solar concentrators now in use. In comparison with functionally equivalent mirror-type solar concentrators, the transmissive, diffractive solar concentrators would weigh and cost less, and would be subject to relaxed mechanical tolerances. A DOE concentrator would be made from a thin, flat disk or membrane of a transmissive material having a suitable index of refraction. By virtue of its thinness, the DOE concentrator would have an areal mass density significantly less than that of a functionally equivalent conventional mirror. The DOE concentrator would have a relatively wide aperture--characterized by a focal-length/aperture-diameter ratio ('f number') on the order of 1. A kinoform (a surface-relief phase hologram) of high diffractive order would be microfabricated onto one face of the disk. The kinoform (see figure) would be designed to both diffract and refract incident solar radiation onto a desired focal region, without concern for forming an image of the Sun. The high diffractive order of this kinoform (in contradistinction to the low diffractive orders of some other kinoforms) would be necessary to obtain the desired f number of 1, which, in turn, would be necessary for obtaining a desired concentration ratio of 2,500 or greater. The design process of optimizing the concentration ratio of a proposed DOE solar concentrator includes computing convolutions of the optical bandwidth of the Sun with the optical transmission of the diffractive medium. Because, as in the cases of other non-imaging, light-concentrating optics, image quality is not a design requirement, the process also includes trading image quality against concentration ratio. A baseline design for one example calls for an aperture diameter of 1 m. This baseline design would be scalable to a diameter as large as 10 m, or to a smaller diameter for a

  12. Heaviside revisited: Distortionless signal transmission through lossy media with application to precision clock synchronization

    NASA Astrophysics Data System (ADS)

    Flake, Robert H.

    2016-02-01

    A recently discovered non-sinusoidal, non-periodic electrical signal in the form of an exponentially rising pulse achieves distortionless propagation at constant velocity through lossy, passive transmission media. This unique property is derived theoretically in the framework of the telegrapher's equation analyzed by Heaviside and confirmed experimentally in propagation of such a pulse along serially connected sections of telephone cable. The utility of the distortion-free pulse within the field of time-domain reflectometry is demonstrated in precise time-of-flight measurement of the reflected signal, with the prospect of enhancing the accuracy of protocols for synchronization of spatially separated clocks.

  13. Absolute stability and synchronization in neural field models with transmission delays

    NASA Astrophysics Data System (ADS)

    Kao, Chiu-Yen; Shih, Chih-Wen; Wu, Chang-Hong

    2016-08-01

    Neural fields model macroscopic parts of the cortex which involve several populations of neurons. We consider a class of neural field models which are represented by integro-differential equations with transmission time delays which are space-dependent. The considered domains underlying the systems can be bounded or unbounded. A new approach, called sequential contracting, instead of the conventional Lyapunov functional technique, is employed to investigate the global dynamics of such systems. Sufficient conditions for the absolute stability and synchronization of the systems are established. Several numerical examples are presented to demonstrate the theoretical results.

  14. Tbit/s Optical Transmission Systems

    NASA Astrophysics Data System (ADS)

    Gunning, Fatima C. G.; Ellis, Andrew D.; Cuenot, Benjamin; Healy, Tadhg; McCarthy, Mary

    2005-10-01

    We discuss our Science Foundation Ireland-funded work to design of a highly spectral efficient Tbit/s optical transmission system for long-haul communications. Such systems are comprised of several wavelength division multiplexing (WDM) channels (or frequency channels), closely spaced (<100 GHz), and modulated at high bit rates (40 Gbit/s). The highest efficiencies have been achieved using combinations of techniques, by increasing the information per channel and minimizing interferometric cross-talk. In conventional systems, incoherent interference occurs when beat signals from adjacent channels fall within the receiver bandwidth. This generates noise if the relative phase is random, e.g., where independent lasers are used for each channel. However, if the optical phase difference between adjacent channels is controlled, the interference signal is deterministic. Therefore, if each channel is modulated with a data signal, any interference effect is distributed in the same way from one bit slot to another, and the relative optical phases may be aligned to either increase or decrease the eye opening. This interference control may be achieved by controlling the phase of each laser individually with optical phase locked loops, or by replacing the typical bank of lasers with one or more coherent comb sources. The wavelengths of adjacent channels are thus phased locked to each other, and the data are encoded with an array of modulators that preserves this relative optical phase. The proposed technique, Coherent WDM, exploits this optical phase-locking mechanism in a simple and cost-effective configuration because it is based on a comb generation (multi-wavelength source) via the use of sine-wave-driven amplitude modulators (generating side-bands), followed by data encoding at the same rate. Recent results show significant improvement in performance over conventional systems. More improvement may come when a combination of approaches is used.

  15. Speed synchronization control for integrated automotive motor-transmission powertrain system with random delays

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoyuan; Zhang, Hui; Fang, Zongde

    2015-12-01

    This paper presents a robust speed synchronization controller design for an integrated motor-transmission powertrain system in which the driving motor and multi-gearbox are directly coupled. As the controller area network (CAN) is commonly used in the vehicle powertrain system, the possible network-induced random delays in both feedback and forward channel are considered and modeled by using two Markov chains in the controller design process. For the application perspective, the control law adopted here is a generalized proportional-integral (PI) control. By employing the system-augmentation technique, a delay-free stochastic closed-loop system is obtained and the generalized PI controller design problem is converted to a static output feedback (SOF) controller design problem. Since there are external disturbances involved in the closed-loop system, the energy-to-peak performance is considered to guarantee the robustness of the controller. And the controlled output is chosen as the speed synchronization error. To further improve the transient response of the closed-loop system, the pole placement is also employed in the energy-to-peak performance based speed synchronization control. The mode-dependent control gains are obtained by using an iterative linear matrix inequality (LMI) algorithm. Simulation results show the effectiveness of the proposed control approach.

  16. Measurement of magnetic moment via optical transmission

    NASA Astrophysics Data System (ADS)

    Heidsieck, Alexandra; Schmid, Daniel; Gleich, Bernhard

    2016-03-01

    The magnetic moment of nanoparticles is an important property for drug targeting and related applications as well as for the simulation thereof. However, the measurement of the magnetic moment of nanoparticles, nanoparticle-virus-complexes or microspheres in solution can be difficult and often yields unsatisfying or incomparable results. To measure the magnetic moment, we designed a custom measurement device including a magnetic set-up to observe nanoparticles indirectly via light transmission in solution. We present a simple, cheap device of manageable size, which can be used in any laboratory as well as a novel evaluation method to determine the magnetic moment of nanoparticles via the change of the optical density of the particle suspension in a well-defined magnetic gradient field. In contrast to many of the established measurement methods, we are able to observe and measure the nanoparticle complexes in their natural state in the respective medium. The nanoparticles move along the magnetic gradient and thereby away from the observation point. Due to this movement, the optical density of the fluid decreases and the transmission increases over time at the measurement location. By comparing the measurement with parametric simulations, we can deduce the magnetic moment from the observed behavior.

  17. Theoretical study of use of optical orthogonal codes for compressed video transmission in optical code division multiple access (OCDMA) system

    NASA Astrophysics Data System (ADS)

    Ghosh, Shila; Chatterji, B. N.

    2007-09-01

    A theoretical investigation to evaluate the performance of optical code division multiple access (OCDMA) for compressed video transmission is shown. OCDMA has many advantages than a typical synchronous protocol time division multiple access (TDMA). A pulsed laser transmission of multi channel digital video can be done using various techniques depending on whether the multi channel data are to be synchronous or asynchronous. A typical form of asynchronous digital operation is wavelength division multiplexing (WDM) in which the digital data of each video source are assigned a specific and separate wavelength. A sophisticated hardware such as accurate wavelength control of all lasers and tunable narrow band optical filters at the receivers is required in this case. A major disadvantage with CDMA is the reduction in per channel data rate (relative to the speeds available in the laser itself) that occurs in the insertion of code addressing. Hence optical CDMA for the video transmission application is meaningful when individual channel video bit rates can be significantly reduced and that can be done by compression of video data. In our work for compression of video image standard JPEG is implemented where a compression ratio of about 60 % is obtained without noticeable image degradation. Compared to the other existing techniques JPEG standard achieves higher compression ration with high S/N ratio. Here we demonstrated the auto and cross correlation properties of the codes. We have shown the implementation of bipolar Walsh coding in OCDMA system and their use in transmission of image/video.

  18. Optical phase dynamics in mutually coupled diode laser systems exhibiting power synchronization

    NASA Astrophysics Data System (ADS)

    Pal, Vishwa; Prasad, Awadhesh; Ghosh, R.

    2011-12-01

    We probe the physical mechanism behind the known phenomenon of power synchronization of two diode lasers that are mutually coupled via their delayed optical fields. In a diode laser, the amplitude and the phase of the optical field are coupled by the so-called linewidth enhancement factor, α. In this work, we explore the role of optical phases of the electric fields in amplitude (and hence power) synchronization through α in such mutually delay-coupled diode laser systems. Our numerical results show that the synchronization of optical phases drives the powers of lasers to synchronized death regimes. We also find that as α varies for different diode lasers, the system goes through a sequence of in-phase amplitude-death states. Within the windows between successive amplitude-death regions, the cross-correlation between the field amplitudes exhibits a universal power-law behaviour with respect to α.

  19. Optical data transmission at the superconducting super collider

    SciTech Connect

    Leskovar, B.

    1989-04-01

    Digital and analog data transmissions via fiber optics for the Superconducting Super Collider have been investigated. The state of the art of optical transmitters, low loss fiber waveguides, receivers and associated electronics components are reviewed and summarized. Emphasis is placed on the effects of the radiation environment on the performance of an optical data transmission system components. Also, the performance of candidate components of the wide band digital and analog transmission systems intended for deployment in the Superconducting Super Collider Detector is discussed.

  20. Colossal optical transmission through buried metal gratings (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Roberts, Christopher M.; Liu, Runyu; Zhao, Xiang; Yu, Lan; Li, Xiuling; Wasserman, Daniel M.; Podolskiy, Viktor A.

    2015-09-01

    In Extraordinary Optical Transmission (EOT), a metallic film perforated with an array of [periodic] apertures exhibits transmission over 100% normalized to the total aperture area, at selected frequencies. EOT devices have potential applications as optical filters and as couplers in hybrid electro-optic contacts/devices. Traditional passive extraordinary optical transmission structures, typically demonstrate un-normalized transmission well below 50%, and are typically outperformed by simpler thin-film techniques. To overcome these limitations, we demonstrate a new breed of extraordinary optical transmission devices, by "burying" an extraordinary optical transmission grating in a dielectric matrix via a metal-assisted-chemical etching process. The resulting structure is an extraordinary optical transmission grating on top of a dielectric substrate with dielectric nano-pillars extruded through the grating apertures. These structures not only show significantly enhanced peak transmission when normalized to the open area of the metal film, but more importantly, peak transmission greater than that observed from the bare semiconductor surface. The structures were modeled using three-dimensional rigorous coupled wave analysis and characterized experimentally by Fourier transform infrared reflection and transmission spectroscopy, and the good agreement between the two has been demonstrated. The drastic enhancement of light transmission in our structures originates from structuring of high-index dielectric substrate, with pillars effectively guiding light through metal apertures.

  1. Low-complexity joint symbol synchronization and sampling frequency offset estimation scheme for optical IMDD OFDM systems.

    PubMed

    Zhang, Zhen; Zhang, Qianwu; Chen, Jian; Li, Yingchun; Song, Yingxiong

    2016-06-13

    A low-complexity joint symbol synchronization and SFO estimation scheme for asynchronous optical IMDD OFDM systems based on only one training symbol is proposed. Numerical simulations and experimental demonstrations are also under taken to evaluate the performance of the mentioned scheme. The experimental results show that robust and precise symbol synchronization and the SFO estimation can be achieved simultaneously at received optical power as low as -20dBm in asynchronous OOFDM systems. SFO estimation accuracy in MSE can be lower than 1 × 10-11 under SFO range from -60ppm to 60ppm after 25km SSMF transmission. Optimal System performance can be maintained until cumulate number of employed frames for calculation is less than 50 under above-mentioned conditions. Meanwhile, the proposed joint scheme has a low level of operation complexity comparing with existing methods, when the symbol synchronization and SFO estimation are considered together. Above-mentioned results can give an important reference in practical system designs. PMID:27410279

  2. Transmission line relay mis-operation detection based on time-synchronized field data

    SciTech Connect

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such, it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.

  3. Transmission line relay mis-operation detection based on time-synchronized field data

    DOE PAGESBeta

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such,more » it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.« less

  4. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, M.A.

    1992-11-10

    A fiber optically isolated and remotely stabilized data transmission systems described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber. 3 figs.

  5. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, Melvin A.

    1992-01-01

    A fiber optically isolated and remotely stabilized data transmission system s described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber.

  6. Synchronous pumping of picosecond dye laser using high efficiency second harmonic generation from optical fibres

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Bernardin, J. P.; Macdonald, R. L.; Demouchy, G.

    1991-01-01

    The stable operation of a mode-locked dye laser synchronously pumped by the second harmonic of an Nd:YAG laser produced in an Nd codoped germanosilicate optical fiber is reported. The optical fiber preparation technique, which results in a second harmonic conversion efficiency of 2 percent, is described. This optical fiber SHG conversion efficiency is the highest reported to date using a continuous-wave mode-locked laser.

  7. Femtosecond all-optical synchronization of an X-ray free-electron laser

    SciTech Connect

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

    2015-01-20

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

  8. Femtosecond all-optical synchronization of an X-ray free-electron laser

    DOE PAGESBeta

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; et al

    2015-01-20

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarilymore » by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.« less

  9. Femtosecond all-optical synchronization of an X-ray free-electron laser

    PubMed Central

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

    2015-01-01

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses. PMID:25600823

  10. Femtosecond all-optical synchronization of an X-ray free-electron laser

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

    2015-01-01

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

  11. Femtosecond all-optical synchronization of an X-ray free-electron laser.

    PubMed

    Schulz, S; Grguraš, I; Behrens, C; Bromberger, H; Costello, J T; Czwalinna, M K; Felber, M; Hoffmann, M C; Ilchen, M; Liu, H Y; Mazza, T; Meyer, M; Pfeiffer, S; Prędki, P; Schefer, S; Schmidt, C; Wegner, U; Schlarb, H; Cavalieri, A L

    2015-01-01

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses. PMID:25600823

  12. System for transmitting and receiving asynchronous nonhomogeneous variable width parallel data over a synchronous high speed serial transmission media

    SciTech Connect

    Scott, P.H.

    1990-09-18

    The patent describes a system witch utilizes a synchronous serial transmission media to transmit data between a data source that generates asynchronous nonhomogeneous variable width parallel data pattern inputs, and a data sink that accepts parallel data pattern outputs corresponding to the inputs. It comprises: transmitter means responsive to each of the parallel data pattern inputs, for synchronously transmitting a serial data pattern representative of a given input over the media; and receiver means, responsive to data transmitted over the media, for generating the parallel data pattern outputs.

  13. Polarization-selective optical transmission through a plasmonic metasurface

    PubMed Central

    Pelzman, Charles; Cho, Sang-Yeon

    2015-01-01

    We present the design, fabrication, and experimental characterization of a nanoslit-based metasurface that offers polarization-selective optical transmission for advanced imaging applications. The metasurface consists of an array of meta-atoms, constructed with two orthogonally coupled subwavelength apertures. Highly enhanced optical transmission was achieved by selective excitation of surface plasmon waves on the metasurface. By rotating the orientation of the linearly polarized incident beam, switching of enhanced optical transmission bands through the metasurface was experimentally demonstrated. This demonstration is a significant step towards developing advanced multispectral imaging devices. PMID:26180264

  14. Optical data transmission at the superconducting super collider

    SciTech Connect

    Leskovar, B.

    1989-02-01

    Digital and analog data transmissions via fiber optics for the Superconducting Super Collider have been investigated. The state of the art of optical transmitters, low loss fiber waveguides, receivers and associated electronics components are reviewed and summarized. Emphasis is placed on the effects of the radiation environment on the performance of an optical data transmission system components. Also, the performance of candidate components of the wide band digital and analog transmission systems intended for deployment of the Superconducting Super Collider Detector is discussed. 27 refs., 15 figs.

  15. Polarization-selective optical transmission through a plasmonic metasurface

    SciTech Connect

    Pelzman, Charles; Cho, Sang-Yeon

    2015-06-22

    We present the design, fabrication, and experimental characterization of a nanoslit-based metasurface that offers polarization-selective optical transmission for advanced imaging applications. The metasurface consists of an array of meta-atoms, constructed with two orthogonally coupled subwavelength apertures. Highly enhanced optical transmission was achieved by selective excitation of surface plasmon waves on the metasurface. By rotating the orientation of the linearly polarized incident beam, switching of enhanced optical transmission bands through the metasurface was experimentally demonstrated. This demonstration is a significant step towards developing advanced multispectral imaging devices.

  16. Modulator bias control based on dither signal in 40Gb/s RZ optical transmission system

    NASA Astrophysics Data System (ADS)

    Zhang, Jianyong; Wang, Muguang; Fu, Yongjun; Cao, Jihong; Qin, Xi; Zhang, Feng; Jian, Shuisheng

    2008-11-01

    The bias drift effect in the packaged LiNbO3 modulator is investigated. The Bessel expansion of the dithered clock shows that the harmonic component equal to the dither frequency can be synchronously demodulated to get the bias drift and avoid the random phase difference between the clock or data and the dither signal. By using the time division control method one control system can track two modulator bias drift in 40Gb/s RZ optical transmission system because the optimum bias point changes very slowly.

  17. Optical Phase-Locked Loops: Performance Investigation and Psk Synchronous Communication System Experiments

    NASA Astrophysics Data System (ADS)

    Atlas, Dogan A.

    1990-01-01

    This thesis study presents the design/analysis considerations, fundamental performance limitations and the experimental set-up of an optical phase-locked loop which is employed in phase-shift keying homodyne and synchronous heterodyne optical fiber communication system experiments. From an optical communication systems point of view, the characteristics of the lightwave sources to be used are important to investigate. Therefore, frequency modulation, frequency noise and intensity noise characteristics of 1320-nm (227 THz) laser-diode-pumped miniature Nd:YAG ring lasers have been investigated. The modulation and noise properties of these lasers are characterized both qualitatively and quantitatively. For applications such as optical phase-locking, phase-shift keying homodyne and synchronous heterodyne optical fiber and optical free -space communication systems, subcarrier multiplexing systems, and microwave phase array antennas diode-pumped Nd:YAG lasers are excellent lightwave sources. The reasons that make these lasers attractive candidates for such a variety of applications include the narrow laser linewidth, the uniformly flat frequency modulation response and the wide frequency modulation bandwidth. A stable second-order optical phase-locked loop has been constructed using two Nd:YAG lasers and a balanced optical receiver. The loop is designed so that the local oscillator laser locks to the frequency/phase variations of the transmitter laser. The frequency/phase tracking performance of the loop is limited by the quantum phase noise and mainly by the frequency drift induced by the temperature variations of both the transmitter and local oscillator laser cavities. Using the loop, optical phase -shift keying homodyne communication system experiments are demonstrated at modulation rates of 140 Mb/s and 2 Gb/s. The receiver sensitivity at 140 Mb/s is 25 photons/bit which is the highest sensitivity reported to date with any optical communication system. An optical

  18. Two chaos synchronization schemes and public-channel message transmission in a mutually coupled semiconductor lasers system

    NASA Astrophysics Data System (ADS)

    Jiang, Ning; Pan, Wei; Yan, Lianshan; Luo, Bin; Yang, Lei; Xiang, Shuiying; Zheng, Di

    2009-06-01

    Chaos synchronization and message transmission of a mutually coupled system consisting of two semiconductor lasers (SLs) and a partially transparent mirror (PTM) in between are investigated theoretically. Analytical results show that two types of chaos synchronization schemes, named as isochronal synchronization (IS) and leader/laggard synchronization (LLS), can be achieved by adjusting the reflectivity and position of PTM. By establishing SIMULINK model, numerical simulations illustrate that as the PTM is positioned at the center of two lasers, IS is available when the reflectivity of PTM is moderate. The LLS is achieved when the reflectivity of PTM equals to 0.5, which means feedback strength equals to coupling strength. Its lag time is just determined by the difference of feedback delay time. The investigations of mutual chaos pass filtering (MCPF) effects and the secure chaotic communication simulations indicate that IS allows real-time bidirectional message transmission on a public-channel, while LLS can achieve higher security chaotic communication by using its lag time as cryptography key. The demonstrated system can be used as a rudiment of array chaos communications system.

  19. An image-based method to synchronize cone-beam CT and optical surface tracking.

    PubMed

    Fassi, Aurora; Schaerer, Joël; Riboldi, Marco; Sarrut, David; Baroni, Guido

    2015-01-01

    The integration of in-room X-ray imaging and optical surface tracking has gained increasing importance in the field of image guided radiotherapy (IGRT). An essential step for this integration consists of temporally synchronizing the acquisition of X-ray projections and surface data. We present an image-based method for the synchronization of cone-beam computed tomography (CBCT) and optical surface systems, which does not require the use of additional hardware. The method is based on optically tracking the motion of a component of the CBCT/gantry unit, which rotates during the acquisition of the CBCT scan. A calibration procedure was implemented to relate the position of the rotating component identified by the optical system with the time elapsed since the beginning of the CBCT scan, thus obtaining the temporal correspondence between the acquisition of X-ray projections and surface data. The accuracy of the proposed synchronization method was evaluated on a motorized moving phantom, performing eight simultaneous acquisitions with an Elekta Synergy CBCT machine and the AlignRT optical device. The median time difference between the sinusoidal peaks of phantom motion signals extracted from the synchronized CBCT and AlignRT systems ranged between -3.1 and 12.9 msec, with a maximum interquartile range of 14.4 msec. The method was also applied to clinical data acquired from seven lung cancer patients, demonstrating the potential of the proposed approach in estimating the individual and daily variations in respiratory parameters and motion correlation of internal and external structures. The presented synchronization method can be particularly useful for tumor tracking applications in extracranial radiation treatments, especially in the field of patient-specific breathing models, based on the correlation between internal tumor motion and external surface surrogates. PMID:26103183

  20. Link optimization for DWDM transmission with an optical phase conjugation.

    PubMed

    Rosa, Paweł; Rizzelli, Giuseppe; Ania-Castañón, Juan Diego

    2016-07-25

    We characterize in-span signal power asymmetry in random distributed feedback ultralong Raman laser-amplified WDM transmission and numerically optimize fiber span length and operating band to achieve the lowest inter-span signal power asymmetry between transmitted and optically conjugated channels in systems relying upon mid-link optical conjugation to combat fiber nonlinear impairments. PMID:27464097

  1. Femtosecond-precision synchronization of the pump-probe optical laser for user experiments at FLASH

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Czwalinna, M. K.; Felber, M.; Predki, P.; Schefer, S.; Schlarb, H.; Wegner, U.

    2013-05-01

    In this paper, we present the long-term stable synchronization of the FLASH pump-probe Ti:sapphire oscillator to an optical reference with sub-10 fs (rms) timing jitter employing a balanced optical cross-correlator. The reference pulse train, transmitted over an actively transit time-stabilized 500m long fiber link, is generated by the FLASH master laser oscillator. This laser also provides the reference for several electron bunch arrival time monitors with sub-10 fs resolution, which in turn enables a longitudinal feedback reducing the electron bunch arrival time jitter to below 25 fs (rms). Combining the precise synchronization of the laser and the longitudinal accelerator feedback enabled a proof-of-principle pump-probe experiment at FLASH, ultimately showing a significant reduction of the timing jitter between the optical laser and the XUV pulses generated by the FEL, compared to the present standard operation.

  2. Rotating optical coupler for signal transmission

    NASA Technical Reports Server (NTRS)

    Ivie, C. V.

    1977-01-01

    Optical coupler using Dove prism assembly to form stationary image of rotating object, transmits data across rotating interface without sliprings or other mechanical contacts. Device can handle many high-bit-rate data channels.

  3. Advances in transmission x-ray optics

    SciTech Connect

    Ceglio, N.M.

    1983-01-01

    Recent developments in x-ray optics are reviewed. Specific advances in coded aperture imaging, zone plate lens fabrication, time and space resolved spectroscopy, and CCD x-ray detection are discussed.

  4. Performance analysis of multiple interference suppression over asynchronous/synchronous optical code-division multiple-access system based on complementary/prime/shifted coding scheme

    NASA Astrophysics Data System (ADS)

    Nieh, Ta-Chun; Yang, Chao-Chin; Huang, Jen-Fa

    2011-08-01

    A complete complementary/prime/shifted prime (CPS) code family for the optical code-division multiple-access (OCDMA) system is proposed. Based on the ability of complete complementary (CC) code, the multiple-access interference (MAI) can be suppressed and eliminated via spectral amplitude coding (SAC) OCDMA system under asynchronous/synchronous transmission. By utilizing the shifted prime (SP) code in the SAC scheme, the hardware implementation of encoder/decoder can be simplified with a reduced number of optical components, such as arrayed waveguide grating (AWG) and fiber Bragg grating (FBG). This system has a superior performance as compared to previous bipolar-bipolar coding OCDMA systems.

  5. Optical signal monitoring in phase modulated optical fiber transmission systems

    NASA Astrophysics Data System (ADS)

    Zhao, Jian

    Optical performance monitoring (OPM) is one of the essential functions for future high speed optical networks. Among the parameters to be monitored, chromatic dispersion (CD) is especially important since it has a significant impact on overall system performance. In this thesis effective CD monitoring approaches for phase-shift keying (PSK) based optical transmission systems are investigated. A number of monitoring schemes based on radio frequency (RF) spectrum analysis and delay-tap sampling are proposed and their performance evaluated. A method for dispersion monitoring of differential phase-shift keying (DPSK) signals based on RF power detection is studied. The RF power spectrum is found to increase with the increase of CD and decrease with polarization mode dispersion (PMD). The spectral power density dependence on CD is studied theoretically and then verified through simulations and experiments. The monitoring sensitivity for nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) based systems can reach 80ps/nm/dB and 34ps/nm/dB respectively. The scheme enables the monitoring of differential group delay (DGD) and CD simultaneously. The monitoring sensitivity of CD and DGD can reach 56.7ps/nm/dB and 3.1ps/dB using a bandpass filter. The effects of optical signal-to-noise ratio (OSNR), DGD, fiber nonlinearity and chirp on the monitoring results are investigated. Two RF pilot tones are employed for CD monitoring of DPSK signals. Specially selected pilot tone frequencies enable good monitoring sensitivity with minimum influence on the received signals. The dynamic range exceeding 35dB and monitoring sensitivity up to 9.5ps/nm/dB are achieved. Asynchronous sampling technique is employed for CD monitoring. A signed CD monitoring method for 10Gb/s NRZ-DPSK and RZ-DPSK systems using asynchronous delay-tap sampling technique is studied. The demodulated signals suffer asymmetric waveform distortion if

  6. Transmissive Nanohole Arrays for Massively-Parallel Optical Biosensing

    PubMed Central

    2015-01-01

    A high-throughput optical biosensing technique is proposed and demonstrated. This hybrid technique combines optical transmission of nanoholes with colorimetric silver staining. The size and spacing of the nanoholes are chosen so that individual nanoholes can be independently resolved in massive parallel using an ordinary transmission optical microscope, and, in place of determining a spectral shift, the brightness of each nanohole is recorded to greatly simplify the readout. Each nanohole then acts as an independent sensor, and the blocking of nanohole optical transmission by enzymatic silver staining defines the specific detection of a biological agent. Nearly 10000 nanoholes can be simultaneously monitored under the field of view of a typical microscope. As an initial proof of concept, biotinylated lysozyme (biotin-HEL) was used as a model analyte, giving a detection limit as low as 0.1 ng/mL. PMID:25530982

  7. Synchronous initiation of optical detonators by Q-switched solid laser sources

    NASA Astrophysics Data System (ADS)

    Goujon, J.; Musset, O.; Marchand, A.; Bigot, C.

    2008-10-01

    The initiation of pyrotechnic substances by a laser light has been studied for more than 30 years. But until recently the use of this technology for defence applications encountered three main technical problems: the volume and the mass of lasers, the linear loss of optical fibres and their possible damage caused by the transport of strong laser power. Recent technical progress performed in the field of electrical and optical devices are now very promising for future opto-pyrotechnic functional chains. The objective of this paper is to present a demonstrator developed in order to initiate in a synchronous way four optical detonators and to measure the dispersion of their functioning times. It includes four compact Q-switched Nd:Cr:GSGG solid laser sources, pumped by flash lamp (energy ~110mJ, FWHM ~8.5 ns), two ultra-fast electro-optical selectors (based on RTP crystals) used to steer the laser beam and six optical fibre lines to transmit the laser pulses to the optical detonators. The set-up integrates also complex control and safety systems, as well as cameras allowing an optimal alignment of optical fibres. Experiments led us to initiate in a synchronous way four detonators with a mean scattering of 50 ns. The perspectives in this domain of initiation concern mainly the miniaturization and the hardening to the environments of electrical and optical components.

  8. Signal subspace analysis for decoherent processes during interferometric fiber-optic gyroscopes using synchronous adaptive filters.

    PubMed

    Li, Yongxiao; Wang, Zinan; Peng, Chao; Li, Zhengbin

    2014-10-10

    Conventional signal processing methods for improving the random walk coefficient and the bias stability of interferometric fiber-optic gyroscopes are usually implemented in one-dimension sequence. In this paper, as a comparison, we allocated synchronous adaptive filters with the calculations of correlations of multidimensional signals in the perspective of the signal subspace. First, two synchronous independent channels are obtained through quadrature demodulation. Next, synchronous adaptive filters were carried out in order to project the original channels to the high related error channels and the approximation channels. The error channel signals were then processed by principal component analysis for suppressing coherent noises. Finally, an optimal state estimation of these error channels and approximation channels based on the Kalman gain coefficient was operated. Experimental results show that this signal processing method improved the raw measurements' variance from 0.0630 [(°/h)2] to 0.0103 [(°/h)2]. PMID:25322393

  9. Fiber optic transmissions in electrical utility applications

    NASA Astrophysics Data System (ADS)

    Lamarche, Louis

    2000-12-01

    The application of optic and photonic technology in electric networks in many cases is subject to constraints that differ from telecommunication or commercial applications. Starting by an overview of the quality of service (QoS) needed, in the first part of this paper we summarise some issues that confronted Hydro-Quebec in applying fibre optic technologies to its network. We explore by presenting lab and field trials some issues related to optical ground wires (OPGW) design and network architecture. We present temperature, vibration, ageing and short circuit current effects. We submit the results and analysis of a first field trial of and OC-48 link over a 265 km OPGW line, PMD measurements and an overview of the final design that is being implemented presently using Raman amplification. In the last section of the paper, we will discuss shortly of non-conventional photonic based technologies, local and distributed sensors and optical phenomenon that are used or have been discovered in utilities optical networks.

  10. Reference frequency transmission over optical fiber

    NASA Technical Reports Server (NTRS)

    Lutes, G.; Kirk, A.

    1986-01-01

    A 100-MHz reference frequency from a hydrogen maser frequency standard has been transmitted via optical fiber over a 14-km distance with a measured stability of 1.5 X 10 to the-15 power for 1000 seconds averaging time. This capability was demonstrated in a frequency distribution experiment performed in April, 1986. The reference frequency was transmitted over a single-mode fiber-optic link from Deep Space Station (DSS) 13 to DSS 12 and back. The background leading up to the experiment and the significance of stable reference frequency distribution in the Deep Space Network (DSN) is discussed. Also described are the experiment, including the fiber-optic link, the measurement method and equipment, and finally the results of the experiment.

  11. FEC for high-speed optical transmission

    NASA Astrophysics Data System (ADS)

    Xie, Changsong; Zhao, Yu; Xiao, Zhiyu; Chang, Deyuan; Yu, Fan

    2011-12-01

    This paper will at first explain the requirement of high speed optical transport network on forward error correction (FEC) codes in terms of code length, code rate, coding gain, burst error correction capability, error floor, latency, coding/decoding complexity. Then, a few code schemes used in current optical transport systems such as Reed-Solomon codes recommended by ITU-T G.709 and enhanced FECs listed in ITU-T, G.975.1 are introduced. Advanced codes recently developed by vendors used for 100Gbps systems and their performances are summarized. Features and special requirements on soft decoding FEC (SDFEC) especially inter-working between SDFEC and equalizer, with and without deferential coding etc. are analyzed. Some perspectives of future FEC for optical transport are also given.

  12. Single-Cycle Optical Pulses Synchronized with Molecular Oscillations

    NASA Astrophysics Data System (ADS)

    Sokolov, Alexei V.

    2002-05-01

    We have previously shown that coherent molecular motion can result in light modulation and subfemtosecond pulse compression. Our technique is based on adiabatic preparation of a macroscopic molecular ensemble in a single vibrational superposition-state [1]. Recently we have demonstrated collinear generation of mutually-coherent spectral sidebands, extending from infrared to far ultraviolet. We adjusted individual spectral phases to allow synthesis of desired single-cycle waveforms at the target, and characterized these waveforms by measuring the pulse-shape dependent multiphoton ionization rate [2]. This Raman source can be used to study multiphoton processes in a regime not accessible by other light sources. In particular, it will allow measurement of ionization and high-order harmonic generation as a function of sub-cycle phase (or the phase of the carrier with respect to the pulse envelope). Moreover, by utilizing an even wider spectrum, this source will produce waveforms with a prescribed non-sinusoidal sub-cycle field shape. By the very nature of the generation process, our light source produces trains of pulses, which are perfectly synchronized with the molecular motion in the given molecular system, and provide a unique tool for studying molecular and electronic dynamics. We envision producing a coherent molecular oscillation, applying a tightly focused train of perfectly timed pulses, adjusting the delay, and studying electronic properties as function of molecular coordinates. We can use the coherent molecular motion to control multiphoton excitations in an EIT-like manner: We can have a destructive or a constructive interference among different multiphoton paths, depending on the relative phase of the molecular motion and the Raman sidebands. Possible extensions of this general technique range from studying complicated multi-mode motion of complex molecules, to probing ultrafast electronic dynamics in atoms. REFERENCES: 1. S. E. Harris and A. V. Sokolov

  13. Add/drop multiplexing and TDM signal transmission in an optical CDMA ring network

    NASA Astrophysics Data System (ADS)

    Chen, Biao; Guo, Changjian; Chen, Jiajia; Zhang, Linjian; Jiang, Qiong; He, Sailing

    2007-08-01

    It is shown that a ring topology is better than a star topology for an optical-code-division multiple access (OCDMA) network as an optical metropolitan or local area network in terms of security and capacity. Each node in an OCDMA ring network requires an OCDMA add/drop multiplexer. We present what we believe to be a novel OCDMA add/drop multiplexer that can simultaneously add and drop multiple code channels, and a proof-of-feasibility experiment is demonstrated. An OCDMA ring may also adapt code channels for time domain multiplexing and other digital signal transmission systems. An experiment for the synchronized digital hierarchy (SDH) signal over a OCDMA link is demonstrated.

  14. Optical design of laser transmission system

    NASA Astrophysics Data System (ADS)

    Zhang, Yulan; Feng, Jinliang; Li, Yongliang; Yang, Jiandong

    1998-08-01

    This paper discusses a design of optical transfer system used in carbon-dioxide laser therapeutic machine. The design of this system is according to the requirement of the therapeutic machine. The therapeutic machine requires the movement of laser transfer system is similar to the movement of human beings arms, which possesses 7 rotating hinges. We use optical hinges, which is composed of 45 degree mirrors. Because the carbon-dioxide laser mode is not good, light beam diameter at focus and divergence angle dissemination are big, we use a collecting lens at the transfer system output part in order to make the light beam diameter at focus in 0.2 to approximately 0.3 mm. For whole system the focus off-axis error is less than 0.5 mm, the transfer power consumption is smaller than 10%. The system can move in three dimension space freely and satisfies the therapeutic machine requirement.

  15. Coherent optical component technologies for WDM transmission systems

    NASA Astrophysics Data System (ADS)

    Mino, S.; Murata, K.; Saida, T.; Ogawa, I.

    2011-01-01

    We review our recent progress toward 100 Gbps and beyond, focusing on integrated optical devices. Topics include our recently developed integrated optical front-ends for 100 Gbps PDM-QPSK based on multi-channel micro collimator optics and hermetically sealed O/E converters, and PLC-LiNbO3 hybrid optical modulators for 100 Gbps PDM-QPSK. We also describe our recent work on exceeding 100 Gbps, including 64 QAM modulators, modulation-level-selectable modulators, and high-speed digital-analog converter ICs for future multi-level transmissions.

  16. Concentric core optical fiber with multiple-mode signal transmission

    DOEpatents

    Muhs, Jeffrey D.

    1997-01-01

    A concentric core optical fiber provides for the simultaneous but independent transmission of signals over a single optical fiber. The concentric optical fiber is constructed of a single-mode or multimode inner optical fiber defined by a core and a cladding of a lower index of refraction than the core and an outer optical fiber defined by additional cladding concentrically disposed around the cladding and of an index of refraction lower than the first mentioned cladding whereby the latter functions as the core of the outer optical fiber. By employing such an optical fiber construction with a single-mode inner core or optical fiber, highly sensitive interferometric and stable less sensitive amplitude based sensors can be placed along the same length of a concentric core optical fiber. Also, by employing the concentric core optical fiber secure telecommunications can be achieved via the inner optical fiber since an intrusion of the concentric optical fiber will first cause a variation in the light being transmitted through the outer optical fiber and this variation of light being used to trigger a suitable alarm indicative of the intrusion.

  17. Concentric core optical fiber with multiple-mode signal transmission

    DOEpatents

    Muhs, J.D.

    1997-05-06

    A concentric core optical fiber provides for the simultaneous but independent transmission of signals over a single optical fiber. The concentric optical fiber is constructed of a single-mode or multimode inner optical fiber defined by a core and a cladding of a lower index of refraction than the core and an outer optical fiber defined by additional cladding concentrically disposed around the cladding and of an index of refraction lower than the first mentioned cladding whereby the latter functions as the core of the outer optical fiber. By employing such an optical fiber construction with a single-mode inner core or optical fiber, highly sensitive interferometric and stable less sensitive amplitude based sensors can be placed along the same length of a concentric core optical fiber. Also, by employing the concentric core optical fiber secure telecommunications can be achieved via the inner optical fiber since an intrusion of the concentric optical fiber will first cause a variation in the light being transmitted through the outer optical fiber and this variation of light being used to trigger a suitable alarm indicative of the intrusion. 3 figs.

  18. Measuring Large Optical Transmission Matrices of Disordered Media

    NASA Astrophysics Data System (ADS)

    Yu, Hyeonseung; Hillman, Timothy R.; Choi, Wonshik; Lee, Ji Oon; Feld, Michael S.; Dasari, Ramachandra R.; Park, YongKeun

    2013-10-01

    We report a measurement of the large optical transmission matrix (TM) of a complex turbid medium. The TM is acquired using polarization-sensitive, full-field interferometric microscopy equipped with a rotating galvanometer mirror. It is represented with respect to input and output bases of optical modes, which correspond to plane wave components of the respective illumination and transmitted waves. The modes are sampled so finely in angular spectrum space that their number exceeds the total number of resolvable modes for the illuminated area of the sample. As such, we investigate the singular value spectrum of the TM in order to detect evidence of open transmission channels, predicted by random-matrix theory. Our results comport with theoretical expectations, given the experimental limitations of the system. We consider the impact of these limitations on the usefulness of transmission matrices in optical measurements.

  19. Measuring large optical transmission matrices of disordered media.

    PubMed

    Yu, Hyeonseung; Hillman, Timothy R; Choi, Wonshik; Lee, Ji Oon; Feld, Michael S; Dasari, Ramachandra R; Park, YongKeun

    2013-10-11

    We report a measurement of the large optical transmission matrix (TM) of a complex turbid medium. The TM is acquired using polarization-sensitive, full-field interferometric microscopy equipped with a rotating galvanometer mirror. It is represented with respect to input and output bases of optical modes, which correspond to plane wave components of the respective illumination and transmitted waves. The modes are sampled so finely in angular spectrum space that their number exceeds the total number of resolvable modes for the illuminated area of the sample. As such, we investigate the singular value spectrum of the TM in order to detect evidence of open transmission channels, predicted by random-matrix theory. Our results comport with theoretical expectations, given the experimental limitations of the system. We consider the impact of these limitations on the usefulness of transmission matrices in optical measurements. PMID:24160602

  20. Infrared transmission measurements of highly curved optical components

    NASA Astrophysics Data System (ADS)

    Tiszauer, Detlev H.; Morrow, Howard E.

    Fourier Transform Infrared Spectrometer (FTIR) measurements on flat witness samples are combined with ray trace results of transmission through a 1/8 inch, 12 mill focal length lens to estimate the net transmission of that lens as it is used in the Geostationary Operational Environmental Satellite (GOES I) Sounder optical train. The ray trace code uses a 'double random' ray method allowing radiometry to be done with a standard ray propagation algorithm.

  1. An optical filter with angular selectivity of the light transmission

    NASA Astrophysics Data System (ADS)

    Zakirullin, Rustam S.

    2015-09-01

    Features of the application of a novel optical filter with angular selectivity of the light transmission to architectural glazing are considered. The filter consists of a sheet transparent substrate with thin-film grating layers on both surfaces. The gratings formed by directionally transmissive strips, alternating with absorptive, reflective, or scattering strips. Their relative position on the input and output surfaces provides angular selectivity of the directional light transmission - as the incidence angle changes, the proportion of radiation that passes through both gratings of the filter also changes. Chromogenic materials currently used in the laminated smart windows, providing control over the intensity and spectrum of the transmitted solar radiation, cannot achieve the selective regulation on the ranges of incidence angles. Such a regulation requires the use of additional daylight-redirecting devices, especially blinds, to dynamically adapt to the position of the sun. The grating optical filter provides angular selectivity of the light transmission of a window without such devices. The features of using this filter in the single and double glazed windows are described. A graphic analytical calculation method is proposed for estimating the effect of geometrical and optical parameters of the filter on the angular characteristics of the light transmission. An algorithm to optimize filtering solar radiation taking into account the geographical coordinates of terrain, time of day and year and the orientation of the window to the cardinal is set. An algorithm to calculating geometrical parameters of the filter with pre-specified characteristics of the light transmission is obtained.

  2. Optical transmission measurements on monocrystalline and polycrystalline cesium iodide

    NASA Technical Reports Server (NTRS)

    Viehmann, W.; Arens, J. F.; Simon, M.

    1973-01-01

    A summary is presented of optical measurements performed on a variety of cesium iodide samples to characterize quantitatively the optical quality of the materials, and to define and measure parameters which determine its suitability as a detector material for high energy cosmic ray experiments on HEAO-A. The general case of light transmission through a long rectangular slab under multiple internal reflections is discussed along with transmission and scattering as a function of wavelength at normal incidence. Scattering parameters are tabulated for encapsulated single crystal CsI and polyscin.

  3. Mode locked Nd:YVO 4 laser with intracavity synchronously pumped optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Zavadilova, Alena; Kubeček, Václav; Čech, Miroslav; Hiršl, Petr; Jelínkova, Helena; Diels, Jean-Claude

    2006-02-01

    The motivation of this work is the development of laser sensor and gyroscope based on short pulse solid state ring laser. In comparison with regular ring laser containing the gain medium and saturable absorber, where counterpropagating pulses overlap, a ring synchronously pumped optical parametric oscillator, in which the pulse crossing point is controlled externally by the time of arrival of the pump pulses, is the ideal source for short pulse laser sensor. The optimum configuration is a synchronously pumped parametric oscillator inserted inside the optical resonator of the diode pumped mode-locked solid state laser. We are developing a such system, as a first step we have demonstrated operation of a diode pumped Nd:YVO 4 passively mode-locked laser using semiconductor saturable absorber with synchronously pumped intracavity optical parametric oscillator in linear configuration. The repetition rate of the pump laser was 132 MHz and the pulse duration of 15 ps. Parametric oscillator was based on 20 mm long Brewster cut single grating (with poling periode of 30.3 μm) periodically poled magnesium doped lithium niobate (MgO:PPLN) crystal. The temperature tuning of parametric luminescence from the crystal with peak wavelength at 1537 nm - 1550 nm for temperature variation from 30 °C to 57 °C was observed.

  4. Plasmonic Brewster Angle: Broadband Extraordinary Transmission through Optical Gratings

    NASA Astrophysics Data System (ADS)

    Alù, Andrea; D'Aguanno, Giuseppe; Mattiucci, Nadia; Bloemer, Mark J.

    2011-03-01

    Extraordinary optical transmission through metallic gratings is a well established effect based on the collective resonance of corrugated screens. Being based on plasmonic resonances, its bandwidth is inherently narrow, in particular, for thick screens and narrow apertures. We introduce here a different mechanism to achieve total transmission through an otherwise opaque screen, based on an ultrabroadband tunneling that can span from dc to the visible range at a given incidence angle. This phenomenon effectively represents the equivalent of Brewster transmission for plasmonic and opaque screens.

  5. Soliton transmission in optical fibers with loss and saturable nonlinearity

    NASA Astrophysics Data System (ADS)

    Aicklen, Gregory H.; Tamil, Lakshman S.

    1996-09-01

    Optical solitons propagating in media exhibiting saturable nonlinearity offer advantages over Kerr-medium solitons for transmission over large distances through optical fibers with loss. Soliton pulses in saturable media offer greater energy for a given peak power, and upper-branch solitons decrease in width with distance traveled. These properties result in pulses that remain distinct and detectable for greater distances than Kerr-medium solitons do with the same peak power. .

  6. Companding transform based SPM compensation in coherent optical OFDM transmission.

    PubMed

    Chung, Hwan Seok; Chang, Sun Hyok; Kim, Kwangjoon

    2011-12-12

    We demonstrate a mitigation of fiber nonlinearity based on μ-law companding transform in coherent optical OFDM transmissions. High peak-to-average power ratio (PAPR) increases fiber nonlinear impairments caused by the Kerr effect in optical fiber. The μ-law companding modifies amplitude profile of OFDM signal with time domain signal processing, which reduces high PAPR of OFDM signal. The effects of companding parameter on noise enhancement and PAPR variation are presented. The impacts of companding transform on system performances are evaluated in a single polarization system as well as polarization multiplexed system. The resolution of analog-to-digital converter (ADC), dispersion map of transmission link, and launch power tolerance are also considered. The results of bit-error-rate (BER) measurements show that the μ-law companding improves OSNR margin over 5.5 dB after transmission of 1,040 km over SMF. PMID:22274091

  7. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes.

    PubMed

    Peer, Akshit; Biswas, Rana

    2016-02-28

    We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ∼750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ∼2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (∼5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ∼40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ∼30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing. PMID:26853881

  8. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes

    DOE PAGESBeta

    Peer, Akshit; Biswas, Rana

    2016-02-01

    In this study, we experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller thanmore » the period, with an enhancement of ~2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ~40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ~30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing.« less

  9. Transmission of a signal that synchronizes cell movements in swarms of Myxococcus xanthus

    PubMed Central

    Kaiser, Dale; Warrick, Hans

    2014-01-01

    We offer evidence for a signal that synchronizes the behavior of hundreds of Myxococcus xanthus cells in a growing swarm. Swarms are driven to expand by the periodic reversing of direction by members. By using time-lapse photomicroscopy, two organized multicellular elements of the swarm were analyzed: single-layered, rectangular rafts and round, multilayered mounds. Rafts of hundreds of cells with their long axes aligned in parallel enlarge as individual cells from the neighborhood join them from either side. Rafts can also add a second layer piece by piece. By repeating layer additions to a raft and rounding each layer, a regular multilayered mound can be formed. About an hour after a five-layered mound had formed, all of the cells from its top layer descended to the periphery of the fourth layer, both rapidly and synchronously. Following the first synchronized descent and spaced at constant time intervals, a new fifth layer was (re)constructed from fourth-layer cells, in very close proximity to its old position and with a number of cells similar to that before the “explosive” descent. This unexpected series of changes in mound structure can be explained by the spread of a signal that synchronizes the reversals of large groups of individual cells. PMID:25149859

  10. Monolithic integration and synchronous operation of germanium photodetectors and silicon variable optical attenuators.

    PubMed

    Park, Sungbong; Tsuchizawa, Tai; Watanabe, Toshifumi; Shinojima, Hiroyuki; Nishi, Hidetaka; Yamada, Koji; Ishikawa, Yasuhiko; Wada, Kazumi; Itabashi, Seiichi

    2010-04-12

    We demonstrate the monolithic integration of germanium (Ge) p-i-n photodetector (PDs) with silicon (Si) variable optical attenuator (VOAs) based on submicrometer Si rib waveguide. A PD is connected to a VOA along the waveguide via a tap coupler. The PDs exhibit low dark current of ~60 nA and large responsivity of ~0.8 A/W at the reverse bias of 1 V at room temperature. These characteristics are uniform over the chip scale. The PDs generate photocurrents precisely with respect to DC optical power attenuated by the VOAs. Two devices work synchronously for modulated optical signals as well. 3-dB cut-off frequency of the VOA is ~100 MHz, while that of the PD is ~1 GHz. The synchronous response speed is limited by the VOA response speed. This is the first demonstration, to the best of our knowledge, of monolithic integration of Ge PDs with high-carrier-injection-based optical modulation devices based on Si. PMID:20588687

  11. Demonstration of optical steganography transmission using temporal phase coded optical signals with spectral notch filtering.

    PubMed

    Hong, Xuezhi; Wang, Dawei; Xu, Lei; He, Sailing

    2010-06-01

    A novel approach is proposed and experimentally demonstrated for optical steganography transmission in WDM networks using temporal phase coded optical signals with spectral notch filtering. A temporal phase coded stealth channel is temporally and spectrally overlaid onto a public WDM channel. Direct detection of the public channel is achieved in the presence of the stealth channel. The interference from the public channel is suppressed by spectral notching before the detection of the optical stealth signal. The approach is shown to have good compatibility and robustness to the existing WDM network for optical steganography transmission. PMID:20588368

  12. Optical performance monitoring technique using software-based synchronous amplitude histograms.

    PubMed

    Choi, H G; Chang, J H; Kim, Hoon; Chung, Y C

    2014-10-01

    We propose and demonstrate a simple technique to monitor both the optical signal-to-noise ratio (OSNR) and chromatic dispersion (CD) by using the software-based synchronous amplitude histogram (SAH) analysis. We exploit the software-based synchronization technique to construct SAHs from the asynchronously sampled intensities of the signal. The use of SAHs facilitates the accurate extraction of the monitoring parameters at the center of the symbol. Thus, unlike in the case of using the technique based on the asynchronous amplitude histogram (AAH), this technique is not affected by the transient characteristics of the modulated signals. The performance of the proposed monitoring technique is evaluated experimentally by using 10-Gbaud quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) signals over wide ranges of OSNR and CD. We also evaluate the robustness of the proposed technique to the signal's transient characteristics. PMID:25321978

  13. Transmission of RF Signals Over Optical Fiber for Avionics Applications

    NASA Technical Reports Server (NTRS)

    Slaveski, Filip; Sluss, James, Jr.; Atiquzzaman, Mohammed; Hung, Nguyen; Ngo, Duc

    2002-01-01

    During flight, aircraft avionics transmit and receive RF signals to/from antennas over coaxial cables. As the density and complexity of onboard avionics increases, the electromagnetic interference (EM) environment degrades proportionately, leading to decreasing signal-to-noise ratios (SNRs) and potential safety concerns. The coaxial cables are inherently lossy, limiting the RF signal bandwidth while adding considerable weight. To overcome these limitations, we have investigated a fiber optic communications link for aircraft that utilizes wavelength division multiplexing (WDM) to support the simultaneous transmission of multiple signals (including RF) over a single optical fiber. Optical fiber has many advantages over coaxial cable, particularly lower loss, greater bandwidth, and immunity to EM. In this paper, we demonstrate that WDM can be successfully used to transmit multiple RF signals over a single optical fiber with no appreciable signal degradation. We investigate the transmission of FM and AM analog modulated signals, as well as FSK digital modulated signals, over a fiber optic link (FOL) employing WDM. We present measurements of power loss, delay, SNR, carrier-to-noise ratio (CNR), total harmonic distortion (THD), and bit error rate (BER). Our experimental results indicate that WDM is a fiber optic technology suitable for avionics applications.

  14. Influence of aero-optical transmission on infrared imaging optical system in the supersonic flight

    NASA Astrophysics Data System (ADS)

    Liu, Li; Meng, Weihua; Li, Yun; Dai, Xiaobing; Zuo, Zhiyong

    2015-01-01

    Aero-optical transmission effect is becoming a crucial issue in the supersonic flight. In our study, the joint influences of the non-uniform aerodynamic flow field and the aerodynamically heated optical window on imaging quality of an airborne infrared optical system are investigated in depth. Both the laminar and turbulent viscous models are used in the simulation of aerodynamic flow because of their distinct influences on aero-optical transmission. On the basis of the computed density field, the ray tracing method is applied to calculate the point spread functions of the aerodynamic flow field and the aerodynamically heated window. The imaging quality is evaluated by using the point spread functions and modulation transfer functions. Experimental results show that the optical transmission through the aerodynamically heated window has a much severer influence on the imaging quality than that through the aerodynamic flow field.

  15. The optical transmission characteristics through coupled metallic nanotube arrays

    NASA Astrophysics Data System (ADS)

    Li, Hongjian; Fu, Shaoli; Xu, Haiqing; Xie, Suxia; Zhou, Xin; Wu, Jinjun

    2010-10-01

    The plasmonic properties in coupled metallic nanotube arrays are investigated theoretically by the finite-difference time-domain (FDTD) method. We calculate the transmission spectra and the electric field distributions. We show that there is a photonic band gap over a wide optical wavelength range and the transmission spectrum depends strongly on the inner radii, the separation distance and the number of the nanotubes. Based on the localized nature of the field distribution, we also clearly show that the presence of local plasmon resonant modes that originate from multipolar plasmon polaritons and a big magnitude of opposing surface charges build up in the gap between adjacent nanotubes.

  16. Synchronously pumped optical parametric oscillation in periodically poled lithium niobate with 1-w average output power.

    PubMed

    Graf, T; McConnell, G; Ferguson, A I; Bente, E; Burns, D; Dawson, M D

    1999-05-20

    We report on a rugged all-solid-state laser source of near-IR radiation in the range of 1461-1601 nm based on a high-power Nd:YVO(4) laser that is mode locked by a semiconductor saturable Bragg reflector as the pump source of a synchronously pumped optical parametric oscillator with a periodically poled lithium niobate crystal. The system produces 34-ps pulses with a high repetition rate of 235 MHz and an average output power of 1 W. The relatively long pulses lead to wide cavity detuning tolerances. The comparatively narrow spectral bandwidth of <15 GHz is suitable for applications such as pollutant detection. PMID:18319928

  17. An Implantable Neural Sensing Microsystem with Fiber-Optic Data Transmission and Power Delivery

    PubMed Central

    Park, Sunmee; Borton, David A.; Kang, Mingyu; Nurmikko, Arto V.; Song, Yoon-Kyu

    2013-01-01

    We have developed a prototype cortical neural sensing microsystem for brain implantable neuroengineering applications. Its key feature is that both the transmission of broadband, multichannel neural data and power required for the embedded microelectronics are provided by optical fiber access. The fiber-optic system is aimed at enabling neural recording from rodents and primates by converting cortical signals to a digital stream of infrared light pulses. In the full microsystem whose performance is summarized in this paper, an analog-to-digital converter and a low power digital controller IC have been integrated with a low threshold, semiconductor laser to extract the digitized neural signals optically from the implantable unit. The microsystem also acquires electrical power and synchronization clocks via optical fibers from an external laser by using a highly efficient photovoltaic cell on board. The implantable unit employs a flexible polymer substrate to integrate analog and digital microelectronics and on-chip optoelectronic components, while adapting to the anatomical and physiological constraints of the environment. A low power analog CMOS chip, which includes preamplifier and multiplexing circuitry, is directly flip-chip bonded to the microelectrode array to form the cortical neurosensor device. PMID:23666130

  18. An implantable neural sensing microsystem with fiber-optic data transmission and power delivery.

    PubMed

    Park, Sunmee; Borton, David A; Kang, Mingyu; Nurmikko, Arto V; Song, Yoon-Kyu

    2013-01-01

    We have developed a prototype cortical neural sensing microsystem for brain implantable neuroengineering applications. Its key feature is that both the transmission of broadband, multichannel neural data and power required for the embedded microelectronics are provided by optical fiber access. The fiber-optic system is aimed at enabling neural recording from rodents and primates by converting cortical signals to a digital stream of infrared light pulses. In the full microsystem whose performance is summarized in this paper, an analog-to-digital converter and a low power digital controller IC have been integrated with a low threshold, semiconductor laser to extract the digitized neural signals optically from the implantable unit. The microsystem also acquires electrical power and synchronization clocks via optical fibers from an external laser by using a highly efficient photovoltaic cell on board. The implantable unit employs a flexible polymer substrate to integrate analog and digital microelectronics and on-chip optoelectronic components, while adapting to the anatomical and physiological constraints of the environment. A low power analog CMOS chip, which includes preamplifier and multiplexing circuitry, is directly flip-chip bonded to the microelectrode array to form the cortical neurosensor device. PMID:23666130

  19. Optical transmission scanning for damage quantification in impacted GFRP composites

    NASA Astrophysics Data System (ADS)

    Khomenko, Anton; Karpenko, Oleksii; Koricho, Ermias G.; Haq, Mahmoodul; Cloud, Gary L.; Udpa, Lalita

    2016-04-01

    Glass fiber reinforced polymer (GFRP) composites constitute nearly 90% of the global composites market and are extensively used in aerospace, marine, automotive and construction industries. While their advantages of lightweight and superior mechanical properties are well explored, non-destructive evaluation (NDE) techniques that allow for damage/defect detection and assessment of its extent and severity are not fully developed. Some of the conventional NDE techniques for GFRPs include ultrasonics, X-ray, IR thermography, and a variety of optical techniques. Optical methods, specifically measuring the transmission properties (e.g. ballistic optical imaging) of specimens, provide noninvasive, safe, inexpensive, and compact solutions and are commonly used in biomedical applications. In this work, this technique is adapted for rapid NDE of GFRP composites. In its basic form, the system for optical transmission scanning (OTS) consists of a light source (laser diode), a photo detector and a 2D translation stage. The proposed technique provides high-resolution, rapid and non-contact OT (optical transmittance)-scans, and does not require any coupling. The OTS system was used for inspection of pristine and low-velocity impacted (damaged) GFRP samples. The OT-scans were compared with conventional ultrasonic C-scans and showed excellent agreement but with better resolution. Overall, the work presented lays the groundwork for cost-effective, non-contact, and rapid NDE of GFRP composite structures.

  20. Versatile transmission ellipsometry to study linear ferrofluid magneto-optics.

    PubMed

    Kooij, E S; Gâlcă, A C; Poelsema, B

    2006-12-01

    Linear birefringence and dichroism of magnetite ferrofluids are studied simultaneously using spectroscopic ellipsometry in transmission mode. It is shown that this versatile technique enables highly accurate characterisation of magneto-optical phenomena. Magnetic field-dependent linear birefringence and dichroism as well as the spectral dependence are shown to be in line with previous results. Despite the qualitative agreement with established models for magneto-optical phenomena, these fail to provide an accurate, quantitative description of our experimental results using the bulk dielectric function of magnetite. We discuss the results in relation to these models, and indicate how the modified dielectric function of the magnetite nanoparticles can be obtained. PMID:16997315

  1. Analytical theory of extraordinary optical transmission through realistic metallic screens.

    PubMed

    Delgado, V; Marqués, R; Jelinek, L

    2010-03-29

    An analytical theory of extraordinary optical transmission (EOT) through realistic metallic screens perforated by a periodic array of subwavelength holes is presented. The theory is based on our previous work on EOT through perfect conducting screens and on the surface impedance concept. The proposed theory is valid for the complete frequency range where EOT has been reported, including microwaves and optics. A reasonably good agreement with electromagnetic simulations is shown in all this frequency range. We feel that the proposed theory may help to clarify the physics underlying EOT and serve as a first step to more accurate analysis. PMID:20389673

  2. Generation and transmission of 85.4 Gb/s real-time 16QAM coherent optical OFDM signals over 400 km SSMF with preamble-less reception.

    PubMed

    Bouziane, Rachid; Schmogrow, Rene; Hillerkuss, D; Milder, P A; Koos, C; Freude, W; Leuthold, J; Bayvel, P; Killey, R I

    2012-09-10

    This paper presents a real-time, coherent optical OFDM transmitter based on a field programmable gate array implementation. The transmitter uses 16QAM mapping and runs at 28 GSa/s achieving a data rate of 85.4 Gb/s on a single polarization. A cyclic prefix of 25% of the symbol duration is added enabling dispersion-tolerant transmission over up to 400 km of SSMF. This is the first transmission experiment performed with a real-time OFDM transmitter running at data rates higher than 40 Gb/s. A key aspect of the paper is the introduction of a novel method for OFDM symbol synchronization without relying on training symbols. Unlike conventional preamble-based synchronization methods which perform cross-correlations at regular time intervals and let the system run freely in between, the proposed method performs synchronization in a continuous manner ensuring correct symbol alignment at all times. PMID:23037279

  3. Spectrally efficient optical transmission based on Stokes vector direct detection.

    PubMed

    Li, An; Che, Di; Chen, Vivian; Shieh, William

    2014-06-30

    We propose a novel detection scheme called Stokes vector direct detection (SV-DD) to realize high electrical spectral efficiency and cost-effective optical communication for short and medium reach. With SV-DD, the signal is modulated in only one polarization and combined with the carrier in the orthogonal polarization for fiber transmission. At reception, the combined signal is detected in Stokes space by three or four photo-detectors. Compared with conventional DD technique, SV-DD is resilient to both chromatic dispersion and signal-to-signal beat noise. Furthermore, SV-DD does not require polarization tracking or narrow band optical filtering for carrier extraction. In this paper, we present for the first time the numerical analysis and experimental demonstration of single-carrier SV-DD. We report 62.5-Gb/s data rate single-carrier SV-DD transmission over 160-km SSMF using 12.5-Gbaud 32-QAM modulation. PMID:24977825

  4. Radiation-hard/high-speed data transmission using optical links

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Abi, B.; Fernando, W.; Kagan, H. P.; Kass, R. D.; Lebbai, M. R. M.; Moore, J. R.; Rizatdinova, F.; Skubic, P. L.; Smith, D. S.

    2009-12-01

    The silicon trackers of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) use optical links for data transmission. An upgrade of the trackers is planned for the Super LHC (SLHC), an upgraded LHC with ten times higher luminosity. We investigate the radiation-hardness of various components for possible application in the data transmission upgrade. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs from various sources using 24 GeV/c protons at CERN. The optical power of VCSEL arrays decreases significantly after the irradiation but can be partially annealed with high drive currents. The responsivities of the PIN diodes also decrease significantly after irradiation, especially for the GaAs devices. We have designed the ASICs for the opto-link applications and find that the degradation with radiation is acceptable.

  5. Optical differentiation wavefront sensor based on binary pixelated transmission filters

    NASA Astrophysics Data System (ADS)

    Qiao, J.; Travinsky, A.; Ding, G.; Dorrer, C.

    2015-03-01

    High-resolution wavefront sensors are used in a wide range of applications. The Shack-Hartmann sensor is the industry standard and mostly used for this kind of analysis. However, with this sensor the analysis can only be performed for narrowband radiation, the recoverable curvature of the wavefront slopes is also restricted by the size of a single lens in the microlens array. The high-resolution Shack Hartmann wavefront sensor (>128×128) is also significantly expensive. The optical differentiation wavefront sensor, on the other hand, consists of only simple and therefore inexpensive components, offers greater signal to noise ratio, allows for high-resolution analysis of wavefront curvature, and is potentially capable of performing broadband measurements. When a transmission mask with linear attenuation along a spatial direction modulates the far field of an optical wave, the spatial wavefront slope along that direction can be recovered from the fluence in the near field after modulation. With two orthogonal measurements one can recover the complete wavefront of the optical wave. In this study the characteristics of such a wavefront sensor are investigated when the linear transmission modulation is implemented with a pixelated binary filter. Such a filter can be produced as a gray-scale quasi-continuous transmission pattern constructed using arrays of small (e.g., 10-micron) transparent or opaque pixels and therefore it can simply be fabricated by conventional lithography techniques. Simulations demonstrate the potential ability of such a pixelated filter to match the performance of a filter with continuously varying transmission, while offering the advantage of better transmission control and reduction of fabrication costs.

  6. Extraordinary optical transmission in nanopatterned ultrathin metal films without holes

    NASA Astrophysics Data System (ADS)

    Peer, Akshit; Biswas, Rana

    2016-02-01

    We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by angle-directed deposition. The gold film was continuous with spatial thickness variation, the film being thinnest at the bottom of the nanocup. Measurements revealed an extraordinary transmission peak at a wavelength just smaller than the period, with an enhancement of ~2.5 compared to the classically expected value. Scattering matrix simulations model well the transmission and reflectance measurements when an ultrathin gold layer (~5 nm), smaller than the skin depth is retained at the bottom of the nanocups. Electric field intensities are enhanced by >100 within the nanocup, and ~40 in the ultrathin gold layer causing transmission through it. We show a wavelength red-shift of ~30 nm in the extraordinary transmission peak when the nanocups are coated with a thin film of a few nanometers, which can be utilized for biosensing. The continuous corrugated metal films are far simpler structures to observe extraordinary transmission, circumventing the difficult process of etching the metal film. Such continuous metal films with ultrathin regions are simple platforms for non-linear optics, plasmonics, and biological and chemical sensing.We experimentally and theoretically demonstrate that a continuous gold film on a periodically textured substrate exhibits extraordinary optical transmission, even though no holes were etched in the film. Our film synthesis started by nanoimprinting a periodic array of nanocups with a period of ~750 nm on a polystyrene film over a glass substrate. A thin non-conformal gold film was sputter-deposited on the polystyrene by

  7. Transmission spectrum of an optical cavity containing N atoms

    SciTech Connect

    Leslie, Sabrina; Shenvi, Neil; Brown, Kenneth R.; Whaley, K. Birgitta; Stamper-Kurn, Dan M.

    2004-04-01

    The transmission spectrum of a high-finesse optical cavity containing an arbitrary number of trapped atoms is presented in the zero-temperature, low saturation limit. We take spatial and motional effects into account and show that in the limit of strong coupling, the important spectral features can be determined for an arbitrary number of atoms, N. We also show that these results have important ramifications in limiting our ability to determine the number of atoms in the cavity.

  8. Optical transmission spectra of porous aluminamembranes with different pore size

    NASA Astrophysics Data System (ADS)

    Matyushkin, L. B.; Muratova, E. N.; Spivak, J. M.; Shimanova, V. V.; Korlyakova, S. A.; Moshnikov, V. A.

    2014-12-01

    Membranes of nanoporous aluminum oxide (alumina) have been obtained using the electrochemical etching technique by varying technological regimes. The surface morphology and cleavages of obtained experimental samples are studied using scanning electron microscopy (SEM). The optical transmission measurements were performed on a spectrophotometer in the wavelength range of 190-1000 nm. It is possible to determine the average size and the dispersion of the pore diameter by UV- visible transmittance spectrum measuring.

  9. Transmission of acceleration from a synchronous vibration exercise platform to the head.

    PubMed

    Caryn, R C; Hazell, T J; Dickey, J P

    2014-04-01

    Exercise vibration platforms are becoming commonplace in homes and fitness centers. However, excessive mechanical energy transferred to the head and eye can cause injury. The purpose of this study was to evaluate how changes in platform frequency and knee flexion angle affect acceleration transmission to the head. Participants (N=12) stood on a whole-body vibration platform with knee flexion angles of 0°, 20°, and 40° to evaluate how changes in knee flexion affected head acceleration. 7 specific platform frequencies were tested between 20-50 Hz at 2 peak-to-peak displacement settings (1 and 2 mm nominal). Accelerations were measured with triaxial accelerometers at the platform and head to generate transmissibility ratios. Platform-to-head transmissibility was not significantly different between the 2 platform peak-to-peak amplitudes (P>0.05). Transmissibility measures varied depending on platform frequency and knee angle (P < 0.05). Flexing the knees resulted in reduced head transmissibility at all frequencies (P<0.05). Platform-to-head transmissibility values exceeded 1.0 at both 20 and 25 Hz platform vibration frequencies with the knees in full extension. To reduce the risk of injury to structures of the head during vibration exercise, using platforms frequencies below 30 Hz with small knee flexion angles (< 40°) should be avoided. PMID:24081617

  10. Optically-synchronized encoder and multiplexer scheme for interleaved photonics analog-to-digital conversion

    NASA Astrophysics Data System (ADS)

    Villa, Carlos; Kumavor, Patrick; Donkor, Eric

    2008-04-01

    Photonics Analog-to-Digital Converters (ADCs) utilize a train of optical pulses to sample an electrical input waveform applied to an electrooptic modulator or a reverse biased photodiode. In the former, the resulting train of amplitude-modulated optical pulses is detected (converter to electrical) and quantized using a conversional electronics ADC- as at present there are no practical, cost-effective optical quantizers available with performance that rival electronic quantizers. In the latter, the electrical samples are directly quantized by the electronics ADC. In both cases however, the sampling rate is limited by the speed with which the electronics ADC can quantize the electrical samples. One way to increase the sampling rate by a factor N is by using the time-interleaved technique which consists of a parallel array of N electrical ADC converters, which have the same sampling rate but different sampling phase. Each operating at a quantization rate of fs/N where fs is the aggregated sampling rate. In a system with no real-time operation, the N channels digital outputs are stored in memory, and then aggregated (multiplexed) to obtain the digital representation of the analog input waveform. Alternatively, for real-time operation systems the reduction of storing time in the multiplexing process is desired to improve the time response of the ADC. The complete elimination of memories come expenses of concurrent timing and synchronization in the aggregation of the digital signal that became critical for a good digital representation of the analog signal waveform. In this paper we propose and demonstrate a novel optically synchronized encoder and multiplexer scheme for interleaved photonics ADCs that utilize the N optical signals used to sample different phases of an analog input signal to synchronize the multiplexing of the resulting N digital output channels in a single digital output port. As a proof of concept, four 320 Megasamples/sec 12-bit of resolution digital

  11. Optically synchronized dual-channel terahertz signals for high-performance transmitter/receiver system

    NASA Astrophysics Data System (ADS)

    Shimizu, Naofumi; Oh, Kyoung-Hwan; Kohjiro, Satoshi; Kikuchi, Ken'ichi; Wakatsuki, Atsushi; Kukutsu, Naoya; Kado, Yuichi

    2010-02-01

    We developed a high-sweeping-speed optically synchronized dual-channel terahertz signal generator, in which the frequency difference between the two terahertz signals is independent of the frequency of the terahertz signals themselves. This feature is essential for heterodyne detection of terahertz signals with various frequencies. With this generator, a frequency-sweepable terahertz transmitter (Tx)/receiver (Rx) system with a wide dynamic range can be realized without sacrificing the high frequency-sweeping speed. Absorption line measurements for water vapor and nitrous oxide show that the developed Tx/Rx system can detect gas absorption with the optical depth of 0.04 or less. This result indicates the potential of the system as a remote gas sensor and gas analyzer.

  12. Pump-seed synchronization for MHz repetition rate, high-power optical parametric chirped pulse amplification.

    PubMed

    Fattahi, Hanieh; Teisset, Catherine Yuriko; Pronin, Oleg; Sugita, Atsushi; Graf, Roswitha; Pervak, Vladimir; Gu, Xun; Metzger, Thomas; Major, Zsuzsanna; Krausz, Ferenc; Apolonski, Alexander

    2012-04-23

    We report on an active synchronization between two independent mode-locked lasers using a combined electronic-optical feedback. With this scheme, seed pulses at MHz repetition rate were amplified in a non-collinear optical parametric chirped pulse amplifier (OPCPA). The amplifier was seeded with stretched 1.5 nJ pulses from a femtosecond Ti:Sapphire oscillator, while pumped with the 1 ps, 2.9 µJ frequency-doubled output of an Yb:YAG thin-disk oscillator. The residual timing jitter between the two oscillators was suppressed to 120 fs (RMS), allowing for an efficient and broadband amplification at 11.5 MHz to a pulse energy of 700 nJ and an average power of 8 W. First compression experiment with 240 nJ amplified pulse energy resulted in a pulse duration of ~10 fs. PMID:22535076

  13. Phase error statistics of a phase-locked loop synchronized direct detection optical PPM communication system

    NASA Technical Reports Server (NTRS)

    Natarajan, Suresh; Gardner, C. S.

    1987-01-01

    Receiver timing synchronization of an optical Pulse-Position Modulation (PPM) communication system can be achieved using a phased-locked loop (PLL), provided the photodetector output is suitably processed. The magnitude of the PLL phase error is a good indicator of the timing error at the receiver decoder. The statistics of the phase error are investigated while varying several key system parameters such as PPM order, signal and background strengths, and PPL bandwidth. A practical optical communication system utilizing a laser diode transmitter and an avalanche photodiode in the receiver is described, and the sampled phase error data are presented. A linear regression analysis is applied to the data to obtain estimates of the relational constants involving the phase error variance and incident signal power.

  14. Transmission of laser light through fiber optic connectors

    NASA Astrophysics Data System (ADS)

    Gajda, Jerzy K.

    2003-10-01

    The connections of the telecommunications tract elements have a significant influence on the quality of the information transmission. In the essay reasons and an analysis of the losses in fiber optic connectors are introduced. The case of fiber optic connectors: PC type and with a surface enlargement are emphasized. Different types of fiber sleeve connectors are discussed. These optical connectors can be divided according to following criteria: structure (ST, FC, Sc, E-2000, F-3000, LC, MT-RJ, MU, etc.) types of applied ferrules (monolithic, with multiple elements) technology of production (standard, Light Crimp - AMP, Hot Melt - 3MCrimp Lok - 3M, Universal Com Lite - Siecor) and tuning. Moreover the quality of DWDM fiber optic connectors, which have high functional density and an impact on the light polarization is touched on. The results of measurements of transmission parameters and of mechanical resistance on vibration, folding of the cable in the fiber, strikes on hard surfaces, multiple connection and disconnecting, pulling out of a cable from the connectors and climate conditions are discussed. The results of the measurements listed above with additional interferometric tests of ferrule head constitute the main factor of the fiber connectors quality analysis. Furthermore, the up to date results of the compatibility analysis of the connectors manufactured by different producers are mentioned and a future development in the field is forecasted.

  15. Quasi-Optical Transmission Line for 94-GHz Radar

    NASA Technical Reports Server (NTRS)

    Perez, Raul M.; Veruttipong, Watt

    2008-01-01

    A quasi-optical transmission line (QOTL) has been developed as a low-loss transmission line for a spaceborne cloudobserving radar instrument that operates at a nominal frequency of 94 GHz. This QOTL could also readily be redesigned for use in terrestrial millimeter-wave radar systems and millimeter-wave imaging systems. In the absence of this or another lowloss transmission line, it would be necessary to use a waveguide transmission line in the original radar application. Unfortunately, transmission losses increase and power-handling capacities of waveguides generally decrease with frequency, such that at 94 GHz, the limitation on transmitting power and the combined transmission and reception losses (greater than 5 dB) in a waveguide transmission line previously considered for the original application would be unacceptable. The QOTL functions as a very-lowloss, three-port circulator. The QOTL includes a shaped input mirror that can be rotated to accept 94-GHz transmitter power from either of two high-power amplifiers. Inside the QOTL, the transmitter power takes the form of a linearly polarized beam radiated from a feed horn. This beam propagates through a system of mirrors, each of which refocuses the beam to minimize diffraction losses. A magnetically biased ferrite disc is placed at one of the foci to utilize the Faraday effect to rotate the polarization of the beam by 45 degrees. The beam is then transmitted via an antenna system. The radar return (scatter from clouds, and/or reflections from other objects) is collected by the same antenna and propagates through the Faraday rotator in the reverse of the direction of propagation of the transmitted beam. In the Faraday rotator, the polarization of the received signal is rotated a further 45 degrees, so that upon emerging from the Faraday rotator, the received beam is polarized at 90 with respect to the transmitted beam. The transmitted and received signals are then separated by a wire-grid polarizer.

  16. Optical Sensor Demands On Real-Time Reconnaissance Data Transmission

    NASA Astrophysics Data System (ADS)

    McAhron, Max C.

    1987-02-01

    The application of optical sensors (photographic, electro-optic, and infrared) to the tactical military reconnaissance scenario is increasing both in number and performance expectations. The resolution and collection rate capabilities of these optical sensors lead to massive amounts of raw data requiring reduction and interpretation. Exploitation of the collected information must be accomplished in near-real-time (immediate to several minutes) to fully realize the sensor's potential in the tactical operating environment. Exploitation delayed hours from collection becomes useless at best and misinformation at worst. Herein, the first objective is to approximately quantify the existing capabilities for data collection, recording, and transmission, both in rate and volume. The second objective is to suggest several means whereby preprocessing may reduce the volume of data without influencing the substantive information. The third objective is to suggest means whereby the sensor utilization is more selective, thereby providing a better focus of the collection process.

  17. Power transmission by laser beam from lunar-synchronous satellites to a lunar rover

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Deyoung, R. J.; Schuster, G. L.; Choi, S. H.; Dagle, J. E.; Coomes, E. P.; Antoniak, Z. I.; Bamberger, J. A.; Bates, J. M.; Chiu, M. A.

    1992-01-01

    This study addresses the possibility of beaming laser power from synchronous lunar orbits (L1 and L2 LaGrange points) to a manned long-range lunar rover. The rover and two versions of a satellite system (one powered by a nuclear reactor; the other by photovoltaics) are described in terms of their masses, geometry, power needs, mission and technological capabilities. Laser beam power is generated by a laser diode array in the satellite and converted to 30 kW of electrical power at the rover. Present technological capabilities, with some extrapolation to near future capabilities, are used in the descriptions. The advantages of the two satellite/rover systems over other such systems and over rovers with on-board power are discussed along with the possibility of enabling other missions.

  18. Chaos-on-a-chip secures data transmission in optical fiber links.

    PubMed

    Argyris, Apostolos; Grivas, Evangellos; Hamacher, Michael; Bogris, Adonis; Syvridis, Dimitris

    2010-03-01

    Security in information exchange plays a central role in the deployment of modern communication systems. Besides algorithms, chaos is exploited as a real-time high-speed data encryption technique which enhances the security at the hardware level of optical networks. In this work, compact, fully controllable and stably operating monolithic photonic integrated circuits (PICs) that generate broadband chaotic optical signals are incorporated in chaos-encoded optical transmission systems. Data sequences with rates up to 2.5 Gb/s with small amplitudes are completely encrypted within these chaotic carriers. Only authorized counterparts, supplied with identical chaos generating PICs that are able to synchronize and reproduce the same carriers, can benefit from data exchange with bit-rates up to 2.5Gb/s with error rates below 10(-12). Eavesdroppers with access to the communication link experience a 0.5 probability to detect correctly each bit by direct signal detection, while eavesdroppers supplied with even slightly unmatched hardware receivers are restricted to data extraction error rates well above 10(-3). PMID:20389532

  19. Optical transmission through a polarization preserving single mode optical fiber at two Ar(+) laser wavelengths

    NASA Technical Reports Server (NTRS)

    Tedjojuwono, Ken K.; Hunter, William W., Jr.

    1989-01-01

    The transmission characteristics of two Ar(+) laser wavelengths through a twenty meter Panda type Polarization Preserving Single Mode Optical Fiber (PPSMOF) were measured. The measurements were done with both single and multi-longitudinal mode radiation. In the single longitudinal mode case, a degrading Stimulated Brillouin Scattering (SBS) is observed as a backward scattering loss. By choosing an optimum coupling system and manipulating the input polarization, the threshold of the SBS onset can be raised and the transmission efficiency can be increased.

  20. Adaptive Quality of Transmission Control in Elastic Optical Network

    NASA Astrophysics Data System (ADS)

    Cai, Xinran

    Optical fiber communication is becoming increasingly important due to the burgeoning demand in the internet capacity. However, traditional wavelength division multiplexing (WDM) technique fails to address such demand because of its inefficient spectral utilization. As a result, elastic optical networking (EON) has been under extensive investigation recently. Such network allows sub-wavelength and super-wavelength channel accommodation, and mitigates the stranded bandwidth problem in the WDM network. In addition, elastic optical network is also able to dynamically allocate the spectral resources of the network based on channel conditions and impairments, and adaptively control the quality of transmission of a channel. This application requires two aspects to be investigated: an efficient optical performance monitoring scheme and networking control and management algorithms to reconfigure the network in a dynamic fashion. This thesis focuses on the two aspects discussed above about adaptive QoT control. We demonstrated a supervisory channel method for optical signal to noise ratio (OSNR) and chromatic dispersion (CD) monitoring. In addition, our proof-of-principle testbed experiments show successful impairment aware reconfiguration of the network with modulation format switching (MFS) only and MFS combined with lightpath rerouting (LR) for hundred-GHz QPSK superchannels undergoing time-varying OSNR impairment.

  1. Optical nonreciprocal transmission in an asymmetric silicon photonic crystal structure

    SciTech Connect

    Wu, Zheng; Chen, Juguang; Ji, Mengxi; Huang, Qingzhong; Xia, Jinsong; Wang, Yi E-mail: ywangwnlo@mail.hust.edu.cn; Wu, Ying E-mail: ywangwnlo@mail.hust.edu.cn

    2015-11-30

    An optical nonreciprocal transmission (ONT) is realized by employing the nonlinear effects in a compact asymmetric direct-coupled nanocavity-waveguide silicon photonic crystal structure with a high loaded quality factor (Q{sub L}) of 42 360 and large extinction ratio exceeding 30 dB. Applying a single step lithography and successive etching, the device can realize the ONT in an individual nanocavity, alleviating the requirement to accurately control the resonance of the cavities. A maximum nonreciprocal transmission ratio of 21.1 dB as well as a working bandwidth of 280 pm in the telecommunication band are obtained at a low input power of 76.7 μW. The calculated results by employing a nonlinear coupled-mode model are in good agreement with the experiment.

  2. Chaos synchronization in vertical-cavity surface-emitting laser based on rotated polarization-preserved optical feedback

    NASA Astrophysics Data System (ADS)

    Nazhan, Salam; Ghassemlooy, Zabih; Busawon, Krishna

    2016-01-01

    In this paper, the influence of the rotating polarization-preserved optical feedback on the chaos synchronization of a vertical-cavity surface-emitting laser (VCSEL) is investigated experimentally. Two VCSELs' polarization modes (XP) and (YP) are gradually rotated and re-injected back into the VCSEL. The anti-phase dynamics synchronization of the two polarization modes is evaluated using the cross-correlation function. For a fixed optical feedback, a clear relationship is found between the cross-correlation coefficient and the polarization angle θp. It is shown that high-quality anti-phase polarization-resolved chaos synchronization is achieved at higher values of θp. The maximum value of the cross-correlation coefficient achieved is -0.99 with a zero time delay over a wide range of θp beyond 65° with a poor synchronization dynamic at θp less than 65°. Furthermore, it is observed that the antiphase irregular oscillation of the XP and YP modes changes with θp. VCSEL under the rotating polarization optical feedback can be a good candidate as a chaotic synchronization source for a secure communication system.

  3. Quantum synchronization of ultracold atoms with dipole-dipole interactions in an optical lattice

    NASA Astrophysics Data System (ADS)

    Zhu, Bihui; Restrepo, Juan; Rey, Ana Maria; Holland, Murray

    2014-05-01

    Ultracold atoms confined in an optical lattice have been utilized as a powerful platform to study versatile many-body physics both experimentally and theoretically. A recent research focus has been the novel phenomena that would emerge with long-range interactions, which become especially important for atomic clocks where ultrahigh precision can amplify these effects. We develop theoretical models treating the two-level atoms as oscillators and study the synchronization of phases among a large ensemble of atoms coupled by dipole-dipole interactions, where the effect of geometry becomes relevant. We investigate the onset of synchronization and the related phase diagram, and further discuss the parameter regime for potential experimental observation using ultracold atoms such as Strontium. By applying different numerical methods, eg., quantum trajectories and truncated Wigner approximations to compare with the mean-field results, we also explore the underlying role of quantum fluctuations. We acknowledge funding from NIST, JILA-NSF-PFC-1125844, NSF-PIF, ARO, ARO-DARPA-OLE, and AFOSR.

  4. Synchronized generation of 1534 and 1572 nm by the mixed optical parameter oscillation

    NASA Astrophysics Data System (ADS)

    Huang, H. T.; He, J. L.; Liu, S. D.; Liu, F. Q.; Yang, X. Q.; Yang, H. W.; Yang, Y.; Yang, H.

    2011-05-01

    A novel nonlinear frequency conversion process was demonstrated to realize the synchronized dual-wavelength emissions at 1534 and 1572 nm by the mixed optical parametric oscillation (OPO) conversion in gray-tracking-resistance KTP (GTR-KTP) and KTA crystals. Both the two crystals were inserted into the diode-pumped Nd:YAG/Cr4+:YAG fundamental resonator, with their Y axes perpendicular to each other. This could eliminate the competition of the two OPO processes in fundamental radiation. Furthermore, the ratio between the length of GTR-KTP and KTA has also been specially designed to satisfy the same OPO thresholds. The synchronized dual-wavelength lasing with the power ratio of 1:1 between 1534 and 1572 nm was successfully realized. At an incident LD pump power of 7 W, the maximum total output power of 460 mW was achieved, with the corresponding pulse width and repetition rate measured to be 3.9 ns and 5.5 kHz, respectively. This mixed conversion opens a new door for the multi-wavelength lasing.

  5. Can precursors improve the transmission of energy at optical frequencies?

    PubMed Central

    Lukofsky, David; Bessette, Jonathan; Jeong, Heejeong; Garmire, Elsa; Österberg, Ulf

    2009-01-01

    The recent interest in precursors has been fuelled by the possibility of using them for the efficient transmission of information through absorbing media at radio or optical frequencies. Here we demonstrate that the low attenuation experienced by the Brillouin precursor is attributed to the inherently low absorption of dispersive media near DC, a characteristic already exploited with communications systems using the extremely low frequency (ELF) band. Pulses, regardless of their temporal width and carrier frequency, always obey Beer's law as long as they propagate in the linear time invariant regime. We conclude with an FDTD simulation of the Maxwell–Bloch equations that shows how optical coherent bleaching effects, which take place in the linear time variant regime of the Lorentz oscillator model, can cause sustained deviations from Beer's law over relatively long distances of water. PMID:19639054

  6. Laser Beam Delivery and Image Transmission Through Multimode Optical Fibers

    NASA Astrophysics Data System (ADS)

    Pan, Anpei

    This dissertation is dedicated to two important branches of optical fiber applications in biomedical engineering: laser beam delivery and image transmission. The optical phase of a light wave is distorted when it propagates through a multimode fiber. To compensate the distortion, a new hologram-generated phase conjugation theoretical model and experimental method has been developed. In the process, a self-pumped phase-conjugating mirror is introduced for recording the hologram. The coherence conditions are carefully matched so that only the desired optical signal is recorded. As a result, a high fidelity phase conjugation wave is produced. The resolution is 4.4 mum, which corresponds the diffraction-limited value of the system. Multimode optical fibers are widely used to deliver laser beams for medical diagnoses and treatments. However the spatial quality of the output beam is very poor. By use of holographic phase precompensation we present a new method to deliver high-quality laser beams. As a result, a highly collimated output beam with only 1.9 mrad divergence, which is 250 times smaller than the usual divergence, is obtained. The brightness is greatly increased. Other desired waves such as spherical wave or Gaussian beams can also be obtained. Another method, which is based on the formation at the remote end of a holographic filter, is also presented. The final output beams are nearly diffraction -limited. The hologram-generated phase conjugation is applied to image transmission through single multimode fibers. By use of Fourier transform theory and the formalism established in this study, the system resolution and the space bandwidth product are analyzed. The resolution of a multimode fiber can be 50 times higher than that of an imaging bundle if their diameters are the same. In the experiments a resolution chart was tested. The experimental results are quite consistent with the theory. A 3-D biological sample--a tooth--was also tested. The limitations of the

  7. Wavelength stabilization of a synchronously pumped optical parametric oscillator: optimizing proportional-integral control.

    PubMed

    Lamour, Tobias P; Sun, Jinghua; Reid, Derryck T

    2010-05-01

    We describe a formal approach to the wavelength stabilization of a synchronously pumped ultrafast optical parametric oscillator using proportional-integral feedback control. Closed-loop wavelength stabilization was implemented by using a position-sensitive detector as a sensor and a piezoelectric transducer to modify the cavity length of the oscillator. By characterizing the frequency response of the loop components, we constructed a predictive model of the controller which showed formally that a proportional-only feedback was insufficient to eliminate the steady state error, consistent with experimental observations. The optimal proportional and integral gain coefficients were obtained from a numerical optimization of the controller model that minimized the settling time while also limiting the overshoot to an acceptable value. Results are presented showing effective wavelength and power stabilization to levels limited only by the relative intensity noise of the pump laser. PMID:20515118

  8. A time/frequency quantum analysis of the light generated by synchronously pumped optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Jiang, Shifeng; Treps, Nicolas; Fabre, Claude

    2012-04-01

    We present in this paper a general model for determining the quantum properties of the light generated by a synchronously pumped optical parametric oscillator (SPOPO) operating below threshold. This model considers time and frequency on an equal footing, which allows us to find new quantum properties, related for example to the carrier envelope offset (CEO) phase, and to consider situations that are close to real experiments. We show that, in addition to multimode squeezing in the so-called ‘supermodes’, the system exhibits quadrature entanglement between frequency combs of opposite CEO phases. We have also determined the quantum properties of the individual pulses and their quantum correlations with the neighboring pulses. Finally, we determine the quantum Cramer-Rao limit for an ultra-short time delay measurement using a given number of pulses generated by the SPOPO.

  9. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    NASA Astrophysics Data System (ADS)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 μm multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  10. Cobalt stabilization of silver extraordinary optical transmission sensing platforms

    DOE PAGESBeta

    Farah, Annette E.; Davidson, Roderick B.; Pooser, Raphael C.; Lawrie, Benjamin J.; Kalyanaraman, Ramki; Malasi, A.

    2016-01-25

    In this study, plasmon-mediated extraordinary optical transmission (EOT) is finding increased interest for biosensing applications. While Ag nanostructures are capable of the highest plasmonic quality factor of all metals, the performance reliability of pure Ag EOT devices is limited by degradation through environmental interactions. Here we show that EOT devices consisting of nanostructured hole arrays in Ag/Co bilayers show comparable transmission with that of identical hole arrays in Agthin films as well as enhanced reliability measured by the rate of resonance peak redshift and broadening with time. The Ag/Co EOT devices showed 2.6× and 1.9× smaller red shift in shortmore » timescales (20 days) and after 100 days, respectively, while they showed a 1.7× steady-state decrease in rate of bandwidth broadening. This improvement is likely due to the Co metal stabilizing the Agfilm from morphological changes by reducing its propensity to diffuse or dewet on the underlying substrate. The improved reliability of Ag/Co bilayer EOT devices could enable the use of their superior plasmonic properties for optical detection of trace chemicals.« less

  11. Ergodic capacity comparison of optical wireless communications using adaptive transmissions.

    PubMed

    Hassan, Md Zoheb; Hossain, Md Jahangir; Cheng, Julian

    2013-08-26

    Ergodic capacity is investigated for the optical wireless communications employing subcarrier intensity modulation with direct detection, and coherent systems with and without polarization multiplexing over the Gamma-Gamma turbulence channels. We consider three different adaptive transmission schemes: (i) variable-power, variable-rate adaptive transmission, (ii) complete channel inversion with fixed rate, and (iii) truncated channel inversion with fixed rate. For the considered systems, highly accurate series expressions for ergodic capacity are derived using a series expansion of the modified Bessel function and the Mellin transformation of the Gamma-Gamma random variable. Our asymptotic analysis reveals that the high SNR ergodic capacities of coherent, subcarrier intensity modulated, and polarization multiplexing systems gain 0.33 bits/s/Hz, 0.66 bits/s/Hz, and 0.66 bits/s/Hz respectively with 1 dB increase of average transmitted optical power. Numerical results indicate that a polarization control error less than 10° has little influence on the capacity performance of polarization multiplexing systems. PMID:24105580

  12. Protecting the DUV process and optimizing optical transmission

    NASA Astrophysics Data System (ADS)

    Dallas, Andrew J.; Arends, Debbie; Fischer, Kristen; Joriman, Jon; Graham, Kristine M.; Ringold, Richard

    2000-06-01

    It has been well documented that DUV lithographic processes are sensitive to airborne contamination such as ammonia and n- methyl-2-pyrrolidone (NMP). Chemical filtration technologies have aided in minimizing the problems associated with these contaminants in the photolithographic process. As the demand for smaller features increases, so will the need to operate within even cleaner environments than are available today. One such area where airborne contamination has proven to be of significant concern, is within the lensing system of the tool. With decreasing feature size, the lithographic process has proven to be more sensitive to contamination of the lens itself, and within the environment surrounding the lens. Condensation on the lens (hazing) and the presence of contamination between the lens and substrate can result in poor optical transmission. To minimize these problems, a purge gas is typically employed. Even though high purity gases are used, contamination within the gas still is an issue. This work describes our efforts directed at understanding the purge gas and lens environments. In addition, we will address our efforts that have focused on the development of chemical filters that provide environments for optimized optical transmission in lithographic applications.

  13. Zebrafish CaV2.1 calcium channels are tailored for fast synchronous neuromuscular transmission.

    PubMed

    Naranjo, David; Wen, Hua; Brehm, Paul

    2015-02-01

    The CaV2.2 (N-type) and CaV2.1 (P/Q-type) voltage-dependent calcium channels are prevalent throughout the nervous system where they mediate synaptic transmission, but the basis for the selective presence at individual synapses still remains an open question. The CaV2.1 channels have been proposed to respond more effectively to brief action potentials (APs), an idea supported by computational modeling. However, the side-by-side comparison of CaV2.1 and CaV2.2 kinetics in intact neurons failed to reveal differences. As an alternative means for direct functional comparison we expressed zebrafish CaV2.1 and CaV2.2 α-subunits, along with their accessory subunits, in HEK293 cells. HEK cells lack calcium currents, thereby circumventing the need for pharmacological inhibition of mixed calcium channel isoforms present in neurons. HEK cells also have a simplified morphology compared to neurons, which improves voltage control. Our measurements revealed faster kinetics and shallower voltage-dependence of activation and deactivation for CaV2.1. Additionally, recordings of calcium current in response to a command waveform based on the motorneuron AP show, directly, more effective activation of CaV2.1. Analysis of calcium currents associated with the AP waveform indicate an approximately fourfold greater open probability (PO) for CaV2.1. The efficient activation of CaV2.1 channels during APs may contribute to the highly reliable transmission at zebrafish neuromuscular junctions. PMID:25650925

  14. Zebrafish CaV2.1 Calcium Channels Are Tailored for Fast Synchronous Neuromuscular Transmission

    PubMed Central

    Naranjo, David; Wen, Hua; Brehm, Paul

    2015-01-01

    The CaV2.2 (N-type) and CaV2.1 (P/Q-type) voltage-dependent calcium channels are prevalent throughout the nervous system where they mediate synaptic transmission, but the basis for the selective presence at individual synapses still remains an open question. The CaV2.1 channels have been proposed to respond more effectively to brief action potentials (APs), an idea supported by computational modeling. However, the side-by-side comparison of CaV2.1 and CaV2.2 kinetics in intact neurons failed to reveal differences. As an alternative means for direct functional comparison we expressed zebrafish CaV2.1 and CaV2.2 α-subunits, along with their accessory subunits, in HEK293 cells. HEK cells lack calcium currents, thereby circumventing the need for pharmacological inhibition of mixed calcium channel isoforms present in neurons. HEK cells also have a simplified morphology compared to neurons, which improves voltage control. Our measurements revealed faster kinetics and shallower voltage-dependence of activation and deactivation for CaV2.1. Additionally, recordings of calcium current in response to a command waveform based on the motorneuron AP show, directly, more effective activation of CaV2.1. Analysis of calcium currents associated with the AP waveform indicate an approximately fourfold greater open probability (PO) for CaV2.1. The efficient activation of CaV2.1 channels during APs may contribute to the highly reliable transmission at zebrafish neuromuscular junctions. PMID:25650925

  15. The Effects of High Temperature and Nuclear Radiation on the Optical Transmission of Silica Optical Fibers

    NASA Astrophysics Data System (ADS)

    Hawn, David P.

    Distributed measurements made with fiber optic instrumentation have the potential to revolutionize data collection for facility monitoring and process control in industrial environments. Dozens of sensors etched into a single optical fiber can be used to instrument equipment and structures so that dozens of spatially distributed temperature measurements, for example, can be made quickly using one optical fiber. Optically based sensors are commercially available to measure temperature, strain, and other physical quantities that can be related to strain, such as pressure and acceleration. Other commercially available technology eliminates the need to etch discrete sensors into an optical fiber and allows temperature measurements to be made along the length of an ordinary silica fiber. Distributed sensing with optical instrumentation is commonly used in the petroleum industry to measure the temperature and pressure profiles in down hole applications. The U.S. Department of Energy is interested in extending the distributed sensing capabilities of optical instrumentation to high temperature reactor radiation environments. For this technology extension to be possible, the survivability of silica optical fibers needed to be determined in this environment. In this work the optical attenuation added to silica optical fiber exposed simultaneously to reactor radiation and temperatures to 1000°C was experimentally determined. Optical transmission measurements were made in-situ from 400nm-2300nm. For easy visualization, all of the results generated in this work were processed into movies that are available publicly [1]. In this investigation, silica optical fibers were shown to survive optically and mechanically in a reactor radiation environment to 1000°C. For the combined high temperature reactor irradiation experiments completed in this investigation, the maximum attenuation increase in the low-OH optical fibers was around 0.5db/m at 1550nm and 0.6dB/m at 1300nm. The

  16. Research on target information optics communications transmission characteristic and performance in multi-screens testing system

    NASA Astrophysics Data System (ADS)

    Li, Hanshan

    2016-04-01

    To enhance the stability and reliability of multi-screens testing system, this paper studies multi-screens target optical information transmission link properties and performance in long-distance, sets up the discrete multi-tone modulation transmission model based on geometric model of laser multi-screens testing system and visible light information communication principle; analyzes the electro-optic and photoelectric conversion function of sender and receiver in target optical information communication system; researches target information transmission performance and transfer function of the generalized visible-light communication channel; found optical information communication transmission link light intensity space distribution model and distribution function; derives the SNR model of information transmission communication system. Through the calculation and experiment analysis, the results show that the transmission error rate increases with the increment of transmission rate in a certain channel modulation depth; when selecting the appropriate transmission rate, the bit error rate reach 0.01.

  17. Transmission electron microscope sample holder with optical features

    DOEpatents

    Milas, Mirko; Zhu, Yimei; Rameau, Jonathan David

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  18. Photoluminescence and optical transmission of diffusion-pump oils.

    NASA Technical Reports Server (NTRS)

    Kroes, R. L.

    1973-01-01

    The photoluminescence and optical transmission of the four widely used diffusion-pump oils, DC-705, DC-704, Convalex-10, and Convoil-20, were measured. Each of the oils was found to be transparent throughout the visible region, showed some absorption in the near-UV region, and became very opaque below approximately 300 nm. Both Convalex-10 and Convoil-20 turned yellow after exposure to UV light. No such change was noted in DC-705 or DC-704. Photoluminescence was produced in each of the four oils when irradiated with UV light. Both DC-705 and DC-704 had a nearly identical luminescence spectra that peaked at 350 nm. The spectra of Convalex-10 and Convoil-20 were fairly complex, with several peaks in the visible region.

  19. Nonlinear band gap transmission in optical waveguide arrays.

    PubMed

    Khomeriki, Ramaz

    2004-02-13

    The effect of nonlinear transmission in coupled optical waveguide arrays is theoretically investigated and a realistic experimental setup is suggested. The beam is injected in a single boundary waveguide, linear refractive index of which (n(0)) is larger than refractive indexes (n) of other identical waveguides in the array. Particularly, the effect holds if omega(n(0)-n)/c>2Q, where Q is a linear coupling constant between array waveguides, omega is a carrier wave frequency, and c is a light velocity. Numerical experiments show that the energy transfers from the boundary waveguide to the waveguide array above a certain threshold intensity of the injected beam. This effect is due to the creation and the propagation of gap solitons in full analogy with a similar phenomenon in sine-Gordon lattice [Phys. Rev. Lett. 89, 134102 (2002)

  20. Transmission of multiplexed video signals in multimode optical fiber systems

    NASA Technical Reports Server (NTRS)

    White, Preston, III

    1988-01-01

    Kennedy Space Center has the need for economical transmission of two multiplexed video signals along multimode fiberoptic systems. These systems must span unusual distances and must meet RS-250B short-haul standards after reception. Bandwidth is a major problem and studies of the installed fibers, available LEDs and PINFETs led to the choice of 100 MHz as the upper limit for the system bandwidth. Optical multiplexing and digital transmission were deemed inappropriate. Three electrical multiplexing schemes were chosen for further study. Each of the multiplexing schemes included an FM stage to help meet the stringent S/N specification. Both FM and AM frequency division multiplexing methods were investigated theoretically and these results were validated with laboratory tests. The novel application of quadrature amplitude multiplexing was also considered. Frequency division multiplexing of two wideband FM video signal appears the most promising scheme although this application requires high power highly linear LED transmitters. Futher studies are necessary to determine if LEDs of appropriate quality exist and to better quantify performance of QAM in this application.

  1. Design of a fiber optic image transmission link

    NASA Astrophysics Data System (ADS)

    Redd, Justin D.

    1991-12-01

    An original design is presented for a fiber optic based digital image transmission link operating at a serial bit rate of 250 Mbits/Second. The link is designed as an integral part of an airborne infrared imaging system with particular emphasis on avoiding problems associated with aircraft electromagnetic interference (EMI). Unique features include simplicity (single PC board transmitter and receiver), low power, low cost (under $3,000), and use of the latest off-the-shelf components (including the Gazelle GA9011/GA9012 HOT ROD chip set). Theoretical modeling is used to predict a bit error rate of better than 10 to the minus 15th power, while actual measurements include transmission of over 10 to 13th power bits without any errors (measured bit error rate of at least 10 to the minus 13th power). Test results also show that the link is capable of transmitting 640 x 480 pixel (12 bits per pixel) images with no significant image degradation.

  2. MFTF-B quasi-optical ECRH transmission system

    SciTech Connect

    Yugo, J.J.; Shearer, J.W.; Ziolkowski, R.W.

    1983-11-07

    The microwave transmission system for ERCH on MFTF-B will utilize quasi-optical transmission techniques. The system consists of ten gyrotron oscillators: two gyrotrons at 28 GHz, two at 35 GHz, and six at 56 GHz. The 28 and 35 GHz gyrotrons both heat the electrons in the end plug (potential peak) while the 56 GHz sources heat the minimum-B anchor region (potential minimum). Microwaves are launched into a pair of cylindrical mirrors that form a pseudo-cavity which directs the microwaves through the plasma numerous times before they are lost out of the cavity. The cavity allows the microwave beam to reach the resonance zone over a wide range of plasma densities and temperatures. The fundamental electron cyclotron resonance moves to higher axial positions as a result of beta-depression of the magnetic field, doppler shifting of the resonance, and relativistic mass corrections for the electrons. With this system the microwave beam will reach the resonance surface at the correct angle of incidence for any density or temperature without active aiming of the antennas. The cavity also allows the beam to make multiple passes through the plasma to increase the heating efficiency at low temperatures and densities when the single pass absorption is low. In addition, neutral beams and diagnostics have an unobstructed view of the plasma.

  3. Reduction of nonlinear phase noise using optical phase conjugation in quasi-linear optical transmission systems.

    PubMed

    Kumar, Shiva; Liu, Ling

    2007-03-01

    An analytical expression for the variance of nonlinear phase noise for a quasi-linear system using the midpoint optical phase conjugation (OPC) is obtained. It is shown that the the system with OPC and dispersion inversion (DI) can exactly cancel the nonlinear phase noise up to the first order in nonlinear coefficient if the amplifier and the end point of the system are equidistant from the OPC. It is found that the nonlinear phase noise variance of the midpoint phase-conjugated optical transmission system with DI is smaller than that of the system without DI. PMID:19532453

  4. Fiber optic multiplexed optical transmission systems for space vehicle launch facilities

    NASA Technical Reports Server (NTRS)

    Bell, C. H.

    1975-01-01

    Low loss Fiber Optic Cable is being evaluated as a potential future replacement for Kennedy Space Center's 13,000 mile Wideband cable system. In order to make economical use of the wide bandwidth characteristic of glass fibers, a Frequency Division Multiplexing (FDM) scheme has been devised to stack many analog and digital data channels on a single fiber. The Multiplexed Optical Transmission System (MOTS) will offer a unique flexibility of plug-in modularity to meet changing data and bandwidth requirements in addition to the standard 'goodies' of immunity to lightning and other EMI, RFI type interferences, and of smaller size and lighter weight.

  5. A novel optical transmission link with DHT-based constant envelope optical OFDM signal

    NASA Astrophysics Data System (ADS)

    Ma, Jianxin; Liang, Hao

    2013-07-01

    In this paper, we have proposed a novel optical OFDM transmission link that takes advantages of discrete Hartley Transform (DHT) and constant envelope (CE) modulation, obtaining DHT-based constant envelope optical OFDM. The numerical results show that this design achieves better performance when compared with conventional O-OFDM in terms of bit error rate (BER) and peak-to-average power ratio (PAPR). The impact of phase modulation index (PMI) on both PAPR and noise tolerance is investigated. Since the scheme has simplified design, it is believed to be a cost-effective in the practical implement.

  6. Combined transmission and reflection optical microscopy of ice core sections

    NASA Astrophysics Data System (ADS)

    Binder, Tobias; Weikusat, Ilka; Kerst, Thomas; Eichler, Jan; Svensson, Anders; Bohleber, Pascal; Garbe, Christoph; Kipfstuhl, Sepp

    2013-04-01

    Microstructure analysis of ice cores is vital to understand the processes controlling the flow of ice on the microscale. To quantify the microstructural variability (and thus occurring processes) on centimeter, meter and kilometer scale along deep polar ice cores, a large number of sections has to be analyzed. In the last decade, two different methods have been applied: On the one hand, transmission optical microscopy of thin sections between crossed polarizers yields information on the distribution of crystal c-axes. On the other hand, reflection optical microscopy of polished and controlled sublimated section surfaces allows to characterize the high resolution properties of a single grain boundary, e.g. its length, shape or curvature. Based on a polar and an alpine ice core we applied both methods to the same set of sections. This enables us to combine all information on crystal orientation and (sub-)grain boundaries. In this contribution we introduce the method of combined transmission-polarization and reflection microscopy as well as an image processing framework for processing and matching both image types [1]. The information content of both analysis methods is limited and influenced by different types of artifacts. It is exemplary shown how the combination allows to compensate for deficiencies of one method. The gray values in images of the grain boundaries on polished ice core sections are influenced by the duration of surface sublimation and the energy/misorientation of the grain boundaries in the section. By combining these gray values with the misorientation obtained from the corresponding thin section imaged between crossed polarizers we try to validate the information content of gray values on the basis of large data sets. This approach is compared to X-ray Laue diffraction measurements (yielding full crystallographic orientation) which validated the sensitivity of the surface sublimation method [2]. As microscopy in transmission mode acquires volume

  7. A new generation of sensors based on extraordinary optical transmission.

    PubMed

    Gordon, Reuven; Sinton, David; Kavanagh, Karen L; Brolo, Alexandre G

    2008-08-01

    [Reaction: see text]. Plasmonic-based chemical sensing technologies play a key role in chemical, biochemical, and biomedical research, but basic research in this area is still attracting interest. Researchers would like to develop new types of plasmonic nanostructures that can improve the analytical figures of merit, such as detection limits, sensitivity, selectivity, and dynamic range, relative to the commercial systems. They are also tackling issues such as cost, reproducibility, and multiplexing with the goal of providing the best plasmonic-based platform for chemical analysis. In this Account, we will describe recent advances in the optical and spectroscopic properties of nanohole arrays in thin gold films and their applications for chemical sensing. These nanostructures support the unusual phenomenon of "extraordinary optical transmission" (EOT), that is, they are more transparent at certain wavelengths than expected by the classical aperture theory. The EOT is a consequence of surface plasmon (SP) excitations; hence, the resonance should respond to the adsorption of organic molecules. We explored this effect and implemented the integration of the arrays of nanoholes as sensing elements in a microfluidic architecture. We then demonstrated how these devices could be applied in biochemical affinity tests. Arrays of nanoholes offer a small sensing footprint and operate at normal transmission mode, which make them more suitable for miniaturization. This new approach for SPR sensing is more compatible with the lab-on-chip concept and offers the possibility of high-throughput analysis from a single sensing chip. We explored the field localization properties of EOT for surface-enhanced spectroscopy. We could control the enhancement factors for SERS and SEFS by adjusting the geometry of the arrays. The shape of the individual nanoholes offers another handle to tune the enhancement factor for surface-enhanced spectroscopy and SPR sensitivity. Apexes in shaped

  8. Synchronizing retinal activity in both eyes disrupts binocular map development in the optic tectum.

    PubMed

    Brickley, S G; Dawes, E A; Keating, M J; Grant, S

    1998-02-15

    Spatiotemporal correlations in the pattern of spontaneous and evoked retinal ganglion cell (RGC) activity are believed to influence the topographic organization of connections throughout the developing visual system. We have tested this hypothesis by examining the effects of interfering with these potential activity cues during development on the functional organization of binocular maps in the Xenopus frog optic tectum. Paired recordings combined with cross-correlation analyses demonstrated that exposing normal frogs to a continuous 1 Hz of stroboscopic illumination synchronized the firing of all three classes of RGC projecting to the tectum and induced similar patterns of temporally correlated activity across both lobes of the nucleus. Embryonic and eye-rotated larval animals were reared until early adulthood under equivalent stroboscopic conditions. The maps formed by each RGC class in the contralateral tectum showed normal topography and stratification after strobe rearing, but with consistently enlarged multiunit receptive fields. Maps of the ipsilateral eye, formed by crossed isthmotectal axons, showed significant disorder and misalignment with direct visual input from the retina, and in the eye-rotated animals complete compensatory reorientation of these maps usually induced by this procedure failed to occur. These findings suggest that refinement of retinal arbors in the tectum and the ability of crossed isthmotectal arbors to establish binocular convergence with these retinal afferents are disrupted when they all fire together. Our data thus provide direct experimental evidence that spatiotemporal activity patterns within and between the two eyes regulate the precision of their developing connections. PMID:9454857

  9. Binary synchronous simulator

    NASA Technical Reports Server (NTRS)

    Rogers, J. R., III

    1980-01-01

    Flexible simulator for trouble-shooting data transmission system uses binary synchronous communications protocol to produce error-free transmission of data between two points. Protocol may be used to replace display generator or be directly fed to display generator.

  10. Coherent Terahertz Wireless Signal Transmission Using Advanced Optical Fiber Communication Technology

    NASA Astrophysics Data System (ADS)

    Kanno, Atsushi; Kuri, Toshiaki; Morohashi, Isao; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Kitayama, Ken-ichi

    2015-02-01

    Coherent terahertz signal transmission with multilevel modulation and demodulation is demonstrated using an optical sub-harmonic IQ mixer (SHIQM), which consists of optical components in advanced optical fiber communication technologies. An optical-frequency-comb-employed signal generator is capable of vector modulation as well as frequency tunability. Digital signal processing (DSP) adopted from the recently developed optical digital coherent communication can easily demodulate multi-level modulated terahertz signals by using electrical heterodyning for intermediate-frequency (IF) down conversion. This technique is applicable for mobile backhauling in the next-generation mobile communication technology directly connected to an optical fiber network as a high-speed wireless transmission link.

  11. Refractive Optics for Hard X-ray Transmission Microscopy

    SciTech Connect

    Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E.; Ahrens, G.; Voigt, A.

    2011-09-09

    For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (<100 nm) full-field imaging. To obtain high image quality at reasonable exposure times, custom-tailored matched pairs of condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

  12. Polarization-dependent extraordinary optical transmission from upconversion nanoparticles.

    PubMed

    Wang, Peng Hui; Salcedo, Walter J; Pichaandi, Jothirmayanantham; van Veggel, Frank C J M; Brolo, Alexandre G

    2015-11-21

    Enhanced upconversion (UC) emission was experimentally demonstrated using gold double antenna nanoparticles coupled to nanoslits in gold films. The transmitted red emission from UC ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb(3+)/Er(3+)) nanoparticles (UC NPs) at ∼665 nm (excited with a 980 nm diode laser) was enhanced relative to the green emission at ∼550 nm. The relatively enhanced UC NP emission could be tuned by the different polarization-dependent extraordinary optical transmission modes coupled to the gold nanostructures. Finite-difference time-domain calculations suggest that the preferential enhanced UC emission is related to a combination of different surface plasmon mode excitation coupling to cavity Fabry-Perot interactions. A maximum UC enhancement of 6-fold was measured for nanoslit arrays in the absence of the double antennas. In the presence of the double nanoantennas inside the nanoslits, the UC enhancement was between 2- and 4-fold, depending on the experimental conditions. PMID:26487270

  13. Dual-channel chaos synchronization and communication based on unidirectionally coupled VCSELs with polarization-rotated optical feedback and polarization-rotated optical injection.

    PubMed

    Liu, Jiao; Wu, Zheng-Mao; Xia, Guang-Qiong

    2009-07-20

    A novel dual-channel chaotic synchronization configuration is proposed. This system is constructed on the basis of two unidirectionally coupled vertical-cavity surface-emitting lasers (VCSELs), where a VCSEL subjected to polarization-rotated optical feedback is used as a transmitter and the other VCSEL subjected to polarization-rotated optical injection is used as a receiver. The synchronization and communication performances of such a system are numerically investigated. The results show that, similar to polarization-preserved coupled system with polarization-preserved optical feedback at the T-VCSEL port and polarization-preserved optical injection at the R-VCSEL port, such polarization-rotated coupled system can also realize complete synchronization between each pair of linear polarization (LP) modes and the total output of T-VCSEL and R-VCSEL. Compared with the polarization-preserved coupled system, this proposed system has higher tolerance to mismatched parameters. Furthermore, the average intensities of two orthogonal LP modes are almost the same so that this framework may be used to realize dual-channel chaos communication. Under the additive chaos modulation (ACM) encryption scheme, the encoded messages can be successfully extracted for both of orthogonal LP modes. PMID:19654666

  14. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays

    NASA Astrophysics Data System (ADS)

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W.; Tolstova, Yulia; Mauser, Kelly W.; Atwater, Harry A.

    2016-08-01

    Subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunnelling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulations predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm-1, corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures.

  15. Hyperbola-parabola primary mirror in Cassegrain optical antenna to improve transmission efficiency.

    PubMed

    Zhang, Li; Chen, Lu; Yang, HuaJun; Jiang, Ping; Mao, Shengqian; Caiyang, Weinan

    2015-08-20

    An optical model with a hyperbola-parabola primary mirror added in the Cassegrain optical antenna, which can effectively improve the transmission efficiency, is proposed in this paper. The optimum parameters of a hyperbola-parabola primary mirror and a secondary mirror for the optical antenna system have been designed and analyzed in detail. The parabola-hyperbola primary structure optical antenna is obtained to improve the transmission efficiency of 10.60% in theory, and the simulation efficiency changed 9.359%. For different deflection angles to the receiving antenna with the emit antenna, the coupling efficiency curve of the optical antenna has been obtained. PMID:26368746

  16. The demonstration of 10 Gbit/s time division multiplexing and 2.5 Gchip/s quasi-synchronous electrical code division multiplexing access passive optical network prototype system

    NASA Astrophysics Data System (ADS)

    Liang, Siyuan; Wang, Liqian; Cao, Yingying; Wang, Zhen; Han, Yamei; Wang, Dao; Chen, Xue

    2012-04-01

    The authors propose a novel architecture of passive optical network (PON), which consists of time division multiplexing (TDM) based downstream (10 Gbit/s) and quasi-synchronization (Q-S) electrical code division multiplexing access (ECDMA) based upstream (2.5 Gchip/s), and realize the prototype of this TDM-ECDMA PON. The high speed (2.5 Gchip/s) all digital en/decoding of upstream have been achieved by field-programmable gate array in this prototype. The frames error rate (FER) free transmission of Q-S ECDMA based upstream is demonstrated after 20 km fiber link. Then receiver sensitivity of optical line terminal in upstream transmission can be improved ~6 dB by coding gain compared with traditional 2.5 Gbit/s TDM PON.

  17. Synchronized delivery of Er:YAG-laser pulses into water studied by a laser beam transmission probe for enhanced endodontic treatment

    NASA Astrophysics Data System (ADS)

    Gregorčič, P.; Lukač, N.; Možina, J.; Jezeršek, M.

    2016-04-01

    We examine the effects of the synchronized delivery of multiple Er:YAG-laser pulses during vapor-bubble oscillations into water. For this purpose, we used a laser beam transmission probe that enables monitoring of the bubble's dynamics from a single shot. To overcome the main drawbacks of this technique, we propose and develop an appropriate and robust calibration by simultaneous employment of shadow photography. By using the developed experimental method, we show that the resonance effect is obtained when the second laser pulse is delivered at the end or slightly after the first bubble's collapse. In this case, the resonance effect increases the mechanical energy of the secondary bubble's oscillations and prolongs their duration. The presented laser method for synchronized delivery of Er:YAG-laser pulses during bubble oscillations has great potential for further improvement of laser endodontic treatment, especially upon their safety and efficiency.

  18. Synchronous time-resolved optical and x-ray emission from simultaneous optical and x-ray streak cameras driven by a master ramp generator

    SciTech Connect

    Balmer, J.E.; Lampert, W.; Roschger, E.; Hares, J.D.; Kilkenny, J.D.

    1985-05-01

    An optical and an x-ray streak camera have been synchronized by driving the deflection plates of both cameras from the same ramp generator. The relative timing of the two cameras was calibrated by running UV light onto the x-ray streak camera. The x-ray streak camera was then used to measure the time of the x-ray emission from a laser plasma with respect to the laser pulse.

  19. Integrated self-cleaning window assembly for optical transmission in combustion environments

    DOEpatents

    Kass, Michael D [Oak Ridge, TN

    2007-07-24

    An integrated window design for optical transmission in combustion environments is described. The invention consists of an integrated optical window design that prevents and removes the accumulation of carbon-based particulate matter and gaseous hydrocarbons through a combination of heat and catalysis. These windows will enable established optical technologies to be applied to combustion environments and their exhaust systems.

  20. Object-oriented classification using quasi-synchronous multispectral images (optical and radar) over agricultural surface

    NASA Astrophysics Data System (ADS)

    Marais Sicre, Claire; Baup, Frederic; Fieuzal, Remy

    2015-04-01

    In the context of climate change (with consequences on temperature and precipitation patterns), persons involved in agricultural management have the imperative to combine: sufficient productivity (as a response of the increment of the necessary foods) and durability of the resources (in order to restrain waste of water, fertilizer or environmental damages). To this end, a detailed knowledge of land use will improve the management of food and water, while preserving the ecosystems. Among the wide range of available monitoring tools, numerous studies demonstrated the interest of satellite images for agricultural mapping. Recently, the launch of several radar and optical sensors offer new perspectives for the multi-wavelength crop monitoring (Terrasar-X, Radarsat-2, Sentinel-1, Landsat-8…) allowing surface survey whatever the cloud conditions. Previous studies have demonstrated the interest of using multi-temporal approaches for crop classification, requiring several images for suitable classification results. Unfortunately, these approaches are limited (due to the satellite orbit cycle) and require waiting several days, week or month before offering an accurate land use map. The objective of this study is to compare the accuracy of object-oriented classification (random forest algorithm combined with vector layer coming from segmentation) to map winter crop (barley, rapeseed, grasslands and wheat) and soil states (bare soils with different surface roughness) using quasi-synchronous images. Satellite data are composed of multi-frequency and multi-polarization (HH, VV, HV and VH) images acquired near the 14th of April, 2010, over a studied area (90km²) located close to Toulouse in France. This is a region of alluvial plains and hills, which are mostly mixed farming and governed by a temperate climate. Remote sensing images are provided by Formosat-2 (04/18), Radarsat-2 (C-band, 04/15), Terrasar-X (X-band, 04/14) and ALOS (L-band, 04/14). Ground data are collected

  1. Paired SSB optical OFDM channels for high spectral efficient signal transmission over DWDM networks

    NASA Astrophysics Data System (ADS)

    Chicharro, Francisco I.; Ortega, Beatriz; Mora, José

    2016-07-01

    A new high spectral efficient SSB-OOFDM DWDM transmission system has been experimentally demonstrated. The proposed transmitter employs paired optical channels consisting of two SSB modulated OFDM signals using opposite sidebands in order to allow an efficient use of the spectrum with optical carriers separation under 10 GHz. Moreover, different paired channels are multiplexed into the 25 GHz grid DWDM fiber transmission link. Optical carrier spacing of 8.75 GHz in paired channels has been demonstrated allowing 40.8 Gb/s signal transmission rate over a 25 GHz paired channel bandwidth.

  2. Self-phase-locking of degenerate synchronously pumped optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Wong, Samuel Tin Bo

    Phase-stable frequency combs have been instrumental in advancing state-of-the-art metrology and high-precision measurements. Extending the combs toward shorter wavelengths in the ultraviolet and X-ray regimes has pushed ultrafast science to the attosecond level and revolutionized atomic physics. While there has not been much development on comb extension toward longer wavelengths, it is nevertheless important for applications that require critical optical phase control in the middle to far-infrared regime, such as vacuum-based laser-driven particle acceleration. Furthermore, the synthesis of phase-locked combs at longer wavelengths would establish absolute optical frequency standards in the IR regime and enable highly precise spectroscopy at wavelengths unavailable to conventional solid-state lasers. To realize frequency combs in the mid-IR, we decided to exploit second-order nonlinear processes for down-conversion to longer wavelengths. Additionally, we took advantage of the fixed phase relationship between pump, signal, and idler in optical parametric oscillation (OPO). We predicted that a mode-locked OPO operating at frequency degeneracy would exhibit phase-locking because the signal and idler combs experience mutual injection locking to become phase-coherent with the pump. Furthermore, the carrier-envelope offset (CEO) frequency of the signal/idler comb would be exactly half of that of the pump in this case. To this end, we demonstrated the first self-phase-locked synchronously pumped OPO (SPOPO) as a sub-harmonic generator. The pump source was a mode-locked Ti:sapphire laser that generated an 80-MHz train of 180-fs pulses at 775 nm. The nonlinear gain element used was a 1-mm-long, type I (e-ee) phase-matched, 5% MgO-doped periodically poled LiNbO3 crystal. Under degenerate operation, the SPOPO formed a broad, continuous spectrum centered at 1550 nm with a bandwidth of 50 nm (200 cm-1), which had a comb broadening factor of almost 3 compared to the pump

  3. Novel optical devices based on the transmission properties of magnetic fluid and their characteristics

    NASA Astrophysics Data System (ADS)

    Zhao, Yong; Lv, Riqing; Zhang, Yuyan; Wang, Qi

    2012-09-01

    Magnetic fluid has many unique optical properties. It has numerous potential applications in developing optical devices because of its versatile optical properties. This paper summarizes the physical origins and control mechanisms of the MF transmission properties, and the related optical devices based on the transmission properties of magnetic fluid. In recent years, there are many applications in optical information communication and sensing technology, such as optical switches, tunable optical gratings, coarse wavelength-division multiplexing, magnetic-field sensors, current sensor. The qualitative and quantitative analysis about the physical configuration, the operating principle, and the characteristics of those optical devices are given. The valuable potential problems and the solutions that are related to optical properties and optical devices based on magnetic fluid are expounded in detail, and potential new types of MF-based optical devices are proposed. It can be concluded that the transmission properties of MF will be improved greatly, and the characteristics of present optical devices based on magnetic fluid will be made better continually and it will play an important role in the fields of optical information communication and sensing technology.

  4. Cable television transmission over a 1550-nm infrared indoor optical wireless link

    NASA Astrophysics Data System (ADS)

    Sakib Chowdhury, M. I.; Kavehrad, Mohsen; Zhang, Weizhi

    2013-10-01

    We experimentally demonstrate transmission of cable television (CATV) radio frequency signals over a pointed indoor optical wireless link. The length of the optical link was 15 m. Collimators used at both the transmitter and the receiver sides required good alignment before sufficient optical power could be received. The system was placed at a height of 2 m, which is more than average human height, so human movements throughout the room did not obstruct the link. The optical wireless propagation path was almost lossless. The originality in this experimental demonstration is the transmission of full range of CATV signals compared to other works in this area. This experiment of radio over free-space optics showed that point-to-point indoor optical wireless links can be utilized as an alternative means for transmission of multimedia data.

  5. Study of light transmission through optical fiber-to-fiber connector assemblies

    SciTech Connect

    Chung, M.; Gutowski, M.; Adams, M.; Solomon, J.

    1998-11-01

    Optical fiber-to-fiber connectors are now being used widely in particle tracking detectors. We describe the properties of the connectors, their production, and measurements of the light transmission through the gap of the connector assembly. We studied light transmission for various types of connectors illuminated by several different light sources. The light transmission was found to be dependent on the angular distribution of the light rays passing through a connector assembly. Two arrangements were studied, a point source and a diffuse source. A green LED with a diffuser is believed to best reproduce the angular distributions of light in the real detector applications. We also studied the transmission as a function of the index of refraction of the optical couplants. The light transmission depends on the index of refraction of an optical couplant placed in the gap, and improves as it approaches the index of refraction of the fiber core. Light transmissions of 80{percent}{approximately}88{percent} were obtained without any optical couplant in the connector gap and transmissions of 89{percent}{approximately}99{percent} with various optical couplants. A Monte Carlo study using measured light distributions from a fiber end produced a reasonable agreement with the transmission measurements made on a connector assembly. {copyright} {ital 1998 American Institute of Physics.}

  6. Precision-analog fiber-optic transmission system

    SciTech Connect

    Stover, G.

    1981-06-01

    This article describes the design, experimental development, and construction of a DC-coupled precision analog fiber optic link. Topics to be covered include overall electrical and mechanical system parameters, basic circuit organization, modulation format, optical system design, optical receiver circuit analysis, and the experimental verification of the major design parameters.

  7. Transmission spectra and optical losses of infiltration-modified hollow photonic-crystal fibres

    SciTech Connect

    Konorov, Stanislav O; Serebryannikov, E E; Zheltikova, D A; Mitrokhin, V P; Sidorov-Biryukov, D A; Fedotov, Andrei B; Zheltikov, Aleksei M; Kilin, Sergei Ya

    2005-09-30

    Transmission spectra and optical losses of hollow photonic-crystal fibres (PCFs) filled with liquid-phase materials are studied. For hollow PCFs with a cladding period of about 5 {mu}m and a core diameter of about 50 {mu}m, infiltration with water increases optical losses by approximately two orders of magnitude relative to the optical losses of the same PCF before infiltration. (optical fibres)

  8. Coherent electro-optical detection of THz-wave generated from synchronously pumped picosecond THz parametric oscillator

    NASA Astrophysics Data System (ADS)

    Takida, Yuma; Ohira, Tatsuya; Tadokoro, Yuzuru; Kumagai, Hiroshi; Nashima, Shigeki

    2012-02-01

    Terahertz (THz) radiation via parametric down-conversion of optical pulses in a nonlinear optical crystal is an attractive way to develop frequency tunable THz-wave sources. Therefore, we have focused on developing low-laser-powerpumped THz-wave parametric sources and then successfully demonstrated a synchronously-pumped picosecond THz parametric oscillator (TPO) in pump-enhanced idler-resonant cavity with a bulk 5 mol% MgO-doped lithium niobate (MgO:LN) crystal. In this paper, toward coherent electro-optical (EO) detection of THz waves generated from our synchronously pumped picosecond TPO, we reported time-domain measurements of the THz electric fields using a bowtie- shaped low-temperature grown gallium arsenide (LT-GaAs) photoconductive (PC) antenna as a THz detector. As a result, we obtained temporal waveforms of the THz electric pulses, for the different number of Si-prism couplers, and then found that the radiated THz waves separated multiple unanticipated pulses by use of the arrayed-prism coupling technique. Also, we compared the time-domain system with a Fourier transform Michelson interferometer using a highresistance silicon (Si) beam splitter, from the some viewpoints. The present results reveal great prospects for the realization of THz spectroscopy and imaging applications using our THz-wave source.

  9. Optical single-sideband OFDM transmission based on a two-segment EAM.

    PubMed

    Cheng, Hsuan-Lin; Chen, Wei-Hung; Wei, Chia-Chien; Chiu, Yi-Jen

    2015-01-26

    This paper presents a novel optical single-sideband (SSB) OFDM modulation scheme using a two-segment electro-absorption modulator (EAM). Differences in the chirp characteristics of two segments of the EAM make it possible to design driving signals capable of suppressing one of the optical sidebands, such that the optical OFDM signal does not suffer from frequency-selective power fading following dispersive fiber transmission. Our experiment results demonstrate optical OFDM transmissions at 13.5-Gbps over a 0 ∼ 200-km IM/DD system without the need for dispersion compensation and distance-dependent bit- and power-loading. PMID:25835857

  10. Chaotic communication on a satellite formation flying—The synchronization issue in a scenario with transmission delays

    NASA Astrophysics Data System (ADS)

    Grzybowski, José Mario Vicensi; Rafikov, Marat; Macau, Elbert Einstein Nehrer

    2010-04-01

    Chaos-based communication schemes have drawn increasing attention in the last years. The intrinsic complexity embedded on the chaotic dynamics with its hallmark property of sensitive dependence on initial conditions provides a masterful framework that can be exploited to develop remarkably fast, efficient and robust communication systems at low cost. As so, they can be used to support intensive communication among process distributed over a network, which is the scenario that may exist when the concept of satellite formation flying is used. In this configuration, the set of satellites operates as a "massive virtual" satellite with a very large capability that would require a huge, complex and expensive monolithic satellite. In this work, we analyze a key issue to accomplish a chaotic based communication system—the synchronization among the communication agents. To allow communication, all of the agents must have their chaotic dynamics synchronized with each other. However, in a scenario involving a satellite formation flying, it is necessary to deal with substantial signal delays on the communication among the satellites. These delays impose severe restrictions or even do not allow the accomplishment of the synchronization process if common strategies are used. Here, we propose an approach that allows to properly obtain synchronization among the communication agents on the satellites of the formation, despite the communication delays. It is based on the optimal linear feedback control theory and takes in consideration the "mean field" of the population of chaotic oscillators.

  11. Adaptation of AMO-FBMC-OQAM in optical access network for accommodating asynchronous multiple access in OFDM-based uplink transmission

    NASA Astrophysics Data System (ADS)

    Jung, Sun-Young; Jung, Sang-Min; Han, Sang-Kook

    2015-01-01

    Exponentially expanding various applications in company with proliferation of mobile devices make mobile traffic exploded annually. For future access network, bandwidth efficient and asynchronous signals converged transmission technique is required in optical network to meet a huge bandwidth demand, while integrating various services and satisfying multiple access in perceived network resource. Orthogonal frequency division multiplexing (OFDM) is highly bandwidth efficient parallel transmission technique based on orthogonal subcarriers. OFDM has been widely studied in wired-/wireless communication and became a Long term evolution (LTE) standard. Consequently, OFDM also has been actively researched in optical network. However, OFDM is vulnerable frequency and phase offset essentially because of its sinc-shaped side lobes, therefore tight synchronism is necessary to maintain orthogonality. Moreover, redundant cyclic prefix (CP) is required in dispersive channel. Additionally, side lobes act as interference among users in multiple access. Thus, it practically hinders from supporting integration of various services and multiple access based on OFDM optical transmission In this paper, adaptively modulated optical filter bank multicarrier system with offset QAM (AMO-FBMC-OQAM) is introduced and experimentally investigated in uplink optical transmission to relax multiple access interference (MAI), while improving bandwidth efficiency. Side lobes are effectively suppressed by using FBMC, therefore the system becomes robust to path difference and imbalance among optical network units (ONUs), which increase bandwidth efficiency by reducing redundancy. In comparison with OFDM, a signal performance and an efficiency of frequency utilization are improved in the same experimental condition. It enables optical network to effectively support heterogeneous services and multiple access.

  12. Optically amplified high capacity transmission at 20 Gbit/s by TDM

    NASA Astrophysics Data System (ADS)

    Lee, W. S.; Pettitt, G. A.; Wakefield, J.; Patel, B. L.; Hadjifotiou, A.

    1994-03-01

    Optical transmission at 20 Gbit/s over standard singlemode and dispersion-shifted fiber has been investigated. By exploiting the chirp characteristic of the LiNbO3 modulator, a sensitivity penalty of less than 1 dB has been demonstrated over 20 km of standard fiber. With dispersion compensation, transmission over a single 80 km span of standard fiber was achieved with -32.7 dBm sensitivity. Transmission over 420 km of dispersion-shifted fiber was also demonstrated with an optical sensitivity of -31.1 dBm.

  13. Analysis of message extraction in optical chaos communications based on injection-locking synchronization of semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Murakami, Atsushi; Shore, K. Alan

    2006-10-01

    In this paper, we employ a simple theory based on driven damped oscillators to clarify the physical basis for message extraction in optical chaos communications using injection-locked semiconductor lasers. The receiver laser is optically driven by injection from the transmitter laser. We have numerically investigated the response characteristics of the receiver when it is driven by periodic (message) and chaotic (carrier) signals. It is thereby revealed that the response of the receiver laser in the two cases is quite different. For the periodic drive, the receiver exhibits a response depending on the signal frequency, while the chaotic drive provides a frequency-independent synchronous response to the receiver laser. CPF can be clearly understood in the difference between the periodic and chaotic drives. Message extraction using CPF is also examined, and the validity of our theoretical explanation for the physical mechanism underlying CPF is thus verified.

  14. Air data measurement using distributed processing and fiber optics data transmission

    NASA Technical Reports Server (NTRS)

    Farry, K. A.

    1982-01-01

    Distributed processing, fiber optics technology, and redundancy management in the aircraft environment are discussed. The project features the development of an angle-of-attack and sideslip data collection system hich features: (1) two independent microprocessor controlled data collection and calibration units; (2) transmission of data to the control system on a fiber optic data bus; and (3) software implemented error detection and recovery.

  15. MTF formalism for measurement of spectral resolution of acousto-optical devices with synthesized transmission function.

    PubMed

    Yushkov, Konstantin B; Molchanov, Vladimir Ya

    2013-09-15

    We demonstrate use of the modulation transfer function method in the spectral domain for dynamic measurement of the spectral resolution and modulation contrast of acousto-optic light dispersive delay lines and programmable filters with synthesized transmission. The method is useful for performance characterization of acousto-optic devices for ultrafast pulse shaping and adaptive spectroscopy. PMID:24104818

  16. V123 BEAM SYNCHRONOUS ENCODER MODULE.

    SciTech Connect

    KERNER,T.; CONKLING,C.R.; OERTER,B.

    1999-03-29

    The V123 Synchronous Encoder Module transmits events to distributed trigger modules and embedded decoders around the RHIC rings where they are used to provide beam instrumentation triggers [1,2,3]. The RHIC beam synchronous event link hardware is mainly comprised of three VMEbus board designs, the central input modules (V201), and encoder modules (V123), and the distributed trigger modules (V124). Two beam synchronous links, one for each ring, are distributed via fiber optics and fanned out via twisted wire pair cables. The V123 synchronizes with the RF system clock derived from the beam bucket frequency and a revolution fiducial pulse. The RF system clock is used to create the beam synchronous event link carrier and events are synchronized with the rotation fiducial. A low jitter RF clock is later recovered from this carrier by phase lock loops in the trigger modules. Prioritized hardware and software triggers fill up to 15 beam event code transmission slots per revolution while tracking the ramping RF acceleration frequency and storage frequency. The revolution fiducial event is always the first event transmitted which is used to synchronize the firing of the abort kicker and to locate the first bucket for decoders distributed about the ring.

  17. Synchronicity from synchronized chaos

    SciTech Connect

    Duane, Gregory

    2015-04-01

    The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related events mysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical) correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind and matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1) synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2) the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable) interpretations if the quantum world resides on a generalized synchronization “manifold”.

  18. Synchronicity from synchronized chaos

    DOE PAGESBeta

    Duane, Gregory

    2015-04-01

    The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related events mysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical) correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind andmore » matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1) synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2) the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable) interpretations if the quantum world resides on a generalized synchronization “manifold”.« less

  19. Nonlinear optical transmission in VOx nanotubes and VOx nanotube composites

    NASA Astrophysics Data System (ADS)

    Xu, J.-F.; Czerw, R.; Webster, S.; Carroll, D. L.; Ballato, J.; Nesper, R.

    2002-08-01

    Optical-limiting behavior of vanadium oxide nanotubes is characterized for the visible and infrared spectral ranges using 8 ns pulses from a Nd:YAG laser with an f/40 optical system. Vanadium oxide nanotube dispersions were investigated in both water suspensions and embedded in solid polymethyl methacrylate films. In each case, these nanotubes exhibit strong optical-limiting at 532 nm (in comparison to carbon nanotubes); however, no nonlinear behavior is observed for 1064 nm. This suggests that a two photon or excited state absorption mechanism is responsible for the observed nonlinearity.

  20. Multi-carrier transmission for hybrid radio frequency with optical wireless communications

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Chen, Genshe; Shen, Dan; Pham, Khanh; Blasch, Erik; Nguyen, Tien M.

    2015-05-01

    Radio frequency (RF) wireless communication is reaching its capacity to support large data rate transmissions due to hardware constraints (e.g., silicon processes), software strategies (e.g., information theory), and consumer desire for timely large file exchanges (e.g., big data and mobile cloud computing). A high transmission rate performance must keep pace with the generated huge volumes of data for real-time processing. Integrated RF and optical wireless communications (RF/OWC) could be the next generation transmission technology to satisfy both the increased data rate exchange and the communications constraints. However, with the promising benefits of RF/OWC, challenges remain to fully develop hybrid RF with wireless optical communications such as uniform waveform design for information transmission and detection. In this paper, an orthogonal frequency division multiplexing (OFDM) transmission scheme, which widely employed in RF communications, is developed for optical communications. The traditional high peak-to-average power ratio (PAPR) in OFDM is reduced to improve system performance. The proposed multi-carrier waveform is evaluated with a frequency-selective fading channel. The results demonstrate that bit error rate (BER) performance of our proposed optical OFDM transmission technique outperforms the traditional OWC on-off keying (OOK) transmission scheme.

  1. Tunable nonreciprocal terahertz transmission and enhancement based on metal/magneto-optic plasmonic lens.

    PubMed

    Fan, Fei; Chen, Sai; Wang, Xiang-Hui; Chang, Sheng-Jiang

    2013-04-01

    A tunable metal/magneto-optic plasmonic lens for terahertz isolator is demonstrated. Based on the magneto-optical effect of the semiconductor material and non-symmetrical structure, this plasmonic lens has not only the focusing feature but also nonreciprocal transmission property. Moreover, a transmission enhancement through this device greatly larger than that of the ordinary metallic slit arrays is contributed by the extraordinary optical transmission effect of the magneto surface plasmon polaritons. The results show that the proposed isolator has an isolation bandwidth of larger than 0.4THz and the maximum isolation of higher than 110dB, and its operating frequency also can be broadly tuned by changing the external magnetic field or temperature. This low-loss, high isolation, broadband tunable nonreciprocal terahertz transmission mechanism has a great potential for terahertz application systems. PMID:23571951

  2. Tracing photon transmission in dye-doped DNA-CTMA optical nanofibers.

    PubMed

    Long, Weihong; Zou, Weiwen; Li, Xing; Jiang, Wenning; Li, Xinwan; Chen, Jianping

    2014-03-24

    We experimentally demonstrate the novel phenomena of photoluminescence (PL) and fluorescence resonance energy transfer (FRET) assisted three-color PL separating in DNA optical nanofibers consisting of the stretched and connected DNA-cetyltrimethyl ammonium wires. The PL experiments are performed to comparatively trace photon transmission between single dye-doped DNA-CTMA optical nanofiber and PMMA optical nanofiber. A cascade FRET including DNA minor groove binder and DNA intercalators is used to further trace photon transmission inside DNA-CTMA wire. These experimental results will help to intrigue the new applications of DNA-CTMA as molecular waveguide in optobioelectronics area. PMID:24663973

  3. Enhanced optical transmission and Fano resonance through a nanostructured metal thin film

    PubMed Central

    Xiao, Bo; Pradhan, Sangram K.; Santiago, Kevin C.; Rutherford, Gugu N.; Pradhan, Aswini K.

    2015-01-01

    Artificial and engineered nanostructures expand the degrees of freedom with which one can manipulate the intricate interplay of light and matter. Certain nanostructural arrangements in the excited state enable the efficient electromagnetic coupling of propagating light with localized fields. Here, we demonstrate that light transmitted through a nanostructured metal thin film without any apertures can be significantly enhanced. Distinct asymmetric Fano resonances are observed in the zero-order transmission spectra using an incoherent light source. The transmission efficiency surpasses that of a metal thin film with the same area and thickness at the resonance maxima. The transmission minima and the sharp resonance maxima bear a strong resemblance to the extraordinary optical transmission observed in sub-wavelength nanohole array structures The resonance wavelength closely matches the nanostructural periodicity. The sensitivity of the resonances to the surrounding medium and the transmission efficiency demonstrate the potential for use in energy harvesting, imaging, optical processing and sensing applications. PMID:25981974

  4. Enhanced optical transmission and Fano resonance through a nanostructured metal thin film

    NASA Astrophysics Data System (ADS)

    Xiao, Bo; Pradhan, Sangram K.; Santiago, Kevin C.; Rutherford, Gugu N.; Pradhan, Aswini K.

    2015-05-01

    Artificial and engineered nanostructures expand the degrees of freedom with which one can manipulate the intricate interplay of light and matter. Certain nanostructural arrangements in the excited state enable the efficient electromagnetic coupling of propagating light with localized fields. Here, we demonstrate that light transmitted through a nanostructured metal thin film without any apertures can be significantly enhanced. Distinct asymmetric Fano resonances are observed in the zero-order transmission spectra using an incoherent light source. The transmission efficiency surpasses that of a metal thin film with the same area and thickness at the resonance maxima. The transmission minima and the sharp resonance maxima bear a strong resemblance to the extraordinary optical transmission observed in sub-wavelength nanohole array structures The resonance wavelength closely matches the nanostructural periodicity. The sensitivity of the resonances to the surrounding medium and the transmission efficiency demonstrate the potential for use in energy harvesting, imaging, optical processing and sensing applications.

  5. Novel synchronous DPSK optical regenerator based on a feed-forward based carrier extraction scheme.

    PubMed

    Ibrahim, Selwan K; Sygletos, Stylianos; Rafique, Danish; O'Dowd, John A; Weerasuriya, Ruwan; Ellis, Andrew D

    2011-05-01

    We experimentally demonstrate a novel synchronous 10.66 Gbit/s DPSK OEO regenerator which uses a feed-forward carrier extraction scheme with an injection-locked laser to synchronize the regenerated signal wavelength to the incoming signal wavelength. After injection-locking, a low-cost DFB laser used at the regenerator exhibited the same linewidth characteristics as the narrow line-width transmitter laser. The phase regeneration properties of the regenerator were evaluated by emulating random Gaussian phase noise applied to the DPSK signal before the regenerator using a phase modulator driven by an arbitrary waveform generator. The overall performance was evaluated in terms of electrical eye-diagrams, BER measurements, and constellation diagrams. PMID:21643202

  6. Prediction of long-term radiation kinetics of transmission spectra of commerical optical glasses

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei I.; Doyle, Dominic B.; Fruit, Michel; Kinet, Damien P.

    2002-09-01

    We analyze the applicability of a number of exponent-type phenomenological kinetics for transmission degradation prediction in commercial optical glasses during and after irradiation. The analysis is based on post-radiation transmission measurements over a 5 years time interval of a commercial boro-silicate glass (BK7, Schott). A conclusion is drawn that the choice should be made between the stretched-exponential and the multi-exponential functions. We apply those kinetics to simulate kinetics of BK7 glass transmission spectra subject to Co60 gamma-radiation in the framework of the previously developed phenomenological model. Calculated transmission spectra agree well with our experimental data.

  7. High-Performance Optical 3R Regeneration for Scalable Fiber Transmission System Applications

    NASA Astrophysics Data System (ADS)

    Zhu, Zuqing; Funabashi, Masaki; Pan, Zhong; Paraschis, Loukas; Harris, David L.; Ben Yoo, S. J.

    2007-02-01

    This paper proposes and demonstrates optical 3R regeneration techniques for high-performance and scalable 10-Gb/s transmission systems. The 3R structures rely on monolithically integrated all-active semiconductor optical amplifier-based Mach Zehnder interferometers (SOA-MZIs) for signal reshaping and optical narrowband filtering using a Fabry Pérot filter (FPF) for all-optical clock recovery. The experimental results indicate very stable operation and superior cascadability of the proposed optical 3R structure, allowing error-free and low-penalty 10-Gb/s [pseudorandom bit sequence (PRBS) 223 - 1] return-to-zero (RZ) transmission through a record distance of 1 250 000 km using 10 000 optical 3R stages. Clock-enhancement techniques using a SOA-MZI are then proposed to accommodate the clock performance degradations that arise from dispersion uncompensated transmission. Leveraging such clock-enhancement techniques, we experimentally demonstrate error-free 125 000-km RZ dispersion uncompensated transmission at 10 Gb/s (PRBS 223 - 1) using 1000 stages of optical 3R regenerators spaced by 125-km large-effective-area fiber spans. To evaluate the proposed optical 3R structures in a relatively realistic environment and to investigate the tradeoff between the cascadability and the spacing of the optical 3R, a fiber recirculation loop is set up with 264- and 462-km deployed fiber. The field-trial experiment achieves error-free 10-Gb/s RZ transmission using PRBS 223} - 1 through 264 000-km deployed fiber across 1000 stages of optical 3R regenerators spaced by 264-km spans.

  8. Simulation of the coherent MDM transmission using principal modes of the optical fiber as signal carriers

    NASA Astrophysics Data System (ADS)

    Lyubopytov, Vladimir S.; Zakirov, Robert A.; Vinogradova, Irina L.; Sultanov, Albert K.

    2015-03-01

    In this paper we demonstrate computer simulation results obtained for the coherent mode division multiplexed (MDM) 5x5 QPSK transmission using principal modes (PMs) of the stepped-index few-mode fiber (FMF) as a basis of independent signal carriers. The output signal recovering and the fiber propagation matrix determination are considered to be carried out in optical domain by means of reconfigurable multibranch diffractive optical elements (DOEs). Both the cases of Gaussian and Nyquist raised-cosine pulse shaping are considered for optical signal modulation. The simulation results show, that the transmission in the basis of PMs in strong coupling regime allows the reliability of the coherent MDM system to be fundamentally improved. As a result, utilization of the optical signal processing for MDM transmission could minimize substantially the DSP circuit complexity required for the real-time recovering of the transmitted signal.

  9. Observing single protein binding by optical transmission through a double nanohole aperture in a metal film

    PubMed Central

    Al Balushi, Ahmed A.; Zehtabi-Oskuie, Ana; Gordon, Reuven

    2013-01-01

    We experimentally demonstrate protein binding at the single particle level. A double nanohole (DNH) optical trap was used to hold onto a 20 nm biotin-coated polystyrene (PS) particle which subsequently is bound to streptavidin. Biotin-streptavidin binding has been detected by an increase in the optical transmission through the DNH. Similar optical transmission behavior was not observed when streptavidin binding sites where blocked by mixing streptavidin with excess biotin. Furthermore, interaction of non-functionalized PS particles with streptavidin did not induce a change in the optical transmission through the DNH. These results are promising as the DNH trap can make an excellent single molecule resolution sensor which would enable studying biomolecular interactions and dynamics at a single particle/molecule level. PMID:24049672

  10. Fabrication of a phase transmission holographic optical element in polycarbonate and its characterization.

    PubMed

    Vadivelan, V; Chandar Shekar, B

    2016-08-10

    The phase transmission holographic optical element in silver halide holographic emulsion, especially for holographic collimator sights, is fabricated and the desired diffraction efficiency is obtained with very high transmission. One of the main drawbacks of these holograms are that they become dark by being exposed under sunlight, and this darkness drastically reduces the visible transmission and diffraction efficiency of a holographic optical element, hence it is not suitable for weapon sight application. To overcome this problem, we transferred a holographic optical element with a reticle image from silver halide into polycarbonate by using copying, electroforming, and recombination techniques. The holographic optical element in polycarbonate has many advantages; the detailed method of fabrication, transfer, and its characterization are presented. The very interesting result of diffraction efficiency variation with angle obtained in polycarbonate is discussed. PMID:27534494

  11. Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

    SciTech Connect

    Liu, Yun; Huang, Chunning; Aleksandrov, Alexander V

    2013-01-01

    We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstration of particle beam profile diagnostics using fiber optic laser pulse transmission line.

  12. Radiation-induced transmission loss of integrated optic waveguide devices

    NASA Astrophysics Data System (ADS)

    Henschel, Henning; Koehn, Otmar; Schmidt, Hans U.

    1993-04-01

    The radiation sensitivity of different integrated optic (IO) devices was compared under standardized test conditions. We investigated four relatively simple device types made by four different manufacturers. The waveguide materials were proton exchanged LiTaO3, LiNbO3:Ti, Tl-diffused glass, and Ag-diffused glass, respectively. In order to standardize the irradiation parameters we followed the 'Procedure for Measuring Radiation-Induced Attenuation in Optical Fibers and Optical Cables' proposed by the NATO NETG as close as possible. In detail we made pulsed irradiations with dose values of about 500 rad*, 104 rad, and 105 rad, as well as continuous irradiations at a 60Co source with a dose rate of 1300 rad*/min up to a total dose of 104 rad. Device temperatures were about 22 degree(s)C, -50 degree(s)C, and +80 degree(s)C.

  13. Measurements of the UV and VUV transmission of optical materials during high energy electron irradiation

    NASA Technical Reports Server (NTRS)

    Palma, G. E.

    1972-01-01

    An experimental program was conducted in which the optical transmission of several transparent materials was measured during high energy electron irradiation. These experiments were conducted using the Dynamitron electron accelerator as a continuous source of 1.5 MeV electrons and the LINAC electron accelerator as a pulsed source of 5-7 MeV electrons. The experimental program consisted of three major portions. The first portion, the optical transmission of fused silica, BeO, MgF2, and LiF was measured at vacuum ultraviolet wavelengths in the range 1550-2000 A during ambient temperature, 1.5 MeV electron irradiation at ionizing dose rates to 0.5 Mrad/sec. In the second portion of the program, the optical transmission of fused silica and BeO was measured in the range 2000-3000 A during high dose rate, elevated temperature 1.5 MeV electron irradiation. In particular, accurate measurements of the optical transmission were made at ionizing dose rates as high as 10 Mrad/sec. In the final portion of the program, the optical transmission of fused silica and BeO was measured in the wavelength range 2000-3000 A during pulsed 5 and 7 MeV electron irradiation from the LINAC accelerator. The maximum time averaged ionizing dose rate was limited to 0.75 Mrad/sec due to accelerator limitations.

  14. Blue-phase liquid crystal cored optical fiber array with photonic bandgaps and nonlinear transmission properties.

    PubMed

    Khoo, Iam Choon; Hong, Kuan Lung; Zhao, Shuo; Ma, Ding; Lin, Tsung-Hsien

    2013-02-25

    Blue-phase liquid crystal (BPLC) is introduced into the pores of capillary arrays to fabricate fiber arrays. Owing to the photonic-crystals like properties of BPLC, these fiber arrays exhibit temperature dependent photonic bandgaps in the visible spectrum. With the cores maintained in isotropic as well as the Blue phases, the fiber arrays allow high quality image transmission when inserted in the focal plane of a 1x telescope. Nonlinear transmission and optical limiting action on a cw white-light continuum laser is also observed and is attributed to laser induced self-defocusing and propagation modes changing effects caused by some finite absorption of the broadband laser at the short wavelength regime. These nonlinear and other known electro-optical properties of BPLC, in conjunction with their fabrication ease make these fiber arrays highly promising for imaging, electro-optical or all-optical modulation, switching and passive optical limiting applications. PMID:23481965

  15. A 10 Gbit/s OCDMA system based on electric encoding and optical transmission

    NASA Astrophysics Data System (ADS)

    Li, Chuan-qi; Hu, Jin-lin; He, Dong-dong; Chen, Mei-juan; Wang, Da-chi; Chen, Yan

    2013-11-01

    An electric encoded/optical transmission system of code division multiple access (CDMA) is proposed. It encodes the user signal in electric domain, and transfers the different code slice signals via the different wavelengths of light. This electric domain encoder/decoder is compared with current traditional encoder/decoder. Four-user modulation/demodulation optical CDMA (OCDMA) system with rate of 2.5 Gbit/s is simulated, which is based on the optical orthogonal code (OCC) designed in our laboratory. The results show that the structure of electric encoding/optical transmission can encode/decode signal correctly, and can achieve the chip rate equal to the user data rate. It can overcome the rate limitation of electronic bottleneck, and bring some potential applications in the electro-optical OCDMA system.

  16. Kansas Communication and Instruction System through Fiber-Optic Transmission.

    ERIC Educational Resources Information Center

    Kansas State Dept. of Education, Topeka.

    Schools and communities will restructure as they move into the next decade. The success of this restructuring will be dependent upon access to and sharing of quality teaching and information through an expanded communication system. One of the major two-way interactive technologies is the fiber-optic cable: a delivery system that will provide…

  17. Electronically tunable extraordinary optical transmission in graphene plasmonic ribbons coupled to subwavelength metallic slit arrays

    PubMed Central

    Kim, Seyoon; Jang, Min Seok; Brar, Victor W.; Tolstova, Yulia; Mauser, Kelly W.; Atwater, Harry A.

    2016-01-01

    Subwavelength metallic slit arrays have been shown to exhibit extraordinary optical transmission, whereby tunnelling surface plasmonic waves constructively interfere to create large forward light propagation. The intricate balancing needed for this interference to occur allows for resonant transmission to be highly sensitive to changes in the environment. Here we demonstrate that extraordinary optical transmission resonance can be coupled to electrostatically tunable graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. Full-wave simulations predict a transmission modulation of 95.7% via this mechanism. Experimental measurements reveal a modulation efficiency of 28.6% in transmission at 1,397 cm−1, corresponding to a 2.67-fold improvement over transmission without a metallic slit array. This work paves the way for enhancing light modulation in graphene plasmonics by employing noble metal plasmonic structures. PMID:27499258

  18. Effect of Charging Electron Exposure on 1064nm Transmission Through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics

    NASA Technical Reports Server (NTRS)

    Ottens, Brian P.; Connelly, Joseph; Brown, Stephen; Roeder, James; Kauder, Lonny; Cavanaugh, John

    2010-01-01

    Experiments measuring the effect of electron exposure on 1064nm transmission for optical sapphire were conducted. Detailed before and after inspections did not identify any resulting Litchenburg patterns. Pre- and post-exposure 1064nm transmission measurements are compared.

  19. Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-coated Sapphire Optics

    NASA Technical Reports Server (NTRS)

    Ottens, Brian P.; Connelly, Joseph; Brown, Stephen; Roeder, james; Kauder, Lonny; Cavanaugh, John

    2008-01-01

    Experiments measuring the effect of electron exposure on 1064nm transmission for optical sapphire were conducted. Detailed before and after inspections did not identify any resulting Litchenburg patterns. Pre- and post-exposure 1064nm transmission measurements are compared.

  20. Structural Study of Hole Assisted Fibers Considering Optical Parallel Transmission

    NASA Astrophysics Data System (ADS)

    Kashima, Norio

    2011-12-01

    Hole-assisted fibers (HAFs) in a fiber ribbon have been studied for high-speed parallel transmission systems. This paper describes the influence of hole-structure variations on the group delay variation caused by stress, the mode field diameter (MFD), and the higher order mode characteristics. Calculations are made using the previously proposed calculation method with finite element method (FEM). We discuss the effectiveness and limitation of the previously proposed parameter based on the calculations.

  1. Dual pulse operation of 1.5 μm picosecond intracavity synchronously pumped optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Zavadilová, Alena; Kubeček, Václav; Diels, Jean-Claude; Šulc, Jan

    2012-02-01

    Singly resonant optical parametric oscillators (OPO) are most promising approach to sensors in which two pulses circulate independently in a cavity. The OPO should be pumped intracavity, not only to access the high intracavity power of the pump laser, but also because the two signal pulses share the same mode. The first synchronously pumped OPO were pumped intracavity by a mode-locked dye laser. Subsequent implementation with solid-state pump lasers has been plagued by a tendency to Q-switching, as well as competition between the two pulses generated in the signal cavity. In this contribution we report the improved and optimized experimental setup of an intracavity synchronously pumped OPO based on a periodically poled LiNbO3 crystal (PPLN) and of the pumping resonator of passively mode locked Nd:YVO4 laser from the point of view of achievability of stable mode-locking and compensation of the astigmatism caused by Brewster angle cut PPLN. This resulted in higher conversion efficiency due to the good overlap of pump and signal beam.

  2. Dual pulse operation of 1.5 μm picosecond intracavity synchronously pumped optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Zavadilová, Alena; Kubeček, Václav; Diels, Jean-Claude; Šulc, Jan

    2011-09-01

    Singly resonant optical parametric oscillators (OPO) are most promising approach to sensors in which two pulses circulate independently in a cavity. The OPO should be pumped intracavity, not only to access the high intracavity power of the pump laser, but also because the two signal pulses share the same mode. The first synchronously pumped OPO were pumped intracavity by a mode-locked dye laser. Subsequent implementation with solid-state pump lasers has been plagued by a tendency to Q-switching, as well as competition between the two pulses generated in the signal cavity. In this contribution we report the improved and optimized experimental setup of an intracavity synchronously pumped OPO based on a periodically poled LiNbO3 crystal (PPLN) and of the pumping resonator of passively mode locked Nd:YVO4 laser from the point of view of achievability of stable mode-locking and compensation of the astigmatism caused by Brewster angle cut PPLN. This resulted in higher conversion efficiency due to the good overlap of pump and signal beam.

  3. Enhanced Optical Transmission Mediated by Localized Plasmons in Anisotropic, 3D Nanohole Arrays

    PubMed Central

    Yang, Jiun-Chan; Gao, Hanwei; Suh, Jae Yong; Zhou, Wei; Lee, Min Hyung; Odom, Teri W.

    2010-01-01

    This paper describes 3D nanohole arrays whose high optical transmission is mediated more by localized surface plasmon (LSP) excitations than by surface plasmon polaritons (SPPs). First, LSPs on 3D hole arrays lead to optical transmission an order of magnitude higher than 2D planar hole arrays. Second, LSP-mediated transmission is broadband and more tunable than SPP-enhanced transmission which is restricted by Bragg coupling. Third, for the first time, two types of surface plasmons can be selectively excited and manipulated on the same plasmonic substrate. This new plasmonic substrate fabricated by high-throughput nanolithography techniques paves the way for cutting-edge optoelectronic and biomedical applications. PMID:20698633

  4. Optical stealth transmission based on super-continuum generation in highly nonlinear fiber over WDM network.

    PubMed

    Zhu, Huatao; Wang, Rong; Pu, Tao; Fang, Tao; Xiang, Peng; Zheng, Jilin; Chen, Dalei

    2015-06-01

    In this Letter, the optical stealth transmission carried by super-continuum spectrum optical pulses generated in highly nonlinear fiber is proposed and experimentally demonstrated. In the proposed transmission scheme, super-continuum signals are reshaped in the spectral domain through a wavelength-selective switch and are temporally spread by a chromatic dispersion device to achieve the same noise-like characteristic as the noise in optical networks, so that in both the time domain and the spectral domain, the stealth signals are hidden in public channel. Our experimental results show that compared with existing schemes where stealth channels are carried by amplified spontaneous emission noise, super-continuum signal can increase the transmission performance and robustness. PMID:26030557

  5. Optical clearing of unsectioned specimens for three-dimensional imaging via optical transmission and emission tomography

    PubMed Central

    Oldham, Mark; Sakhalkar, Harshad; Oliver, Tim; Johnson, G. Allan; Dewhirst, Mark

    2009-01-01

    Optical computed tomography (optical-CT) and optical emission computed tomography (optical-ECT) are new techniques that enable unprecedented high-resolution 3-D multimodal imaging of tissue structure and function. Applications include imaging macroscopic gene expression and microvasculature structure in unsectioned biological specimens up to 8 cm3. A key requisite for these imaging techniques is effective sample preparation including optical clearing, which enables light transport through the sample while preserving the signal (either light absorbing stain or fluorescent proteins) in representative form. We review recent developments in optical-CT and optical-ECT, and compatible “fluorescence-friendly” optical clearing protocols. PMID:18465962

  6. [Transmission grating spectrograph for soft X-ray spectrum measurements with a pre-optics].

    PubMed

    Wang, Z; Tian, Z; Chen, B; Wang, Z; Gao, J; Tian, X; Chen, Z; Fan, P; Chen, X

    1999-12-01

    A novel diffraction spectroscopic instrument consisting of a large area transmission grating and a grazing-incidence pre-optics comprising of a toroidal mirror, a slit and a cylindrical mirror has been implemented. A nearly perfect stigmatism and a medium spectral resolution are due to the separation of the focusing and dispersing function. The experimental results show that it is possible to construct large area transmission grating spectrograph with high collecting efficiency and good spatial resolution. PMID:15822323

  7. 20 Gb/s optical OFDM transmission for long haul transmission

    NASA Astrophysics Data System (ADS)

    Aldhaibani, Abdullahomar; Aljunid, Syed Alwee; Fadhil, Hilal; Safar, Anuar Mat

    2015-05-01

    Optical OFDM system is considered to be the essential backbone of the next generation of ultra-high-speed networks. A dispersion effect is considered one of the common limitations in optical OFDMA system especially at very high date rate. When the pulse width reaches less than a few pico-seconds, not only the second-order but even higher-order dispersion must be taken into account. In this paper OOFDM system designed with traditional dispersion compensating devices such as Dispersion compensating fiber (DCF) used in multi spans with single mode fiber to reach to 288 km distance at 20 Gb/s. moreover, single side band (SSB) used to reduce the dispersion as well. Therefore, the overall system performance based on SNR, spectral analyzer and constellation diagram for the single side band (SSB) OOFDM system gives a good result with 16 QAM modulation.

  8. Synchronous triple-optical-path digital speckle pattern interferometry with fast discrete curvelet transform for measuring three-dimensional displacements

    NASA Astrophysics Data System (ADS)

    Gu, Guoqing; Wang, Kaifu; Wang, Yanfang; She, Bin

    2016-06-01

    Digital speckle pattern interferometry (DSPI) is a well-established and widely used optical measurement technique for obtaining qualitative as well as quantitative measurements of objects deformation. The simultaneous measurement of an object's surface displacements in three dimensions using DSPI is of great interest. This paper presents a triple-optical-path DSPI based method for the simultaneous and independent measurement of three-dimensional (3D) displacement fields. In the proposed method, in-plane speckle interferometers with dual-observation geometry and an out-of-plane interferometer are optimally combined to construct an integrated triple-optical-path DSPI system employing the phase shift technique, which uses only a single laser source and three cameras. These cameras are placed along a single line to synchronously capture real-time visible speckle fringe patterns in three dimensions. In addition, a pre-filtering method based on the fast discrete curvelet transform (FDCT) is utilized for denoising the obtained wrapped phase patterns to improve measurement accuracy. Finally, the simultaneous measurement of the 3D displacement fields of a simple beam and a composite laminated plate respectively subjected to three-point and single-point bend loading are investigated to validate the feasibility and effectiveness of the proposed method.

  9. SONET synchronization: What's happening

    NASA Technical Reports Server (NTRS)

    Cubbage, Robert W.

    1993-01-01

    Almost everyone that has heard of SONET knows that the acronym stands for Synchronous Optical NETwork. There has been a host of magazine articles on SONET rings, SONET features, even SONET compatibility with digital radio. What has not been highly publicized is the critical relationship between SONET, network synchronization, and payload jitter. This topic is addressed.

  10. SONET synchronization: What's happening

    NASA Astrophysics Data System (ADS)

    Cubbage, Robert W.

    1993-06-01

    Almost everyone that has heard of SONET knows that the acronym stands for Synchronous Optical NETwork. There has been a host of magazine articles on SONET rings, SONET features, even SONET compatibility with digital radio. What has not been highly publicized is the critical relationship between SONET, network synchronization, and payload jitter. This topic is addressed.

  11. Study on micro-bend light transmission performance of novel liquid-core optical fiber

    NASA Astrophysics Data System (ADS)

    Ma, Junyan; Zhao, Zhimin; Wang, Kaisheng; Guo, Linfeng

    2007-01-01

    With the increasing development of material technology and electronic integration technology, optical fiber and its using in smart structure have become hot in the field of material research. And liquid-core optical fiber is a special kind of optical fiber, which is made using liquid material as core and polymer material as optical layer and protective covering, and it has the characteristics of large core diameter, high numerical aperture, large-scope and efficient spectrum transmission and long life for using. So the liquid-core optical fiber is very suitable for spectrum cure, ultraviolet solidification, fluorescence detection, criminal investigation and evidence obtainment, etc, and especially as light transfer element in some new structures for the measurement of some signals, such as concentration, voltage, temperature, light intensity and so on. In this paper, the novel liquid-core optical fiber is self-made, and then through the test of its light transmission performance in free state, the relation between axial micro-bend and light-intensity loss are presented. When the liquid-core optical fiber is micro-bent axially, along with the axial displacement's increase, output power of light is reducing increasingly, and approximately has linear relation to micro-displacement in a range. According to the results liquid-core fiber-optic micro-bend sensor can be designed to measure micro-displacement of the tested objects. Experimental data and analysis provide experimental basis for further application of liquid-core optical fiber.

  12. Transmission medium and full fiber-optic setup for quantum key distribution applications

    NASA Astrophysics Data System (ADS)

    Tsakiris, Stavros I.; Uzunoglu, Nikolaos K.

    2006-12-01

    A fiber-optic-based coupled waveguide transmission medium is proposed to distribute secret keys in a single-photon polarization-based quantum cryptography setup. Polarization maintenance properties and coupling phenomena of the transmission medium are exploited to achieve accuracy and security of the transferred key. Elliptic fibers and fiber couplers are used to prepare the transmitted photons at the sender as well as analyze them at the receiver. The uniqueness of the setup stands on the exclusive use of fiber-optic components, enabling its construction on a single fiber line.

  13. Application of the transmission line method for the study of highly nonlinear multilayer optical structures

    NASA Astrophysics Data System (ADS)

    Moshonas, Nikolaos; Pagiatakis, Gerasimos K.; Papagiannis, Panagiotis; Savaidis, Stylianos P.; Stathopoulos, Nikolaos A.

    2014-11-01

    In this work, we numerically investigate and analyze the properties of an optical structure composed of successive thin film layers that can possess high values of nonlinear susceptibility, affecting the refractive index and/or the absorption coefficient. By applying the transmission line method properly modified to resolve the inclusion of third-order nonlinearity, the spectral reflectivity and transmission of such a device are presented. Specifically, the method is applied to a conceptual design of a distributed Bragg reflector. Optical bistability can be observed, which translates not only to a change in the value of reflectivity as the input power increases, but also to a shift of the Bragg wavelength.

  14. Optical up-conversion for WDM-RoF transmission using multiple optical carrier suppression in OFCG

    NASA Astrophysics Data System (ADS)

    Zhang, Chan; Ning, TiGang; Li, Jing; Chen, Hongyao; Li, Chao; Liu, Zhiming

    2016-03-01

    A tunable optical frequency comb generator (OFCG) by cascading an Electro-absorption modulator (EAM) followed by a phase modulator (PM) and an intensity modulator (IM) is proposed for wavelength division multiplexing radio-over-fiber (WDM-RoF) transmission. The generated OFCG serves as the carriers of WDM-RoF system to realize all-optical up-conversion afterwards. In the proposal, each comb line is modulated by the radio-frequency (RF) signal via multiple optical carrier suppression (OCS) after optical comb generation. We have systematically compared the performances of the optical up-conversion based on different modulation schemes. Among three schemes, the OCS modulation scheme shows the highest receiver sensitivity and smallest power penalty over long-distance transmission. What's more, the OCS modulation scheme can be easily implemented with a large number of WDM channels simultaneously without any power saturation or other nonlinear impact. In the numerical simulation, 15 WDM channels each carrying 15 Gb/s×5 Gb/s baseband signal have been up-converted to 10 GHz simultaneously. This method still provides high performance after 20 km transmission, which shows simple cost-efficient configuration and good performance over long distance delivery.

  15. Synchronized signaling delivery for broadband 60 GHz in-building optical wireless network based on digital frequency division multiplexing and digital Nyquist shaping.

    PubMed

    Cao, Z; Li, F; Okonkwo, C M; van den Boom, H P A; Chen, M; Yang, B; Zou, S; Tangdiongga, E; Chen, L; Koonen, A M J

    2013-01-14

    A simple and low-cost synchronized signaling delivery scheme has been proposed for a 60 GHz in-building optical wireless network with 12.7Gbps throughput based on digital frequency division multiplexing and digital Nyquist shaping. PMID:23388920

  16. Vibration analysis of the Thomson Scattering diagnostics optical transmission system on EAST tokamak

    NASA Astrophysics Data System (ADS)

    Shao, Chunqiang; Zang, Qing; Zhao, Junyu; Hu, Ailan; Han, Xiaofeng; Chen, Hui; He, Liangliang; Wang, Tengfei

    2014-09-01

    A series of vibration source from the EAST tokamak complicated experimental environment would result in the laser path misalignment and the collected scattered laser signal attenuation, which leads to a measurement error of the Thomson Scattering (TS) diagnostics system. Two methods have been designed for the vibration analysis of the TS diagnostics optical transmission system, a passive one and an active one. The optical transmission system contains of a double deck optical table with 4 reflectors and a photon collection system. The vibration analysis includes 4 points of reflectors along the laser path, 1 point of the photon collection system, and the ground of EAST experimental hall. The passive method used a vibration spectrum analyzer and 7 vertical speed sensors measuring the standard deviation of the vibration noise, which refers to the virtual value of vibration, and a data analysis system. The active method used a hammer to simulate the vibration source of the experimental hall ground, and 15 accelerometers to measure the three-dimensional vibration spectrum of 5 points along the optical transmission system. The vibration isolation efficiency (IE) of the optical transmission system has been presented, and the vibration asynchrony of the 5 points also has been observed. The results of two methods are comparatively studied, and the active one is considered to be more credible.

  17. Multiplexed Optical Transmission System For Automobiles Using Polymer Fiber With High Heat Resistance

    NASA Astrophysics Data System (ADS)

    Sasayama, Takao; Asano, Hideki; Taketani, Noriaki

    1989-02-01

    A multiplexed optical transmission system for automobiles utilizing newly developed polymer fiber has been proposed. The system is composed with a star-shaped optical network, in which the ootical signals can be transmitted bi-directionally through polymer optical fiber and optical branches with the central and local controllers. The polymer fiber has been developed for this purpose in order to overcome the conventional problems which prevented its wide use for a long time. The new polymer fiber is fabricated with a thereto-setting resin for core which is pushed out from heating furnace after the process of polymerization. The fiber shows the desirable characteristics for this application, that is, the heat resistance is as high as 200°C, and the transmission loss is as low as 0.5003/m at 660 nm wavelength.

  18. 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.

  19. 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.

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

    PubMed

    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. PMID:24387470

  1. Ideal optical backpropagation of scalar NLSE using dispersion-decreasing fibers for WDM transmission.

    PubMed

    Liang, Xiaojun; Kumar, Shiva; Shao, Jing

    2013-11-18

    An ideal optical backpropagation (OBP) scheme to compensate for dispersion and nonlinear effects of the transmission fibers is proposed. The scheme consists of an optical phase conjugator (OPC), N spans of dispersion-decreasing fibers (DDFs) and amplifiers, placed at the end of the fiber optic link. In order to compensate for the nonlinear effects of the transmission fibers exactly, the nonlinear coefficient of the backpropagation fiber has to increase exponentially with distance or equivalently the power in the backpropagation fiber should increase exponentially with distance if the nonlinear coefficient is constant. In this paper, it is shown that a combination of DDFs and amplifiers can compensate for the nonlinear effects exactly. An analytical expression for the dispersion profile of the DDF is derived. Numerical simulation of a long haul wavelength division multiplexing (WDM) fiber optic system with the proposed OBP scheme shows that the system reach can be enhanced by 54% as compared to digital backpropagation (DBP). PMID:24514378

  2. Damage characteristics at optical fiber connector for high power light transmission

    NASA Astrophysics Data System (ADS)

    Matsuda, S.; Shibuya, T.; Wakaki, M.

    2008-01-01

    In the field of optical communication, either fusion splicing of optical fibers or physical contact between optical-fibers using a fiber connector has been utilized as the typical method of optical fiber connection. Optical fiber connectors have been widely employed in optical transmission systems according to their features of easy and quick connection without special apparatus to connect fibers. The power of laser diodes for light sources became more intense and the multiplexing of wavelength (WDM) of a light source was enhanced with increasing traffic data. As a result, intense light transmits through the optical fiber. The high power transmission characteristics of the optical fiber connector are important factors to realize dense wavelength division multiplexing systems (DWDM). In this paper, we present an experimental investigation about the degradation of the transmission properties through the optical fiber connector by introducing the contamination between the end faces of a connector. The metal foils to simulate the contamination at the end of the core were inserted between the optical fibers to cover the core of an optical fiber partially. As metal foils, Nickel, SUS304, and Phosphor Bronze which were typically used as the components of the ferrule and sleeve were selected. The Nd: YAG laser with the wavelength of 1064 nm was used as a high power light source at various output powers. The transmission loss was set by adjusting the insertion of a metal foil into the core region of the fiber and the temperature rising of the connector induced by the absorption of incident light was measured at a sleeve portion. The damage at the end face of the physical contact region was observed using an optical microscope. The temperatures increase of the core of the fiber was estimated for the fiber connector with a zirconia ferrule through the thermal simulation using the MSC Visual Nastran. The damage of the fiber end face was recognized depending on the species of

  3. Limitations on High Data Rate Optical Fiber Transmission Systems Due to Transmission Impairment

    SciTech Connect

    Menyuk, Curtis R.

    2002-03-15

    This project supplemented our regular DOE grant from the Basic Energy Sciences organization with the goal of fostering industrial partnerships and student internships. During the project period, we have interacted with between 15 and 20 companies in the optical fiber telecommunications equipment industry, and our students have participated in a number of highly visible projects with companies such as Ciena, Science Applications International Corporation, KDD, ATT, Virtual Photonics, Inc., Phaethon Telecommunications, PhotonEx, and others. The project led to many successful interactions and numerous job offers for our students.

  4. Optical fiber cable for transmission of high power laser energy over great distances

    DOEpatents

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Moxley, Joel F.; Koblick, Yeshaya

    2016-05-24

    There is provided a system and apparatus for the transmission of high power laser energy over great distances without substantial power loss and without the presence of stimulated Raman scattering. There is further provided systems and optical fiber cable configurations and optical fiber structures for the delivering high power laser energy over great distances to a tool or surface to perform an operation or work with the tool or upon the surface.

  5. Design of a fiber-optic transmitter for microwave analog transmission with high phase stability

    NASA Technical Reports Server (NTRS)

    Logan, R. T., Jr.; Lutes, G. F.; Primas, L. E.; Maleki, L.

    1990-01-01

    The principal considerations in the design of fiber-optic transmitters for highly phase-stable radio frequency and microwave analog transmission are discussed. Criteria for a fiber-optic transmitter design with improved amplitude and phase-noise performance are developed through consideration of factors affecting the phase noise, including low-frequency laser-bias supply noise, the magnitude and proximity of external reflections into the laser, and temperature excursions of the laser-transmitter package.

  6. Optical fiber configurations for transmission of laser energy over great distances

    SciTech Connect

    Rinzler, Charles C; Zediker, Mark S

    2013-10-29

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  7. Optical fiber configurations for transmission of laser energy over great distances

    SciTech Connect

    Rinzler, Charles C; Zediker, Mark S

    2014-11-04

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  8. Hardware authentication using transmission spectra modified optical fiber.

    SciTech Connect

    Grubbs, Robert K.; Romero, Juan A.

    2010-09-01

    The ability to authenticate the source and integrity of data is critical to the monitoring and inspection of special nuclear materials, including hardware related to weapons production. Current methods rely on electronic encryption/authentication codes housed in monitoring devices. This always invites the question of implementation and protection of authentication information in an electronic component necessitating EMI shielding, possibly an on board power source to maintain the information in memory. By using atomic layer deposition techniques (ALD) on photonic band gap (PBG) optical fibers we will explore the potential to randomly manipulate the output spectrum and intensity of an input light source. This randomization could produce unique signatures authenticating devices with the potential to authenticate data. An external light source projected through the fiber with a spectrometer at the exit would 'read' the unique signature. No internal power or computational resources would be required.

  9. Experimental investigations in transmission performance of real-time long-reach adaptively modulated direct-detection optical-orthogonal frequency division multiplexing systems

    NASA Astrophysics Data System (ADS)

    Chen, Ming; He, Jing; Tang, Jin; Chen, Lin

    2014-09-01

    A real-time base-band orthogonal frequency division multiplexing (OFDM) transceiver with symbol synchronization, channel equalization, sampling clock frequency synchronization, and adaptive modulation technique is successfully implemented by field programmable gate arrays and a 2.5-GSps digital-to-analog converter and analog-to-digital converter. The real-time optical OFDM signal at a raw bit rate of 5.156 Gbps within about 1.1-GHz bandwidth transmission over 100-km standard single-mode fiber (SSMF) is experimentally investigated in a simple intensity-modulation and direct-detection system. The experimental results show that the real-time system has a good bit error rate (BER) performance by using an adaptive modulation technique according to the conditions on the subchannels. After 100-km SSMF transmission, at a BER of 1×10-3, the power penalty is <1 dB. Moreover, there is a negligible penalty between the off-line and real-time digital signal processing results.

  10. Optimizing diffraction efficiency for transmission holographic optical elements with HARMAN holographic materials

    NASA Astrophysics Data System (ADS)

    Smith, Steven L.; Harvey, Karen; Richardson, Martin; Blyth, Jeff

    2011-02-01

    HARMAN technology's new holographic emulsions; red sensitive and green sensitive assisted by smaller grain sizes, novel sensitization and coating technology have been shown to achieve high diffraction efficiencies and narrow band reconstruction capabilities. Authors demonstrate processing optimizations and material behavior characteristics for Transmission image Masters as well as Holographic Optical Elements (HOE's).

  11. Error probabilities in optical data transmission systems with an atmospheric channel and pointing inaccuracies

    NASA Astrophysics Data System (ADS)

    Mal'Tsev, G. N.

    1991-11-01

    A study is made of the combined effect of atmospheric distortions and antenna pointing errors on the noise immunity of optical data transmission systems with direct detection. The possibility of compensating for the effect of perturbations by increasing the power potential of the system is analyzed. The relative importance of atmospheric distortions and pointing errors is estimated.

  12. Transcutaneous Optical Information Transmission System for a Totally Implantable Artificial Heart

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takahiko; Koshiji, Kohji

    A transcutaneous optical information transmission system (TOITS) offers the most promising method for noninvasively transmitting the information to control a total artificial heart (TAH). We had used light-emitting diode (LED) and photo diode (PD) with different wavelengths for full-duplex bidirectional communication in the TOITS. In this study, reduction of optical crosstalk in full-duplex bidirectional communication was investigated by using a combination of two orthogonal polarizers with the same wavelength. As a result, we confirmed that optical crosstalk could be prevented for communication through a cow's skin (3.5 mm thick) and that the signal waveform could be transmitted satisfactorily.

  13. Power-efficient method for IM-DD optical transmission of multiple OFDM signals.

    PubMed

    Effenberger, Frank; Liu, Xiang

    2015-05-18

    We propose a power-efficient method for transmitting multiple frequency-division multiplexed (FDM) orthogonal frequency-division multiplexing (OFDM) signals in intensity-modulation direct-detection (IM-DD) optical systems. This method is based on quadratic soft clipping in combination with odd-only channel mapping. We show, both analytically and experimentally, that the proposed approach is capable of improving the power efficiency by about 3 dB as compared to conventional FDM OFDM signals under practical bias conditions, making it a viable solution in applications such as optical fiber-wireless integrated systems where both IM-DD optical transmission and OFDM signaling are important. PMID:26074605

  14. Equipment for measuring of transmission of infrared optic materials in high temperature

    NASA Astrophysics Data System (ADS)

    Xu, Rongguo; Wang, Lei; Yin, Wanhong; Zhou, Xin

    2015-02-01

    An equipment for measuring transmission index of optic material in high temperature is introduced in the paper. A kyptol was used as infrared light source and narrow band filter was used to generate the monochrome light. Two parallel flat reflectors separated the light source into two ways, one was sample beam and the other was reference beam. A chopper was used to modulate the light and a lock-in amplifier was used to detect the infrared light. High precision temperature heater was used to control the temperature of sample material. The equipment has the ability to measure the transmission index of optic material from 1μm to 14μm and the temperature scope from room temperature to 700°. Measurement principle and makeup of the equipment are introduced in the paper. Transmissions of Al2O3 and germanium in high temperature were reported in the end.

  15. Influence of modulation formats on FWM noises in FDM optical fiber transmission systems

    NASA Astrophysics Data System (ADS)

    Ito, Yoshitaka; Onishi, Jun; Kojima, Shinya; Numai, Takahiro

    2008-09-01

    In long-haul frequency-division-multiplexing (FDM) lightwave transmission systems, transmission characteristics are degraded by four-wave mixing (FWM) in optical fibers. To overcome this problem in equally-spaced (ES) allocations, modified repeated unequally-spaced (RUS) allocations such as equally-spaced RUS (ERUS) and unequally-spaced RUS (URUS) allocations have been already examined. In this paper, we focus on the fact that FWM noises are closely related to modulation formats and frequency allocations. To reduce FWM noises in FDM optical fiber transmission systems, FWM noises are analyzed for ES, RUS, ERUS, and URUS with modulation formats such as non-return-to-zero (NRZ), random return-to-zero (RZ), differential phase-shift keying (DPSK), and bit-phase arranged RZ (BARZ). It is found that FWM noises are lowest in URUS with BARZ.

  16. Resonant optical transmission through a one-dimensional photonic crystal adjacent to a thin metal film

    NASA Astrophysics Data System (ADS)

    Yuan, Chang-Sheng; Tang, Han; He, Cheng; Chen, Xiao-Lin; Ni, Xu; Lu, Ming-Hui; Chen, Yan-Feng; Ming, Nai-Ben

    2011-05-01

    We theoretically and experimentally reveal that the large resonant optical transmission (ROT) can be realized through a one-dimensional photonic crystal adjacent to a thin metal film, at a frequency in the original band-gap of the photonic crystal (PC). The influence of periodic number of PC and the thickness of the adjacent metal on the transmission frequency and intensity is studied in detail. An optimum design is given to reach the maximum transmission efficiency, meanwhile a mechanism underlining the ROT phenomenon is proposed. An effective admittance-matching theory is proposed to understand this effect and quantitatively determine the operating frequency, which matches very well with the simulated and measured results. The effects might be very useful to realize some optical filters and sensor devices since the structure is easy for mass production and is matured technically to be prepared in industry.

  17. Coherent optical DFT-spread OFDM transmission using orthogonal band multiplexing.

    PubMed

    Yang, Qi; He, Zhixue; Yang, Zhu; Yu, Shaohua; Yi, Xingwen; Shieh, William

    2012-01-30

    Coherent optical OFDM (CO-OFDM) combined with orthogonal band multiplexing provides a scalable and flexible solution for achieving ultra high-speed rate. Among many CO-OFDM implementations, digital Fourier transform spread (DFT-S) CO-OFDM is proposed to mitigate fiber nonlinearity in long-haul transmission. In this paper, we first illustrate the principle of DFT-S OFDM. We then experimentally evaluate the performance of coherent optical DFT-S OFDM in a band-multiplexed transmission system. Compared with conventional clipping methods, DFT-S OFDM can reduce the OFDM peak-to-average power ratio (PAPR) value without suffering from the interference of the neighboring bands. With the benefit of much reduced PAPR, we successfully demonstrate 1.45 Tb/s DFT-S OFDM over 480 km SSMF transmission. PMID:22330476

  18. Analysis of the static magnetic field-dependent optical transmission of Ni nanorod colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Krämer, Florian; Gratz, Micha; Tschöpe, Andreas

    2016-07-01

    The magnetic field-dependent optical transmission of dilute Ni nanorod aqueous suspensions was investigated. A series of four samples of nanorods were synthesized using the AAO template method and processed to stable colloids. The distributions of their length and diameter were characterized by analysis of TEM images and revealed average diameters of ˜25 nm and different lengths in the range of 60 nm-1100 nm. The collinear magnetic and optical anisotropy was studied by static field-dependent transmission measurements of linearly polarized light parallel and perpendicular to the magnetic field direction. The experimental results were modelled assuming the field-dependent orientation distribution function of a superparamagnetic ensemble for the uniaxial ferromagnetic nanorods in liquid dispersion and extinction cross sections for longitudinal and transversal optical polarization derived from different approaches, including the electrostatic approximation and the separation of variables method, both applied to spheroidal particles, as well as finite element method simulations of spheroids and capped cylindrical particles. The extinction cross sections were compared to reveal the differences associated with the approximations of homogeneous polarization and/or particle shape. The consequences of these approximations for the quantitative analysis of magnetic field-dependent optical transmission measurements were investigated and a reliable protocol derived. Furthermore, the changes in optical cross sections induced by electromagnetic interaction between two nanorods in parallel end-to-end and side-by-side configuration as a function of their separation were studied.

  19. Radiation effects on the transmission of various optical glasses and epoxies

    NASA Technical Reports Server (NTRS)

    Shetter, M. T.; Abreu, V. J.

    1979-01-01

    A recent study for the Dynamics Explorer satellite project involved the determination of the effects of gamma radiation (at 1.33 and 1.17 MeV) on the transmission of several optical glasses and epoxies to be used in the construction of interference filters. The samples studied included a control sample of pure fused silica, a cerium-stabilized radiation-resistant glass (Schott BK-7G), two pieces of quartz cemented with EPO-TEK 305 optical epoxy, two pieces of quartz cemented with APCO 5313 epoxy, a sample of Schott OG-590 glass, and a sample of Corning Corion glass. The transmission of different optical components was measured as a function of wavelength for several radiation doses.

  20. Scrambled coherent superposition for enhanced optical fiber communication in the nonlinear transmission regime.

    PubMed

    Liu, Xiang; Chandrasekhar, S; Winzer, P J; Chraplyvy, A R; Tkach, R W; Zhu, B; Taunay, T F; Fishteyn, M; DiGiovanni, D J

    2012-08-13

    Coherent superposition of light waves has long been used in various fields of science, and recent advances in digital coherent detection and space-division multiplexing have enabled the coherent superposition of information-carrying optical signals to achieve better communication fidelity on amplified-spontaneous-noise limited communication links. However, fiber nonlinearity introduces highly correlated distortions on identical signals and diminishes the benefit of coherent superposition in nonlinear transmission regime. Here we experimentally demonstrate that through coordinated scrambling of signal constellations at the transmitter, together with appropriate unscrambling at the receiver, the full benefit of coherent superposition is retained in the nonlinear transmission regime of a space-diversity fiber link based on an innovatively engineered multi-core fiber. This scrambled coherent superposition may provide the flexibility of trading communication capacity for performance in future optical fiber networks, and may open new possibilities in high-performance and secure optical communications. PMID:23038549

  1. Signal processing algorithm for transmission-type Fabry-Pérot interferometric optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Lee, Jung-Ju; Kwon, Dong-Soo

    2001-08-01

    The recently developed transmission-type extrinsic Fabry-Pérot interferometric (TEFPI) optical fiber sensor can simply and effectively compensate for the difficult distinction of the measured direction of conventional EFPI optical fiber sensors. The TEFPI optical fiber sensor signal is composed of fringes and signal level variations, which correspond to the measured quantity and measured directions, respectively. In this paper, the signal processing algorithm, the fringe tracking method, is presented for TEFPI optical fiber sensors with a signal that differs from conventional interferometric sensors. The algorithm is verified by application to simulated and experimental sensor signals from strain measurements. The algorithm successfully processed TEFPI optical fiber sensor signals by finding the correct positions of peaks, valleys and signal levels, and by calculating the exact measured quantity and directions.

  2. Dependent and multiple scattering in transmission and backscattering optical coherence tomography.

    PubMed

    Nguyen, V Duc; Faber, D J; van der Pol, E; van Leeuwen, T G; Kalkman, J

    2013-12-01

    We use transmission and backscattering optical coherence tomography (OCT) to distinguish and quantify dependent and multiple scattering effects in turbid media. With transmission OCT the dependent scattering coefficients for a range of monodisperse silica particle suspensions are determined. An excellent agreement is observed between the measured dependent scattering coefficients and calculations based on Mie calculations, the Percus-Yevick radial distribution function, and coherent light scattering theory. Backscattering OCT measurements are fitted using the extended Huygens-Fresnel (EHF) model with the dependent scattering coefficients obtained from the transmission OCT measurements as input parameters. Good agreement between the EHF model and the backscattering OCT measurements is observed. For large particles, the rms scattering angle θrms obtained from the EHF fit is in fair agreement with θrms calculated from the transmission OCT data. PMID:24514466

  3. An Exploration of Professional Culture Differentials and Their Potential Impact on the Information Assurance Component of Optical Transmission Networks Design

    ERIC Educational Resources Information Center

    Cuthrell, Michael Gerard

    2011-01-01

    Optical transmission networks are an integral component of the critical infrastructures for many nations. Many people believe that optical transmission networks are impenetrable. In actuality, these networks possess weaknesses that can be exploited to bring about harm. An emerging Information Assurance (IA) industry has as its goals: to…

  4. Forward error correcting codes in fiber-optic synchronous code-division multiple access networks

    NASA Astrophysics Data System (ADS)

    Srivastava, Anand; Kar, Subrat; Jain, V. K.

    2002-02-01

    In optical code-division multiple access (OCDMA) networks, the performance is limited by optical multiple access interference (OMAI), amplified spontaneous emission (ASE) noise and receiver noise. To reduce OMAI and noise effects, use of forward error correcting (FEC) (18880, 18865) and (2370, 2358) Hamming codes are explored for STM-1 (155 Mbps) bit stream. The encoding is carried out at the multiplex-section layer. The check bits are embedded in the unused bytes of multiplex section overhead (MSOH). The expression for probability of error is derived taking into consideration OMAI, various sources of noise and effect of group velocity dispersion (GVD). It is observed that for a BER of 10 -9, use of FEC gives a coding gain of 1.4-2.1 dB depending upon the type of coding scheme used. It is also seen that there is a sensitivity improvement of about 3 dB if the source is suitably pre-chirped.

  5. Analysis of Optical CDMA Signal Transmission: Capacity Limits and Simulation Results

    NASA Astrophysics Data System (ADS)

    Garba, Aminata A.; Yim, Raymond M. H.; Bajcsy, Jan; Chen, Lawrence R.

    2005-12-01

    We present performance limits of the optical code-division multiple-access (OCDMA) networks. In particular, we evaluate the information-theoretical capacity of the OCDMA transmission when single-user detection (SUD) is used by the receiver. First, we model the OCDMA transmission as a discrete memoryless channel, evaluate its capacity when binary modulation is used in the interference-limited (noiseless) case, and extend this analysis to the case when additive white Gaussian noise (AWGN) is corrupting the received signals. Next, we analyze the benefits of using nonbinary signaling for increasing the throughput of optical CDMA transmission. It turns out that up to a fourfold increase in the network throughput can be achieved with practical numbers of modulation levels in comparison to the traditionally considered binary case. Finally, we present BER simulation results for channel coded binary and[InlineEquation not available: see fulltext.]-ary OCDMA transmission systems. In particular, we apply turbo codes concatenated with Reed-Solomon codes so that up to several hundred concurrent optical CDMA users can be supported at low target bit error rates. We observe that unlike conventional OCDMA systems, turbo-empowered OCDMA can allow overloading (more active users than is the length of the spreading sequences) with good bit error rate system performance.

  6. Temperature sensing in high voltage transmission lines using fiber Bragg grating and free-space-optics

    NASA Astrophysics Data System (ADS)

    Floridia, Claudio; Rosolem, Joao B.; Leonardi, Ariovaldo A.; Hortencio, Claudio A.; Fonseca, Romeu F.; Moreira, Rodrigo O. C.; Souza, Giovani C. L.; Melo, Altair L.; Nascimento, Carlos A. M.

    2013-05-01

    In this work we proposed the use of free-space-optics (FSO) to transmit and receive the optical signals from optical fiber placed in ground potential to the FBG fiber optics at high voltage potential, using a pair of optical collimators. The technique evaluation was performed in a prototype for the study of sensitivity to optical alignment and in an external environment using emulated sensing systems for both bus bar and overhead transmission line with real isolator chain. It has been shown that the FSO system allows collimators operate at distances of 500 mm to 2.000 mm. This range of distances is similar to the length of insulator's chain up to 230 kV. It was also shown that the proposed system can be used in real external environment for bus bar temperature monitoring in substations, where, even if the time out of the system is of 45%, with major interruption time of almost 15 hours, the majority of the interruption time was less than 18 minutes long. On the other hand, system has to be improved in order to be used in overhead transmission line. As tested for a real isolator chain the system shown a time out of 80.3%, with significant number of events of interruption acquisition time greater than 150 minutes. It is believed that for overhead power lines, system must be installed in rigid surge arresters or in a line post where it is expected to have similar results as in substation bus bars monitoring.

  7. Optical Frequency Upconversion Technique for Transmission of Wireless MIMO-Type Signals over Optical Fiber

    PubMed Central

    Shaddad, R. Q.; Mohammad, A. B.; Al-Gailani, S. A.; Al-Hetar, A. M.

    2014-01-01

    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength. PMID:24772009

  8. Advances in coherent optical modems and 16-QAM transmission with feedforward carrier recovery

    NASA Astrophysics Data System (ADS)

    Noé, Reinhold; Hoffmann, Sebastian; Wördehoff, Christian; Al-Bermani, Ali; El-Darawy, Mohamed

    2011-01-01

    Polarization multiplexing and quadrature phase shift keying (QPSK) both double spectral efficiency. Combined with synchronous coherent polarization diverse intradyne receivers this modulation format is ultra-robust and cost-efficient. A feedforward carrier recovery is required in order to tolerate phase noise of normal DFB lasers. Signal processing in the digital domain permits compensation of at least chromatic and polarization mode dispersion. Some companies have products on the market, others are working on them. For 100 GbE transmission, 50 GHz channel spacing is sufficient. 16ary quadrature amplitude modulation (16-QAM) is attractive to double capacity once more, possibly in a modulation format flexible transponder which is switched down to QPSK only if system margin is too low. For 16-QAM the phase noise problem is sharply increased. However, also here a feedforward carrier recovery has been implemented. A number of carrier phase angles is tested in parallel, and the recovered data is selected for that phase angle where squared distance of recovered data to the nearest constellation point, averaged over a number of symbols, is minimum. An intradyne/selfhomodyne synchronous coherent 16-QAM experiment (2.5 Gb/s, 81 km) is presented.

  9. Local surface plasmon mediated extraordinary optical transmission of multi-spatial-mode quantum noise reduction

    SciTech Connect

    Lawrie, Benjamin J; Evans, Philip G; Pooser, Raphael C

    2013-01-01

    We demonstrate the coherent transduction of quantum noise reduction, or squeezed light, by Ag localized surface plasmons (LSPs). Squeezed light, generated through four-wave-mixing in Rb vapor, is coupled to a Ag nanohole array designed to exhibit LSP mediated extraordinary-optical transmission (EOT) spectrally coincident with the squeezed light source at 795 nm. We demonstrate that quantum noise reduction as a function of transmission is found to match closely with linear attenuation models, thus demonstrating that the photon-LSP-photon transduction process is coherent near the LSP resonance.

  10. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Feist, Armin; Echternkamp, Katharina E.; Schauss, Jakob; Yalunin, Sergey V.; Schäfer, Sascha; Ropers, Claus

    2015-05-01

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven `quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers.

  11. Highly Stable Wideband Microwave Extraction by Synchronizing Widely Tunable Optoelectronic Oscillator with Optical Frequency Comb

    PubMed Central

    Hou, D.; Xie, X. P.; Zhang, Y. L.; Wu, J. T.; Chen, Z. Y.; Zhao, J. Y.

    2013-01-01

    Optical frequency combs (OFCs), based on mode-locked lasers (MLLs), have attracted considerable attention in many fields over recent years. Among the applications of OFCs, one of the most challenging works is the extraction of a highly stable microwave with low phase noise. Many synchronisation schemes have been exploited to synchronise an electronic oscillator with the pulse train from a MLL, helping to extract an ultra-stable microwave. Here, we demonstrate novel wideband microwave extraction from a stable OFC by synchronising a single widely tunable optoelectronic oscillator (OEO) with an OFC at different harmonic frequencies, using an optical phase detection technique. The tunable range of the proposed microwave extraction extends from 2 GHz to 4 GHz, and in a long-term synchronisation experiment over 12 hours, the proposed synchronisation scheme provided a rms timing drift of 18 fs and frequency instabilities at 1.2 × 10−15/1 s and 2.2 × 10−18/10000 s. PMID:24336459

  12. Electrically controlled infrared optical transmission and reflection through metallic grating using NEMS technology

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Kenzo; Fujii, Masamitsu

    2015-12-01

    The enhanced optical properties of metallic subwavelength gratings with very narrow slits have recently been extensively studied in the field of plasmonics. The optical transmission and reflection of such nanostructures, which act as nano-electro-mechanical systems (NEMS) actuators, can be electrically controlled by varying their geometrical parameters, giving them great flexibility for numerous applications in photonics, opto-electronics, and sensing. The previous challenges in controlling the optical properties were overcome by forming a metallic subwavelength grating with an NEMS actuator in mid-air, allowing the grating to be physically moved with the bias voltage. The device can shift the plasmon resonance wavelength with an electrical signal. The resonance wavelength for Wood's anomaly at the infrared region is predicted through simulations to shift by approximately 150 nm. We discuss the effect of polarization on the optical properties and grating mechanism. The reported effect may be used to achieve active spectral tuning and switching in a wide range of applications.

  13. Optical radio-photonic channel for transmission of a coherent narrowband analog signal

    NASA Astrophysics Data System (ADS)

    Zhuk, D. I.; Denisyuk, I. Yu.; Fokina, M. I.

    2015-10-01

    The channel of an optical transmission line of coherent narrowband analog signal consisting of a continuous-wave laser, an electro-optic modulator, and a vector phase rotator based on electrically controlled fiber-optical 1 × 2 splitter and fixed delay lines is analyzed. The scheme is constructed from commercially available components used in digital optical communication systems. The applicability of components for analog and small-signal circuits is determined. Variation of radio signal phase in the range from 0° to 170° for radio signal frequencies between 1 and 2 GHz is demonstrated experimentally. It is shown that phase variation is a linear function of frequency in this range.

  14. Optical parametric oscillators synchronously pumped by fundamental and second harmonic radiation of femtosecond Yb:KGW laser

    NASA Astrophysics Data System (ADS)

    StankevičiÅ«tÄ--, K.; PipinytÄ--, I.; Vengelis, J.; MarcinkevičiÅ«tÄ--, A.; Å uminas, R.; Grigonis, R.; Eckardt, R. C.; Sirutkaitis, V.

    2013-09-01

    We present experimental data obtained during investigation of synchronously pumped optical parametric oscillators (SPOPO's) pumped by fundamental (1030 nm) and second harmonic (515 nm) radiation of mode-locked Yb:KGW laser, providing 105 fs pulses at 76 MHz repetition rate with an average power of 4 W. Different nonlinear crystals such as beta barium borate (BBO), and periodically poled lithium niobate (PPLN) and MgO doped PPLN (MgO:PPLN) were tested to estimate wavelength tuning capabilities and SPOPO's efficiency. Rotation of BBO nonlinear crystal and SPOPO's cavity length variation and, in the case of SPOPO based on PPLN, change of grating period and cavity length allowed signal wavelength tuning in 630 - 1030 nm and 1350 - 1700 nm spectral ranges, respectively. Parametric light conversion from pump power to signal power efficiency was as high as 25 %. Including the idler pulses the tuning ranges were from 630 to 2400 nm and from 1350 to 4000 nm in case of BBO and PPLN crystals, respectively. SPOPO based on BBO wsithout intracavity group velocity dispersion (GVD) compensation generates longer than transform limited pulses, so SPOPO based on BBO with dispersive prisms were investigated.

  15. Transportable cavity-stabilized laser system for optical carrier frequency transmission experiments.

    PubMed

    Parker, B; Marra, G; Johnson, L A M; Margolis, H S; Webster, S A; Wright, L; Lea, S N; Gill, P; Bayvel, P

    2014-12-10

    We report the design and performance of a transportable laser system at 1543 nm, together with its application as the source for a demonstration of optical carrier frequency transmission over 118 km of an installed dark fiber network. The laser system is based around an optical reference cavity featuring an elastic mounting that bonds the cavity to its support, enabling the cavity to be transported without additional clamping. The cavity exhibits passive fractional frequency insensitivity to vibration along the optical axis of 2.0×10(-11)  m(-1) s(2). With active fiber noise cancellation, the optical carrier frequency transmission achieves a fractional frequency instability, measured at the user end, of 2.6×10(-16) at 1 s, averaging down to below 3×10(-18) after 20,000 s. The fractional frequency accuracy of the transfer is better than 3×10(-18). This level of performance is sufficient for comparison of state-of-the-art optical frequency standards and is achieved in an urban fiber environment. PMID:25608055

  16. 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. PMID:25638112

  17. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels

    NASA Astrophysics Data System (ADS)

    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. Complementary chiral metasurface with strong broadband optical activity and enhanced transmission

    SciTech Connect

    Jia, Yan-Peng; Zhang, Yong-Liang; Dong, Xian-Zi E-mail: xmduan@mail.ipc.ac.cn; Zheng, Mei-Ling; Li, Jing; Liu, Jie; Zhao, Zhen-Sheng; Duan, Xuan-Ming E-mail: xmduan@mail.ipc.ac.cn

    2014-01-06

    We present the design and realization of ultra-thin chiral metasurfaces with giant broadband optical activity in the infrared wavelength. The chiral metasurfaces consisting of periodic hole arrays of complementary asymmetric split ring resonators are fabricated by femtosecond laser two-photon polymerization. Enhanced transmission with strong polarization conversion up to 97% is observed owing to the chiral surface plasmons resulting from mirror symmetry broken. The dependence of optical activity on the degree of structural asymmetry is investigated. This simple planar metasurface is expected to be useful for designing ultra-thin active devices and tailoring the polarization behavior of complex metallic nanostructures.

  19. Optical transmission measurements for in-line monitoring of turbid oil-water emulsions

    NASA Astrophysics Data System (ADS)

    Metz, Philipp; Dopf, Katja; Aichholz, Markus; Riedel, Boris; Lemmer, Uli; Freudig, Barbara; Zimmermann, Clifton; Gerken, Martina

    2014-05-01

    For absorbing media the concentration may be calculated directly from the optical transmission following the logarithmic dependence given in the Lambert-Beer law. Due to multiple scattering events in oil-water emulsions (e.g. milk, cream, etc.), these exhibit a nonlinear relationship between the attenuation and the oil concentration. We demonstrate that for increasing oil content in oil-water emulsions the attenuation first increases, then levels out, and finally even decreases for a fat content of 60%. Single-wavelength optical transmission measurements are found to be well suited for the in-line monitoring of oil-water emulsions of fat contents below 20%, e.g., for the in-line fat content monitoring of milk. Using experiments and ray-tracing simulations we evaluate system optimization.

  20. Secure chaotic transmission of electrocardiography signals with acousto-optic modulation under profiled beam propagation.

    PubMed

    Almehmadi, Fares S; Chatterjee, Monish R

    2015-01-10

    Electrocardiography (ECG) signals are used for both medical purposes and identifying individuals. It is often necessary to encrypt this highly sensitive information before it is transmitted over any channel. A closed-loop acousto-optic hybrid device acting as a chaotic modulator is applied to ECG signals to achieve this encryption. Recently improved modeling of this approach using profiled optical beams has shown it to be very sensitive to key parameters that characterize the encryption and decryption process, exhibiting its potential for secure transmission of analog and digital signals. Here the encryption and decryption is demonstrated for ECG signals, both analog and digital versions, illustrating strong encryption without significant distortion. Performance analysis pertinent to both analog and digital transmission of the ECG waveform is also carried out using output signal-to-noise, signal-to-distortion, and bit-error-rate measures relative to the key parameters and presence of channel noise in the system. PMID:25967617

  1. Simulation and properties of highly nonlinear multilayer optical structures using the transmission line method

    NASA Astrophysics Data System (ADS)

    Moshonas, Nikolaos; Pagiatakis, Gerasimos K.; Papagiannis, Panagiotis; Savaidis, Stylianos P.; Stathopoulos, Nikolaos A.

    2014-05-01

    In this work we numerically investigate and analyse the properties of an optical structure comprised of successive thin film layers that can possess high values of nonlinear susceptibility, affecting the refractive index and/or the absorption coefficient. By applying the Transmission Line Method (TLM), properly modified to resolve the inclusion of third order nonlinearity, the spectral reflectivity and transmission of such a device are presented. Specifically, the method is applied for the case of conceptual design of a Distributed Bragg Reflector (DBR). Optical bistability can be observed, which translates not only to a change in the value of reflectivity, as the input power increases, but also to a shift of the Bragg wavelength.

  2. 3D Polymer Weld Seam Characterization Based on Optical Coherence Tomography for Laser Transmission Welding Applications

    NASA Astrophysics Data System (ADS)

    Schmitt, Robert; Mallmann, Guilherme; Devrient, Martin; Schmidt, Michael

    Laser transmission welding is an established single-stage plastic joining process, which enables hermetically sealed joints under the workpiece surface. The process requires joining partners with proper degrees of transmission and absorption to the processing wavelength. For reaching a stable process an in-process quality assurance is very valuable. Current monitoring systems have a limited usage, as no quantitative information of the weld itself is obtained without its destruction. In medical and pharmaceutical applications a weld with leakage is e.g. unacceptable. The main objective of this paper is the presentation of the optical coherence tomography as a tool for the quality assurance in laser transmission welding. This approach enables the measurement of any residual gap, weld geometry, internal pores and leaks. The presented results show that this technique allows even the characterization of welds using joining partners with thicknesses of 2 mm or with glass fiber reinforcement levels of 30% per weight.

  3. Optical diversity transmission using WDM signal and phase-conjugate lights through multi-core fiber.

    PubMed

    Koga, Masafumi; Moroi, Mitsuki; Takara, Hidehiko

    2016-05-01

    This paper proposes a maximum-ratio combining (MRC) scheme for a WDM signal and phase-conjugate pair (PCP) diversity transmission to cancel nonlinear phase-shift. A transfer function approximation for nonlinear phase-shift cancellation is formulated. It shows, with the help of a numerical calculation, that span-by-span chromatic dispersion compensation is more effective than the lumped equivalent at the receiver. This is confirmed in a 2-core diversity 5 channel WDM transmission experiment over 3-spans of 60km MCF with 25 Gbit/s-QPSK PCP. The peak Q-value was enhanced by 3.6dB through MRC, resulting in superior bitrate-distance product and optical power density limit, compared to twice the single core transmission. PMID:27137550

  4. [Analysis of LCD aging with polarized optical texture and transmission spectrum].

    PubMed

    Huang, Chong; Zhou, Xue-Ping; Liu, Ji; Ouyang, Yan-Dong

    2006-08-01

    Light radiation experiment was done to a group of liquid crystal display devices, and the influence of light radiation on the display quality of liquid crystal display devices was studied. The changes in their polarized textures after light radiation were observed with a polarized optical microscope. Parallel stripe texture and black holes, which lost extinction function, appeared in liquid crystal texture. With the increase of light radiation time, more and more black holes result, and the area of black holes gets bigger and bigger. The authors tested the transmission spectrum with computer-controlled ultraviolet/visible light spectrometer, finding that the transmission rate declines with the increase of light radiation time. The results show that the appearance of stripe texture and black holes resulted from the changes in liquid crystal molecular structure after ultraviolet radiation, and the occurrence of black holes, which lost extinction function, is the main reason for the continuous decline of transmission rate. PMID:17058936

  5. 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.

  6. Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation

    PubMed Central

    Chiu, Ming-Hung; Tan, Chen-Tai; Tsai, Ming-Hung; Yang, Ya-Hsin

    2015-01-01

    This full-field transmission-type three-dimensional (3D) optical microscope is constructed based on the angle deviation method (ADM) and the algorithm of reflectivity-height transformation (RHT). The surface height is proportional to the deviation angle of light passing through the object. The angle deviation and surface height can be measured based on the reflectivity closed to the critical angle using a parallelogram prism and two CCDs. PMID:26504645

  7. Development of Fault Point Locating System for Underground Transmission Lines using Optical Fiber Current Sensors

    NASA Astrophysics Data System (ADS)

    Kurosawa, Kiyoshi; Kondo, Reishi; Nasukawa, Shinsuke; Yamaguchi, Tatsushi; Amano, Kazuo

    Fault point locating systems based on surge current detection have recently been used for fast recovery of underground transmission line from the fault. Electromagnetic induction type sensors have mainly been used for detection of the surge current. However they are susceptible to electromagnetic noise which causes unstable system operation. To solve this problem, Tokyo Electric Power Co., Toko Electric Corporation and Fujikura Ltd., by a joint research, have developed a new system that applies optical fiber current sensors.

  8. Optical transmission through hexagonal arrays of subwavelength holes in thin metal films.

    PubMed

    Ctistis, G; Patoka, P; Wang, X; Kempa, K; Giersig, M

    2007-09-01

    We have studied the light transmission through hexagonal arrays of subwavelength holes in thin gold and aluminum films, varying the film thickness between 20 and 120 nm while the hole diameter as well as the interhole distance have been kept constant at approximately 300 and approximately 500 nm, respectively. The films were characterized by means of UV-vis spectroscopy and scanning near-field optical microscopy (SNOM). PMID:17715985

  9. Semiconductor optical amplifiers and Raman amplification for 1310-nm dense wavelength division multiplexed transmission

    NASA Astrophysics Data System (ADS)

    Mazurek, Paweł; Czyżak, Paweł; de Waardt, Huug; Turkiewicz, Jarosław Piotr

    2015-11-01

    We investigate the utilization of semiconductor optical amplifiers (SOAs) and quantum-dot laser-based Raman amplifiers in high-capacity dense wavelength division multiplexed (DWDM) 1310-nm transmission systems. Performed simulations showed that in a 10×40 Gbit/s system, the utilization of a single Raman amplifier in a back-propagation scheme can extend the maximum error-free (bit error rate <10-9) transmission distance by approximately 25 km in comparison with the same system utilizing only an SOA used as a preamplifier. We successfully applied a Raman amplifier in an 8×2×40 Gbit/s 1310-nm polarization multiplexed (PolMux) DWDM transmission over 25 km. Conducted experiments showed that the utilization of a Raman amplifier in this system leads to 4-dB improvement of the average channel sensitivity in comparison to the same system utilizing SOAs. This sensitivity improvement can be translated into a higher power budget. Moreover, lower input optical power in a system utilizing a Raman amplifier reduces the four-wave mixing interactions. The obtained results prove that Raman amplification can be successfully applied in 1310-nm high-capacity transmission systems, e.g., to extend the reach of 400G and 1T Ethernet systems.

  10. Focal ratio degradation and transmission in VIRUS-P optical fibers

    NASA Astrophysics Data System (ADS)

    Murphy, Jeremy D.; MacQueen, Phillip J.; Hill, Gary J.; Grupp, Frank; Kelz, Andreas; Palunas, Povilas; Roth, Martin; Fry, Alexander

    2008-07-01

    We have conducted extensive tests of both transmission and focal ratio degradation (FRD) on two integral field units currently in use on the VIRUS-P integral field spectrograph. VIRUS-P is a prototype for the VIRUS instrument proposed for the Hobby-Eberly Telescope at McDonald Observatory. All tests have been conducted at an input f-ratio of F/3.65 and with an 18% central obscuration in order to simulate optical conditions on the HET. Transmission measurements were conducted with narrow-band interference filters (FWHM: 10 nm) at 10 discrete wavelengths (337 to 600 nm), while FRD tests were made at 365 nm, 400 nm and 600 nm. The influence of wavelength, end immersion, fiber type and length on both FRD and transmission is explored. Most notably, we find no wavelength dependence on FRD down to 365 nm. All fibers tested are within the VIRUS instrument specifications for both FRD and transmission. We present the details of our differential FRD testing method and explain a simple and robust technique of aligning the test bench and optical fiber axes to within +/-0.1 degrees.

  11. An optical transmission spectrum (4000-10000 Å) of the super-Earth GJ 1214b

    NASA Astrophysics Data System (ADS)

    Rackham, Benjamin; Espinoza, Nestor; Apai, Daniel; Jordan, Andres; Lopez-Morales, Mercedes; Fraine, Jonathan; Lewis, Nikole; Rodler, Florian; Fortney, Jonathan; Osip, David

    2014-11-01

    One of the most surprising results of the Kepler mission has been the abundance of super-Earths (1.25-2 Earth-radii) and Neptune-sized planets (2-6 Earth-radii), including the close-in “hot” Neptunes. Given the degeneracies in mass-radius relationships, distinguishing between the diversity of worlds that may exist at this transition requires measurements of the transmission spectra of their atmospheres. The recently launched Arizona-CfA-Católica Exoplanet Spectroscopy Survey (ACCESS) is addressing this need by compiling a uniform sample of exoplanet optical transmission spectra from hot Jupiters through hot Neptunes to super-Earths, enabling comparative studies of exoplanets over a wide range of masses, radii, and irradiation conditions. Here we present our first results from a planet at the hot Neptune / super-Earth transition: an optical transmission spectrum of GJ 1214b obtained during three transits with Magellan/IMACS. We discuss the experimental techniques used to collect the spectrum, the statistical methods employed in the data analysis, and the application of the optical spectrum to proposed models of GJ 1214b’s atmosphere.

  12. Design and fabrication of transmission quarter phase retarder at wavelength 1064 nm, using optical nanometric thin films

    NASA Astrophysics Data System (ADS)

    Moradi, Zahra; Jahanshah, Fariborz; Fallah, Hamid Reza; Haji Mahmoodzade, Morteza; Sahraee, Masoume; Zabolian, Hosein

    2016-08-01

    We designed and fabricated the transmission quarter-wave plate phase retarder at 1064 nm using optical nanometric thin films of silicon oxide and titanium oxide. Final design consists of 32 layers. Transmissions of polarizations are equal and ≥99 % and their phase difference is 90°. System consists of two 16 layers systems that coated with the same condition on BK7 glass substrates then attached together with optical glue. Electron beam evaporation method was used for depositing materials. Photo spectrometer was used for measuring transmission spectrum of system. Transmission of polarizations was ≥95 % and equal. A polarimeter was used for testing systems. Polarization of beam was circular.

  13. Laser Injection Optics for High-Intensity Transmission in Multimode Fibers

    SciTech Connect

    SETCHELL,ROBERT E.

    2000-08-29

    An increasing number of applications are requiring fiber transmission of high-intensity laser pulses. The authors particular interests have led them to examine carefully the fiber transmission of Q-switched pulses from multimode Nd:YAG lasers at their fundamental wavelength. The maximum pulse energy that can be transmitted through a particular fiber is limited by the onset of laser-induced breakdown and damage mechanisms. Laser breakdown at the fiber entrance face is often the first limiting process to be encountered, but other mechanisms can result in catastrophic damage at either fiber face, within the initial entry segment of the fiber, and at other internal sites along the fiber path. In the course of their studies they have examined a number of factors that govern the relative importance of different mechanisms, including laser characteristics, the design and alignment of injection optics, fiber end-face preparation, and fiber routing. The present study emphasizes the important criteria for injection optics in high-intensity fiber transmission, and illustrates the opportunities that now exist for innovative designs of optics to meet these criteria. The consideration of diffractive optics to achieve desired injection criteria began in 1993, and they have evaluated a progression of designs since that time. In the present study, two recent designs for injection optics are compared by testing a sufficient number of fibers with each design to establish statistics for the onset of laser-induced breakdown and damage. In this testing they attempted to hold constant other factors that can influence damage statistics. Both designs performed well, although one was less successful in meeting all injection criteria and consequently showed a susceptibility to a particular damage process.

  14. Quantum mechanism of light transmission by the intermediate filaments in some specialized optically transparent cells.

    PubMed

    Makarov, Vladimir; Zueva, Lidia; Golubeva, Tatiana; Korneeva, Elena; Khmelinskii, Igor; Inyushin, Mikhail

    2017-01-01

    Some very transparent cells in the optical tract of vertebrates, such as the lens fiber cells, possess certain types of specialized intermediate filaments (IFs) that have essential significance for their transparency. The exact mechanism describing why the IFs are so important for transparency is unknown. Recently, transparency was described also in the retinal Müller cells (MCs). We report that the main processes of the MCs contain bundles of long specialized IFs, each about 10 nm in diameter; most likely, these filaments are the channels providing light transmission to the photoreceptor cells in mammalian and avian retinas. We interpret the transmission of light in such channels using the notions of quantum confinement, describing energy transport in structures with electroconductive walls and diameter much smaller than the wavelength of the respective photons. Model calculations produce photon transmission efficiency in such channels exceeding 0.8, in optimized geometry. We infer that protein molecules make up the channels, proposing a qualitative mechanism of light transmission by such structures. The developed model may be used to describe light transmission by the IFs in any transparent cells. PMID:27570792

  15. Seamless Transmission between Single-Mode Optical Fibers Using Free Space Optics System

    NASA Astrophysics Data System (ADS)

    Yoshida, Koichi; Tsujimura, Takeshi

    This paper presents a free space optics system installed between two single-mode optical fibers (SMFs). The result looks as if the two SMFs were seamlessly connected without the need for any photoelectric devices. Misalignments between the two SMFs caused by disturbances are actively compensated for by introducing a laser beam controller that incorporates an opto-mechatronic mechanism with four degrees of freedom. Experiments using a prototype are conducted to verify the effectiveness of the proposed FSO system for initial beam acquisition and beam tracking when there is a vibration disturbance.

  16. Investigations on optimizing the energy transmission of ultrafast optical pulses in pure water

    NASA Astrophysics Data System (ADS)

    Lukofsky, David

    Many of today's communication and imaging technologies share the common challenge of signal deterioration due to water's large absorption coefficient. As an example, it is water molecules that contaminate the fused silica of optical fibers and account for most of the absorption they exhibit at communication wavelengths. It is also water (in the form of vapor) that makes it challenging to devise practical THz spectroscopic systems. As such, this thesis examines how the transmission of electromagnetic radiation through water could be improved as a stepping stone towards bettering a wide array of communication and imaging applications. Recent time-domain approaches have noted the connection between pulse rise-time and precursor waveform absorption. This thesis represents the first in-depth analysis of precursors using an intuitive frequency-domain approach. It was shown with well-known physical metrics that precursors are a linear effect resulting from the temporal representation of a Beer's law of absorption for broadband pulses. Experimental validation was achieved with a spatial light modulator used in conjunction with Frequency-Resolved-Optical-Gating (FROG) to obtain the first measurement of the amplitude and phase of an optical precursor. The semi-classical two-level atom model was used to infer the transitional dipole moments of the 1447 nm and 2:94 mum vibrational resonances of the medium. These values supported finite-difference-time-domain simulations suggesting how 52 fs sech2 pulses of 220 GW/cm2 peak intensity could propagate with negligible attenuation over 15 absorption lengths when tuned to the 2:94 mum transition of water. Extensive use of 1550 nm lasers in communication systems and the presence of the second vibrational overtone resonance of water at 1447 nm were the motivation for transmission experiments completed at the Naval Research Laboratory (Washington, DC) at this transition. As much as a 500% increase in absolute transmission was observed

  17. Optical fiber sources and transmission controls for multi-Tb/s systems

    NASA Astrophysics Data System (ADS)

    Nowak, George Adelbert

    The accelerating demand for bandwidth capacity in backbone links of terrestrial communications systems is projected to exceed 1Tb/s by 2002. Lightwave carrier frequencies and fused-silica optical fibers provide the natural combination of high passband frequencies and low- loss medium to satisfy this evolving demand for bandwidth capacity. This thesis addresses three key technologies for enabling multi-Tb/s optical fiber communication systems. The first technology is a broadband source based on supercontinuum generation in optical fiber. Using a single modelocked laser with output pulsewidths of 0.5psec pulses, we generate in ~2m of dispersion-shifted fiber more that 200nm of spectral continuum in the vicinity of 1550nm that is flat to better than +/- 0.5 dB over more than 60nm. The short fiber length prevents degradation of timing jitter of the seed pulses and preserves coherence of the continuum by inhibiting environmental perturbations and mapping of random noise from the vicinity of the input pulse across the continuum. Through experiments and simulations, we find that the continuum characteristics result from 3rd order dispersion effects on higher-order soliton compression. We determine optimal fiber properties to provide desired continuum broadness and flatness for given input pulsewidth and energy conditions. The second technology is a novel delay-shifted nonlinear optical loop mirror (DS-NOLM) that performs a transmission control function by serving as an intensity filter and frequency compensator for <5psec soliton transmission systems. A theoretical and experimental study of the DS-NOLM as a transmission control element in a periodically amplified soliton transmission system is presented. We show that DS-NOLMs enable 4ps soliton transmission over 75km of standard dispersion fiber, with 25km spacing between amplifiers, by filtering the dispersive waves and compensating for Raman-induced soliton self-frequency shift. The third technology is all

  18. Novel approach for simultaneous wireless transmission and evaluation of optical sensors

    NASA Astrophysics Data System (ADS)

    Neumann, Niels; Schuster, Tobias; Plettemeier, Dirk

    2014-11-01

    Optical sensors can be used to measure various quantities such as pressure, strain, temperature, refractive index, pH value and biochemical reactions. The interrogation of the sensor can be performed spectrally or using a simple power measurement. However, the evaluation of the sensor signal and the subsequent radio transmission of the results is complicated and costly. A sophisticated system setup comprising a huge number of electrooptical components as well as a complete radio module is required. This is not only expensive and unreliable but also impractical within harsh environment, in limited space and in inaccessible areas. Radio-over-Fiber (RoF) technology implies signals modulated on an electrical carrier being transmitted over fiber by using optical carriers. Combining RoF techniques and optical sensors, a new class of measurement devices readable by a radio interfaces is introduced in this paper. These sensors use a modulated input signal generated by a RoF transmitter that { after being influenced by the optical sensor-is directly converted into a radio signal and transmitted. This approach enables remote read-outs of the sensor by means of wireless evaluation. Thus, costly, voluminous, power hungry and sensitive equipment in the vicinity of the measurement location is avoided. The equipment can be concentrated in a central location supporting existing radio transmission schemes (e.g. WiFi).

  19. Development of Laser Beam Transmission Strategies for Future Ground-to-Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Wilson, Keith E.; Kovalik, Joseph M.; Biswas, Abhijit; Roberts, William T.

    2007-01-01

    Optical communications is a key technology to meet the bandwidth expansion required in the global information grid. High bandwidth bi-directional links between sub-orbital platforms and ground and space terminals can provide a seamless interconnectivity for rapid return of critical data to analysts. The JPL Optical Communications Telescope Laboratory (OCTL) is located in Wrightwood California at an altitude of 2.2.km. This 200 sq-m facility houses a state-of- the-art 1-m telescope and is used to develop operational strategies for ground-to-space laser beam propagation that include safe beam transmission through navigable air space, adaptive optics correction and multi-beam scintillation mitigation, and line of sight optical attenuation monitoring. JPL has received authorization from international satellite owners to transmit laser beams to more than twenty retro-reflecting satellites. This paper presents recent progress in the development of these operational strategies tested by narrow laser beam transmissions from the OCTL to retro-reflecting satellites. We present experimental results and compare our measurements with predicted performance for a variety of atmospheric conditions.

  20. Secure Communications in High Speed Fiber Optical Networks Using Code Division Multiple Access (CDMA) Transmission

    SciTech Connect

    Han, I; Bond, S; Welty, R; Du, Y; Yoo, S; Reinhardt, C; Behymer, E; Sperry, V; Kobayashi, N

    2004-02-12

    This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple access (CDMA) is emerging as a bandwidth enhancing technique for fiber optic networks, (3) the realization that CDMA of sufficient complexity forms the basis for almost unbreakable one-time key transmissions, (4) our concepts for superior components for implementing CDMA, (5) our expertise in semiconductor device processing and (6) our Center for Nano and Microtechnology, which is where the majority of the experimental work was done. Here we present a novel device concept, which will push the limits of current technology, and will simultaneously solve system implementation issues by investigating new state-of-the-art fiber technologies. This will enable the development of secure communication systems for the transmission and reception of messages on deployed commercial fiber optic networks, through the CDMA phase encoding of broad bandwidth pulses. CDMA technology has been developed as a multiplexing technology, much like wavelength division multiplexing (WDM) or time division multiplexing (TDM), to increase the potential number of users on a given communication link. A novel application of the techniques created for CDMA is to generate secure communication through physical layer encoding. Physical layer encoding devices are developed which utilize semiconductor waveguides with fast carrier response times to phase encode spectral components of a secure signal. Current commercial technology, most commonly a spatial light modulator, allows phase codes to be changed at rates of only 10's of Hertz ({approx}25ms response). The use of fast (picosecond to nanosecond) carrier dynamics of semiconductors, as

  1. Temporal spying and concealing process in fibre-optic data transmission systems through polarization bypass

    PubMed Central

    Bony, P.Y.; Guasoni, M.; Morin, P.; Sugny, D.; Picozzi, A.; Jauslin, H.R.; Pitois, S.; Fatome, J.

    2014-01-01

    Recent research has been focused on the ability to manipulate a light beam in such a way to hide, namely to cloak, an event over a finite time or localization in space. The main idea is to create a hole or a gap in the spatial or time domain so as to allow for an object or data to be kept hidden for a while and then to be restored. By enlarging the field of applications of this concept to telecommunications, researchers have recently reported the possibility to hide transmitted data in an optical fibre. Here we report the first experimental demonstration of perpetual temporal spying and blinding process of optical data in fibre-optic transmission line based on polarization bypass. We successfully characterize the performance of our system by alternatively copying and then concealing 100% of a 10-Gb s−1 transmitted signal. PMID:25135759

  2. Transmission and division of total optical depth method: A universal calibration method for Sun photometric measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Gong, Wei; Ma, Yingying; Wang, Lunche; Chen, Zhongyong

    2016-03-01

    Sun photometric measurements, which provide accurate and timely information on atmospheric components such as aerosols, clouds, and gases are important to climate research. For regions with heavy and variable aerosol loading, the traditional Langley plot method cannot be applied for Sun photometric instrument calibration, as almost no suitable prolonged periods with stable atmosphere and low-aerosol loading occurs. An improved calibration method, namely, the transmission and division of total optical depth method, is proposed in this study. Atmospheric total optical depth variation information obtained via other methods is transmitted, and period groups with similar atmospheric extinction effects are selected for Langley regression. This method is validated through calibration of a multifilter rotating shadowband radiometer under heavy aerosol-loading conditions. The obtained aerosol optical depth (AOD) compares well with the interpolated AOD from a Cimel Sun-sky radiometer.

  3. Nonlinear optical transmission of an integrated optical bent coupler in semiconductor-doped glass

    NASA Astrophysics Data System (ADS)

    Guntau, Matthias; Possner, Torsten; Braeuer, Andreas H.; Dannberg, Peter

    1991-08-01

    A technology for monomode slab and strip waveguide fabrication in semiconductor-doped glasses (SDG) is presented. On this basis, directional couplers consisting of both parallel (DC) and bent (BC) couplers of strip waveguides were realized. The optically linear and nonlinear behavior of these devices is described.

  4. SOLITONS AND OPTICAL FIBERS: Multiwavelength pulse transmission in an optical fibre — amplifier system

    NASA Astrophysics Data System (ADS)

    Panoiu, N.-C.; Mel'nikov, I. V.; Mihalache, D.; Etrich, C.; Lederer, F.

    2002-11-01

    The structure and dynamics of solitary waves created in the interaction of multiwavelength pulses in a single-mode optical fibre with amplification, filtering, and amplitude modulation is analysed. It is shown that there is a critical wavelength separation between channels above which wavelength-division multiplexing with solitons is feasible and that this separation increases with the number of channels.

  5. Application of Shack-Hartmann wavefront sensing technology to transmissive optic metrology

    NASA Astrophysics Data System (ADS)

    Rammage, Ron R.; Neal, Daniel R.; Copland, Richard J.

    2002-11-01

    Human vision correction optics must be produced in quantity to be economical. At the same time every human eye is unique and requires a custom corrective solution. For this reason the vision industries need fast, versatile and accurate methodologies for characterizing optics for production and research. Current methods for measuring these optics generally yield a cubic spline taken from less than 10 points across the surface of the lens. As corrective optics have grown in complexity this has become inadequate. The Shack-Hartmann wavefront sensor is a device that measures phase and irradiance of light in a single snapshot using geometric properties of light. Advantages of the Shack-Hartmann sensor include small size, ruggedness, accuracy, and vibration insensitivity. This paper discusses a methodology for designing instruments based on Shack-Hartmann sensors. The method is then applied to the development of an instrument for accurate measurement of transmissive optics such as gradient bifocal spectacle lenses, progressive addition bifocal lenses, intrarocular devices, contact lenses, and human corneal tissue. In addition, this instrument may be configured to provide hundreds of points across the surface of the lens giving improved spatial resolution. Methods are explored for extending the dynamic range and accuracy to meet the expanding needs of the ophthalmic and optometric industries. Data is presented demonstrating the accuracy and repeatability of this technique for the target optics.

  6. Design of optical system for spectrometer involving a volume phase holographic transmission grating

    NASA Astrophysics Data System (ADS)

    Ren, Zhong; Liu, Guodong; Huang, Zhen

    2014-08-01

    At present, spectrometer has popularly being used into varieties of fields including environment, food, medical health monitoring and metal industry because it has the advantages of noninvasive, high efficient and convenient etc. The performance of the spectrometer is determined by its optical system. Normally, according to the apparatus and principle of splitting-light, optical system of spectrometer can be classified into several categories, for example, filter-typed, dispersion typed, Fourier transform typed and acousto-optic tunable typed. The grating typed optical system has been popularly used into the spectrometer due to the features of higher diffraction efficiency, resolution and dispersion rate etc. In the grating-typed optical system, although the traditional plane and concave grating have usually been used into some spectrometers, some disadvantages of them still limit their applications, such as, large aberration, worse spectral flatness and low deficiency, etc. In this paper, to overcome these disadvantages of the traditional plane and concave grating, a novel optical system for spectrometer (OSS) based on volume phase holographic transmission (VPHT) grating was designed. For this novel grating, its manufacture and theories were investigated, and its diffraction efficiency was firstly numerically simulated according to different parameters. In order to prove the feasibility of this designed OSS, the spectral calibration experiment was performed and the spectral resolution reached 2nm.

  7. Rate-adaptive modulation and coding for optical fiber transmission systems

    NASA Astrophysics Data System (ADS)

    Gho, Gwang-Hyun; Kahn, Joseph M.

    2011-01-01

    Rate-adaptive optical transmission techniques adjust information bit rate based on transmission distance and other factors affecting signal quality. These techniques enable increased bit rates over shorter links, while enabling transmission over longer links when regeneration is not available. They are likely to become more important with increasing network traffic and a continuing evolution toward optically switched mesh networks, which make signal quality more variable. We propose a rate-adaptive scheme using variable-rate forward error correction (FEC) codes and variable constellations with a fixed symbol rate, quantifying how achievable bit rates vary with distance. The scheme uses serially concatenated Reed-Solomon codes and an inner repetition code to vary the code rate, combined with singlecarrier polarization-multiplexed M-ary quadrature amplitude modulation (PM-M-QAM) with variable M and digital coherent detection. A rate adaptation algorithm uses the signal-to-noise ratio (SNR) or the FEC decoder input bit-error ratio (BER) estimated by a receiver to determine the FEC code rate and constellation size that maximizes the information bit rate while satisfying a target FEC decoder output BER and an SNR margin, yielding a peak rate of 200 Gbit/s in a nominal 50-GHz channel bandwidth. We simulate single-channel transmission through a long-haul fiber system incorporating numerous optical switches, evaluating the impact of fiber nonlinearity and bandwidth narrowing. With zero SNR margin, we achieve bit rates of 200/100/50 Gbit/s over distances of 650/2000/3000 km. Compared to an ideal coding scheme, the proposed scheme exhibits a performance gap ranging from about 6.4 dB at 650 km to 7.5 dB at 5000 km.

  8. Delivery of very high bandwidth with ATM switches and SONET. [Asynchronous Transfer Mode (ATM), Synchronous Optical NETwork (SONET)

    SciTech Connect

    Gossage, S.A.

    1992-10-01

    The choice of technologies for the delivery of very high bandwidth throughout a facility capable of ultimately achieving gigabits per second performance, is a crucial one for any high technology facility. The components of a high bandwidth delivery system include high performance sources and sinks in the form of central facilities (major mainframes, large file storage and specialized peripherals) and powerful, full bandwidth distributed local area networks (LANs). In order to deliver bandwidth among the sources and sinks, a ubiquitous inter-/intra-building cable plant consisting of single mode and multimode fiber as well as twisted pair copper is required. The selection of the glue'' to transport and interconnect the LANs with the central facility over the pervasive cable plant is the focus of this paper. A design philosophy for high performance communications systems is proposed. A description of the traditional problems that must be overcome to provide very high bandwidth beyond the narrow confines of a computer center is given. The advantages of ATM switching and SONET physical transport are explored in the structured design presentation. The applicability of Asynchronous Transfer Mode (ATM) switching (interconnection) and Synchronous Optical NETwork (SONET) (transport) for high bandwidth delivery is described using the environment and requirements of Sandia National Laboratories as a context to examine the suitability of those technologies. The synergy and utility of ATM and SONET in the campus network are explored. Other methods for distributing high data rates are compared and contrasted to ATM and SONET with respect to cable plant impact, reliability/availability, maintainability, and capacity. Sandia is implementing a standards based foundation utilizing a pervasive single mode fiber cable plant, SONET transport, and ATM switching to meet the goals of gigabit networking.

  9. Factorial Based Response Surface Modeling with Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon

    EPA Science Inventory

    We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...

  10. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope.

    PubMed

    Feist, Armin; Echternkamp, Katharina E; Schauss, Jakob; Yalunin, Sergey V; Schäfer, Sascha; Ropers, Claus

    2015-05-14

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven 'quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers. PMID:25971512

  11. Optical wireless transmission of 405 nm, 1.45 Gbit/s optical IM/DD-OFDM signals through a 4.8 m underwater channel.

    PubMed

    Nakamura, Kazuhiko; Mizukoshi, Izumi; Hanawa, Masanori

    2015-01-26

    In this paper, we experimentally demonstrate wireless transmission of optical intensity modulation/direct detection-orthogonal frequency division multiplexing (IM/DD-OFDM) signals in an underwater channel using a field programmable gate array based real-time transmitter. The real-time transmission of a 405 nm 1.45 Gbit/s optical OFDM signal through a 4.8 m underwater channel with an error vector magnitude of approximately 10% was successfully achieved. PMID:25835913

  12. Optical transmission and thermal heating effects due to irradiation of nonlinear optic and conductive polymers for space-based electro-optic applications

    NASA Astrophysics Data System (ADS)

    Grote, James G.; Taylor, Edward W.; Zetts, John S.; Winter, James E.; Sanchez, Anthony D.; Craig, Douglas M.; Hopkins, Frank K.

    2000-10-01

    A nonlinear optic polymer blend of disperse red 1 in poly methyl methacrylate, spin cast on an indium tin oxide coated borosilicate glass substrate and a conductive polymer blend of polyethylene dioxythiophene/poly styrene sulphonate (Baytron P) in poly vinyl alcohol, spin cast on an uncoated borosilicate glass substrate were irradiated by 63.3 MeV proton to a dose of 1 Mrad (Si) of proton particles. The pre and post irradiated optical transmission characteristics of these polymer films over a wavelength range of 400 - 2000 nm, as well as in-situ thermal heating generated by irradiation are presented.

  13. Layered ACO-OFDM for intensity-modulated direct-detection optical wireless transmission.

    PubMed

    Wang, Qi; Qian, Chen; Guo, Xuhan; Wang, Zhaocheng; Cunningham, David G; White, Ian H

    2015-05-01

    Layered asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) with high spectral efficiency is proposed in this paper for optical wireless transmission employing intensity modulation with direct detection. In contrast to the conventional ACO-OFDM, which only utilizes odd subcarriers for modulation, leading to an obvious spectral efficiency loss, in layered ACO-OFDM, the subcarriers are divided into different layers and modulated by different kinds of ACO-OFDM, which are combined for simultaneous transmission. In this way, more subcarriers are used for data transmission and the spectral efficiency is improved. An iterative receiver is also proposed for layered ACO-OFDM, where the negative clipping distortion of each layer is subtracted once it is detected so that the signals from different layers can be recovered. Theoretical analysis shows that the proposed scheme can improve the spectral efficiency by up to 2 times compared with conventional ACO-OFDM approaches with the same modulation order. Meanwhile, simulation results confirm a considerable signal-to-noise ratio gain over ACO-OFDM at the same spectral efficiency. PMID:25969323

  14. Characterization of devices, circuits, and high-temperature superconductor transmission lines by electro-optic testing

    NASA Technical Reports Server (NTRS)

    Whitaker, John F.

    1991-01-01

    The development of a capability for testing transmission lines, devices, and circuits using the optically-based technique of electro-optics sampling was the goal of this project. Electro-optic network analysis of a high-speed device was demonstrated. The project involved research on all of the facets necessary in order to realize this result, including the discovery of the optimum electronic pulse source, development of an adequate test fixture, improvement of the electro-optic probe tip, and identification of a device which responded at high frequency but did not oscillate in the test fixture. In addition, during the process of investigating patterned high-critical-temperature superconductors, several non-contacting techniques for the determination of the transport properties of high T(sub c) films were developed and implemented. These are a transient, optical pump-probe, time-resolved reflectivity experiment, an impulsive-stimulated Raman scattering experiment, and a terahertz-beam coherent-spectroscopy experiment. The latter technique has enabled us to measure both the complex refractive index of an MgO substrate used for high-T(sub c) films and the complex conductivity of a YBa2Cu3O(7-x) sample. This information was acquired across an extremely wide frequency range: from the microwave to the submillimeter-wave regime. The experiments on the YBCO were conducted without patterning of, or contact to, the thin film. Thus, the need for the more difficult transmission-line experiments was eliminated. Progress in all of these areas was made and is documented in a number of papers. These papers may be found in the section listing the abstracts of the publications that were issued during the course of the research.

  15. Potential of optical spectral transmission measurements for joint inflammation measurements in rheumatoid arthritis patients

    NASA Astrophysics Data System (ADS)

    Meier, A. J. Louise; Rensen, Wouter H. J.; de Bokx, Pieter K.; de Nijs, Ron N. J.

    2012-08-01

    Frequent monitoring of rheumatoid arthritis (RA) patients enables timely treatment adjustments and improved outcomes. Currently this is not feasible due to a shortage of rheumatologists. An optical spectral transmission device is presented for objective assessment of joint inflammation in RA patients, while improving diagnostic accuracy and clinical workflow. A cross-sectional, nonrandomized observational study was performed with this device. In the study, 77 proximal interphalangeal (PIP) joints in 67 patients have been analyzed. Inflammation of these PIP joints was also assessed by a rheumatologist with a score varying from 1 (not inflamed) to 5 (severely inflamed). Out of 77 measurements, 27 were performed in moderate to strongly inflamed PIP joints. Comparison between the clinical assessment and an optical measurement showed a correlation coefficient r=0.63, p<0.001, 95% CI [0.47, 0.75], and a ROC curve (AUC=0.88) that shows a relative good specificity and sensitivity. Optical spectral transmission measurements in a single joint correlate with clinical assessment of joint inflammation, and therefore might be useful in monitoring joint inflammation in RA patients.

  16. 500  Gb/s free-space optical transmission over strong atmospheric turbulence channels.

    PubMed

    Qu, Zhen; Djordjevic, Ivan B

    2016-07-15

    We experimentally demonstrate a high-spectral-efficiency, large-capacity, featured free-space-optical (FSO) transmission system by using low-density, parity-check (LDPC) coded quadrature phase shift keying (QPSK) combined with orbital angular momentum (OAM) multiplexing. The strong atmospheric turbulence channel is emulated by two spatial light modulators on which four randomly generated azimuthal phase patterns yielding the Andrews spectrum are recorded. The validity of such an approach is verified by reproducing the intensity distribution and irradiance correlation function (ICF) from the full-scale simulator. Excellent agreement of experimental, numerical, and analytical results is found. To reduce the phase distortion induced by the turbulence emulator, the inexpensive wavefront sensorless adaptive optics (AO) is used. To deal with remaining channel impairments, a large-girth LDPC code is used. To further improve the aggregate data rate, the OAM multiplexing is combined with WDM, and 500 Gb/s optical transmission over the strong atmospheric turbulence channels is demonstrated. PMID:27420516

  17. A ground-based optical transmission spectrum of WASP-6b

    SciTech Connect

    Jordán, Andrés; Espinoza, Néstor; Rabus, Markus; Eyheramendy, Susana; Sing, David K.; Désert, Jean-Michel; Bakos, Gáspár Á.; Fortney, Jonathan J.; López-Morales, Mercedes; Szentgyorgyi, Andrew; Maxted, Pierre F. L.; Triaud, Amaury H. M. J.

    2013-12-01

    We present a ground-based optical transmission spectrum of the inflated sub-Jupiter-mass planet WASP-6b. The spectrum was measured in 20 spectral channels from 480 nm to 860 nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the Inamori-Magellan Areal Camera and Spectrograph on the Baade Telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensates in the atmosphere of WASP-6b. WASP-6b therefore appears to be yet another massive exoplanet with evidence for a mostly featureless transmission spectrum, underscoring the importance that hazes and condensates can have in determining the transmission spectra of exoplanets.

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

    DOE PAGESBeta

    Donev, E. U.; Suh, J. Y.; Lopez, R.; Feldman, L. C.; Haglund, R. F.

    2008-01-01

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

  19. Bubble formation induced by nanosecond laser ablation in water and its diagnosis by optical transmission technique

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Akbari Jafarabadi, M.

    2014-09-01

    In this paper, bubble formation and ablation rate in laser ablation of a thin-film aluminum target are studied. The target was an aluminum thin-film coated on a quartz substrate and interacted by a nanosecond Nd:YAG laser beam in ambient air and distilled water. Measuring optical transmission of a He-Ne beam through the ablation region shows that the ablation rate in water is higher than that in ambient air. The results also show that an initial peak appears in the transmission signal which is an evidence for bubble formation in water. Analyzing the data is useful for monitoring the bubble formation in water and relatively estimating the ablation rate.

  20. Study on ameliorating the FEC coding techniques in current high-rate optical transmission systems

    NASA Astrophysics Data System (ADS)

    Yuan, Jianguo; Ye, Wenwei; Jiang, Ze; Mao, Youju; Wang, Wei

    2007-01-01

    In this paper, the three ameliorated new coding schemes of the Super-FEC (Forward Error Correction) concatenatedcodes (namely, the inner-outer concatenated-code, the parallel concatenated-code and the successive concatenated-code with interleaving) are proposed after the development trend of high-rate optical transmission systems and the defects of the FEC codes in the current optical transmission systems have been analyzed. The system simulation of the inner-outer concatenated-codes is implemented and the schemes of encoding/decoding the parallel concatenated-codes are proposed. Furthermore, the two successive concatenated-codes with interleaving of the RS(255,239)+RS(255,239) code and the RS(255,239)+RS(255,223) code are simulated, and the analyses for the simulation results show that the two successive concatenated-codes with interleaving, compared with the classic RS (255,239) code and other codes, are a superior code type with the advantages of the better correction error, moderate redundancy and easy realization. And their net coding gains (NCG) are respectively 1.5dB, 2.5dB more than that of the classic RS(255,239) code at the BER (Bit Error Rate) of 10 -12. At last, based on the ITU-T G.709, the frame format of the new concatenated-code on applying in high-rate optical transmission systems is proposed and designed, this lays a firm foundation in order to design its hardware in future and pioneers a direction in its physical application.

  1. Analysis of the eastern range multiplexed fiber optic IRIG B120 distribution system

    NASA Technical Reports Server (NTRS)

    Duncan, Michael J.; Martell, John S.; Wright, James L.

    1993-01-01

    A study was conducted to assess the effects of transmitting a precision clock synchronization signal over a commercial multiplexed fiber optic communication system. This study is an evaluation of the distortion and jitter introduced into the signal by this type of transmission system. An analysis comparing signal quality at the multiplexing and demultiplexing ends of the fiber optic communication system shows that the amplitude and phase distortion added to the clock synchronization signal by the transmission system is minimal.

  2. DSP-based optical modulation technique for long-haul transmission

    NASA Astrophysics Data System (ADS)

    Yoshida, T.; Sugihara, T.; Uto, K.

    2015-01-01

    Fiber nonlinearity and equalization-enhanced phase noise (EEPN) generate rapid perturbations and critically limit the system capacity and range of long-haul optical transmission. It is possible to cancel the rapid perturbations by introducing a particular correlation between multiple signals at the transmitter and analyzing the received signals using digital signal processing. In this paper, we review our proposed techniques to cancel rapid perturbations of polarization multiplexed signals due to fiber nonlinearity and EEPN. Numerical simulation of quaternary phase-shift keying based signals shows 1.2 dB and 0.5 dB improvement respectively from the proposed cancellation techniques for fiber nonlinearity and EEPN.

  3. Electro-optic system for online light transmission control of polymer-dispersed liquid crystal windows

    NASA Astrophysics Data System (ADS)

    Sanchez-Pena, Jose M.; Vazquez, Carmen; Perez, I.; Rodriguez, Inmaculada; Oton, Jose M.

    2002-07-01

    Polymer-dispersed liquid crystals (PDLCs) are formed by microdroplets of liquid crystal embedded in a flexible matrix and sandwiched between transparent electrodes. Large area units (several square meters) can be easily prepared. Opaque, transparent, and intermediate light transmission states can be achieved by applying appropriate electric fields. These features allow their use in active windows for illumination, greenhouse regulation, and privacy, both on buildings and vehicles. An electro-optic system based on a microcontrolled driver was implemented for on-line control of PDLC windows. The system may self-regulate daylight or may be used as remote control.

  4. Single-mode optical fiber for high-power, low-loss UV transmission.

    PubMed

    Colombe, Yves; Slichter, Daniel H; Wilson, Andrew C; Leibfried, Dietrich; Wineland, David J

    2014-08-11

    We report large-mode-area solid-core photonic crystal fibers made from fused silica that resist ultraviolet (UV) solarization even at relatively high optical powers. Using a process of hydrogen loading and UV irradiation of the fibers, we demonstrate stable single-mode transmission over hundreds of hours for fiber output powers of 10 mW at 280 nm and 125 mW at 313 nm (limited only by the available laser power). Fiber attenuation ranges from 0.9 dB/m to 0.13 dB/m at these wavelengths, and is unaffected by bending for radii above 50 mm. PMID:25321060

  5. Analytical expressions for the nonlinear interference in dispersion managed transmission coherent optical systems

    NASA Astrophysics Data System (ADS)

    Qiao, Yaojun; Li, Ming; Yang, Qiuhong; Xu, Yanfei; Ji, Yuefeng

    2015-01-01

    Closed-form expressions of nonlinear interference of dense wavelength-division-multiplexed (WDM) systems with dispersion managed transmission (DMT) are derived. We carry out a simulative validation by addressing an ample and significant set of the Nyquist-WDM systems based on polarization multiplexed quadrature phase-shift keying (PM-QPSK) subcarriers at a baud rate of 32 Gbaud per channel. Simulation results show the simple closed-form analytical expressions can provide an effective tool for the quick and accurate prediction of system performance in DMT coherent optical systems.

  6. Data transmission with twisted light through a free-space to fiber optical communication link

    NASA Astrophysics Data System (ADS)

    Brüning, Robert; Ndagano, Bienvenu; McLaren, Melanie; Schröter, Siegmund; Kobelke, Jens; Duparré, Michael; Forbes, Andrew

    2016-03-01

    Mode division multiplexing (MDM), where information is transmitted in the spatial modes of light, is mooted as a future technology with which to transmit large bits of information. However, one of the key issues in optical communication lies in connecting free-space to optical fiber networks, otherwise known as the ‘last mile’ problem. This is particularly problematic for MDM as the eigenmodes of free-space and fibers are in general not the same. Here we demonstrate a data transmission scheme across a free-space and fiber link using twisted light in the form of Laguerre-Gaussian (LG) azimuthal modes. As a proof-of-principle we design and implement a custom fiber where the supported LG modes can be grouped into five non-degenerate sets, and successfully transmit a gray-scale image across the composite link using one mode from each group, thereby ensuring minimal crosstalk.

  7. Contentionless transmission in buffer-less slotted optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Asghari, Masoud; Ghaffarpour Rahbar, Akbar

    2016-07-01

    Contention of optical packets in optical packet switched (OPS) networks is a major problem, and it is even more critical in buffer-less OPS networks. In this paper, an innovative contention avoidance technique is proposed which uses combination of special traffic shaping at ingress switches and special time slot reservation technique through the path of traffic flows in core network. This novel protocol is called contentionless transmission OPS (CLTOPS) suitable for buffer-less slotted OPS networks. Performance evaluations show that the CLTOPS can outperform the original slotted-OPS architecture in terms of packet loss rate (PLR) performance, with or without using wavelength conversion. It is shown that there is a trade-off between the amount of improvement in PLR and additional delay applied to the users' packets at the ingress switches buffers. However, appropriate parameters can be selected to make the additional delay tolerable for users' applications.

  8. Optical transmission and laser ablation of pathologically changed eye lens capsule

    NASA Astrophysics Data System (ADS)

    Gamidov, A. A.; Bolshunov, A. V.; Yuzhakov, A. V.; Shcherbakov, E. M.; Baum, O. I.; Sobol, E. N.

    2015-02-01

    Optical transmission and ablation mechanisms in the secondary cataract films under the impact of 1.06-mm laser radiation are studied. The comparison of incident and transmitted (paraxial) radiation power at different values of the power density is carried out for two types of the eye lens capsule tissue (hard and soft) possessing different optical and mechanical properties. It is found that the effective attenuation coefficient for soft films is almost five times as large as that for the hard ones. The obtained measurement data on the transparency variation in the process of laser action allow the temperature evaluation and the determination of dominant mechanism of laser ablation, as well as the development of recommendations, providing the prevention or reduction of possible side effects. The obtained results can be used to optimise the regimes of laser impact in the process of the opacified lens capsule removal.

  9. Effect of second order signal-noise interactions in nonlinearity compensated optical transmission systems.

    PubMed

    Al-Khateeb, Mohammad A Z; McCarthy, Mary; Sánchez, Christian; Ellis, Andrew

    2016-04-15

    In this Letter, we theoretically and numerically analyze the performance of coherent optical transmission systems that deploy inline or transceiver based nonlinearity compensation techniques. For systems where signal-signal nonlinear interactions are fully compensated, we find that beyond the performance peak the signal-to-noise ratio degradation has a slope of 3  dBSNR/dBPower suggesting a quartic rather than quadratic dependence on signal power. This is directly related to the fact that signals in a given span will interact not only with linear amplified spontaneous emission noise, but also with the nonlinear four-wave mixing products generated from signal-noise interaction in previous (hitherto) uncompensated spans. The performance of optical systems employing different nonlinearity compensation schemes were numerically simulated and compared against analytical predictions, showing a good agreement within a 0.4 dB margin of error. PMID:27082361

  10. LDEF (Prelaunch), S0109 : Fiber Optic Data Transmission Experiment, Tray C12

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The prelaunch photograph was taken in SAEF II at KSC prior to installation of the Fiber Optic Data Transmission Experiment (FODTE) on the LDEF. The FODTE occupies a six (6) inch deep LDEF peripheral tray and consist of an aluminum internal support structure, four aluminum mounting plates, an aluminum cover plate, ten fiber optic cable samples with connectors, aluminum brackets and non-magnet fasteners required to assemble the experiment. Four optical fiber cables (two black, one blue and one bright orange), each configured in the form of a planar, helix coil, are attached to the thermally isolated mounting plates with black anodized aluminum clips cushioned with silicone-rubber spacers. The four mounting plates are coated with a Catalac off-white thermal control paint and the exposed surface of the cover plate is painted with Chemglaze II A-276 white to meet thermal control requirements. Six additional coils of optical fiber cable samples, secured with nylon cable ties, are located in the bottom of the tray, four below the mounting plates and two below the cover plate. Each sample terminates in connectors mounted in brackets located in the tray bottom or on the backside of the thermally isolated mounting plates.

  11. High speed optical wireless data transmission system for particle sensors in high energy physics

    NASA Astrophysics Data System (ADS)

    Ali, W.; Corsini, R.; Ciaramella, E.; Dell'Orso, R.; Messineo, A.; Palla, F.

    2015-08-01

    High speed optical fiber or copper wire communication systems are frequently deployed for readout data links used in particle physics detectors. Future detector upgrades will need more bandwidth for data transfer, but routing requirements for new cables or optical fiber will be challenging due to space limitations. Optical wireless communication (OWC) can provide high bandwidth connectivity with an advantage of reduced material budget and complexity of cable installation and management. In a collaborative effort, Scuola Superiore Sant'Anna and INFN Pisa are pursuing the development of a free-space optical link that could be installed in a future particle physics detector or upgrade. We describe initial studies of an OWC link using the inner tracker of the Compact Muon Solenoid (CMS) detector as a reference architecture. The results of two experiments are described: the first to verify that the laser source transmission wavelength of 1550 nm will not introduce fake signals in silicon strip sensors while the second was to study the source beam diameter and its tolerance to misalignment. For data rates of 2.5 Gb/s and 10 Gb/s over a 10 cm working distance it was observed that a tolerance limit of ±0.25 mm to ±0.8 mm can be obtained for misaligned systems with source beam diameters of 0.38 mm to 3.5 mm, respectively.

  12. Transmission polarized optical microscopy of short-pitch cholesteric liquid crystal shells

    NASA Astrophysics Data System (ADS)

    Geng, Yong; Noh, JungHyun; Lagerwall, Jan P. F.

    2016-03-01

    We recently demonstrated that colloidal crystal arrangements of monodisperse droplets or shells of planar-aligned cholesteric liquid crystal exhibit intricate patterns of circularly polarized reflection spots of different colors. The spots appear as a result of photonic cross communication between droplets, hence the patterns reflect the macroscopic arrangement of droplets or shells. Apart from being an interesting optical phenomenon, it offers attractive application opportunities in photonics and beyond, due to the unique characteristics of the patterns. It turns out that the optical quality of shells is much enhanced compared to that of droplets, hence we focus our attention primarily on shells, of varying thickness. Here we analyze and explain the intriguing textures arising when studying planar-aligned short-pitch cholesteric shells in transmission polarizing optical microscopy. In this case, the texture reflects the properties of each individual shell, without any sign of cross communication, yet also this pattern holds some fascinating mysteries. These can only be elucidated by considering all the peculiar optical properties of cholesterics together, as well as the unusual situation given by the spherical shell geometry.

  13. Further Constraints on the Optical Transmission Spectrum of HAT-P-1b

    NASA Astrophysics Data System (ADS)

    Montalto, M.; Iro, N.; Santos, N. C.; Desidera, S.; Martins, J. H. C.; Figueira, P.; Alonso, R.

    2015-09-01

    We report on novel observations of HAT-P-1 aimed at constraining the optical transmission spectrum of the atmosphere of its transiting hot-Jupiter exoplanet. Ground-based differential spectrophotometry was performed over two transit windows using the DOLORES spectrograph at the Telescopio Nazionale Galileo. Our measurements imply an average planet to star radius ratio equal to Rp/R* = (0.1159 ± 0.0005). This result is consistent with the value obtained from recent near-infrared measurements of this object, but differs from previously reported optical measurements, being lower by around 4.4 exoplanet scale heights. Analyzing the data over five different spectral bins of ∼600 Å wide, we observed a single peaked spectrum (3.7 σ level) with a blue cutoff corresponding to the blue edge of the broad absorption wing of sodium and an increased absorption in the region in-between 6180 and 7400 Å. We also infer that the width of the broad absorption wings due to alkali metals is likely narrower than the one implied by solar abundance clear atmospheric models. We interpret the result as evidence that HAT-P-1b has a partially clear atmosphere at optical wavelengths with a more modest contribution from an optical absorber than previously reported.

  14. Capacity estimates for optical transmission based on the nonlinear Fourier transform.

    PubMed

    Derevyanko, Stanislav A; Prilepsky, Jaroslaw E; Turitsyn, Sergei K

    2016-01-01

    What is the maximum rate at which information can be transmitted error-free in fibre-optic communication systems? For linear channels, this was established in classic works of Nyquist and Shannon. However, despite the immense practical importance of fibre-optic communications providing for >99% of global data traffic, the channel capacity of optical links remains unknown due to the complexity introduced by fibre nonlinearity. Recently, there has been a flurry of studies examining an expected cap that nonlinearity puts on the information-carrying capacity of fibre-optic systems. Mastering the nonlinear channels requires paradigm shift from current modulation, coding and transmission techniques originally developed for linear communication systems. Here we demonstrate that using the integrability of the master model and the nonlinear Fourier transform, the lower bound on the capacity per symbol can be estimated as 10.7 bits per symbol with 500 GHz bandwidth over 2,000 km. PMID:27611059

  15. Stability of glass versus plastics for transmissive high-power LED optics

    NASA Astrophysics Data System (ADS)

    Paßlick, C.; Hellwig, A.; Geyer, U.; Heßling, T.; Hübner, M. C.

    2014-09-01

    In the past, the major part of transmissive LED optics was made from injection molded polymers like PMMA or PC. Recent LED developments now show constantly increasing levels of luminous flux and energy densities, which restrict the usability of such polymer optics due to their limitations in thermal stability. Thermal simulations have shown that light guiding/mixing structures (rods) made from polymer materials can easily reach temperatures above their melting point due to the absorption characteristics. However, there is a great demand for such light rods from the automotive and entertainment industry and thus glass is becoming increasingly important as an optical material. Glass has typical transformation temperatures of hundreds of degrees Celsius and therefore withstands the conditions seen with LED without any problems. Square-shaped glass light guides show temperature advantages over round light rods, which are known for being able to produce caustics inside the material causing absorption and temperature hot spots, respectively. This paper presents some comparative thermal simulations by means of the Finite Element Method for a light conductor as an example and gives corresponding assistance for an appropriate material and light guide shape selection for highpower LED optics.

  16. Determination of Load Angle for Salient-pole Synchronous Machine

    NASA Astrophysics Data System (ADS)

    Sumina, D.; Šala, A.; Malarić, R.

    2010-01-01

    This paper presents two methods for load angle determination for salient-pole synchronous generator. The first method uses optical encoder to detect the rotor position. In some cases the end of the rotor shaft is not free to be used and mounting of an encoder is impossible. Therefore, the second method proposes estimation of the load angle based on the measured electrical values that have been already used in excitation control system of the synchronous generator. Estimation method uses corresponding voltage-current vector diagram and parameters of the synchronous generator, transformer and transmission lines. Both methods were experimentally verified on the digital control system and synchronous generator connected to power system. The estimation and measured results were compared. The accuracy of load angle estimation method depends on voltage and current measurement accuracy as well as generator, transformer and transmission line parameter accuracy. The estimation method gives satisfactory accuracy for load angles less than 120° el. Thus, it can be applied in excitation control system to provide stable work of synchronous generator in under-excitation operating area.

  17. High-sweeping-speed optically synchronized dual-channel terahertz-signal generator for driving a superconducting tunneling mixer and its application to active gas sensing.

    PubMed

    Oh, Kyoung-Hwan; Shimizu, Naofumi; Kohjiro, Satoshi; Kikuchi, Ken'ichi; Wakatsuki, Atsushi; Kukutsu, Naoya; Kado, Yuichi

    2009-10-12

    We propose a high-sweeping-speed optically synchronized dual-channel terahertz (THz) signal generator for an active gas-sensing system with a superconductor-insulator-superconductor (SIS) mixer. The generator can sweep a frequency range from 200 to 500 GHz at a speed of 375 GHz/s and a frequency resolution of 500 MHz. With the developed gas-sensing system, a gas-absorption-line measurement was successfully carried out with N(2)O gas in that frequency range. PMID:20372575

  18. 250-MHz synchronously pumped optical parametric oscillator at 2.25-2.6 μm and 4.1-4.9 μm.

    PubMed

    Coluccelli, Nicola; Fonnum, Helge; Haakestad, Magnus; Gambetta, Alessio; Gatti, Davide; Marangoni, Marco; Laporta, Paolo; Galzerano, Gianluca

    2012-09-24

    A compact and versatile femtosecond mid-IR source is presented, based on an optical parametric oscillator (OPO) synchronously pumped by a commercial 250-MHz Er:fiber laser. The mid-IR spectrum can be tuned in the range 2.25-2.6 μm (signal) and 4.1-4.9 μm (idler), with average power from 20 to 60 mW. At 2.5 μm a minimum pulse duration of 110 fs and a power of 40 mW have been obtained. Active stabilization of the OPO cavity length has been achieved in the whole tuning range. PMID:23037354

  19. Improvement in the synchronization between the radio frequency signal and the image detector in an acousto-optic tunable filter imaging spectrometer.

    PubMed

    Zhao, Huijie; Li, Chongchong; Zhang, Ying; Xu, Zefu

    2014-04-10

    An improved synchronization between the radio frequency (RF) signal and the image detector in an acousto-optic tunable filter (AOTF) imaging spectrometer is proposed to optimize power consumption and eliminate image smear. The RF signal is controlled on and off alternately to match the exposure of the image sensor. This scheme reduces the RF power and rejects the light illumination on the image sensor in the interval of charge transfer. An experiment using a visible AOTF, a frame transfer charge-coupled device camera, and an incandescent lamp is conducted for demonstration. The average RF power decreases 7.6%, and the image smear is eliminated. PMID:24787400

  20. Coherent light transmission properties of commercial photonic crystal hollow core optical fiber.

    PubMed

    Cranch, G A; Miller, G A

    2015-11-01

    Photonic crystal hollow core fiber (PC-HCF) has enabled many exciting new applications in nonlinear optics and spectroscopy. However, to date there has been less impact in coherent applications where preservation of optical phase over long fiber lengths is crucial. This paper presents characteristics of three commercially available PC-HCFs relevant to coherent applications including higher-order mode analysis, birefringence and polarization-dependent loss, and their impact on coherent light transmission in PC-HCF. Multipath interference due to higher-order mode propagation and Fresnel reflection is shown to generate excess intensity noise in transmission, which can be suppressed by up to 20 dB through high frequency phase modulation of the source laser. To demonstrate the potential of PC-HCF in high performance sensing, a Mach-Zehnder interferometer (MZI) incorporating 10 m of PC-HCF in each arm is characterized and demonstrates a phase resolution (59×10(-9)  rad/Hz(1/2) at 30 kHz) close to the shot noise limit, which is better than can be achieved in a MZI made with the same length of single mode solid core fiber because of the limit set by fundamental thermodynamic noise (74×10(-9)  rad/Hz(1/2) at 30 kHz). PMID:26560626

  1. Design of an ultrashort optical transmission cell for vacuum ultraviolet spectroscopy of supercritical fluids.

    PubMed

    Janik, Ireneusz; Marin, Timothy W

    2015-01-01

    We present the design and characteristics of an ultrathin flow cell optimized for vacuum ultraviolet transmission spectroscopy experiments on supercritical fluids. The cell operates satisfactorily at pressures up to 300 bar and temperatures up to 390 °C. The variable path length concept of the cell allows for optical transmission studies of analytes ranging from dense condensed-phase systems to gas-phase systems. The path length of the cell can be adjusted from hundreds of nanometers to hundreds of micrometers by an exchange of a variable thickness spacer sandwiched between two sapphire windows. In the path length range from nanometers to single micrometers, metal vapor deposited on one or both of the two sandwiched optical windows constitute the spacer. Spacers with thicknesses of 2 μm and greater can be constructed from simple commercially available metal foils. The cell has been used to measure the lowest-lying absorption band of water in both the vapor and condensed phases from room temperature up to and above the critical point. It has also found application in the studies of aqueous ions and nonaqueous liquids including various common organic solvents and carbon dioxide. PMID:25638117

  2. Green Distributed Quality of Transmission Aware Routing and Wavelength Assignment in All-Optical Networks

    NASA Astrophysics Data System (ADS)

    Kakekhani, Amir; Rahbar, Akbar Ghaffarpour

    2013-06-01

    The Routing and Wavelength Assignment (RWA) algorithms that consider quality of transmission (QoT) in light-path setup spend more time than their conventional counterparts due to exhaustive search and QoT estimation. This paper proposes distributed Quality of Transmission Aware Routing and Wavelength Assignment (QARWA) algorithm to handle dynamic light-path provisioning in wavelength routed all-optical networks taking energy consumption of optical switch nodes into account. Specifically, the QARWA considers bit-error rate (BER), setup delay, and energy consumption constraints at the same time, and establishes light-paths with small BER, low setup latency, and reduced energy consumption. We present and evaluate an enhanced wavelength-assignment solution in the QARWA to handle the wavelength continuity constraint. In QARWA, a source node determines the connection path by means of the shortest path algorithm and a destination node selects a wavelength based on the BER limitation and decreasing order of setup latency. Relating energy consumption to processing time, we show that QARWA can decrease the total energy consumption by reducing the processing time at each node. Under QARWA, when a node finishes the processing of the last control packet, it makes transition to either sleep state or idle state. Hence, QARWA can provide the best performance since it can reduce processing time in control units, light-path setup latency, and energy consumption of nodes.

  3. Fabrication and optical transmission characteristics of polymers woodpile photonic crystal structures with different crystal planes

    NASA Astrophysics Data System (ADS)

    Chen, Ling-Jing; Dong, Xian-Zi; Zhao, Yuan-Yuan; Zhang, Yong-Liang; Liu, Jie; Zheng, Mei-Ling; Duan, Xuan-Ming; Zhao, Zhen-Sheng

    2015-10-01

    The photonic band gap effect which originates from the translational invariance of the periodic lattice of dielectrics has been widely applied in the technical applications of microwave, telecommunication and visible wavelengths. Among the various examples, polymers based three dimensional (3D) photonic crystals (PhCs) have attracted considerable interest because they can be easily fabricated by femo-second (fs) ultrafast laser direct writing (DLW) method. However, it is difficult to realize complete band gap in polymers PhCs due to the low index contrast between polymers and air. Here, we report the design and experimental realization of light's nonreciprocal propagation in woodpile PhCs fabricated with DLW method. Firstly, we fabricated several polymers woodpile PhCs on glass substrate with different crystal planes. The Fourier transform infrared spectroscopy (FTIR) measurements are in agreement with the theoretical predictions, which proves the validity and the accuracy of our DLW method. Further measurements of the transmission spectra with respect to the incident angle reveal that the surface crystal planes and incident wave vectors play important roles in the optical response. Furthermore, we designed and fabricated a 30° PhC wedge. And we find nonreciprocal transmission effect between the forward and backward waves, resulting from the nonsymmetrical refraction of the light in different planes. Our results may find potential applications in future 3D photonic integrated circuits and pave the way for the fabrication of other photonic and optical devices with DLW method.

  4. Achievable information rates calculation for optical OFDM few-mode fiber long-haul transmission systems.

    PubMed

    Lin, Changyu; Djordjevic, Ivan B; Zou, Ding

    2015-06-29

    We propose a method to estimate the lower bound of achievable information rates (AIRs) of high speed orthogonal frequency-division multiplexing (OFDM) in spatial division multiplexing (SDM) optical long-haul transmission systems. The estimation of AIR is based on the forward recursion of multidimensional super-symbol efficient sliding-window Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm. We consider most of the degradations of fiber links including nonlinear effects in few-mode fiber (FMF). This method does not consider the SDM as a simple multiplexer of independent data streams, but provides a super-symbol version for AIR calculation over spatial channels. This super-symbol version of AIR calculation algorithm, in principle, can be used for arbitrary multiple-input-multiple-output (MIMO)-SDM system with channel memory consideration. We illustrate this method by performing Monte Carlo simulations in a complete FMF model. Both channel model and algorithm for calculation of the AIRs are described in details. We also compare the AIRs results for QPSK/16QAM in both single mode fiber (SMF)- and FMF-based optical OFDM transmission. PMID:26191696

  5. Relationship between the effective cloud optical depth and different atmospheric transmission factors

    NASA Astrophysics Data System (ADS)

    Serrano, D.; Marín, M. J.; Núñez, M.; Gandía, S.; Utrillas, M. P.; Martínez-Lozano, J. A.

    2015-06-01

    This study examines the sensitivity of cloud optical depth (COD) for overcast conditions to radiation transmission using data collected in Valencia, Spain. These relationships are provided as simple empirical functions, therefore avoiding the need to apply complex model minimisation schemes to obtain COD. Comparisons are presented between COD obtained by a minimization method and several radiation transmission factors comprising a clearness index (kt), a modified version (kt'), a cloud modification factor (CMF) and its modified version (CMF'). Additionally, a statistical model of COD proposed by J.C. Barnard and C.N. Long (2004) is tested with our data. Statistical relationships between COD and these variables were developed for measurements in the ultraviolet Erythema Radiation (UVER) range as well as for broadband measurements covering the full solar spectrum. Measurements collected in 2011 were used to develop power and exponential relationships relating COD to the above transmission factors, and subsequently tested with independent data collected in 2012. In general, expressions relating COD to CMF perform better and exhibit a higher correlation than equivalent expressions relating COD to clearness indices, especially in the UVER range. The expression of Barnard and Long is potentially adequate for the estimation of COD for both UVER and broadband solar radiation in Valencia, but the regression coefficients need tuning for local conditions.

  6. Study on coarse wavelength division multiplexing using polymer optical fiber transmission window

    NASA Astrophysics Data System (ADS)

    Zhang, Yongsheng; Ma, Hui; Zhang, Tao; Wang, Zhuo; Wang, Dong; Zheng, Rongsheng; Yang, Haipeng; Ming, Hai

    2005-01-01

    Inexpensive PMMA based Polymer Optical Fiber (POF) has the feature of a large core diameter, high numerical aperture and great flexibility, thus allow low connection cost and cheap LED source. These advantages make it a promising candidate for short distance communication. In this article, coarse wavelength division multiplexing (CWDM) test was performed with commercially available POF using its low loss transmission window. Light of two different wavelengths (650nm and 530nm) were sending on a single POF. Here 650nm red light was used for duplex IP data digital signal transmission and 530nm green light was used for voice signal transmission. Light sources are LEDs. A POF Coupler (Splitter) of 1:1 ratio was employed as multiplexer and prisms were used for demultiplexing. The channel isolation and insert loss of both channels were measured, for 650nm channel they are 20.5dB and 17.65dB, for 530nm channel they are 19.16dB and 20.55dB.

  7. Safety analysis and realization of safe information transmission optical LAN on high-speed railway

    NASA Astrophysics Data System (ADS)

    Tao, Ying; Wu, Chongqing; Li, Zuoyi

    2001-10-01

    High-speed railway that has been progressing very quickly is one of the greatest techniques in present time because of its high speed, economy, comfort, environment benefits and other advantages. And among all of these, safe is the backbone and lifeline, so the chief task in developing high-speed railway is to establish safety guarantee system. Also in this safety guarantee system, train control is one of the key techniques to guarantee safe train operation and to advance ability of transportation, so operation safe is located in the hardcore position. That is to say, it is imperative to set up a safe, real-time and reliable automatic train control system. And we can easily find out that this kind of system is now developed and applied in many countries. Important information related to train control, such as the received and transmitted information of track-sided equipment, is called safe information, because it deals with train operation's safe, reliability, and even directly with people's life and wealth. It is so important that if there were some kind of fault with its making, transmission, or processing, fatal accident would occur. So to some degree, it is impossible to transmit and process this information through present railway communication network because of the former's extreme importance and the latter's no safe capability. Therefore, a specific communication network that mainly considers about safe transmission and management should be established in order to realize the specific function for this specific information. High-speed railway safe information transmission optical LAN, which adopts optical fiber as transmission media and transmits safe information, is a kind of LAN designed for the request for safe, real-time and highly reliable automatic train control system in the process of our country's high-speed railway construction and commonly train speed. In this paper, after analyzing the characteristics of automatic train control system and the

  8. Unveiling nanometric plasmons optical properties with advanced electron spectroscopy in the Scanning Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Kociak, Mathieu

    Since the pioneering work of Yamamoto, the use of electron spectroscopy such as Cathodoluminescence (CL) and Electron Energy Loss Spectroscopy (EELS) in a Scanning (Transmission) Electron Microscope (STEM) has considerably helped improving our understanding of the optical properties of metallic nanoparticles. The resemblance of spectroscopic signals from electron and pure optical techniques leads to the intuition that both types of techniques are very close, an idea theoretically discussed by F.J. Garcia de Abajo and coworkers. However, it is also quite intuitive that CL and EELS should be different. For example, EELS helps detecting any sort of modes while CL can only detect radiative ones. On the other hand, even between optical spectroscopy techniques, clear differences such as energy shifts or spectral shapes changes are expected in the case of plasmons. The lack of adapted instrumentation capable of performing combined EELS and CL, as well as theoretical developments allowing to account for the generic difference between EELS and CL and their optical counterparts impeached a comprehensive understanding of plasmons physics with the otherwise amazing electron spectroscopies. In this talk, I will present recent experimental results showing combined EELS and CL spectral mapping of plasmonic properties for nanoparticles with several shapes (triangles, cubes, stars...) and composition (gold, silver, aluminum...). Helped with different theoretical tools, I will try to show how these results can be related to their optical counterparts (extinction, scattering), and what type of physical insights can be gained from these combined measurements. Finally, if time allows, pointing the weaknesses of state-of-the-art CL and EELS (in terms of spectral range and/or spectral resolution), I will present EELS results obtained on highly monochromated electron beams that could cope with these limitations

  9. [The Effects of Skin Thickness on Optical Transmission Characteristics in Fruits Tissues].

    PubMed

    Shi, Shu-ning; Tan, Zuo-jun; Xie, Jing; Lu, Jun

    2015-07-01

    Fruit quality inspection techniques play a very important role in the production and consumption of fruits. In the field of quality non-destructive inspection and grading for fruits, the light-based techniques using optical properties of fruit products were widely used as one of the most practical and the most successful techniques. Quantitative understanding of light interaction with fruits is critical to designing better optical systems for inspection of food quality. In this paper, a fruit model consisted of two layer tissues was developed using Monte Carlo simulations to explore the light transport process and properties in the pome fruits, such as apples and mandarins, which were used as the thin-skinned and thick-skinned fruits respectively. The simulation results obtained are based on the assumption that the light source is a Gaussian beam at the wavelength 808 nm. This paper reports that the effects of skin thickness on light transmission characteristics in fruit tissues, including diffuse reflectance, transmittance, absorptivity, penetration depth etc. The inspection efficiency of flesh tissues was also demonstrated. The results indicated that the transmittance and the penetration depth decreases with the fruit skin increasing. As for the absorbed energy density, the fruit skin tissues have the wider distribution at the radial distance than the fruit flesh tissues. The absorbed energy density always tended to decrease with the inside depth of the fruit tissues increasing, especially decreased more apparently at the radial direction. The diffuse reflectance at the radial distance from 0.2 to 1.2 cm decreased with the decreasing of fruit skin, however it showed the inverse relationship in the radial distance range from 1.2 to 4.0 cm, the diffuse reflectance decreases with the increasing fruit skin. This paper proposed that the interaction between light and fruits skin in transmission or reflective approach, should be considered for developing optical

  10. Transmission in near-infrared optical windows for deep brain imaging.

    PubMed

    Shi, Lingyan; Sordillo, Laura A; Rodríguez-Contreras, Adrián; Alfano, Robert

    2016-01-01

    Near-infrared (NIR) radiation has been employed using one- and two-photon excitation of fluorescence imaging at wavelengths 650-950 nm (optical window I) for deep brain imaging; however, longer wavelengths in NIR have been overlooked due to a lack of suitable NIR-low band gap semiconductor imaging detectors and/or femtosecond laser sources. This research introduces three new optical windows in NIR and demonstrates their potential for deep brain tissue imaging. The transmittances are measured in rat brain tissue in the second (II, 1,100-1,350 nm), third (III, 1,600-1,870 nm), and fourth (IV, centered at 2,200 nm) NIR optical tissue windows. The relationship between transmission and tissue thickness is measured and compared with the theory. Due to a reduction in scattering and minimal absorption, window III is shown to be the best for deep brain imaging, and windows II and IV show similar but better potential for deep imaging than window I. PMID:26556561

  11. Dual frequency optical carrier technique for transmission of reference frequencies in dispersive media

    NASA Technical Reports Server (NTRS)

    Maleki, Lutfollah (Inventor)

    1993-01-01

    Two different carrier frequencies modulated by a reference frequency are transmitted to each receiver to be synchronized therewith. Each receiver responds to local phase differences between the two received signals to correct the phase of one of them so as to maintain the corrected signal as a reliable synchronization reference.

  12. Prototype positron emission tomography insert with electro-optical signal transmission for simultaneous operation with MRI

    NASA Astrophysics Data System (ADS)

    Olcott, Peter; Kim, Ealgoo; Hong, Keyjo; Lee, Brian J.; Grant, Alexander M.; Chang, Chen-Ming; Glover, Gary; Levin, Craig S.

    2015-05-01

    The simultaneous acquisition of PET and MRI data shows promise to provide powerful capabilities to study disease processes in human subjects, guide the development of novel treatments, and monitor therapy response and disease progression. A brain-size PET detector ring insert for an MRI system is being developed that, if successful, can be inserted into any existing MRI system to enable simultaneous PET and MRI images of the brain to be acquired without mutual interference. The PET insert uses electro-optical coupling to relay all the signals from the PET detectors out of the MRI system using analog modulated lasers coupled to fiber optics. Because the fibers use light instead of electrical signals, the PET detector can be electrically decoupled from the MRI making it partially transmissive to the RF field of the MRI. The SiPM devices and low power lasers were powered using non-magnetic MRI compatible batteries. Also, the number of laser-fiber channels in the system was reduced using techniques adapted from the field of compressed sensing. Using the fact that incoming PET data is sparse in time and space, electronic circuits implementing constant weight codes uniquely encode the detector signals in order to reduce the number of electro-optical readout channels by 8-fold. Two out of a total of sixteen electro-optical detector modules have been built and tested with the entire RF-shielded detector gantry for the PET ring insert. The two detectors have been tested outside and inside of a 3T MRI system to study mutual interference effects and simultaneous performance with MRI. Preliminary results show that the PET insert is feasible for high resolution simultaneous PET/MRI imaging for applications in the brain.

  13. Prototype positron emission tomography insert with electro-optical signal transmission for simultaneous operation with MRI.

    PubMed

    Olcott, Peter; Kim, Ealgoo; Hong, Keyjo; Lee, Brian J; Grant, Alexander M; Chang, Chen-Ming; Glover, Gary; Levin, Craig S

    2015-05-01

    The simultaneous acquisition of PET and MRI data shows promise to provide powerful capabilities to study disease processes in human subjects, guide the development of novel treatments, and monitor therapy response and disease progression. A brain-size PET detector ring insert for an MRI system is being developed that, if successful, can be inserted into any existing MRI system to enable simultaneous PET and MRI images of the brain to be acquired without mutual interference. The PET insert uses electro-optical coupling to relay all the signals from the PET detectors out of the MRI system using analog modulated lasers coupled to fiber optics. Because the fibers use light instead of electrical signals, the PET detector can be electrically decoupled from the MRI making it partially transmissive to the RF field of the MRI. The SiPM devices and low power lasers were powered using non-magnetic MRI compatible batteries. Also, the number of laser-fiber channels in the system was reduced using techniques adapted from the field of compressed sensing. Using the fact that incoming PET data is sparse in time and space, electronic circuits implementing constant weight codes uniquely encode the detector signals in order to reduce the number of electro-optical readout channels by 8-fold. Two out of a total of sixteen electro-optical detector modules have been built and tested with the entire RF-shielded detector gantry for the PET ring insert. The two detectors have been tested outside and inside of a 3T MRI system to study mutual interference effects and simultaneous performance with MRI. Preliminary results show that the PET insert is feasible for high resolution simultaneous PET/MRI imaging for applications in the brain. PMID:25856511

  14. Fiber-optic dipping liquid analyzer: theoretical and experimental study of light transmission

    SciTech Connect

    Zhou Ai; Liu Zhihai; Yuan Libo

    2009-12-20

    A fiber-optic dipping liquid analyzer (FDLA) is developed for measuring liquid properties such as concentration, refractive index, surface tension, and viscosity. An important feature of the FDLA is that a liquid drop is introduced on the end face of a fiber probe, and the drop can be regarded as a planar-convex lens. The light transmitting path and receiving power are affected by the refractive index of the liquid drop. We present a theoretical and experimental analysis of the light transmission. A mathematical model of receiving power is established based on paraxial refraction imaging and fiber reflective intensity modulation methods. Sucrose-water solutions were tested with the FDLA. The experimental results agree well with the theoretical analysis.

  15. An optical transmission spectrum of the giant planet WASP-36 b

    NASA Astrophysics Data System (ADS)

    Mancini, L.; Kemmer, J.; Southworth, J.; Bott, K.; Mollière, P.; Ciceri, S.; Chen, G.; Henning, Th.

    2016-06-01

    We present broad-band photometry of five transits in the planetary system WASP-36, totalling 17 high-precision light curves. Four of the transits were simultaneously observed in four passbands (g', r', i', z'), using the telescope-defocusing technique, and achieving scatters of less than 1 mmag per observation. We used these data to improve the measured orbital and physical properties of the system, and obtain an optical transmission spectrum of the planet. We measured a decreasing radius from bluer to redder passbands with a confidence level of more than 5σ. The radius variation is roughly 11 pressure scale heights between the g' and the z' bands. This is too strong to be Rayleigh scattering in the planetary atmosphere, and implies the presence of a species which absorbs strongly at bluer wavelengths.

  16. Linear and nonlinear transfer functions of single mode fiber for optical transmission systems.

    PubMed

    Binh, Le Nguyen

    2009-07-01

    The transmittance transfer function of single mode optical fibers operating in both linear and nonlinear regions is presented. For the linear domain, Fresnel sine and cosine integrals are obtained via the Fourier transform. In the nonlinear region dominated by self-phase-modulation effects, the Volterra series is essential to obtain the nonlinear transfer function. A convergence criterion for the Volterra series transfer function (VSTF) approach is described for solving the nonlinear Schrödinger wave propagation equation. Soliton transmission over single fibers is demonstrated as a case study of the application of the VSTF and a modified VSTF with a number of segmented steps whose distance is within the limit of the convergence of the VSTF. PMID:19568291

  17. Broadband transmission filters from the 2013 Optical Interference Coatings manufacturing problem contest [invited].

    PubMed

    Li, Li; Dobrowolski, J A; Jacobson, Michael; Cooksey, Catherine

    2014-02-01

    A broadband transmission filter from 400 to 1100 nm was selected for the manufacturing problem contest. The purpose of the contest is to test the state of the art of current optical thin film manufacturing capabilities. A total of 37 people from 15 teams participated in the contest and submitted 17 samples. Diverse approaches were taken by participants to tackle the problem. A range of different solutions was obtained where the number of layers varied from 22 to 608, and the total layer thickness ranged from 1.859 to 23.099 μm. Two independent laboratories performed sample evaluation measurements. Three teams shared the best result with the lowest average measured merit function. PMID:24514223

  18. Full-field optical thickness profilometry of semitransparent thin films with transmission densitometry

    SciTech Connect

    Johnson, Jay; Harris, Tequila

    2010-05-20

    A novel bidirectional thickness profilometer based on transmission densitometry was designed to measure the localized thickness of semitransparent films on a dynamic manufacturing line. The densitometer model shows that, for materials with extinction coefficients between 0.3 and 2.9 D/mm, 100-500 {mu}m measurements can be recorded with less than {+-}5% error at more than 10,000 locations in real time. As a demonstration application, the thickness profiles of 75 mmx100 mm regions of polymer electrolyte membrane (PEM) were determined by converting the optical density of the sample to thickness with the Beer-Lambert law. The PEM extinction coefficient was determined to be 1.4 D/mm, with an average thickness error of 4.7%.

  19. Gigabit Ethernet signal transmission using asynchronous optical code division multiple access.

    PubMed

    Ma, Philip Y; Fok, Mable P; Shastri, Bhavin J; Wu, Ben; Prucnal, Paul R

    2015-12-15

    We propose and experimentally demonstrate a novel architecture for interfacing and transmitting a Gigabit Ethernet (GbE) signal using asynchronous incoherent optical code division multiple access (OCDMA). This is the first such asynchronous incoherent OCDMA system carrying GbE data being demonstrated to be working among multi-users where each user is operating with an independent clock/data rate and is granted random access to the network. Three major components, the GbE interface, the OCDMA transmitter, and the OCDMA receiver are discussed in detail. The performance of the system is studied and characterized through measuring eye diagrams, bit-error rate and packet loss rate in real-time file transfer. Our Letter also addresses the near-far problem and realizes asynchronous transmission and detection of signal. PMID:26670529

  20. Experimental study of non-binary LDPC coding for long-haul coherent optical QPSK transmissions.

    PubMed

    Zhang, Shaoliang; Arabaci, Murat; Yaman, Fatih; Djordjevic, Ivan B; Xu, Lei; Wang, Ting; Inada, Yoshihisa; Ogata, Takaaki; Aoki, Yasuhiro

    2011-09-26

    The performance of rate-0.8 4-ary LDPC code has been studied in a 50 GHz-spaced 40 Gb/s DWDM system with PDM-QPSK modulation. The net effective coding gain of 10 dB is obtained at BER of 10(-6). With the aid of time-interleaving polarization multiplexing and MAP detection, 10,560 km transmission over legacy dispersion managed fiber is achieved without any countable errors. The proposed nonbinary quasi-cyclic LDPC code achieves an uncoded BER threshold at 4×10(-2). Potential issues like phase ambiguity and coding length are also discussed when implementing LDPC in current coherent optical systems. PMID:21996844

  1. Development of an improved optical transmission technique for black carbon (BC) analysis

    NASA Astrophysics Data System (ADS)

    Ballach, J.; Hitzenberger, R.; Schultz, E.; Jaeschke, W.

    A new optical transmission technique for black carbon (BC) analysis was developed to minimize interferences due to scattering effects in filter samples. A standard thermal analysis method (VDI, 1999) is used to link light attenuation by the filter samples to elemental carbon (EC) concentration. Scattering effects are minimized by immersion of the filters in oil of a similar refractive index, as is often done for microscopy purposes. Light attenuation was measured using both a white light source and a red LED of 650 nm. The usual increase in overestimation of BC concentrations with decreasing BC amount in filter samples was found considerably reduced. Some effects of BC properties (e.g. fractal dimension, microstructure and size distribution) on the specific attenuation coefficient BATN, however, are still present for the treated samples. BATN was found close to 1 m 2 g -1 for dry-dispersed industrial BC and 7 m 2 g -1 for nebulized BC. Good agreement was found between the oil immersion, integrating sphere and a polar photometer technique and Mie calculations. The average specific attenuation coefficient of ambient samples in oil varied between 7 and 11 m 2 g -1 for white light and 6 and 9 m 2 g -1 for red light (LED). BATN was found to have much less site variation for the treated than for the untreated samples. The oil immersion technique improved also the correlation with thermally analyzed EC. This new immersion technique therefore presents a considerable improvement over conventional optical transmission techniques and may therefore serve as a simple, fast and cost-effective alternative to thermal methods.

  2. Performance evaluation of hybrid DPSK-MPPM techniques in long-haul optical transmission.

    PubMed

    El-Fiqi, Abdulaziz E; Morra, Ahmed E; Hegazy, Salem F; Shalaby, Hossam M H; Kato, Kazutoshi; Obayya, Salah S A

    2016-07-20

    In this paper, we evaluate the performance of hybrid differential phase shift keying-multipulse pulse position modulation (DPSK-MPPM) techniques in long-haul nonlinear-dispersive optical fiber transmission. An expression for the nonlinear interference variance is obtained analytically using the Gaussian noise (GN) model. We derive upper-bound expressions that take into account the fiber nonlinearity impact on the DPSK-MPPM system's performance for both bit- and symbol-error rates (BER and SER). The tightness of the BER's upper bound is verified using Monte Carlo simulation. The numerical analysis is carried out based on the proposed setup supplemented by a realistic simulation scenario for the DPSK-MPPM long-haul optical transmission system. Our results reveal that while the hybrid DPSK-MPPM technique outperforms both traditional DPSK and MPPM techniques under amplified spontaneous emission (ASE) noise (linear limit), it is less robust when fiber nonlinearity is considered. However, under the impact of low nonlinearity, the performance of a hybrid technique still surpasses the traditional ones. We also discuss the effect of some wavelength-division multiplexing (WDM) parameters on optimal system performance. The nonlinear interference penalties on the maximum reachable distances by both hybrid and traditional modulation systems are then investigated at a forward-error correction (FEC) requirement (BER=10-3). In particular, at an average launch power of -8  dBm, the hybrid DQPSK-MPPM system with a total frame length of eight time slots including two signal time slots outreaches a traditional DQPSK system by 950 km. PMID:27463915

  3. Study of glass preforms for glass fiber optics applications (study of space processing of ceramic materials). [light transmission

    NASA Technical Reports Server (NTRS)

    Wang, F. F. Y.

    1974-01-01

    The feasibility, and technical and economic desirability was studied of space processing of glass preforms for optical fiber transmission applications. The results indicate that space processing can produce glass preforms of equal quality at lower cost than earth bound production, and can produce diameter modulation in the glass preform which promotes mode coupling and lowers the dispersion. The glass composition can be modified through the evaporative and diffusion processes, and graded refractive index profiles can be produced. A brief summary of the state of the art in optical fiber transmission is included.

  4. Performances and reliability predictions of optical data transmission links using a system simulator for aerospace applications

    NASA Astrophysics Data System (ADS)

    Bechou, L.; Deshayes, Y.; Aupetit-Berthelemot, C.; Guerin, A.; Tronche, C.

    Space missions for Earth Observation are called upon to carry a growing number of instruments in their payload, whose performances are increasing. Future space systems are therefore intended to generate huge amounts of data and a key challenge in coming years will therefore lie in the ability to transmit that significant quantity of data to ground. Thus very high data rate Payload Telemetry (PLTM) systems will be required to face the demand of the future Earth Exploration Satellite Systems and reliability is one of the major concern of such systems. An attractive approach associated with the concept of predictive modeling consists in analyzing the impact of components malfunctioning on the optical link performances taking into account the network requirements and experimental degradation laws. Reliability estimation is traditionally based on life-testing and a basic approach is to use Telcordia requirements (468GR) for optical telecommunication applications. However, due to the various interactions between components, operating lifetime of a system cannot be taken as the lifetime of the less reliable component. In this paper, an original methodology is proposed to estimate reliability of an optical communication system by using a dedicated system simulator for predictive modeling and design for reliability. At first, we present frameworks of point-to-point optical communication systems for space applications where high data rate (or frequency bandwidth), lower cost or mass saving are needed. Optoelectronics devices used in these systems can be similar to those found in terrestrial optical network. Particularly we report simulation results of transmission performances after introduction of DFB Laser diode parameters variations versus time extrapolated from accelerated tests based on terrestrial or submarine telecommunications qualification standards. Simulations are performed to investigate and predict the consequence of degradations of the Laser diode (acting as a

  5. Hubble Space Telescope STIS Optical Transit Transmission Spectra of the Hot Jupiter HD 209458b

    NASA Astrophysics Data System (ADS)

    Sing, David K.; Vidal-Madjar, A.; Désert, J.-M.; Lecavelier des Etangs, A.; Ballester, G.

    2008-10-01

    We present the transmission spectra of the hot Jupiter HD 209458b taken with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Our analysis combines data at two resolutions and applies a complete pixel-by-pixel limb-darkening correction to fully reveal the spectral line shapes of atmospheric absorption features. Terrestrial-based Na I and H I contamination are identified that mask the strong exoplanetary absorption signature in the Na core, which we find reaches total absorption levels of ~0.11% in a 4.4 Å band. The Na spectral line profile is characterized by a wide absorption profile at the lowest absorption depths and a sharp transition to a narrow absorption profile at higher absorption values. The transmission spectra also show the presence of an additional absorber at ~6250 Å, observed at both medium and low resolutions. We performed various limb-darkening tests, including using high-precision limb-darkening measurements of the Sun to characterize a general trend of ATLAS models to slightly overestimate the amount of limb darkening at all wavelengths, likely due to the limitations of the model's one-dimensional nature. We conclude that, despite these limitations, ATLAS models can still successfully model limb darkening in high signal-to-noise ratio transits of solar-type stars, like HD 209458, to a high level of precision over the entire optical regime (3000-10000 Å) at transit phases between second and third contact.

  6. Binary prefix for sampling frequency offset estimation in dispersive optical transmissions.

    PubMed

    Cheng, Lin; Liu, Xiang; Chand, Naresh; Effenberger, Frank; Chang, Gee-Kung

    2015-10-01

    We propose and experimentally demonstrate a method for sampling frequency offset (SFO) estimation in optical communication systems based on periodically inserted identical binary prefix. Different from conventional cyclic prefix, binary prefix provides not only high tolerance to chromatic dispersion in dispersive fiber transmission, but also the ability to estimate SFO by simple receiver-side digital signal processing. Moreover, this binary prefix based scheme is generally applicable to any advanced modulation formats. A proof-of-concept experiment is conducted to quantify the accuracy and tolerance of the scheme in estimating SFO. It is found that over a wide SFO range up to 341 ppm, the estimation error is kept under 20 ppb and signals are recovered with the same quality as with zero-offset sampling. The experimental results also confirm that this method is tolerant to link signal-to-noise ratio loss and dispersion, showing no additional penalty after transmission over a 40-km standard single-mode fiber at 1550 nm. PMID:26480132

  7. System and method for ultrafast optical signal detecting via a synchronously coupled anamorphic light pulse encoded laterally

    DOEpatents

    Heebner, John E.

    2010-08-03

    In one general embodiment, a method for ultrafast optical signal detecting is provided. In operation, a first optical input signal is propagated through a first wave guiding layer of a waveguide. Additionally, a second optical input signal is propagated through a second wave guiding layer of the waveguide. Furthermore, an optical control signal is applied to a top of the waveguide, the optical control signal being oriented diagonally relative to the top of the waveguide such that the application is used to influence at least a portion of the first optical input signal propagating through the first wave guiding layer of the waveguide. In addition, the first and the second optical input signals output from the waveguide are combined. Further, the combined optical signals output from the waveguide are detected. In another general embodiment, a system for ultrafast optical signal recording is provided comprising a waveguide including a plurality of wave guiding layers, an optical control source positioned to propagate an optical control signal towards the waveguide in a diagonal orientation relative to a top of the waveguide, at least one optical input source positioned to input an optical input signal into at least a first and a second wave guiding layer of the waveguide, and a detector for detecting at least one interference pattern output from the waveguide, where at least one of the interference patterns results from a combination of the optical input signals input into the first and the second wave guiding layer. Furthermore, propagation of the optical control signal is used to influence at least a portion of the optical input signal propagating through the first wave guiding layer of the waveguide.

  8. Investigations of high-speed optical transmission systems employing Absolute Added Correlative Coding (AACC)

    NASA Astrophysics Data System (ADS)

    Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin

    2016-07-01

    A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ∼-28.3 dBm and ∼336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.

  9. Optical and Nanoparticle Analysis of Normal and Cancer Cells by Light Transmission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Deatsch, Alison; Sun, Nan; Johnson, Jeffery; Stack, Sharon; Szajko, John; Sander, Christopher; Rebuyon, Roland; Easton, Judah; Tanner, Carol; Ruggiero, Steven

    2015-03-01

    We have investigated the optical properties of human oral and ovarian cancer and normal cells. Specifically, we have measured the absolute optical extinction for intra-cellular material (lysates) in aqueous suspension. Measurements were conducted over a wavelength range of 250 to 1000 nm with 1 nm resolution using Light Transmission Spectroscopy (LTS). This provides both the absolute extinction of materials under study and, with Mie inversion, the absolute number of particles of a given diameter as a function of diameter in the range of 1 to 3000 nm. Our preliminary studies show significant differences in both the extinction and particle size distributions associated with cancer versus normal cells, which appear to be correlated with differences in the particle size distribution in the range of approximately 50 to 250 nm. Especially significant is a clearly higher density of particles at about 100 nm and smaller for normal cells. Department of Physics, Harper Cancer Research Institute, and the Office of Research at the University of Notre Dame.

  10. Probing quantum phases of ultracold atoms in optical lattices by transmission spectra in cavity quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Mekhov, Igor B.; Maschler, Christoph; Ritsch, Helmut

    2007-05-01

    Studies of ultracold gases in optical lattices provide a means for testing fundamental and application-oriented quantum many-body concepts of condensed-matter physics in well controllable atomic systems; examples include strongly correlated phases and quantum-information processing. Standard methods to observe quantum properties of Bose-Einstein condensates are based on matter-wave interference between atoms released from traps, a method that ultimately destroys the system. Here, we propose a new approach on the basis of optical measurements that conserves the number of atoms. We prove that atomic quantum statistics can be mapped on transmission spectra of high-Q cavities, where atoms create a quantum refractive index. This can be useful for studying phase transitions-for example, between Mott insulator and superfluid states-as various phases show qualitatively distinct light scattering. Joining the paradigms of cavity quantum electrodynamics and ultracold gases could enable conceptually new investigations of both light and matter at ultimate quantum levels. We predict effects accessible in experiments that recently became possible.

  11. Investigations of high-speed optical transmission systems employing Absolute Added Correlative Coding (AACC)

    NASA Astrophysics Data System (ADS)

    Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin

    2016-07-01

    A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ˜-28.3 dBm and ˜336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.

  12. Synchronization in Superradiant Lasers

    NASA Astrophysics Data System (ADS)

    Cox, Kevin; Weiner, Joshua; Bohnet, Justin; Thompson, James

    2015-05-01

    Superradiant (or bad-cavity) lasers based on highly forbidden transitions in cold atoms are expected to produce light with coherence properties exceeding the state-of-the-art, finding applications in optical atomic clocks and other precision measurements. We study experimentally and theoretically the response of a superradiant Raman laser to an applied coherent drive. We observe two forms of synchronization (injection locking) between the superradiant ensemble and the applied drive: one attractive and one repulsive in nature, in which the atomic spin degrees of freedom play a crucial role in determining the dynamics. Additionally, we present time dynamics and steady state behavior of two interacting superradiant lasers. Understanding the synchronization physics of superradiant lasers could inform future implementations with technologically relevant phase noise properties and explorations for understanding synchronization in a quantum regime.

  13. LDEF (Flight), S0109 : Fiber Optic Data Transmission Experiment, Tray C12

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Fiber Optic Data Transmission Experiment (FODTE) flight photograph was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on clamp blocks at each end of the experiment tray lower flange appear to be discolored. The FODTE occupies a six (6) inch deep LDEF peripheral tray and consist of an aluminum internal support structure, four aluminum mounting plates, an aluminum cover plate, ten fiber optic cable samples with connectors, aluminum brackets and non-magnet fasteners required to assemble the experiment. Four optical fiber cables (two black, one blue and one bright orange), each configured in the form of a planar, helix coil, are attached to the thermally isolated mounting plates with black anodized aluminum clips cushioned with silicone-rubber spacers. The four mounting plates are coated with a Catalac off-white thermal control paint and the exposed surface of the cover plate is painted with Chemglaze II A-276 white to meet thermal control requirements. Six additional coils of optical fiber cable samples, secured with nylon cable ties, are located in the bottom of the tray, four below the mounting plates and two below the cover plate. Each sample terminates in connectors mounted in brackets located in the tray bottom or on the backside of the thermally isolated mounting plates. The FODTE appears to be intact with no apparent physical damage. A flow pattern of discoloration appears to the right of each fastener used to secure the four mounting plates. Colors of two of the four exposed coils of fiber optic cables have changed significantly. The cable located in the upper right corner, originally a bright orange, appears to be dark blue and the cable in the lower left position has faded from a light blue to a blue-gray color. The color of the silicone-rubber spacers under the coil attach clips appears to have changed from clear to brown. Two brown circular discolorations have appeared, one

  14. Synchronization of Micromechanical Oscillators Using Light

    NASA Astrophysics Data System (ADS)

    Zhang, Mian; Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Barnard, Arthur; McEuen, Paul; Lipson, Michal

    2012-12-01

    Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through an optical cavity radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path toward reconfigurable synchronized oscillator networks.

  15. Optical transmission of nematic liquid crystal 5CB doped by single-walled and multi-walled carbon nanotubes.

    PubMed

    Lisetski, L N; Fedoryako, A P; Samoilov, A N; Minenko, S S; Soskin, M S; Lebovka, N I

    2014-08-01

    Comparative studies of optical transmission of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), dispersed in nematic liquid crystal matrix 5CB, were carried out. The data evidence violations of Beer-Lambert-Bouguer (BLB) law both in cell thickness and concentration dependencies. The most striking is the fact that optical transmission dependencies for SWCNTs and MWCNTs were quite different in the nematic phase, but they were practically indistinguishable in the isotropic phase. Monte Carlo simulations of the impact of aggregation on direct transmission and violation of BLB law were also done. The results were discussed accounting for the tortuous shape of CNTs, their physical properties and aggregation, as well as strong impact of perturbations of the nematic 5CB structure inside coils and in the vicinity of CNT aggregates. PMID:25106504

  16. Enhanced Optical Transmission and Sensing of a Thin Metal Film Perforated with a Compound Subwavelength Circular Hole Array

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangnan; Liu, Guiqiang; Liu, Zhengqi; Hu, Ying; Cai, Zhengjie

    2015-12-01

    We propose and numerically investigate the optical transmission behaviors of a sub-wavelength metal film perforated with a two-dimensional square array of compound circular holes. Enhanced optical transmission is obtained by using the finite-difference time-domain (FDTD) method, which can be mainly attributed to the excitation and coupling of localized surface plasmon resonances (LSPRs) and surface plasmon polaritons (SPPs), and Fano Resonances. The redshift of the transmission peak can be achieved by enlarging the size and number of small holes, the environmental dielectric constant. These indicate that the proposed structure has potential applications in integrated optoelectronic devices such as plasmonic filters and sensors. supported by National Natural Science Foundation of China (Nos. 11464019, 11264017, 11004088), Young Scientist Development Program of China (No. 20142BCB23008) and the Natural Science Foundation of Jiangxi Province, China (Nos. 2014BAB212001, 20112BBE5033)

  17. In-band simultaneous transmission of baseband and broadcast signals in wavelength reused bidirectional passive optical network

    NASA Astrophysics Data System (ADS)

    Choudhury, Pallab K.

    2015-11-01

    Reflective semiconductor optical amplifier (RSOA) based bidirectional wavelength division multiplexing passive optical network (WDM-PON) is proposed and analyzed for broadcasting services along with conventional baseband signal. The downstream baseband signal is spectrally shaped for in-band transmission of broadcast signal, which ensures effective utilization of transmission bandwidth. The modulated downstream optical signal is further reused for upstream data modulation and transmitted over the same fiber with suppressed re-modulation and rayleigh backscattering noises. The proposed WDM-PON is successfully demonstrated for 10 Gb/s downstream baseband signal, 100 Mb/s 16-QAM (quadrature amplitude modulation) in-band broadcast signal and wavelength reused 1.25 Gb/s upstream signal. Error free operation for both the baseband signals as well as low value of error vector magnitude (EVM) for broadcast data are simultaneously achieved in acceptable receiver sensitivity.

  18. Back-etch method for plan view transmission electron microscopy sample preparation of optically opaque films.

    PubMed

    Yao, Bo; Coffey, Kevin R

    2008-04-01

    Back-etch methods have been widely used to prepare plan view transmission electron microscopy (TEM) samples of thin films on membranes by removal of the Si substrate below the membrane by backside etching. The conventional means to determine when to stop the etch process is to observe the color of the light transmitted through the sample, which is sensitive to the remaining Si thickness. However, most metallic films thicker than 75 nm are opaque, and there is no detectable color change prior to film perforation. In this paper, a back-etch method based on the observation of an abrupt change of optical reflection contrast is introduced as a means to determine the etch endpoint to prepare TEM samples for these films. As the acid etchant removes the Si substrate material a rough interface is generated. This interface becomes a relatively smooth and featureless region when the etchant reaches the membrane (film/SiO2). This featureless region is caused by the mirror reflection of the film plane (film/SiO2 interface) through the optically transparent SiO2 layer. The lower etch rate of SiO2 (compared with Si) gives the operator enough time to stop the etching without perforating the film. A clear view of the morphology and control of Si roughness during etching are critical to this method, which are discussed in detail. The procedures of mounting wax removal and sample rinsing are also described in detail, as during these steps damage to the membrane may easily occur without appropriate consideration. As examples, the preparation of 100-nm-thick Fe-based amorphous alloy thin film and 160-nm-thick Cu-thin film samples for TEM imaging is described. PMID:18227137

  19. Synchronous identification of friendly targets

    DOEpatents

    Telle, John M.; Roger, Stutz A.

    1998-01-01

    A synchronous communication targeting system for use in battle. The present invention includes a transceiver having a stabilizing oscillator, a synchronous amplifier and an omnidirectional receiver, all in electrical communication with each other. A remotely located beacon is attached to a blackbody radiation source and has an amplitude modulator in electrical communication with a optical source. The beacon's amplitude modulator is set so that the optical source transmits radiation frequency at approximately the same or lower amplitude than that of the blackbody radiation source to which the beacon is attached. The receiver from the transceiver is adapted to receive frequencies approximately at or below blackbody radiation signals and sends such signals to the synchronous amplifier. The synchronous amplifier then rectifies and amplifies those signals which correspond to the predetermined frequency to therefore identify whether the blackbody radiation source is friendly or not.

  20. Revisiting binary sequence length requirements to accurately emulate optical transmission systems in highly dispersive regime

    NASA Astrophysics Data System (ADS)

    Grellier, Edouard; Antona, Jean-Christophe; Bononi, Alberto; Bigo, Sébastien

    2008-11-01

    When increasing channel bit rate beyond 10Gb/s or when operating over fiber lines with sparse or no in-line dispersion compensation, Kerr-like non-linear effects can be considered as second order with respect to dispersive effects, because pulse broadening can expand over numerous neighbor pulses, before optical non-linear effects imprint their signature noticeably. To accurately emulate the interactions between pulses in this case, a few studies emphasized that Pseudo- Random Binary Sequences (PRBS) should be used, with exponential dependence of the required PRBS length on bit rate and accumulated dispersion. In this paper, we explain our strategy to numerically estimate the required number of random, noisy bits for Monte-Carlo simulations, and show that it weakly increases in presence of pulse to pulse correlations and commonly tolerated levels of non-linearities (i.e. leading to transmission penalties as high as 1.5dB, for reference BERs of 10-2, 10-3 or 10-5) . Then we determine the actual required PRBS length that yields the same (sufficient) BER accuracy as the MC method. We demonstrate its actual dependence on BER, and show that MC theory provides a reliable upper bound in FEC-assisted, highly dispersive systems.

  1. Optical-bistability-enabled control of resonant light transmission for an atom-cavity system

    NASA Astrophysics Data System (ADS)

    Sawant, Rahul; Rangwala, S. A.

    2016-02-01

    The control of light transmission through a standing-wave Fabry-Pérot cavity containing atoms is theoretically and numerically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained. The response of the intracavity intensity to an intersecting beam on atomic resonance is understood in the presence of stationary atoms (closed system) and nonstatic atoms (open system) in the cavity. The nonstatic system of atoms is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, which corresponds to a thermal environment where atoms are moving in and out of the cavity mode volume. The control behavior with three- and two-level atomic systems is also studied, and the rich physics arising out of these systems for closed and open atomic systems is discussed. The solutions to the models are used to interpret the steady-state and transient behavior observed by Sharma et al. [Phys. Rev. A 91, 043824 (2015)], 10.1103/PhysRevA.91.043824.

  2. Transmissive grating-reflective mirror-based fiber optic accelerometer for stable signal acquisition in industrial applications

    NASA Astrophysics Data System (ADS)

    Lee, Yeon-Gwan; Kim, Dae-Hyun; Kim, Chun-Gon

    2012-05-01

    This paper discusses an applicable fiber-optic accelerometer composed of a transmissive grating panel, a reflection mirror, and two optical fibers with a separation of quarter grating pitch as transceivers that monitor the low-frequency accelerations of civil engineering structures. This sensor structure brings together the advantages of both a simple sensor structure, which leads to simplified cable design by 50% in comparison with the conventional transmission-type fiber optic accelerometer, and a stable reflected signals acquisition with repeatability in comparison to the researched grating-reflection type fiber optic accelerometer. The vibrating displacement and sinusoidal acceleration measured from the proposed fiber optic sensor demonstrated good agreement with those of a commercial laser displacement sensor and a MEMS accelerometer without electromagnetic interference. The developed fiber optic accelerometer can be used in frequency ranges below 4.0 Hz with a margin of error that is less than 5% and a high sensitivity of 5.06 rad/(m/s)2.

  3. LDEF (Postflight), S0109 : Fiber Optic Data Transmission Experiment, Tray C12

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Fiber Optic Data Transmission Experiment (FODTE) postflight photograph was taken in the SAEF II at KSC after the experiment was removed from the LDEF. The experiment trays lower flange has a light tan discoloration that is visible in areas not protected by the tray clamp blocks. Dark brown discolorations can be seen near the center of the tray left flange and on the upper and lower flanges near the corners of the white cover plate. The tray sidewalls appear to be heavily stained in corners, along the three areas adjacent to the white cover plate and at the intersection of the sidewalls with the experiment sup- port structure. The FODTE occupies a six (6) inch deep LDEF peripheral tray and consist of an aluminum internal support structure, four aluminum mounting plates, an aluminum cover plate, ten fiber optic cable samples with connectors, aluminum brackets and non-magnet fasteners required to assemble the experiment. Four optical fiber cables (two black, one blue and one bright orange), each configured in the form of a planar, helix coil, are attached to the thermally isolated mounting plates with black anodized aluminum clips cushioned with silicone-rubber spacers. The four mounting plates are coated with a Catalac off-white thermal control paint and the exposed surface of the cover plate is painted with Chemglaze II A-276 white to meet thermal control requirements. Six additional coils of optical fiber cable samples, secured with nylon cable ties, are located in the bottom of the tray, four below the mounting plates and two below the cover plate. Each sample terminates in connectors mounted in brackets located in the tray bottom or on the backside of the thermally isolated mounting plates. The FODTE appears to be intact with no apparent physical damage. A flow pattern of discoloration appears to flow in a downward direction from fasteners used to secure the four mounting plates. The colors of two coils of the externally mounted fiber optic cables have

  4. Synchronous demodulator

    NASA Technical Reports Server (NTRS)

    Sutton, John F. (Inventor)

    1991-01-01

    A synchronous demodulator includes a switch which is operated in synchronism with an incoming periodic signal and both divides and applies that signal to two signal channels. The two channels each include a network for computing and holding, for a predetermined length of time, the average signal value on that channel and applies those valves, in the form of two other signals, to the inputs of a differential amplifier. The networks may be R-C networks. The output of the differential amplifier may or may not form the output of the synchronous detector and may or may not be filtered. The output will not include a periodic signal due to the presence of a dc offset. Additionally, the output will not contain any substantial ripple due to periodic components in the input signal. In a somewhat more complex version, containing twice the structural components of the above synchronous demodulator with a more complex switching mechanism, essentially all ripple due to periodic components in the input signal are eliminated.

  5. Synchronizing Fireflies

    ERIC Educational Resources Information Center

    Zhou, Ying; Gall, Walter; Nabb, Karen Mayumi

    2006-01-01

    "Imagine a tenth of a mile of river front with an unbroken line of trees with fireflies on ever leaf flashing in synchronism. ... Then, if one's imagination is sufficiently vivid, he may form some conception of this amazing spectacle." So wrote the naturalist Hugh Smith. In this article we consider how one might model mathematically the…

  6. Low complexity MIMO method based on matrix transformation for few-mode multi-core optical transmission system

    NASA Astrophysics Data System (ADS)

    Pan, Xiaolong; Liu, Bo; Li, Li; Tian, Qinghua

    2016-07-01

    This paper proposes and demonstrates a low complexity multiple-input multiple-output (MIMO) equalization digital signal processing (DSP) method for the few mode multi-core (FMMC) fiber optical transmission system. The MIMO equalization algorithm offers adaptive equalization taps according to the degree of crosstalk in cores or modes, which eliminates the interference among different modes and cores in space division multiplexing (SDM) transmission system. Compared with traditional MIMO method, the proposed scheme has increased the convergence rate by 4 times and reduced the number of finite impulse response (FIR) filters by 55% when the numbers of mode and core are three.

  7. Design of transmission line driven slot waveguide Mach-Zehnder interferometers and application to analog optical links.

    PubMed

    Witzens, Jeremy; Baehr-Jones, Thomas; Hochberg, Michael

    2010-08-01

    Slot waveguides allow joint confinement of the driving electrical radio frequency field and of the optical waveguide mode in a narrow slot, allowing for highly efficient polymer based interferometers. We show that the optical confinement can be simply explained by a perturbation theoretical approach taking into account the continuity of the electric displacement field. We design phase matched transmission lines and show that their impedance and RF losses can be modeled by an equivalent circuit and linked to slot waveguide properties by a simple set of equations, thus allowing optimization of the device without iterative simulations. We optimize the interferometers for analog optical links and predict record performance metrics (V(pi) = 200 mV @ 10 GHz in push-pull configuration) assuming a modest second order nonlinear coefficient (r(33) = 50 pm/V) and slot width (100 nm). Using high performance optical polymers (r(33) = 150 pm/V), noise figures of state of the art analog optical links can be matched while reducing optical power levels by approximately 30 times. With required optical laser power levels predicted at 50 mW, this could be a game changing improvement by bringing high performance optical analog link power requirements in the reach of laser diodes. A modified transmitter architecture allows shot noise limited performance, while reducing power levels in the slot waveguides and enhancing reliability. PMID:20721082

  8. Management of light absorption in extraordinary optical transmission based ultra-thin-film tandem solar cells

    NASA Astrophysics Data System (ADS)

    Mashooq, Kishwar; Talukder, Muhammad Anisuzzaman

    2016-05-01

    Although ultra-thin-film solar cells can be attractive in reducing the cost, they suffer from low absorption as the thickness of the active layer is usually much smaller than the wavelength of incident light. Different nano-photonic techniques, including plasmonic structures, are being explored to increase the light absorption in ultra-thin-film solar cells. More than one layer of active materials with different energy bandgaps can be used in tandem to increase the light absorption as well. However, due to different amount of light absorption in different active layers, photo-generated currents in different active layers will not be the same. The current mismatch between the tandem layers makes them ineffective in increasing the efficiency. In this work, we investigate the light absorption properties of tandem solar cells with two ultra-thin active layers working as two subcells and a metal layer with periodically perforated holes in-between the two subcells. While the metal layer helps to overcome the current mismatch, the periodic holes increase the absorption of incident light by helping extraordinary optical transmission of the incident light from the top to the bottom subcell, and by coupling the incident light to plasmonic and photonic modes within ultra-thin active layers. We extensively study the effects of the geometry of holes in the intermediate metal layer on the light absorption properties of tandem solar cells with ultra-thin active layers. We also study how different metals in the intermediate layer affect the light absorption; how the geometry of holes in the intermediate layer affects the absorption when the active layer materials are changed; and how the intermediate metal layer affects the collection of photo-generated electron-hole pairs at the terminals. We find that in a solar cell with 6,6-phenyl C61-butyric acid methyl ester top subcell and copper indium gallium selenide bottom subcell, if the periodic holes in the metal layer are square or

  9. Multiple-access channels without synchronization

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.; Posner, E. C.

    1977-01-01

    This paper discusses models for multiple-access communications which take into account the fact that the channel users may not be able to synchronize their transmissions. It is shown that for a broad class of such channels, the capacity region is the same as it would be with user synchronization. Some open problems are discussed.

  10. Nanoimprint-defined, large-area meta-surfaces for unidirectional optical transmission with superior extinction in the visible-to-infrared range.

    PubMed

    Yao, Yuhan; Liu, He; Wang, Yifei; Li, Yuanrui; Song, Boxiang; Wang, Richard P; Povinelli, Michelle L; Wu, Wei

    2016-07-11

    Optical devices with asymmetric transmission have important applications in optical systems, but optical isolators with the modal asymmetry can only be built using magneto-optical or nonlinear materials, as dictated by the Lorentz reciprocity theorem. However, optical devices with the power asymmetry can be achieved by linear materials such as metals and dielectrics. In this paper, we report a large-area, nanoimprint-defined meta-surface (stacked subwavelength gratings) with high-contrast asymmetric transmittance in the visible-to-infrared wavelength range for TM-polarized light. The physical origin of asymmetric transmission through the meta-surface is studied by analyzing the scattering matrix. PMID:27410812

  11. Parameter design of signal processing for transmission/reflection-type hybrid extrinsic Fabry Perot interferometric optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Lee, Jung-Ju

    2005-02-01

    A transmission/reflection-type hybrid extrinsic Fabry-Perot interferometric (TRHEFPI) optical fiber sensor presents transmission-type and reflection-type sensor signals simultaneously, and measurement directions can be robustly distinguished with the phase lead or lag of the linear combination signal from the original sensor signal. This sensor principle compensates for the ambiguous distinction of the measurement directions and direction changes of conventional interferometric optical fiber sensors, including extrinsic Fabry-Perot interferometric optical fiber sensors, due to the exclusive use of fringe counting in signal processing. Designing a sensor coefficient in the linear combination signal is one of the most important works in signal processing for the TRHEFPI optical fiber sensor because the magnitude of the phase shifts depends on the sensor coefficient. A design method of the sensor coefficient is presented in this research. The method was verified with experimental sensor signals and applied to strain measurement experiments. A method of absolute measurement using the TRHEFPI optical fiber sensor is also presented.

  12. Fabrication of MEMS-Based Microshutter Arrays for Optical Transmission Selection

    NASA Technical Reports Server (NTRS)

    Lynch, Bernard A.; Franz, David E.; Hu, R. G.; Jhabvala, M. D.; Kotecki, C. A.; Li, M. J.; Oh, H.; Zheng, Y.

    2004-01-01

    A MEMS-based programmable aperture mask is under development at the NASA Goddard Space Flight Center. Termed the Microshutter (u-shutter) Array, the device will be used to control the transmission of light, with both high efficiency and contrast, to a multi-object spectrometer on the James Webb Space Telescope. Fabrication of the p-shutter array employs several novel designs and processing techniques. The current generation of micro-shutters consists of 128x64 pixel arrays with unit cell dimensions of 100x200 microns. Shutters are patterned in silicon nitride and sit on a 100 micron silicon frame that is DRIE etched below each shutter. The front and back sides of the device are shown. A magnetic cobalt-iron alloy patterned on top of the shutter allows it to be actuated 90 degrees out-of-plane, into the frame, by an external magnetic field. An electrode on the shutter and a vertical electrode on the sidewall of the frame, approximately 90pm deep, allow them to be electrostatically latched in their rotated position. The vertical electrode is deposited and patterned on the backside of the frame in a single step using a directionally controlled evaporation. Individual addressing of shutters for electrostatic latching is accomplished via a crosspoint addressing scheme, with no on-chip active components. A portion of an array with shutters in the open, latched, and closed positions is shown. Light loss at shutter edges is minimized by an overhanging aluminum light-shield that is anchored to the frame. A photoresist sacrificial layer is used to raise the light-shield up and over the 2 micron gap that surrounds each pixel. After completion, arrays are subjected to life cycle, environmental and optical testing. Fabricated devices have survived 10(exp 6) actuation cycles at both room and cryogenic temperatures and a 14g rms launch-simulation test. Optical testing has shown contrast measurements between open and closed shutters up to 10000:1.

  13. Development of simultaneous measurement system of birefringence, optical rotational power, and transmission spectra for chiral liquid crystal phases

    NASA Astrophysics Data System (ADS)

    Feng, Zhengyu; Ishikawa, Ken

    2016-05-01

    A novel experimental setup used to measure the important optical properties of liquid crystal materials is proposed. The setup allows us to measure electric-field-induced birefringence, optical rotational power, and transmission spectra consecutively. This system can be widely applied to characterize liquid crystal materials including blue phases, ferroelectric liquid crystals, and other chiral phases. We adopted this system to study the phase transition behavior of a V-shape switching ferroelectric liquid crystal mixture and made an important correction of experimental results previously reported by Sandhya et al. [ Europhys. Lett. 90, 56005 (2010)]. This finding proves the advantage of this system compared with the measurement method using individual systems.

  14. Issues arising with the application of optical fiber transmission in class 1E systems in nuclear power plants

    SciTech Connect

    Korsah, K.; Antonescu, C.

    1993-12-31

    The application of fiber optic links and networks in safety-critical systems in the next generation of nuclear power plants, as well as in some digital upgrades in present-day plants, will mean that these links must be highly reliable and able to withstand the effect of environmental stressors present at the installation location. This paper discusses the failure modes and age-related mechanisms of fiber optic transmission components and identifies environmental stressors that could adversely affect their reliability over the long term. Some of the standards that could be used in their qualification for safety-critical applications are also discussed briefly.

  15. In-situ optical transmission electron microscope study of exciton phonon replicas in ZnO nanowires by cathodoluminescence

    SciTech Connect

    Yang, Shize; Tian, Xuezeng; Wang, Lifen; Wei, Jiake; Qi, Kuo; Li, Xiaomin; Xu, Zhi E-mail: xdbai@iphy.ac.cn Wang, Wenlong; Zhao, Jimin; Bai, Xuedong E-mail: xdbai@iphy.ac.cn; Wang, Enge E-mail: xdbai@iphy.ac.cn

    2014-08-18

    The cathodoluminescence spectrum of single zinc oxide (ZnO) nanowires is measured by in-situ optical Transmission Electron Microscope. The coupling between exciton and longitudinal optical phonon is studied. The band edge emission varies for different excitation spots. This effect is attributed to the exciton propagation along the c axis of the nanowire. Contrary to free exciton emission, the phonon replicas are well confined in ZnO nanowire. They travel along the c axis and emit at the end surface. Bending strain increases the relative intensity of second order phonon replicas when excitons travel along the c-axis.

  16. Numerical Investigation on Performance of In-Building Plastic Optical Fiber Transmission Systems and Role of Digital Television Broadcasting

    NASA Astrophysics Data System (ADS)

    Matera, Francesco; Tiano, Stefania; Settembre, Marina

    2012-07-01

    This article reports a numerical investigation on the transmission performance of multilevel systems operating in building links encompassing step-index plastic optical fibers. For such an aim, a simplified model for the multimode fiber propagation is introduced. A sub-carrier multiplexing technique is also simulated to demonstrate the distribution of broadcasting television channels by adopting such fibers. The reported results show that a unique building network based on step-index plastic optical fibers is suitable to carry both Ethernet and broadcast TV signals in all rooms.

  17. Gold Nanohole Array with Sub-1 nm Roughness by Annealing for Sensitivity Enhancement of Extraordinary Optical Transmission Biosensor

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Irannejad, Mehrdad; Yavuz, Mustafa; Cui, Bo

    2015-05-01

    Nanofabrication technology plays an important role in the performance of surface plasmonic devices such as extraordinary optical transmission (EOT) sensor. In this work, a double liftoff process was developed to fabricate a series of nanohole arrays of a hole diameter between 150 and 235 nm and a period of 500 nm in a 100-nm-thick gold film on a silica substrate. To improve the surface quality of the gold film, thermal annealing was conducted, by which an ultra-smooth gold film with root-mean-square (RMS) roughness of sub-1 nm was achieved, accompanied with a hole diameter shrinkage. The surface sensitivity of the nanohole arrays was measured using a monolayer of 16-mercaptohexadecanoic acid (16-MHA) molecule, and the surface sensitivity was increased by 2.5 to 3 times upon annealing the extraordinary optical transmission (EOT) sensor.

  18. Experimental demonstration of optical MIMO transmission for SCFDM-PON based on polarization interleaving and direct detection

    NASA Astrophysics Data System (ADS)

    Lin, Bangjiang; Li, Juhao; Yang, Hui; Jiang, Song; Zhu, Lixin; He, Yongqi; Chen, Zhangyuan

    2012-11-01

    The OFDM-PON and SCFDM-PON based on powerful digital signal processing (DSP) are promising candidates for next-generation optical access networks. Recently polarization-division-multiplexing (PDM) transmission with direct detection has been proposed for OFDM-PON to effectively reduce the bandwidth requirement of optical and electrical components. However, the PDM scheme has high algorithm complexity. In this paper, we propose a polarization interleaving (PI) approach, which can significantly reduce the bandwidth requirement for components while achieving a similar 2×2 MIMO algorithm with coherently-detected PDM-OFDM scheme. Downstream PI-SCFDM transmission is experimentally demonstrated. The scheme can be easily extended to OFDM-PON.

  19. QoS differentiation scheme with multiple burst transmission and virtual resource reservation for optical burst switching networks

    NASA Astrophysics Data System (ADS)

    Arakawa, Yutaka; Yamanaka, Naoaki

    2007-08-01

    We propose what we believe to be a new scheme to provide basic quality of service (QoS) in optical burst switching networks. Our proposal consists of multiple burst transmission (MBT) and virtual resource reservation (VRR). With MBT, consecutive bursts headed to the same destination are serially transmitted, and, at the transmission of high-priority bursts, the wavelength resource reserved by the head burst is kept reserving for the following bursts. We call it VRR. Computer simulations show that our proposal offers a larger differentiation of burst loss than the conventional offset-based QoS differentiation scheme. Also, it can improve the burst loss rate of both high-priority and low-priority bursts. Moreover, it can minimize the burst loss rate of high-priority bursts even when the high-priority traffic occupies a large percentage of the network traffic. The proposed scheme can be applied to the future multiservice optical network architecture.

  20. Optical phase conjugation in phase-modulated transmission systems: experimental comparison of different nonlinearity-compensation methods.

    PubMed

    Minzioni, Paolo; Pusino, Vincenzo; Cristiani, Ilaria; Marazzi, Lucia; Martinelli, Mario; Langrock, Carsten; Fejer, M M; Degiorgio, Vittorio

    2010-08-16

    We experimentally compare the effectiveness of three different optical-phase-conjugation-based nonlinearity-compensation strategies on a transmission system employing phase-modulated signals, and hence affected by the Gordon-Mollenauer effect. We demonstrate that it is possible to obtain significant nonlinearity compensation, but that no improvement is obtained using configurations specifically aimed at the compensation of the nonlinear phase noise. PMID:20721200

  1. A novel approach to smart grid technology for electrical power transmission lines by a self-organized optical network node based on optical bistability

    NASA Astrophysics Data System (ADS)

    Nakanishi, Soichiro; Sasaki, Wakao

    2011-01-01

    In this work, we have demonstrated a new smart grid model by our novel green photonics technology based on selforganized optical networks realizing an autonomous peer-to-peer electric power transmissions without centralized control for the power grid. In this optical network, we introduced an adaptive algorithm for concurrent peer-to-peer communications, by utilizing optical nonlinearity depending only on the signal strength passing through the network. This method is applicable for autonomous organization of functions for ad-hoc electric power distribution systems for the power grid. For this purpose, a simple optical- electrical hybrid bistable circuit composed of such as light emitting diode (LED) and photo diode (PD), has been incorporated into the network node. In the experiment, the method uses a simple, local adaptation of transmission weights at each network node, which enables self-organizing functions of the network, such as self-routing, self-optimization, self-recovery and self-protection. Based on this method, we have demonstrated experimentally a new smart grid model applicable for ad-hoc electric power distribution systems mediated by power comsumptions. In this model, electric power flow is controlled autonomously through the self-organized network nodes associated with individual power facilities having photovoltaics and electric storage devices, etc., and the nodes convert the amounts of electric power supply and/or comsumption to the light intensity values using above mentioned transmission weights at each node. As a consequence, we have experimentally demonstrated a simple shorthaul system model for ad-hoc electric power distribution with a self-organized optical network as a novel green photonics technology application for smart grid.

  2. Synchronization in an optomechanical cavity.

    PubMed

    Shlomi, Keren; Yuvaraj, D; Baskin, Ilya; Suchoi, Oren; Winik, Roni; Buks, Eyal

    2015-03-01

    We study self-excited oscillations (SEO) in an on-fiber optomechanical cavity. Synchronization is observed when the optical power that is injected into the cavity is periodically modulated. A theoretical analysis based on the Fokker-Planck equation evaluates the expected phase space distribution (PSD) of the self-oscillating mechanical resonator. A tomography technique is employed for extracting PSD from the measured reflected optical power. Time-resolved state tomography measurements are performed to study phase diffusion and phase locking of the SEO. The detuning region inside which synchronization occurs is experimentally determined and the results are compared with the theoretical prediction. PMID:25871175

  3. 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.

  4. Optical data transmission technology for fixed and drag-on STS payload umbilicals, volume 2

    NASA Technical Reports Server (NTRS)

    St.denis, R. W.

    1981-01-01

    Optical data handling methods are studied as applicable to payload communications checkout and monitoring. Both payload umbilicals and interconnecting communication lines carrying payload data are examined for the following: (1) ground checkout requirements; (2) optical approach (technical survey of optical approaches, selection of optimum approach); (3) survey and select components; (4) compare with conventional approach; and (5) definition of follow on activity.

  5. FITC-Dextran entrapped and silica coated gadolinium oxide nanoparticles for synchronous optical and magnetic resonance imaging applications.

    PubMed

    Kumar, Shailja; Meena, Virendra Kumar; Hazari, Puja Panwar; Sharma, Rakesh Kumar

    2016-06-15

    We report, microemulsion mediated synthesis of FITC-dextran dye entrapped and silica coated Gd2O3 nanoparticles (NPs) for dual purpose of optical and magnetic resonance imaging, in the present study. TEM image revealed that the average size of the NPs is 18nm and hydrodynamic diameter of the particles as measured by DLS comes out to be about 16nm. Gd2O3 core show paramagnetism which is affirmed by the NMR line broadening effect on neighboring water proton spectrum and also by magnetization curve obtained in VSM analysis. The fluorescence of the entrapped dye is confirmed by the UV-vis and fluorescence spectroscopy. Nanoencapsulation of FITC-dextran fluorophore was found to increase its optical activity and provided a blanket against quenching. Moreover, TGA data revealed that entrapment of dye imparts thermal stability to it and enhances its fluorescence in comparison to bare dye. The release kinetic pattern (at pH 7.4) of the entrapped dye revealed that these particles behave as non-releasing system. The in-vitro cell viability (SRB) assay of the particles done on normal cell line (HEK-293) as well as cancerous cell line (A-549) indicated non-cytotoxic nature of the particles. In a nut-shell, these particles have the potential to be efficiently used for optical and magnetic resonance imaging. We anticipate that further optimization of these particles can be done by either conjugating or entrapping a drug for targeted drug delivery which would open more prospective options in biomedical field. PMID:27032564

  6. Universal method for crosstalk noise and transmission loss analysis for N-port nonblocking optical router for photonic networks-on-chip

    NASA Astrophysics Data System (ADS)

    Xie, Yiyuan; Zhang, Zhendong; Song, Tingting; He, Chao; Li, Jiachao; Wang, Guijin

    2016-05-01

    Crosstalk noise and transmission loss are two key elements in determining the performance of optical routers. We propose a universal method for crosstalk noise and transmission loss analysis for the N-port nonblocking optical router used in photonic networks-on-chip. Utilizing this method, we study the crosstalk noise and transmission loss for the five-, six-, seven-, and eight-port optical routers. We ascertain that the crosstalk noise and transmission loss are different for different input-output pairs. For the five-port optical router, the maximum crosstalk noise ranges from 0 to -7.07 dBm, and the transmission loss ranges from -9.05 to -0.51 dB. Furthermore, based on the crosstalk noise and transmission loss, we analyze optical signal-to-noise ratio (OSNR) and bit error ratio (BER) for the five-, six-, seven-, and eight-port nonblocking optical routers. As the number of ports increases, the minimum average OSNR decreases and the average BER increases. In addition, in order to present the performance of the routers more visually, a fiber-optic communications system is designed to simulate the transmission processes of the signals of the different paths of the routers in Optisystem. The results show that the power amplitude of the input signal is obviously higher than the corresponding output signal. With this method, we can easily evaluate the transmission loss, crosstalk noise, OSNR, and BER of high-radix nonblocking optical routers and conveniently study the performance of the N-port optical router.

  7. Signal processing algorithm of newly developed transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Lee, Jung-Ju; Kwon, Il-Bum

    2000-06-01

    The newly developed TEFPI (transmission-type extrinsic Fabry- Perot interferometric) optical fiber sensor can distinguish the direction of measurement more simply and effectively than the conventional reflection-type EFPI optical fiber sensors. The output signal of the TEFPI optical fiber sensor has the characteristics that the signal level of fringes shows a negative slope for a tensile direction and a positive slope for a compressive direction. Based on these characteristics, the direction of measurement of the TEFPI optical fiber sensor can be distinguished with ease. In this paper, the signal processing algorithm adequate to the TEFPI optical fiber sensor was developed. This algorithm can process signal with recognition of the positions of peaks, valleys and signal levels of fringes. Thus this can determine a measurement direction and the positions of direction changes by using the change trend of signal levels. The developed algorithm makes the post-process and real-time process of the signal of the TEFPI optical fiber sensor possible.

  8. Study on laser damage of high transmission single layer optical thin film for fused silica glass induced by inclusion

    NASA Astrophysics Data System (ADS)

    Hao, Ming-ming; Lu, Guo-guang; Zhu, Hong-bo; Wang, Li-na

    2015-08-01

    In order to research the laser damage mechanism of high transmission single layer optical thin film for fused silica glass, finite element method was used to calculate laser induced damage threshold (LIDT) and an optical test system with a nanosecond solid-state lasers was set up to determine the LIDT according to standard of ISO 11254. Firstly, finite element model was created at COMSOL multi-physics software and the temperature of inclusion in the optical thin film was calculated with different physical parameter. It is found that temperature at center of the inclusion firstly decreases and then increase with the increasing of inclusion depth. It is also found that the temperature constantly increase with the radius increasing from 20nm to 100nm. Moreover, the inclusion temperature for MgF2 thin film is higher than that of CaF2 thin film. Lastly, LIDT were measured by the optical test system, and the average value of LIDT is 3.7J/cm2 for MgF2 thin film and 4.6J/cm2 for CaF2 thin film, which is well fit with the value calculated by COMSOL software. The study shows that finite element method is an effective method to calculate LIDT for optical thin film and impurity has significant impact on the LIDT of optical thin film and therefore decreasing the density of the impurity would increase the LIDT of the thin film.

  9. Synchronization System for Next Generation Light Sources

    SciTech Connect

    Zavriyev, Anton

    2014-03-27

    An alternative synchronization technique – one that would allow explicit control of the pulse train including its repetition rate and delay is clearly desired. We propose such a scheme. Our method is based on optical interferometry and permits synchronization of the pulse trains generated by two independent mode-locked lasers. As the next generation x-ray sources will be driven by a clock signal derived from a mode-locked optical source, our technique will provide a way to synchronize x-ray probe with the optical pump pulses.

  10. Polarization-independent operation of an acousto-optical device at the transmit end of a single-laser transmission system using self-heterodyning

    NASA Astrophysics Data System (ADS)

    Olivier, L.; Rocks, M.

    1991-03-01

    This paper describes the way in which a new integrated acousto-optical LiNbO 3 device combining the three functions of an electro-optical phase modulator, an acousto-optical TE/TM or TM/TE mode converter and an acousto-optical frequency shifter can be operated in a polarization-independent manner as a transmitter unit in a single-laser transmission system using self-heterodyning.

  11. Determination of thickness and optical constants of solgel derived polyvinylpyrrolidone/ZrO2 films from transmission spectra using different dispersion models.

    PubMed

    Jia, Hongbao; Sun, Jinghua; Xu, Yao; Wu, Dong

    2012-10-10

    Transmission measurements have been used to investigate the optical properties of polyvinylpyrrolidone (PVP)/ZrO(2) films synthesized by the solgel route. The optical constants of PVP/ZrO(2) films deposited on quartz substrates were determined by fitting transmission spectra in the wavelength range of 200-800 nm with the Tauc-Lorentz and Cody-Lorentz physical models. Combined with Urbach tail, both models give a good description of transmission data and reveal that refractive index of film slightly decreases with increasing PVP mass fraction. X-ray reflectivity (XRR) measurements were also performed on PVP/ZrO(2) films to complement the thicknesses. The value of film thickness, including interface information from transmission spectra, is consistent with that result obtained from XRR, indicating that fitting transmission spectrum is a high reliable optical characterization. PMID:23052070

  12. Ultrahigh brilliance quasi-monochromatic MeV γ-rays based on self-synchronized all-optical Compton scattering.

    PubMed

    Yu, Changhai; Qi, Rong; Wang, Wentao; Liu, Jiansheng; Li, Wentao; Wang, Cheng; Zhang, Zhijun; Liu, Jiaqi; Qin, Zhiyong; Fang, Ming; Feng, Ke; Wu, Ying; Tian, Ye; Xu, Yi; Wu, Fenxiang; Leng, Yuxin; Weng, Xiufeng; Wang, Jihu; Wei, Fuli; Yi, Yicheng; Song, Zhaohui; Li, Ruxin; Xu, Zhizhan

    2016-01-01

    Inverse Compton scattering between ultra-relativistic electrons and an intense laser field has been proposed as a major route to generate compact high-brightness and high-energy γ-rays. Attributed to the inherent synchronization mechanism, an all-optical Compton scattering γ-ray source, using one laser to both accelerate electrons and scatter via the reflection of a plasma mirror, has been demonstrated in proof-of-principle experiments to produce a x-ray source near 100 keV. Here, by designing a cascaded laser wakefield accelerator to generate high-quality monoenergetic e-beams, which are bound to head-on collide with the intense driving laser pulse via the reflection of a 20-um-thick Ti foil, we produce tunable quasi-monochromatic MeV γ-rays (33% full-width at half-maximum) with a peak brilliance of ~3 × 10(22) photons s(-1) mm(-2) mrad(-2) 0.1% BW at 1 MeV. To the best of our knowledge, it is one order of magnitude higher than ever reported value of its kinds in MeV regime. This compact ultrahigh brilliance γ-ray source may provide applications in nuclear resonance fluorescence, x-ray radiology and ultrafast pump-probe nondestructive inspection. PMID:27405540

  13. Ultrahigh brilliance quasi-monochromatic MeV γ-rays based on self-synchronized all-optical Compton scattering

    PubMed Central

    Yu, Changhai; Qi, Rong; Wang, Wentao; Liu, Jiansheng; Li, Wentao; Wang, Cheng; Zhang, Zhijun; Liu, Jiaqi; Qin, Zhiyong; Fang, Ming; Feng, Ke; Wu, Ying; Tian, Ye; Xu, Yi; Wu, Fenxiang; Leng, Yuxin; Weng, Xiufeng; Wang, Jihu; Wei, Fuli; Yi, Yicheng; Song, Zhaohui; Li, Ruxin; Xu, Zhizhan

    2016-01-01

    Inverse Compton scattering between ultra-relativistic electrons and an intense laser field has been proposed as a major route to generate compact high-brightness and high-energy γ-rays. Attributed to the inherent synchronization mechanism, an all-optical Compton scattering γ-ray source, using one laser to both accelerate electrons and scatter via the reflection of a plasma mirror, has been demonstrated in proof-of-principle experiments to produce a x-ray source near 100 keV. Here, by designing a cascaded laser wakefield accelerator to generate high-quality monoenergetic e-beams, which are bound to head-on collide with the intense driving laser pulse via the reflection of a 20-um-thick Ti foil, we produce tunable quasi-monochromatic MeV γ-rays (33% full-width at half-maximum) with a peak brilliance of ~3 × 1022 photons s−1 mm−2 mrad−2 0.1% BW at 1 MeV. To the best of our knowledge, it is one order of magnitude higher than ever reported value of its kinds in MeV regime. This compact ultrahigh brilliance γ-ray source may provide applications in nuclear resonance fluorescence, x-ray radiology and ultrafast pump-probe nondestructive inspection. PMID:27405540

  14. High-Gain Thompson-Scattering X-Ray Free-Electron Laser by Time-Synchronic Laterally Tilted Optical Wave

    NASA Astrophysics Data System (ADS)

    Chang, Chao; Tang, Chuanxiang; Wu, Juhao

    2013-02-01

    A novel approach to generating coherent x rays with 109-1010 photons and femtoseconds duration per laser pulse is proposed. This high intensity x-ray source is realized first by the pulse front tilt of a lateral fed laser to extend the electron-laser synchronic interaction time by several orders, which accomplishes the high-gain free-electron-laser-type exponential growth process and coherent emission with highly microbunched electron beam. Second, two methods are presented to enhance the effective optical undulator strength parameter. One is to invoke lenses to focus two counterpropagating lasers that are at normal incidence to the electron beam as a transverse standing wave; the other is to invent a periodic microstructure that can significantly enhance the center electromagnetic field realized by a resonant standing wave and the quadrupole waveguides. The energy coupling efficiency between the electron beam and laser is therefore greatly improved to generate the high brightness x rays, which is demonstrated by analytical and simulation results.

  15. Ultrahigh brilliance quasi-monochromatic MeV γ-rays based on self-synchronized all-optical Compton scattering

    NASA Astrophysics Data System (ADS)

    Yu, Changhai; Qi, Rong; Wang, Wentao; Liu, Jiansheng; Li, Wentao; Wang, Cheng; Zhang, Zhijun; Liu, Jiaqi; Qin, Zhiyong; Fang, Ming; Feng, Ke; Wu, Ying; Tian, Ye; Xu, Yi; Wu, Fenxiang; Leng, Yuxin; Weng, Xiufeng; Wang, Jihu; Wei, Fuli; Yi, Yicheng; Song, Zhaohui; Li, Ruxin; Xu, Zhizhan

    2016-07-01

    Inverse Compton scattering between ultra-relativistic electrons and an intense laser field has been proposed as a major route to generate compact high-brightness and high-energy γ-rays. Attributed to the inherent synchronization mechanism, an all-optical Compton scattering γ-ray source, using one laser to both accelerate electrons and scatter via the reflection of a plasma mirror, has been demonstrated in proof-of-principle experiments to produce a x-ray source near 100 keV. Here, by designing a cascaded laser wakefield accelerator to generate high-quality monoenergetic e-beams, which are bound to head-on collide with the intense driving laser pulse via the reflection of a 20-um-thick Ti foil, we produce tunable quasi-monochromatic MeV γ-rays (33% full-width at half-maximum) with a peak brilliance of ~3 × 1022 photons s‑1 mm‑2 mrad‑2 0.1% BW at 1 MeV. To the best of our knowledge, it is one order of magnitude higher than ever reported value of its kinds in MeV regime. This compact ultrahigh brilliance γ-ray source may provide applications in nuclear resonance fluorescence, x-ray radiology and ultrafast pump-probe nondestructive inspection.

  16. Effects of Temperature, Pressure, and Metal Promoter on the Recrystallized Structure and Optical Transmission of Chemical Vapor Deposited Zinc Sulfide

    SciTech Connect

    McCloy, John S.; Korenstein, Ralph; Zelinski, Brian

    2009-08-01

    Structural changes from processing in polytype-rich ZnS are complex and poorly understood In this study, recrystallization was induced in chemical vapor deposited (CVD) ZnS by annealing and hot isostatic pressing (HIPing). Samples were characterized using optical microscopy, SEM, TEM, electron diffraction, polycrystalline and powder x-ray diffraction, and transmission spectroscopy. Recrystallization was found to reduce the hexagonality and increase the texture of as deposited ZnS. Changes in hexagonality and texture can occur independently of each other. HIP’d ZnS with superior transmission exhibits both a change in texture as well as a reduction in hexagonal content. Reduction in hexagonality, alone, was not sufficient to improve optical transmission from the visible to the infrared. For the first time, the effects of pressure, temperature, and the presence of platinum on recrystallization during commercial ZnS HIPing are separated and identified. Platinum was found to actively promote recrystallization and silver demonstrated a similar effect. Several theories focusing on the unique polytypic nature of ZnS are offered to explain the changes in structure and properties occurring during recrystallization, These findings contribute to a broader understanding of the nature of order-disorder and martensitic phase transformations in ceramic materials.

  17. Optical OFDM transmission for long-haul, metro/access, and data center applications

    NASA Astrophysics Data System (ADS)

    Srivastava, Anand

    2013-12-01

    Orthogonal frequency division multiplexing (OFDM) is a modulation technique which is now used in most new and emerging broadband wired and wireless communication systems because it is an effective solution to inter-symbol interference caused by a dispersive channel. Very recently a number of researchers have shown that OFDM is also a promising technology for optical communications. This paper gives a overview of OFDM for long-haul, metro/access and data center highlighting the aspects that are likely to be important in optical applications. To achieve good performance in optical systems OFDM must be adapted in various ways. The constraints imposed by optical channel are discussed and the new forms of optical OFDM which have been developed are outlined. The main drawbacks of OFDM are its high peak to average power ratio and its sensitivity to phase noise and frequency offset. The impairments that these cause are described and their implications for optical systems discussed.

  18. 1-D, 2-D and 3-D Negative-Refraction Metamaterials at Optical Frequencies: Optical Nano-Transmission-Line and Circuit Theory

    NASA Astrophysics Data System (ADS)

    Engheta, Nader; Alu, Andrea

    2006-03-01

    In recent years metamaterials have offered new possibilities for overcoming some of the intrinsic limitations in wave propagation. Their realization at microwave frequencies has followed two different paths; one consisting of embedding resonant inclusions in a host dielectric, and the other following a transmission-line approach, i.e., building 1-D, 2-D, or 3-D cascades of circuit elements, respectively, as linear, planar or bulk right- or left-handed metamaterials. The latter is known to provide larger bandwidth and better robustness to ohmic losses. Extending these concepts to optical frequencies is a challenging task, due to changes in material response to electromagnetic waves at these frequencies. However, recently we have studied theoretically how it may be possible to have circuit nano-elements at these frequencies by properly exploiting plasmonic resonances. Here we present our theoretical work on translating the circuit concepts of right- and left-handed metamaterials into optical frequencies by applying the analogy between nanoparticles and nanocircuit elements in transmission lines. We discuss how it is possible to synthesize optical negative-refraction metamaterials by properly cascading plasmonic and non-plasmonic elements in 1-D, 2-D and 3-D geometries.

  19. Long-reach transmission experiment of a wavelength division multiplexed-passive optical networks transmitter based on reflective semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Jeon, Sie-Wook; Kim, Youngbok; Park, Chang-Soo

    2012-01-01

    We propose and demonstrate a long-reach wavelength division multiplexed-passive optical networks (WDM-PON) based on reflective semiconductor optical amplifiers (RSOAs) with easy maintenance of the optical source. Unlike previous studies the proposed WDM-PON uses two RSOAs: one for wavelength-selected light generation to provide a constant seed light to the second RSOA, the other for active external modulation. This method is free from intensity-fluctuated power penalties inherent to directly modulated single-RSOA sources, making long-reach transmission possible. Also, the wavelength of the modulated signal can easily be changed for the same RSOA by replacing the external feedback reflector, such as a fiber Bragg grating, or via thermal tuning. The seed light has a high-side-mode suppression ratio (SMSR) of 45 dB, and the bit error rate (BER) curve reveals that the upstream 1.25-Gb/s nonreturn-to-zero (NRZ) signal with a pseudo-random binary sequence (PRBS) of length of 215-1 has power penalties of 0.22 and 0.69 dB at BERs of 10-9 after 55-km and 110-km transmission due to fiber dispersion, respectively.

  20. 107 Gb/s coherent optical OFDM transmission over 1000-km SSMF fiber using orthogonal band multiplexing.

    PubMed

    Shieh, W; Yang, Q; Ma, Y

    2008-04-28

    Coherent optical OFDM (CO-OFDM) has emerged as an attractive modulation format for the forthcoming 100 Gb/s Ethernet. However, even the spectral-efficient implementation of CO-OFDM requires digital-to-analog converters (DAC) and analog-to-digital converters (ADC) to operate at the bandwidth which may not be available today or may not be cost-effective. In order to resolve the electronic bandwidth bottleneck associated with DAC/ADC devices, we propose and elucidate the principle of orthogonal-band-multiplexed OFDM (OBM-OFDM) to subdivide the entire OFDM spectrum into multiple orthogonal bands. With this scheme, the DAC/ADCs do not need to operate at extremely high sampling rate. The corresponding mapping to the mixed-signal integrated circuit (IC) design is also revealed. Additionally, we show the proof-of-concept transmission experiment through optical realization of OBM-OFDM. To the best of our knowledge, we present the first experimental demonstration of 107 Gb/s QPSK-encoded CO-OFDM signal transmission over 1000 km standard-single- mode-fiber (SSMF) without optical dispersion compensation and without Raman amplification. The demonstrated system employs 2x2 MIMO-OFDM signal processing and achieves high electrical spectral efficiency with direct-conversion at both transmitter and receiver. PMID:18545341

  1. Development of tellurium oxide and lead-bismuth oxide glasses for mid-wave infra-red transmission optics

    NASA Astrophysics Data System (ADS)

    Zhou, Beiming; Rapp, Charles F.; Driver, John K.; Myers, Michael J.; Myers, John D.; Goldstein, Jonathan; Utano, Rich; Gupta, Shantanu

    2013-03-01

    Heavy metal oxide glasses exhibiting high transmission in the Mid-Wave Infra-Red (MWIR) spectrum are often difficult to manufacture in large sizes with optimized physical and optical properties. In this work, we researched and developed improved tellurium-zinc-barium and lead-bismuth-gallium heavy metal oxide glasses for use in the manufacture of fiber optics, optical components and laser gain materials. Two glass families were investigated, one based upon tellurium and another based on lead-bismuth. Glass compositions were optimized for stability and high transmission in the MWIR. Targeted glass specifications included low hydroxyl concentration, extended MWIR transmission window, and high resistance against devitrification upon heating. Work included the processing of high purity raw materials, melting under controlled dry Redox balanced atmosphere, finning, casting and annealing. Batch melts as large as 4 kilograms were sprue cast into aluminum and stainless steel molds or temperature controlled bronze tube with mechanical bait. Small (100g) test melts were typically processed in-situ in a 5%Au°/95%Pt° crucible. Our group manufactured and evaluated over 100 different experimental heavy metal glass compositions during a two year period. A wide range of glass melting, fining, casting techniques and experimental protocols were employed. MWIR glass applications include remote sensing, directional infrared counter measures, detection of explosives and chemical warfare agents, laser detection tracking and ranging, range gated imaging and spectroscopy. Enhanced long range mid-infrared sensor performance is optimized when operating in the atmospheric windows from ~ 2.0 to 2.4μm, ~ 3.5 to 4.3μm and ~ 4.5 to 5.0μm.

  2. Application of fiber-optic bragg grating sensors in monitoring environmental loads of overhead power transmission lines.

    PubMed

    Bjerkan, L

    2000-02-01

    We demonstrate the capability of using fiber-optic sensors for measurements on environmental loads on a high-power, overhead transmission line. A trial system with three Bragg gratings, including a temperature reference, was installed on a 160-m span of a 60-kV line. An interrogation system with a tunable distributed Bragg reflector laser source was used. Several measurements of the induced loads on a conductor were recorded in various wind conditions. In particular, aeolian vibrations were frequently observed, and several measurements of this phenomenon were made. The results correlate well with simple theoretical predictions and visual observations. PMID:18337925

  3. Giant-enhancement of extraordinary optical transmission through nanohole arrays blocked by plasmonic gold mushroom caps

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Hu, Pidong; Liu, Chengpu

    2015-01-01

    An improved plasmonic hole array nanostructure model with the holes blocked by gold mushroom caps is proposed and it can realize a giant transmission with efficiency up to 65%, 182% larger than the unblocked nanohole array, due to the strong coupling between caps and holes, which plays the role of a cavity antenna. Moreover, the numerical investigation confirms that it provides more consistency with the practical experimental situations, than the nanodisk model instead. As expected, the light transmission sensitively depends on the geometric parameters of this new nanostructure; as the cap-hole's gap or cap's diameter vary, there always exists an optimal transmission efficiency. More interesting is that the corresponding optimal wavelength decreases with the gap's increment or the diameter's decrement, particularly in an exponential decaying way, and the decay rate is obviously influenced by the cap's parameters.

  4. Experimental Investigation on Transmission Control Protocol Throughput Behavior in Optical Fiber Access Networks

    NASA Astrophysics Data System (ADS)

    Tego, Edion; Matera, Francesco; del Buono, Donato

    2016-03-01

    This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.

  5. Vector 8QAM signal generation and transmission based on optical carrier suppression

    NASA Astrophysics Data System (ADS)

    Xiao, Jiangnan; Zhang, Zirang; Li, Xingying; Xu, Yuming; Chen, Long; Yu, Jianjun

    2015-11-01

    We experimentally demonstrate how to generate photonic eight quadrature amplitude modulation (M-QAM) vector signal by using only one Mach-Zehnder modulator (MZM). Because of the 'square-law' characteristic of the photodetector (PD), the amplitudes and the phase of the driving radio-frequency (RF) signal are changed after detection. The pre-coding for the amplitudes and the phase of the driving radio-frequency (RF) signal before they drive the MZM will take the advantages of restoring the driving precoding signal to regular signal after PD. The transmission performance with different date rates at 1, 2, and 3-Gbaud over single-mode fiber (SMF) transmission is experimentally demonstrated. The bit-error ratios (BERs) of the transmission system are less than the forward-error-correction (FEC) threshold of 3.8×10-3.

  6. Optical transmission through double-layer, laterally shifted metallic subwavelength hole arrays

    SciTech Connect

    Marset, zsolt; Hang, z. h.; Chan, C. T.; Kravchenko, Ivan I; Bower, J. E.

    2010-01-01

    We measure the transmission of infra-red radiation through double-layer metal lms with periodic arrays of subwavelength holes. When the two metal lms are placed in su ciently close proximity, two types of transmission resonances emerge. For the surface plasmon mode, the electromagnetic eld is concentrated on the outer surface of the entire metallic layer stack. In contrast, for the guided mode the eld is con ned to the gap between the two metal layers. Our measurements indicate that as the two layers are laterally shifted from perfect alignment, the peak transmission frequency of the guided mode decreases signi cantly, while that of the surface plasmon mode remains largely unchanged, in agreement with numerical calculations.

  7. Image fiber optic space-CDMA parallel transmission experiment using 8 x 8 VCSEL/PD arrays.

    PubMed

    Nakamura, Moriya; Kitayama, Ken-ichi; Igasaki, Yasunori; Shamoto, Naoki; Kaneda, Keiji

    2002-11-10

    We experimentally demonstrate space-code-division multiple access (space-CDMA) based twodimensional (2-D) parallel optical interconnections by using image fibers and 8 x 8 vertical-cavity surface-emitting laser (VCSEL)/photo diode (PD) arrays. Two spatially encoded four-bit (2 x 2) parallel optical signals were emitted fiom 2-D VCSEL arrays and transmitted through image fibers. The encoded signals were multiplexed by an image-fiber coupler and detected by a 2-D PD array on the receiver side. The receiver recovered the intended parallel signal by decoding the signal. The transmission speed was 64 Mbps/ch (total throughput: 512 Mbps). Bit-error-rate (BER) measurement with a laterally misaligned PD array showed the array had a misalignment tolerance of 25 microm for a BER performance of 10(-9). PMID:12440546

  8. Optical-fiber-transmission laser sheet technique for flow visualization in intermittent high-speed wind tunnels

    NASA Astrophysics Data System (ADS)

    Hu, Chenghang

    2003-04-01

    The light sheet technique provides a unique method of visualization for off-body flow fields at subsonic through supersonic speeds. But conventional mirror tansmission laser systems have some shortcomings: The harsh environments of high speed wind tunnels often cause the misalignment of the optical components and the contamination of the mirror surfaces. The exposed laser beam is dangerous to the persons at the work sites. This paper presents an advanced optical-fiber-transmission laser sheet system, which provides a solution to the problems above and greatly improves the quality, safety and reliability of the light sheet. The emphasis is laid on the detailed composition of the new type visualization system. Some examples of its applications in transonic/supersonic wind tunnels are also given in this paper.

  9. Synchronized Flashing Lights For Approach And Docking

    NASA Technical Reports Server (NTRS)

    Book, Michael L.; Howard, Richard T.; Bryan, Thomas C.; Bell, Joseph L.

    1994-01-01

    Proposed optoelectronic system for guiding vehicle in approaching and docking with another vehicle includes active optical targets (flashing lights) on approached vehicle synchronized with sensor and image-processing circuitry on approaching vehicle. Conceived for use in automated approach and docking of two spacecraft. Also applicable on Earth to manually controlled and automated approach and docking of land vehicles, aircraft, boats, and submersible vehicles, using GPS or terrestrial broadcast time signals for synchronization. Principal advantage: optical power reduced, with consequent enhancement of safety.

  10. Acoustic waveguide technique for sensing incipient faults in underground power-transmission cables: including acousto-optic techniques. Final report

    SciTech Connect

    Harrold, R.T.

    1981-09-01

    The feasibility of using acoustic waveguide techniques for sensing incipient faults in underground power transmission cables was determined. Theoretical and practical studies were made of both the acoustic emission spectrum signatures associated with cable incipient faults, and the attenuation of acoustic waves in waterfilled metal tubes used as waveguides. Based on critical data, it can be estimated that in favorable circumstances, the acoustic waveguide system would only be useful for sensing incipient faults in underground cables of approx. 800 meters (approx. 0.5 miles) or less in length. As underground power transmission cables are often several kilometers in length, it was clear at this stage of the study, that simple acoustic waveguide sensing techniques would not be adequate, and some modification would be needed. With DOE approval it was decided to investigate acousto-optic sensing techniques in order to extend the detection range. In particular, a system in which acoustic emissions from cable incipient faults impinge on a fiber-optic lightguide and locally change its refractive indes, and as a consequence, modulate laser light transmitted along the light guide. Experiments based on this concept were successful, and it has been demonstrated that it is possible to sense acoustic emissions with energy levels below one micro-joule. A practical test of this system in the laboratory using a section of compressed gas-insulated cable with an internal flashover was successfully carried out. Long distance fault sensing with this technique should be feasible as laser light can be transmitted several kilometers in fiber optic lightguides. It is believed that laser-acousto-optic fault sensing is a viable technique which, with development, could be applied for fault sensing in power cables and other apparatus.

  11. Four-dimensional optical multiband-OFDM for beyond 1.4 Tb/s serial optical transmission.

    PubMed

    Djordjevic, Ivan; Batshon, Hussam G; Xu, Lei; Wang, Ting

    2011-01-17

    We propose a four-dimensional (4D) coded multiband-OFDM scheme suitable for beyond 1.4 Tb/s serial optical transport. The proposed scheme organizes the N-dimensional (ND) signal constellation points in the form of signal matrix; employs 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and exploits both orthogonal polarizations. This scheme can fully exploit advantages of OFDM to deal with chromatic dispersion, PMD and PDL effects; and multidimensional signal constellations to improve OSNR sensitivity of conventional optical OFDM. The improvement of 4D-OFDM over corresponding polarization-multiplexed QAM (with the same number of constellation points) ranges from 1.79 dB for 16 signal constellation point-four-dimensional-OFDM (16-4D-OFDM) up to 4.53 dB for 128-4D-OFDM. PMID:21263627

  12. 26 Tbit s-1 line-rate super-channel transmission utilizing all-optical fast Fourier transform processing

    NASA Astrophysics Data System (ADS)

    Hillerkuss, D.; Schmogrow, R.; Schellinger, T.; Jordan, M.; Winter, M.; Huber, G.; Vallaitis, T.; Bonk, R.; Kleinow, P.; Frey, F.; Roeger, M.; Koenig, S.; Ludwig, A.; Marculescu, A.; Li, J.; Hoh, M.; Dreschmann, M.; Meyer, J.; Ben Ezra, S.; Narkiss, N.; Nebendahl, B.; Parmigiani, F.; Petropoulos, P.; Resan, B.; Oehler, A.; Weingarten, K.; Ellermeyer, T.; Lutz, J.; Moeller, M.; Huebner, M.; Becker, J.; Koos, C.; Freude, W.; Leuthold, J.

    2011-06-01

    Optical transmission systems with terabit per second (Tbit s-1) single-channel line rates no longer seem to be too far-fetched. New services such as cloud computing, three-dimensional high-definition television and virtual-reality applications require unprecedented optical channel bandwidths. These high-capacity optical channels, however, are fed from lower-bitrate signals. The question then is whether the lower-bitrate tributary information can viably, energy-efficiently and effortlessly be encoded to and extracted from terabit per second data streams. We demonstrate an optical fast Fourier transform scheme that provides the necessary computing power to encode lower-bitrate tributaries into 10.8 and 26.0 Tbit s-1 line-rate orthogonal frequency-division multiplexing (OFDM) data streams and to decode them from fibre-transmitted OFDM data streams. Experiments show the feasibility and ease of handling terabit per second data with low energy consumption. To the best of our knowledge, this is the largest line rate ever encoded onto a single light source.

  13. Optical vortex beam transmission with different OAM in scattering beads and brain tissue media

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Shi, Lingyan; Lindwasser, Lukas; Marque, Paulo; Lavery, M. P. J.; Alfano, R. R.

    2016-03-01

    Light transmission of Laguerre Gaussian (LG) vortex beams with different orbital angular momentum (OAM) values (L) in scattering beads and mouse brain tissue media were experimentally investigated for the first time in comparison with Gaussian (G) beams. The LG beams with different OAM were generated using a spatial light modulator (SLM) in reflection mode. The scattering beads media consist of various sizes and concentrations of latex beads in water solutions. The transmissions of LG and G beams through scattering beads and brain tissue media were measured with different ratios of sample thicknesses (z) to scattering mean free path (ls) of the turbid media, z/ls. The results indicate that within the ballistic region where z/ls is small, the LG and G beams show no significant difference, while in the diffusive region where z/ls is higher, the vortex beams show higher transmission than G beams. In the diffusive region, the LG beams with higher L values show higher transmission than the beams with lower L values due to the eigen channels in the media. The transition points from the ballistic to diffusive regions for different scattering beads and brain tissue media were studied.

  14. Fermi Timing and Synchronization System

    SciTech Connect

    Wilcox, R.; Staples, J.; Doolittle, L.; Byrd, J.; Ratti, A.; Kaertner, F.X.; Kim, J.; Chen, J.; Ilday, F.O.; Ludwig, F.; Winter, A.; Ferianis, M.; Danailov, M.; D'Auria, G.

    2006-07-19

    The Fermi FEL will depend critically on precise timing of its RF, laser and diagnostic subsystems. The timing subsystem to coordinate these functions will need to reliably maintain sub-100fs synchronicity between distant points up to 300m apart in the Fermi facility. The technology to do this is not commercially available, and has not been experimentally demonstrated in a working facility. Therefore, new technology must be developed to meet these needs. Two approaches have been researched by different groups working with the Fermi staff. At MIT, a pulse transmission scheme has been developed for synchronization of RF and laser devices. And at LBL, a CW transmission scheme has been developed for RF and laser synchronization. These respective schemes have advantages and disadvantages that will become better understood in coming years. This document presents the work done by both teams, and suggests a possible system design which integrates them both. The integrated system design provides an example of how choices can be made between the different approaches without significantly changing the basic infrastructure of the system. Overall system issues common to any synchronization scheme are also discussed.

  15. Moldable AR microstructures for improved laser transmission and damage resistance in CIRCM fiber optic beam delivery systems

    NASA Astrophysics Data System (ADS)

    MacLeod, Bruce D.; Hobbs, Douglas S.; Sabatino, Ernest, III

    2011-06-01

    Anti-reflecting (AR) surface relief microstructures (ARMs) are being developed as a replacement for thin-film AR coatings in laser-based systems to improve light transmission, power handling, operational bandwidth, and system reliability. Because ARMs textures have the potential to be replicated using simple embossing methods, the performance advantage and robustness of ARMs can be extended to moldable mid-infrared transmitting materials such as chalcogenide optical fibers. In this work, the optical performance of mid-infrared transparencies incorporating ARMs textures replicated from a master template has been modeled, and multiple master stamping tools have been fabricated in materials such as diamond, silicon carbide, nickel, silicon, and sapphire. Images from ARMs texture embossing trials using arsenic sulfide and arsenic selenide (AMTIR2) glasses, and fluoride glasses such as ZBLAN and indium fluoride provided by IRPhotonics, show excellent pattern transfer and fidelity. Transmission measurements of ARMs textures stamped into arsenic sulfide and arsenic selenide windows show broadband infrared performance equivalent to ARMs textured windows processed by direct patterning and etch methods. A system for molding ARMs textures directly into the end facets of multi-mode mid-infrared transmitting fibers is yielding promising initial results.

  16. A novel construction scheme of QC-LDPC codes based on the RU algorithm for optical transmission systems

    NASA Astrophysics Data System (ADS)

    Yuan, Jian-guo; Liang, Meng-qi; Wang, Yong; Lin, Jin-zhao; Pang, Yu

    2016-03-01

    A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check (QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke (RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain ( NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 dB, 1.25 dB and 0.29 dB more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate ( BER) of 10-6. The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.

  17. HfO2/SiO2 multilayer based reflective and transmissive optics from the IR to the UV

    NASA Astrophysics Data System (ADS)

    Wang, Jue; Hart, Gary A.; Oudard, Jean Francois; Wamboldt, Leonard; Roy, Brian P.

    2016-05-01

    HfO2/SiO2 multilayer based reflective optics enable threat detection in the short-wave/middle-wave infrared and high power laser targeting capability in the near infrared. On the other hand, HfO2/SiO2 multilayer based transmissive optics empower early missile warning by taking advantage of the extremely low noise light detection in the deep-ultraviolet region where solar irradiation is strongly absorbed by the ozone layer of the earth's atmosphere. The former requires high laser damage resistance, whereas the latter needs a solar-blind property, i.e., high transmission of the radiation below 290 nm and strong suppression of the solar background from 300 nm above. The technical challenges in both cases are revealed. The spectral limits associated with the HfO2 and SiO2 films are discussed and design concepts are schematically illustrated. Spectral performances are realized for potential A and D and commercial applications.

  18. Data Transmission Concepts.

    ERIC Educational Resources Information Center

    Christenson, Chris

    1995-01-01

    Introduces some basic concepts related to the transmission of data from a computer to its peripherals to help distance educators make decisions regarding computer equipment purchases for their institutions. The following data transmission concepts are described: cables, serial and parallel, synchronous and asynchronous, bandwidth, and analog and…

  19. Theoretical and experimental investigation of compatible SSB modulation for single channel long-distance optical OFDM transmission.

    PubMed

    Zhang, Yuanyuan; O'Sullivan, Maurice; Hui, Rongqing

    2010-08-01

    We present the first experimental demonstration of compatible single-sideband (compatible-SSB) modulated OFDM optical system at 11.1Gb/s data rate for long distance transmission over 675 km uncompensated standard single-mode fiber. Compatible-SSB modulation employing a simple dual-drive Mach-Zehnder modulator (MZM) in the transmitter and direct-detection at the receiver provides an OFDM system implementation with reduced complexity. It does not require a guard-band between the carrier and the OFDM sideband and so makes full use of available digital-to-analog converter (DAC) bandwidth. We demonstrate digital pre-compensation applied in the transmitter to correct MZM nonlinear transfer function and to improve the system transmission performance. We show that optimum modulation index value decreases with increasing transmission distance. We have also investigated the impact of self-phase modulation (SPM) on the system performance, and show that a compatible-SSB modulated system is less vulnerable to SPM in comparison to the conventional offset-SSB modulation at the same data rate. PMID:20721066

  20. Comparison of radiation-induced transmission degradation of borosilicate crown optical glass from four different manufacturers

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei; Doyle, Dominic; Glebov, Leonid; Berghmans, Francis

    2005-09-01

    Space-born optical systems must be tolerant to radiation to guarantee that the required system performance is maintained during prolonged mission times. The radiation-induced absorption in optical glasses is often related with the presence of impurities, which are, intentionally or not, introduced during the manufacturing process. Glass manufacturers use proprietary fabrication processes and one can expect that the radiation sensitivity of nominally identical optical glasses from different manufacturers is different. We studied the gamma-radiation induced absorption of several crown glasses with nd ≈ 1.516 and vd ≈ 64, i.e. NBK7 (Schott), S-BSL7 (Ohara), BSC 517642 (Pilkington) and K8 (Russia). NBK7 recently replaced the well-known BK7. We therefore also compared the radiation response of NBK7 and BK7 glass. Our results show that whereas the glasses are optically similar before irradiation, they show a different induced absorption after irradiation and also different post-radiation recovery kinetics. Taking these differences into account can help to improve the radiation tolerance of optical systems for space applications.

  1. Analysis of Faraday rotation and magneto-optical transmission in monolayer graphene

    NASA Astrophysics Data System (ADS)

    Wang, Xinyang; Shovkovy, Igor

    2011-10-01

    Graphene, a single atomic layer of graphite, was isolated in 2004. To understand the properties of this two dimensional material is one of the most popular and important research areas in condensed matter and materials physics. The study of optical conductivity in a strong magnetic field provides an interesting response that sheds light on the nature of spontaneous symmetry breaking of an approximate favor symmetry and causes the anomalous quantum Hall effect. We will discuss the possibility of different types of order parameters, associated with the quantum Hall ferromagnetism and magnetic catalysis. We use the results for the optical conductivity to calculate the magneto-optical absorption and the Faraday rotation angle, and compare the results with recent experiments. Also, we present a theoretical prediction for these properties in the regimes not yet explored in experiments.

  2. Role of amplified spontaneous emission in optical free-space communication links with optical amplification: impact on isolation and data transmission and utilization for pointing, acquisition, and

    NASA Astrophysics Data System (ADS)

    Winzer, Peter J.; Kalmar, Andras; Leeb, Walter R.

    1999-04-01

    We investigate the role of amplified spontaneous emission (ASE) produced by an optical booster amplifier at the transmitter of free-space optical communication links. In a communication terminal with a single telescope for both transmission and reception, this ASE power has to be taken into account in connection with transmit-to-receive channel isolation, especially since it partly occupies the same state of polarization and the same frequency band as the receive signal. We show that the booster ASE intercepted by the receiver can represent a non-negligible source of background radiation: In a typical optical intersatellite link scenario, the ASE power spectral density generated by the booster amplifier at the transmitter and coupled to the receiver will be on the order of 10-20 W/Hz, which equals the background radiation of the sun. Exploiting these findings for pointing, acquisition, and tracking (PAT) purposes, we describe a patent-pending PAT system doing without beacon lasers and without the need for diverting a part of the data signal for PAT. Utilizing the transmit booster ASE over a bandwidth of e.g. 20 nm at the receiver, a total power of about -46 dBm is available for PAT purposes without extra power consumption at the transmitter and without the need for beacon lAser alignment.

  3. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses.

    PubMed

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-01-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals. PMID:26323238

  4. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses

    PubMed Central

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-01-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals. PMID:26323238

  5. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses

    NASA Astrophysics Data System (ADS)

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-09-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals.

  6. Optical reflection, transmission and absorption properties of single-layer black phosphorus from a model calculation

    NASA Astrophysics Data System (ADS)

    Margulis, Vl A.; Muryumin, E. E.; Gaiduk, E. A.

    2016-05-01

    An effective anisotropic tight-binding model is developed to analytically describe the low-energy electronic structure and optical response of phosphorene (a black phosphorus (BP) monolayer). Within the framework of the model, we derive explicit closed-form expressions, in terms of elementary functions, for the elements of the optical conductivity tensor of phosphorene. These relations provide a convenient parametrization of the highly anisotropic optical response of phosphorene, which allows the reflectance, transmittance, and absorbance of this material to be easily calculated as a function of the frequency of the incident radiation at arbitrary angles of incidence. The results of such a calculation are presented for both a free-standing phosphorene layer and the phosphorene layer deposited on a {{SiO}}2 substrate, and for the two principal cases of polarization of the incident radiation either parallel to or normal to the plane of incidence. Our findings (e.g., a ‘quasi-Brewster’ effect in the reflectance of the phosphorene/{{SiO}}2 overlayer system) pave the way for developing a new, purely optical method of distinguishing BP monolayers.

  7. Microscopic [ital T]-Violating Optical Potential: Implications for Neutron-Transmission Experiments

    SciTech Connect

    Engel, J.; Gould, C.R.; Hnizdo, V. Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 Department of Physics and Schonland Research Centre for Nuclear Sciences, University of the Witwatersrand, Johannesburg, 2050 )

    1994-12-26

    We derive a [ital T]-violating [ital P]-conserving optical potential for neutron-nucleus scattering, starting from a uniquely determined two-body [rho]-exchange interaction with the same symmetry. We then obtain limits on the [ital T]-violating [rho]-nucleon coupling [ital [bar g

  8. Investigation of fade-out mechanism of resonance modes in optical transmission using stacked metallic sub-wavelength slit arrays

    NASA Astrophysics Data System (ADS)

    Tokuda, Yasunori; Sakaguchi, Koichiro; Takano, Keisuke; Fukushima, Takehiro; Hangyo, Masanori

    2014-06-01

    We investigated the behavior of optical transmission modes in stacked systems composed of metallic sub-wavelength slit-array plates separated by air gaps using simulations based on the finite-difference time-domain method. In double- and triple-stacked structures without a lateral displacement between the plates, the Fabry-Perot-like waveguide resonance modes are classified according to whether the resonance frequencies depend strongly on the air-gap spacing. By introducing a lateral displacement of the plates for both double- and triple-stacked structures, we found that the modes of one category, which were barely affected by changes in the air-gap spacing without the displacement, vary their resonance frequencies considerably when the optical paths are extremely narrow within the air-gap regions and, then, rapidly but continuously attenuate through mixing with the modes of the other category. We demonstrate that this marked behavior results from a manifest distortion in the spatial distribution of the electromagnetic fields for the modes of the first category, induced by the boundary condition at the slit ends changing from open-open to open-closed. Although all resonance modes in the two-tier system disappear continuously through cooperative mode mixing, some modes remain in the three-tier system that vanishes independently and discontinuously as the optical paths become blocked. These findings are indispensable for practical applications and for gaining a deeper understanding of this type of metamaterial.

  9. Anisotropic optical transmission of femtosecond laser induced periodic surface nanostructures on indium-tin-oxide films

    PubMed Central

    Wang, Chih; Wang, Hsuan-I; Luo, Chih-Wei; Leu, Jihperng

    2012-01-01

    Two types of periodic nanostructures, self-organized nanodots and nanolines, were fabricated on the surfaces of indium-tin-oxide (ITO) films using femtosecond laser pulse irradiation. Multiple periodicities (approximately 800 nm and 400 nm) were clearly observed on the ITO films with nanodot and nanoline structures and were identified using two-dimensional Fourier transformation patterns. Both nanostructures show the anisotropic transmission characteristics in the visible range, which are strongly correlated with the geometry and the metallic content of the laser-induced nanostructures. PMID:23066167

  10. Holographic particle image velocimetry: optical conjugate reconstruction using a simplified transmission geometry

    NASA Astrophysics Data System (ADS)

    Alcock, Rob D.; Garner, Colin P.; Halliwell, Neil A.; Coupland, Jeremy M.

    2003-11-01

    A new simplified Holographic Particle Image Velocimetry technique to make simultaneous measurements of 3D velocity vector information throughout a complex fluid flow is presented in this paper. The method uses a variation of Optical Conjugate Reconstruction with complex correlation analysis and dispenses with the need to have a Holographic Optical Element to correct for distortions introduced by non-uniform windows. Subsequent analysis to extract a map of particle velocity is performed digitally using ray tracing techniques to model the effect of the windows. Results are presented for measurements made within a thick windowed diesel engine, showing that flow velocity vectors can be measured to an accuracy of 3% using the technique and, illustrating the ray trace mapping procedure.

  11. Modeling of gamma-radiation impact on transmission characteristics of optical glasses

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei I.; Doyle, Dominic B.

    2002-01-01

    Optical systems operating in space must maintain their performance over long mission times. Glasses are well known to darken upon exposure to radiation, due to formation of color centers, resulting in performance degradation. Despite increasing demand, an approach which would allow accurate prediction of the end-of-life performance characteristics of space optical instruments, has not been elaborated yet. We propose here a phenomenological methodology that should help to solve the problem. In our model, functional dependencies describing defect generation and annealing are derived from mathematical models, taking into account dose levels and irradiation times relevant for space missions. Numerical values for the parameters come from experimental data. Our experimental methodology is also described. We apply this model to analyze the results obtained for BK7 glass subject to Co60 gamma-radiation.

  12. Channel modelling for free-space optical inter-HAP links using adaptive ARQ transmission

    NASA Astrophysics Data System (ADS)

    Parthasarathy, S.; Giggenbach, D.; Kirstädter, A.

    2014-10-01

    Free-space optical (FSO) communication systems have seen significant developments in recent years due to growing need for very high data rates and tap-proof communication. The operation of an FSO link is suited to diverse variety of applications such as satellites, High Altitude Platforms (HAPs), Unmanned Aerial Vehicles (UAVs), aircrafts, ground stations and other areas involving both civil and military situations. FSO communication systems face challenges due to different effects of the atmospheric channel. FSO channel primarily suffers from scintillation effects due to Index of Refraction Turbulence (IRT). In addition, acquisition and pointing becomes more difficult because of the high directivity of the transmitted beam: Miss-pointing of the transmitted beam and tracking errors at the receiver generate additional fading of the optical signal. High Altitude Platforms (HAPs) are quasi-stationary vehicles operating in the stratosphere. The slowly varying but precisely determined time-of-flight of the Inter-HAP channel adds to its characteristics. To propose a suitable ARQ scheme, proper theoretical understanding of the optical atmospheric propagation and modeling of a specific scenario FSO channel is required. In this paper, a bi-directional symmetrical Inter-HAP link has been selected and modeled. The Inter-HAP channel model is then investigated via simulations in terms of optical scintillation induced by IRT and in presence of pointing error. The performance characteristic of the model is then quantified in terms of fading statistics from which the Packet Error Probability (PEP) is calculated. Based on the PEP characteristics, we propose suitable ARQ schemes.

  13. Spatial-domain-based multidimensional modulation for multi-Tb/s serial optical transmission.

    PubMed

    Djordjevic, Ivan B; Arabaci, Murat; Xu, Lei; Wang, Ting

    2011-03-28

    The multidimensional channel capacity studies indicate that the employment of multiple photon degrees of freedom-such as subcarrier, amplitude, phase, polarization, and space-can improve the spectral efficiency by several orders of magnitude higher than that claimed in any fiber-optic experiment reported to date. This dramatic increase in spectral efficiency through multiple photon degrees of freedom can provide revolutionary capabilities for future optical networks. Moreover, photons can carry both spin angular momentum (SAM) associated with polarization, and orbital angular momentum (OAM) associated with the azimuthal phase of the complex electric field. Because OAM eigenstates are orthogonal, an arbitrary number of bits per photon can be transmitted in principle. The ability to generate the OAM modes, such as Bessel modes, in multimode fibers (MMFs) will allow realization of fiber-optic communication networks with ultra-high bits-per-photon efficiencies. To this end, we propose here a spatial-domain-based multidimensional coded-modulation scheme as an enabling technology for multi-Tb/s serial optical transport. To demonstrate the capabilities of the proposed scheme, we show that an eight-dimensional (8D) spatial-domain-based coded modulation scheme outperforms a prior-art 128-point 4D scheme by 3.88 dB at BER of 10(-8) while providing 120 Gb/s higher aggregate information bit rate. The proposed 8D scheme also outperforms its conventional polarization-multiplexed QAM counterpart by even a larger, and indeed striking, margin of 8.39 dB (also at the BER of 10(-8)). PMID:21451712

  14. Computationally efficient analysis of extraordinary optical transmission through infinite and truncated subwavelength hole arrays

    NASA Astrophysics Data System (ADS)

    Camacho, Miguel; Boix, Rafael R.; Medina, Francisco

    2016-06-01

    The authors present a computationally efficient technique for the analysis of extraordinary transmission through both infinite and truncated periodic arrays of slots in perfect conductor screens of negligible thickness. An integral equation is obtained for the tangential electric field in the slots both in the infinite case and in the truncated case. The unknown functions are expressed as linear combinations of known basis functions, and the unknown weight coefficients are determined by means of Galerkin's method. The coefficients of Galerkin's matrix are obtained in the spatial domain in terms of double finite integrals containing the Green's functions (which, in the infinite case, is efficiently computed by means of Ewald's method) times cross-correlations between both the basis functions and their divergences. The computation in the spatial domain is an efficient alternative to the direct computation in the spectral domain since this latter approach involves the determination of either slowly convergent double infinite summations (infinite case) or slowly convergent double infinite integrals (truncated case). The results obtained are validated by means of commercial software, and it is found that the integral equation technique presented in this paper is at least two orders of magnitude faster than commercial software for a similar accuracy. It is also shown that the phenomena related to periodicity such as extraordinary transmission and Wood's anomaly start to appear in the truncated case for arrays with more than 100 (10 ×10 ) slots.

  15. A transmission line model for propagation in elliptical core optical fibers

    NASA Astrophysics Data System (ADS)

    Georgantzos, E.; Papageorgiou, C.; Boucouvalas, A. C.

    2015-12-01

    The calculation of mode propagation constants of elliptical core fibers has been the purpose of extended research leading to many notable methods, with the classic step index solution based on Mathieu functions. This paper seeks to derive a new innovative method for the determination of mode propagation constants in single mode fibers with elliptic core by modeling the elliptical fiber as a series of connected coupled transmission line elements. We develop a matrix formulation of the transmission line and the resonance of the circuits is used to calculate the mode propagation constants. The technique, used with success in the case of cylindrical fibers, is now being extended for the case of fibers with elliptical cross section. The advantage of this approach is that it is very well suited to be able to calculate the mode dispersion of arbitrary refractive index profile elliptical waveguides. The analysis begins with the deployment Maxwell's equations adjusted for elliptical coordinates. Further algebraic analysis leads to a set of equations where we are faced with the appearance of harmonics. Taking into consideration predefined fixed number of harmonics simplifies the problem and enables the use of the resonant circuits approach. According to each case, programs have been created in Matlab, providing with a series of results (mode propagation constants) that are further compared with corresponding results from the ready known Mathieu functions method.

  16. A transmission line model for propagation in elliptical core optical fibers

    SciTech Connect

    Georgantzos, E.; Boucouvalas, A. C.; Papageorgiou, C.

    2015-12-31

    The calculation of mode propagation constants of elliptical core fibers has been the purpose of extended research leading to many notable methods, with the classic step index solution based on Mathieu functions. This paper seeks to derive a new innovative method for the determination of mode propagation constants in single mode fibers with elliptic core by modeling the elliptical fiber as a series of connected coupled transmission line elements. We develop a matrix formulation of the transmission line and the resonance of the circuits is used to calculate the mode propagation constants. The technique, used with success in the case of cylindrical fibers, is now being extended for the case of fibers with elliptical cross section. The advantage of this approach is that it is very well suited to be able to calculate the mode dispersion of arbitrary refractive index profile elliptical waveguides. The analysis begins with the deployment Maxwell’s equations adjusted for elliptical coordinates. Further algebraic analysis leads to a set of equations where we are faced with the appearance of harmonics. Taking into consideration predefined fixed number of harmonics simplifies the problem and enables the use of the resonant circuits approach. According to each case, programs have been created in Matlab, providing with a series of results (mode propagation constants) that are further compared with corresponding results from the ready known Mathieu functions method.

  17. Microwave and Electro-optical Transmission Experiments in the air-sea Boundary Layer

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.

    2002-12-01

    Microwave and electro-optical signal propagation over a wind-roughened sea is strongly dependent on signal interaction with the sea surface, the mean profiles of pressure (P), humidity (Q), temperature (T), wind (U) and their turbulent fluctuations (p, q, t, u). Yet, within the marine surface layer, these mechanisms are not sufficiently understood nor has satisfactory data been taken to validate propagation models, especially under conditions of high seas, high winds, and large surface gradients of Q and T. To address this deficiency, the Rough Evaporation Duct (RED) experiment was designed to provide first data for validation of meteorological, microwave, and electro-optical models in the marine surface layer for rough surface conditions including the effects of surface waves. The RED experiment was conducted offshore of the Hawaiian Island of Oahu in late summer, mid-August to mid-September, of 2001. R/P FLIP, moored about 10 km off of the NE coast of Oahu, hosted the primary meteorological sensor suites and served as a terminus for the propagation links. There were eleven scientists and engineers aboard R/P FLIP who installed instruments measuring mean and turbulent meteorological quantities, sea wave heights, directions, and kinematics, upward and downward radiance, near surface bubble generation, atmospheric particle size distributions, laser probing of the atmosphere, and sources for both microwave and electro-optic signals. In addition to R/P FLIP, two land sites were instrumented with microwave and electro-optic receivers and meteorological sensors, two buoys were deployed, a small boat was instrumented, and two aircraft flew various tracks to sense both sea and atmospheric conditions. In all, more than 25 people from four countries, six universities, and four government agencies were directly involved with the RED experiment. While the overall outcome of the RED experiment is positive, we had a number of major and minor problems with the outfitting

  18. Adaptive 4~64 QAM real-time coherent optical transmission over 320 km with FPGA-based transmitter and receiver.

    PubMed

    Yoshida, Masato; Hirooka, Toshihiko; Kasai, Keisuke; Nakazawa, Masataka

    2014-06-30

    We demonstrate the first real-time adaptive optical coherent QAM transmission with variable multiplicities (4-, 16- and 64-QAM) using an FPGA-based transmitter and receiver. Rate-variable transmission (20~60 Gbit/s) was successfully achieved with a polarization multiplexing scheme at 5 Gsymbol/s over 320 km, where the OSNR margins were increased by 9 and 17 dB, respectively, by changing the modulation level from 64 to 16 and 4. PMID:24977901

  19. Time domain zero-padding based adaptive-PAM signal transmission with high spectral efficiency in IMDD optical communication system

    NASA Astrophysics Data System (ADS)

    Zhang, Fangliu; He, Jing; Deng, Rui; Cheng, Yun; Xiao, Minlei; Chen, Lin

    2016-08-01

    In this paper, an adaptive pulse amplitude modulation (APAM) scheme is proposed and experimentally demonstrated in the intensity-modulation and direct-detection (IMDD) optical communications system. In the proposed scheme, the channel is divided into two sub-channels, and different PAM mapping can be chosen for different sub-channel according to the fading conditions. In addition, the 20-km standard single mode fiber (SSMF) transmission of 24 Gbit/s 16/4-APAM signal with the spectral efficiency (SE) up to 6 bit/s/Hz is experimentally demonstrated. The experiment results show that the bit error rate (BER) of the 16/4-APAM signal can be achieved less than 2.4e-2.

  20. 1-Tb/s single-channel coherent optical OFDM transmission over 600-km SSMF fiber with subwavelength bandwidth access.

    PubMed

    Ma, Yiran; Yang, Qi; Tang, Yan; Chen, Simin; Shieh, William

    2009-05-25

    A 1-Tb/s single-channel coherent optical OFDM (CO-OFDM) signal consisting of continuous 4,104 spectrally-overlapped subcarriers is generated using a novel device of recirculating frequency shifter (RFS). The RFS produces 320.6-GHz wide spectrum using a single laser with superior flatness and tone-to-noise ratio (TNR). The 1-Tb/s CO-OFDM signal is comprised of 36 uncorrelated orthogonal bands achieved by adjusting the delay of the RFS to an integer number of OFDM symbol periods. The 1- Tb/s CO-OFDM signal with a spectral efficiency of 3.3 bit/s/Hz is successfully received after transmission over 600-km SSMF fiber without either Raman amplification or dispersion compensation. PMID:19466194

  1. Optical spectroscopy and energy-filtered transmission electron microscopy of surface plasmons in core-shell nanoparticles.

    SciTech Connect

    Eggeman, A. S.; Dobson, P. J.; Petford-Long, A. K.; Materials Science Division; Oxford Univ.

    2007-01-01

    Silica-silver core-shell nanoparticles were produced using colloidal chemistry methods. Surface plasmon resonances in the silver shells were investigated using optical absorption measurements in ultraviolet-to-visible (UV-vis) spectroscopy and the effect of shell thickness on the wavelength of the resonance was noted. Further studies of the resonances were performed using electron-energy-loss spectroscopy (EELS) and energy-filtered transmission electron microscope (EFTEM) imaging. The plasmon resonance was seen in an EELS spectrum at an energy corresponding to the wavelengths measured in an UV-vis spectrophotometer, and EFTEM images confirmed that the resonance was indeed localized at the surface of the silver shell. Further features were seen in the EELS spectrum and confirmed as bulk-plasmon features of silica and the carbon support film in the TEM specimen.

  2. 512QAM Nyquist sinc-pulse transmission at 54 Gbit/s in an optical bandwidth of 3 GHz.

    PubMed

    Schmogrow, R; Hillerkuss, D; Wolf, S; Bäuerle, B; Winter, M; Kleinow, P; Nebendahl, B; Dippon, T; Schindler, P C; Koos, C; Freude, W; Leuthold, J

    2012-03-12

    We demonstrate for the first time transmission of 54 Gbit/s and 48 Gbit/s over 44 km and 150 km, respectively, utilizing an optical bandwidth of only 3 GHz. We used polarization division multiplexed 512QAM and 256QAM modulation formats in combination with Nyquist pulse shaping having virtually zero roll-off. The resulting spectral efficiencies range up to 18 bit/s/Hz and 16 bit/s/Hz, respectively. Taking into account the overhead required for forward error correction, the occupied signal bandwidth corresponds to net spectral efficiencies of 14.4 bit/s/Hz and 15 bit/s/Hz, which could be achieved in a wavelength division multiplexed network without spectral guard bands. PMID:22418526

  3. Development of two-dimensional multiwire-type neutron detector system with individual line readout and optical signal transmission

    NASA Astrophysics Data System (ADS)

    Toh, K.; Nakamura, T.; Sakasai, K.; Soyama, K.; Hino, M.; Kitaguchi, M.; Yamagishi, H.

    2013-10-01

    A multiwire-type two-dimensional neutron detector system with a sensitive area of 128×128 mm2 is developed for use in the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. The system can achieve a short response time and high spatial resolution using the individual line readout method. Optical devices have been incorporated in the system for long-distance signal transmission and insulation between a detector head in the neutron shielding and signal processing circuits in the data acquisition room. The detector system exhibits a pulse-pair resolution of 1 μs, an average spatial resolution of less than 2 mm full width at half-maximum in the sensitive region, and a two-dimensional homogeneity of 8.3% in all pixels.

  4. Null testing of nonrotational symmetry transmission optical freeform: design, modeling, and inspection on the basis of Fermat principles

    NASA Astrophysics Data System (ADS)

    Qiu, Gufeng; Cui, Xudong

    2015-11-01

    We present a general design method for a type of transmission freeforms without rotational symmetry and achieve the null testing by putting a well-designed Fermat reflector on the transmitting optical path. The design principle of the reflector is given, and an eccentric spherical surface with 1-mm deviation is used as an example of testing freeform. We fabricated the reflector and the freeform with the single-point diamond turning machine. Both conventional interference inspection and our approach give consistent results. The design error is less than 106 mm, and the measurement accuracy is nearly completely determined by the fabrication precision. This approach can also be applied to the inspections of reflecting freeforms with low costs.

  5. Preliminary results of Terabit-per-second long-range free-space optical transmission Experiment THRUST

    NASA Astrophysics Data System (ADS)

    Giggenbach, D.; Poliak, J.; Mata-Calvo, R.; Fuchs, C.; Perlot, N.; Freund, R.; Richter, T.

    2015-10-01

    Future Very High Throughput Satellite Systems (VHTS) will perform at several Tbit/s throughput and thus face the challenge of limited feeder-link spectrum. Whereas with conventional RF feeder links several tens of ground gateway stations would be required, the total capacity can alternatively be linked through a single optical ground station using Dense Wavelength Division Multiplexing (DWDM) techniques as known from terrestrial fiber communications. While intermittent link blockage by clouds can be compensated by ground station diversity, the optical uplink signal is directly affected by scintillation and beam wander induced by the atmospheric index-of-refraction turbulence. The transmission system must be capable to mitigate these distortions by according high-speed tracking and fading compensation techniques. We report on the design of a near-ground long-range (10km) atmospheric transmission test-bed which is, with its relatively low elevation of 1.8 degrees, exemplary for a worst case GEO uplink scenario. The transmitting side of the test-bed consists of a single telescope with a a fine pointing assembly in order to track the atmospheric angle-ofarrival and precisely aim towards the beacon of the receiver. On the other side of the test-bed, the receiver telescope is also capable of fine pointing by tracking the transmitted signal. The GEO uplink scenario is modelled by a precise scaling of the beam divergence and the receiver's field of view as well as by the beacon offset to model the point-ahead angle. In order to make the experimental test-bed correspond to an actual feeder link scenario, the link budget as well as the turbulence profile of the experimental scenario are modelled and compared to the GEO uplink. Several DWDM channels are multiplexed to reach the total link capacity of above one Tbit/s.

  6. Measurements of the relative transmission properties of optical fiber for use on Proto-MPEX

    NASA Astrophysics Data System (ADS)

    Biewer, T. M.; Collins, K.; Johnson, B.; Lancaster, A.; Mosby, R.; Ray, H.; Shaw, G.; Young, B.

    2014-10-01

    The prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being developed at Oak Ridge National Laboratory (ORNL). This machine plans to study plasma-material interaction (PMI) physics relevant to future fusion reactors. Measurements of plasma emission will be made on Proto-MPEX using spectrometers and filterscopes, which are coupled to the plasma by fiberoptic cables. The transmission properties of these fiberoptics are critical to the accurate estimation of the plasma emission levels. This presentation will highlight some of the issues encountered during calibration of hardware for use on Proto-MPEX. This work was supported by the US. D.O.E. Contract DE-AC05-00OR22725, and the Oak Ridge Associated Universities ARC program.

  7. 110 km transmission of 160 Gbit/s RZ-DQPSK signals by midspan polarization-insensitive optical phase conjugation in a Ti:PPLN waveguide.

    PubMed

    Hu, Hao; Nouroozi, Rahman; Ludwig, Reinhold; Schmidt-Langhorst, Carsten; Suche, Hubertus; Sohler, Wolfgang; Schubert, Colja

    2010-09-01

    We demonstrate 160 Gbit/s return-to-zero (RZ) differential quarternary phase-shift keying (DQPSK) signal transmission over a 110 km single-mode fiber by taking advantage of mid-span optical phase conjugation (OPC). The technique is based on nonlinear wavelength conversion by cascaded second harmonic and difference frequency generation in a Ti:PPLN waveguide. Error-free operation with a negligible optical signal-to-noise ratio penalty for the signal after the OPC transmission without and with polarization scrambling was achieved. The results also show the polarization insensitivity of the OPC system using a polarization diversity scheme. PMID:20808351

  8. Metallic attenuated total reflection infrared hollow fibers for robust optical transmission systems

    SciTech Connect

    Jing, Chengbin; Guo, Hong; Hu, Zhigao; Yang, Pingxiong; Chu, Junhao; Liu, Aiyun; Shi, Yiwei

    2014-07-07

    A durable metallic attenuated total reflection (ATR) hollow fiber (bore size: 1.45 mm, wall thickness: 50 μm) was designed and fabricated based on a nickel capillary tube and hexagonal germanium dioxide (GeO{sub 2}). The anomalous dispersion of the hexagonal GeO{sub 2} layer grown inside a nickel tube achieves low-loss light transmission at two peak-power wavelengths for CO{sub 2} laser devices (10.2 and 10.6 μm). An 11–28 W, 10.2 or 10.6 μm CO{sub 2} laser power was steadily delivered via a fiber elastically bent from 0° to 90° (radius: 45 cm) for over 40 min (transmission loss: 0.22 to 4.2 dB/m). Theoretically fitting the measured temperatures showed that front-end clipping caused greater thermal loading than the distributed mode absorption. The maximum external temperature of a nickel ATR fiber is much lower than that of a silica glass ATR fiber owing to their different heat dissipation abilities. The HE{sub 11} mode purity of the output beam profiles decreased from 90.3% to 44.7% as the bending angle increased from 0° to 90°. Large core sizes and wall roughnesses (scattering loss 0.04 dB/m) contributed to mode mixing and excess losses that were above the value predicted by the classical Marcatili and Schmeltzer equation (0.024–0.037 dB/m).

  9. Evaluation of multi-layered graphene surface plasmon resonance-based transmission type fiber optic sensor.

    PubMed

    Kim, Jang Ah; Kulkarni, Atul; Kang, Junmo; Amin, Rashid; Choi, Jae-Boong; Park, Sung Ha; Kim, Taesung

    2012-07-01

    Graphene is a zero band-gap semi-metal with remarkable electromagnetic and mechanical characteristics. This study is the first ever attempt to use graphene in the surface plasmon resonance (SPR) sensor as replacement material for gold/silver. Graphene, comprised of a single atomic layer of carbon, is a purely two-dimensional material and it is an ideal candidate for use as a biosensor because of its high surface-to-volume ratio. This sensor is based on the resonance occasion of the surface plasmon wave (SPW) according to the dielectric constants of each metal film and detected material in gas or aqueous phase. Graphene in the SPR sensor is expected to enlarge the range of analyte to bio-aerosols based on the superior electromagnetic properties of graphene. In this study, a SPR-based fiber optic sensor coated with multi-layered graphene is described. The multi-layered graphene film synthesized by chemical vapor deposition (CVD) on Ni substrate was transferred on the sensing region of an optical fiber. The graphene coated SPR sensor is used to analyze the interaction between structured DNA biotin and Streptavidin is analyzed. Transmitted light after passing through the sensing region is measured by a spectrometer and multimeter. As the light source, blue light which of 450 to 460 nm in wavelength was used. We observed the SPR phenomena in the sensor and show the contrary trends between bare fiber and graphene coated fiber. The fabricated graphene based fiber optic sensor shows excellent detection sensitivity of the interaction between structured DNA and Streptavidin. PMID:22966575

  10. Active photonic sensor communication cable for field application of optical data and power transmission

    NASA Astrophysics Data System (ADS)

    Suthau, Eike; Rieske, Ralf; Zerna, Thomas

    2014-10-01

    Omitting electrically conducting wires for sensor communication and power supply promises protection for sensor systems and monitored structures against lightning or high voltages, prevention of explosion hazards, and reduction of susceptibility to tampering. The ability to photonically power remote systems opens up the full range of electrical sensors. Power-over-fiber is an attractive option in electromagnetically sensitive environments, particularly for longterm, maintenance-free applications. It can deliver uninterrupted power sufficient for elaborate sensors, data processing or even actuators alongside continuous high speed data communication for remote sensor application. This paper proposes an active photonic sensor communication system, which combines the advantages of optical data links in terms of immunity to electromagnetic interference (EMI), high bandwidth, hardiness against tampering or eavesdropping, and low cable weight with the robustness one has come to expect from industrial or military electrical connectors. An application specific integrated circuit (ASIC) is presented that implements a closed-loop regulation of the sensor power supply to guarantee continuous, reliable data communications while maintaining a highly efficient, adaptive sensor supply scheme. It is demonstrated that the resulting novel photonic sensor communication cable can handle sensors and actuators differing orders of magnitude with respect to power consumption. The miniaturization of the electro-optical converters and driving electronics is as important to the presented development as the energy efficiency of the detached, optically powered sensor node. For this reason, a novel photonic packaging technology based on wafer-level assembly of the laser power converters by means of passive alignment will be disclosed in this paper.

  11. Selective optical control of synaptic transmission in the subcortical visual pathway by activation of viral vector-expressed halorhodopsin.

    PubMed

    Kaneda, Katsuyuki; Kasahara, Hironori; Matsui, Ryosuke; Katoh, Tomoko; Mizukami, Hiroaki; Ozawa, Keiya; Watanabe, Dai; Isa, Tadashi

    2011-01-01

    The superficial layer of the superior colliculus (sSC) receives visual inputs via two different pathways: from the retina and the primary visual cortex. However, the functional significance of each input for the operation of the sSC circuit remains to be identified. As a first step toward understanding the functional role of each of these inputs, we developed an optogenetic method to specifically suppress the synaptic transmission in the retino-tectal pathway. We introduced enhanced halorhodopsin (eNpHR), a yellow light-sensitive, membrane-targeting chloride pump, into mouse retinal ganglion cells (RGCs) by intravitreously injecting an adeno-associated virus serotype-2 vector carrying the CMV-eNpHR-EYFP construct. Several weeks after the injection, whole-cell recordings made from sSC neurons in slice preparations revealed that yellow laser illumination of the eNpHR-expressing retino-tectal axons, putatively synapsing onto the recorded cells, effectively inhibited EPSCs evoked by electrical stimulation of the optic nerve layer. We also showed that sSC spike activities elicited by visual stimulation were significantly reduced by laser illumination of the sSC in anesthetized mice. These results indicate that photo-activation of eNpHR expressed in RGC axons enables selective blockade of retino-tectal synaptic transmission. The method established here can most likely be applied to a variety of brain regions for studying the function of individual inputs to these regions. PMID:21483674

  12. High-Throughput All-Optical Analysis of Synaptic Transmission and Synaptic Vesicle Recycling in Caenorhabditis elegans

    PubMed Central

    Wabnig, Sebastian; Liewald, Jana Fiona; Yu, Szi-chieh; Gottschalk, Alexander

    2015-01-01

    Synaptic vesicles (SVs) undergo a cycle of biogenesis and membrane fusion to release transmitter, followed by recycling. How exocytosis and endocytosis are coupled is intensively investigated. We describe an all-optical method for identification of neurotransmission genes that can directly distinguish SV recycling factors in C. elegans, by motoneuron photostimulation and muscular RCaMP Ca2+ imaging. We verified our approach on mutants affecting synaptic transmission. Mutation of genes affecting SV recycling (unc-26 synaptojanin, unc-41 stonin, unc-57 endophilin, itsn-1 intersectin, snt-1 synaptotagmin) showed a distinct ‘signature’ of muscle Ca2+ dynamics, induced by cholinergic motoneuron photostimulation, i.e. faster rise, and earlier decrease of the signal, reflecting increased synaptic fatigue during ongoing photostimulation. To facilitate high throughput, we measured (3–5 times) ~1000 nematodes for each gene. We explored if this method enables RNAi screening for SV recycling genes. Previous screens for synaptic function genes, based on behavioral or pharmacological assays, allowed no distinction of the stage of the SV cycle in which a protein might act. We generated a strain enabling RNAi specifically only in cholinergic neurons, thus resulting in healthier animals and avoiding lethal phenotypes resulting from knockdown elsewhere. RNAi of control genes resulted in Ca2+ measurements that were consistent with results obtained in the respective genomic mutants, albeit to a weaker extent in most cases, and could further be confirmed by opto-electrophysiological measurements for mutants of some of the genes, including synaptojanin. We screened 95 genes that were previously implicated in cholinergic transmission, and several controls. We identified genes that clustered together with known SV recycling genes, exhibiting a similar signature of their Ca2+ dynamics. Five of these genes (C27B7.7, erp-1, inx-8, inx-10, spp-10) were further assessed in respective

  13. Effect of optical channel impairments on measured jitter at 10 Gbps

    NASA Astrophysics Data System (ADS)

    Frost, Charles E.; Bianchi, Charles H.

    2003-08-01

    Operators of today's high-speed optical communications networks are required to deliver error-free transmission and continuously increasing bit rates. The complexity of synchronous optical networks (SONET, SDH) and high-speed data communications systems (Gigabit Ethernet) allows little tolerance for signal impairment. As a result, strict requirements on performance metrics such as synchronization, jitter, bit error rate (BER), and availability are all necessary. This paper reviews jitter and how it may affect the performance of optical communications systems. This will include discussion of important jitter parameters, sources of jitter, and test methods used to measure jitter in optical networks. Measurements of various jitter scenarios on OC-192 transmission will be presented, and the impact of optical signal impairments on OC-192 performance will be shown. Finally, the relationships between optical signal impairments, observed jitter, and 10GbE stressed-eye tests will be discussed.

  14. A study of regeneration and optical transmission in SONET/WDM rings and long haul networks

    NASA Astrophysics Data System (ADS)

    Sevian, Armen

    Current work studies the problem of regeneration in SONET/WDM Rings with the objective to find regenerator placement scenarios to minimize the number of regenerators when different line rates are combined in UPSR and BLSR/2 architectures. The classes of rings are found that satisfy minimum hop condition, and for those classes we first prove the existence of lower and upper bounds for randomly positioned nodes in hubbed and all-to-all traffic cases, and show that the obtained bounds can be used for optimization purposes and also for "quick" quantitative estimates of regeneration cost. We then analyze the survivability profiles for both ring architectures. Although the protection switching mechanism is different for BLSR/2, the result shows that the survivability profile is identical to that of UPSR. Based on a developed Cayley set representation we address the non-uniform traffic problem and compare different traffic cases in terms of introduced network dimension ratio. We prove that it is the Cayley traffic patterns that minimize the regeneration cost with maximum bandwidth allocated to these set connections in the UPSR case. The advantage of NZDSF optical fiber over conventional single-mode fiber in the ring network is presented in terms of regeneration. The results of the effects attributed to the distortion in the optical multichannel systems is presented in this work where the main focus is on the fiber induced BER due to chromatic dispersion and fiber nonlinearities.

  15. Photonic generation of high frequency millimeter-wave and transmission over optical fiber.

    PubMed

    Kumar, Amitesh; Priye, Vishnu

    2016-08-01

    A novel technique of photonic generation of millimeter-waves beyond the presently reported 120 GHz and with a wider tunability (∼240  GHz) is proposed and demonstrated through a simulation experiment. The scheme consists of generating 24 times the frequency of a conventional low frequency microwave source using a combination of a LiNbO3 Mach-Zehnder modulator and four-wave mixing in a semiconductor optical amplifier. The filtering of a high frequency sideband and the suppression of a carrier are achieved by incorporating an optical band pass and fiber Bragg grating filters, respectively. Next, the spectral purity of the generated millimeter-wave parameters is evaluated after propagation through a conventional fiber of different lengths by digitally modulating it at 2.5 Gbps and generating an eye diagram. The constraints on the selection of the frequency of the millimeter-wave and length of fiber are discussed. The present method of millimeter-wave generation and distribution will find applications in photonic up/down conversion, phase-array antennas, photonic sensors, radars, and terahertz applications. PMID:27505360

  16. Intensity modulation and direct detection Alamouti polarization-time coding for optical fiber transmission systems with polarization mode dispersion

    NASA Astrophysics Data System (ADS)

    Reza, Ahmed Galib; Rhee, June-Koo Kevin

    2016-07-01

    Alamouti space-time coding is modified in the form of polarization-time coding to combat against polarization mode dispersion (PMD) impairments in exploiting a polarization diversity multiplex (PDM) gain with simple intensity modulation and direct detection (IM/DD) in optical transmission systems. A theoretical model for the proposed IM/DD Alamouti polarization-time coding (APTC-IM/DD) using nonreturn-to-zero on-off keying signal can surprisingly eliminate the requirement of channel estimation for decoding in the low PMD regime, when a two-transmitter and two-receiver channel is adopted. Even in the high PMD regime, the proposed APTC-IM/DD still reveals coding gain demonstrating the robustness of APTC-IM/DD. In addition, this scheme can eliminate the requirements for a polarization state controller, a coherent receiver, and a high-speed analog-to-digital converter at a receiver. Simulation results reveal that the proposed APTC scheme is able to reduce the optical signal-to-noise ratio requirement by ˜3 dB and significantly enhance the PMD tolerance of a PDM-based IM/DD system.

  17. Bundled hollow optical fibers for transmission of high-peak-power Q-switched Nd:YAG laser pulses

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ozgur; Miyagi, Mitsunobu; Matsuura, Yuji

    2006-09-01

    A hollow-fiber bundle was designed and used to deliver high-peak-power pulses from a Q-switched Nd:YAG laser. An 80 cm long bundle with a total diameter of 5.5 mm was composed of 37 glass capillaries with bore diameters of 0.7 mm. Beam-resizing optics with two lenses were used to couple the laser beam into the bundle. The measured coupling loss due to the limited aperture ratio of the bundle was 2.3 dB, and the transmission loss at wavelengths of 1064 and 532 nm was 0.3 dB. When an inert gas flowed through the bores of the capillaries, the maximum output pulse energy was 200 mJ, which was the limit of the laser used in the experiment. Hollow-fiber bundles withstand irradiation better than single hollow fibers and silica-glass optical fibers do. They are suitable for many dermatological applications because they can be used to irradiate a large area.

  18. Multiwavelength laser light transmission of hollow optical fiber from the visible to the mid-infrared

    NASA Astrophysics Data System (ADS)

    Shi, Yi Wei; Ito, Kentaro; Matsuura, Yuji; Miyagi, Mitsunobu

    2005-11-01

    We report on low-loss multiwavelength laser delivery of hollow optical fiber in a wide wavelength region, from the visible to the infrared. Improved methods of liquid-phase coating were used to fabricate the hollow fiber with inner films of a silver and a cyclic olefin polymer (COP) layer. The surface roughness of the silver layer was reduced dramatically by pretreatment on the inner glass surface with an SnCl2 solution. The COP layer roughness was also decreased by using an ambient atmosphere of tetrahydrofuran (THF) solvent during the COP layer formation. Owing to the smooth surfaces, hollow fiber with optimum COP film thickness for CO2 laser light simultaneously yields low losses for a Er:YAG laser and a red pilot beam. The power durability of CO2 and Er:YAG lasers, as well as the loss properties for the pilot beam, is demonstrated.

  19. Micro-optic reflection and transmission interferometer for complete microlens characterization

    NASA Astrophysics Data System (ADS)

    Gomez, Virginia; Ghim, Young-Sik; Ottevaere, Heidi; Gardner, Neil; Bergner, Brent; Medicus, Kate; Davies, Angela; Thienpont, Hugo

    2009-02-01

    A combined Twyman-Green and Mach-Zehnder interferometer especially designed for the characterization of refractive microlenses is presented. This instrument allows for the quantitative characterization of the microlens form, the transmitted wavefront errors, the radius of curvature and the front focal length without removing the sample under test. All of these microlens properties are important when benchmarking different microlens fabrication technologies (Ottevaere et al 2006 J. Opt. A: Pure Appl. Opt. 8 S407-29). The interferometer was calibrated by the random ball test method. This paper describes the optical design and demonstrates the performance with the characterization of the instrument bias and measurements of a typical microlens. The performance is also compared with that of a semi-commercial instrument.

  20. Reduced optical transmission of SiO{sub 2} fibers used in controlled fusion diagnostics

    SciTech Connect

    Ramsey, A.T.; Adler, H.G.; Hill, K.W.

    1993-02-01

    We have subjected a silica core fiber optic cable to 4 years of low-level neutron and gamma radiation from Princeton`s TFTR controlled fusion experiment The accumulated dose was 200 Gy. As a result of the radiation, we have measured increased attenuations of 100--300 db/km in the visible part of the spectrum, and a decrease of the numerical aperture. An attempt to decrease this damage by photobleaching failed. We argue that this failure is not unexpected, since the rate of damage is so slow and the time scale so long that the self-annealing process keeps the residual damage at the irreducible level seen in other experiments. The implications of these findings for controlled fusion diagnostics during upcoming experiments with highly reactive deuterium-tritium plasmas are discussed.