Amnon Yariv

Bio: Amnon Yariv is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Laser & Semiconductor laser theory. The author has an hindex of 103, co-authored 1082 publications receiving 55256 citations. Previous affiliations of Amnon Yariv include University of California, Santa Barbara & Watkins-Johnson Company.

Reduction of relative intensity noise of the output field of semiconductor lasers due to propagation in dispersive optical fiber

Abstract: The effect of dispersive, linear propagation (e.g., in single‐mode optical fiber) on the intensity noise from semiconductor lasers is investigated. Relations between the frequency and amplitude noise variations of semiconductor lasers are obtained from the laser rate equations and used to calculate the change in the relative intensity noise (RIN) spectrum that occurs during dispersive propagation. Propagation in fiber with positive dispersion (D≳0) over moderate distances (several km for standard single‐mode fiber at 1.55 μm) is found to reduce the RIN over a wide range of frequencies. Measurements with a 1.56 μm distributed feedback laser confirm the main theoretical results and demonstrate reductions in RIN of up to 11 dB with 4 km of standard fiber.

Slowing light with Fabry-Perot resonator arrays

Abstract: We analyze the transmission of light through coupled-resonator optical waveguides in the form of evanescently coupled Fabry-Perot resonator arrays. We develop a transfer matrix method to calculate the amplitude and phase responses of the arrays. We also discuss the inclusion of optical gain in the system to compensate for losses in these structures. Owing to the compact length along the propagation direction in evanescently coupled arrays, large slowing factors of the order of 10^2-10^3 can be achieved even with a weak index contrast of ∼0.1%. The large slowing factor, coupled with weak index contrast, makes this structure a promising candidate for artificial slow light system.

A CCD based neural network integrated circuit with 64K analog programmable synapses

Abstract: A report is presented on the design, fabrication, and testing of a neural network integrated circuit with 65536 analog programmable synapses (256 fully interconnected neurons). The integrated circuit utilizes charge-coupled devices (CCDs) based on a generic architecture that the authors proposed (1987). Preliminary testing of the CCD neural processor indicates that the operating speed is 0.5t109 analog interconnect updates/s. Loading of the synaptic interaction matrix can be accomplished either electrically or optically within 0.5 ms or 1 ms, respectively

Spiro-oxazine photochromic fiber optical switch

Abstract: A photochromic all-optical switch in telecommunication-grade fiber is fabricated by filling a fiber Bragg grating Fabry-Perot resonator with a spiro-oxazine solution. The narrow linewidth of the resonator allows for a high sensitivity of the resonance wavelengths to the index change. The switch is controlled by low intensity UV light exposure, and operation at infrared telecommunication wavelengths is demonstrated. The switching speed on the order of minutes has been achieved.

Simple methods of measuring the net photorefractive phase shift and coupling constant.

Abstract: We report measurements of the photorefractive phase shift and coupling constant of several photorefractive materials. We solve the problem of beam coupling and diffraction in a material with a dynamically written grating for arbitrary input beams. These solutions are used to determine the beam coupling as a function of the photorefractive phase φ and coupling constant g when one beam is either sinusoidally phase modulated or ramped in phase. Experimental results are obtained for LiNbO3, BaTiO3, and for paraelectric potassium lithium tantalate niobate as a function of applied electric field.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

A comprehensive review of zno materials and devices

Abstract: The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

Digital communications

Abstract: Spread Spectrum It’s not just for breakfast anymore! Don't blame me, the title is the work of this month's guest columnist, Steve Bible, N7HPR (n7hpr@tapr.org). While cruising the net recently, I noticed a sudden bump in the number of times Spread Spectrum (SS) techniques were mentioned in the amateur digital areas. While QEX has discussed SS in the past, we haven't touched on it in this forum. Steve was a frequent cogent contributor, so I asked him to give us some background. Steve enlisted in the Navy in 1977 and became a Data Systems Technician, a repairman of shipboard computer systems. In 1985 he was accepted into the Navy’s Enlisted Commissioning Program and attended the University of Utah where he studied computer science. Upon graduation in 1988 he was commissioned an Ensign and entered Nuclear Power School. His subsequent assignment was onboard the USS Georgia, a trident submarine stationed in Bangor, Washington. Today Steve is a Lieutenant and he is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California. His areas of interest are digital communications, amateur satellites, VHF/UHF contesting, and QRP. His research area closely follows his interest in amateur radio. His thesis topic is Multihop Packet Radio Routing Protocol Using Dynamic Power Control. Steve is also the AMSAT Area Coordinator for the Monterey Bay area. Here's Steve, I'll have some additional comments at the end.

Plasmonics: Fundamentals and Applications

Abstract: Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.