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Free-Space Laser Communication Technologies iii

作者： Nohara, Mitsuo Harada, Takashi Fujise, Masayuki ATR Optical and Radio Communications Research Lab Kyoto Japan

The authors have designed an optical intersatellite link (ISL) transmitter which uses a high power laser diode (LD) amplifier so as to achieve a high output power, fast frequency response and good beam profile, all simultaneously. Calculation results indicated that a good beam profile could be achieved with a travelling-wave type (TW) broad area LD amplifier when an input beam is focused just in front of the input facet of the LD amplifier. Experimental results also showed that optical output power is controllable as a parameter of the injection current to the LD amplifier.

关键词： Telecommunication links, optical

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ADAPTIVE OPTICS - A PROGRESS REVIEW

ADAPTIVE OPTICS - A PROGRESS REVIEW

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CONF ON ACTIVE AND ADAPTIVE optical SYSTEMS

作者： HARDY, JW Litton Itek Optical Systems (United States)

ISBN: (纸本)0819406708

Active and adaptive optics technology has emerged from the laboratory and is being applied to improve the performance of optical imaging and laser systems. In the last few years, development of both systems and components has accelerated. Many new concepts and devices have appeared, among which are high-performance deformable mirrors, new types of wavefront sensors, and more sophisticated wavefront processing algorithms. Equally important, a better understanding of the system design aspects of adaptive optics has been reached, particularly of the need for optimizing each system according to its application. For example, the dominant requirement in laser systems is to achieve a high Strehl ratio, whereas for ground-based astronomy the availability of guide stars is a major concern. current developments in adaptive optics for ground-based astronomy include the use of IR wavelengths, partial wavefront compensation using natural guide stars, and the use of laser guide stars to allow all-sky coverage with full compensation at visible wavelengths. While progress to date has been impressive, much work remains to bring this technology into general use.

关键词： Adaptive optics Mirrors Wavefronts Sensors Telescopes Imaging systems Stars Active optics Wavefront sensors Astronomy

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optical CORRELATOR TECHNIQUES APPLIED TO ROBOTIC VISION 3

OPTICAL CORRELATOR TECHNIQUES APPLIED TO ROBOTIC VISION

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CONF ON optical INFORMATION PROCESSING SYSTEMS AND ARCHITECTURES 3

作者： HINE, BP REID, MB DOWNIE, JD NASA/Ames Research Ctr. (United States)

ISBN: (纸本)0819406929

Vision processing is one of the most computationally intensive tasks required of an autonomous robot. The data flow from a single typical imaging sensor is roughly 60 Mbits/sec, which can easily overload current on-board processors. optical correlator-based processing can be used to perform many of the functions required of a general robotic vision system, such as object recognition, tracking, and orientation determination, and can perform these functions fast enough to keep pace with the incoming sensor data. We describe a hybrid digital electronic/analog optical robotic vision processing system developed at Ames Research Center to test concepts and algorithms for autonomous construction, inspection, and maintenance of space-based habitats. We discuss the system architecture design and implementation, its performance characteristics, and our future plans. In particular, we compare the performance of the system to a more conventional all digital electronic system developed concurrently. The hybrid system consistently outperforms the digital electronic one in both speed and robustness.

关键词： optical correlators Databases optical filters Image filtering optical signal processing Robotic systems Digital electronics Robot vision Spatial light modulators Algorithm development

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COMPUTATIONAL FLUID-DYNAMICS AND ITS APPLICATION TO TRANSPORT PROCESSES

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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY 1991年第1期52卷 5-47页

作者： COLLINS, MW CIOFALO, M Thermo-Fluids Engineering Research Centre City University London EC1V 0BH UK

Fluid transport behaviour is of great importance within the chemical process industry and in biotechnology. The complexity of this behaviour, reflected in the nature of the fundamental partial differential equations which describe it analytically, means that it has to be treated by numerical methods. In this paper the basic equations are given, and the approaches necessary to treat laminar and turbulent flows are carefully explained. As digital computers have increased in size, so has the comprehensiveness of the problems which can be treated, and the development of typical computer programs is described. Problems of accuracy and experimental validation are also surveyed, and it is shown that recent developments in whole-field optical measurement methods, and image and data processing are all involved here. Then, a review of work at City University is shown to comprise typical examples of applications to engineering situations and biotechnology problems. Chosen instances of the former are flow and heat transfer behaviour for convective enhancement caused by roughness elements, and the design balancing of a thermosyphon. The latter include such diverse studies as blood flows in arterial bifurcations, and heat and mass transport in grain storage. They involve the three-dimensional and transient capabilities of current codes, and their applicability to non-standard geometries.

关键词： COMPUTATIONAL FLUID DYNAMICS CODE VALIDATION

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Pointing, acquisition and tracking system of SILEX european program. A major technological step for intersatellites optical communication

Pointing, acquisition and tracking system of SILEX european ...

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Free-Space Laser Communication Technologies iii

作者： Bailly, Michel Perez, Eric MATRA-ESPACE Velizy-Villacoublay France

This paper is concerned with the overall architecture and the performances of the Pointing, Acquisition and Tracking (PAT) subsystem of the European SILEX program (Semiconductor laser Intersatellite Link Experiment). Starting from the description of the mission constraints, it deals with the retained baseline built around a two-stages beam steering system, an open loop point-ahead control and a full digital implementation. Performance prediction is based upon signal processing, control algorithms and detailed modelling of equipments and flexible structures. It shows how such an accurate performance in the order of a microradian can be achieved with a correct allocation of the performance for each equipment of the system. In particular the rejection of the microvibrations coming from the platform when the Terminal is operating will be pointed out as a key-feature of the design. The PAT equipments and softwares - sensors, electromechanisms, control units - are presented showing which technological step is achieved (from current advanced C/D phase programs) or still to be achieved.

关键词： optical Communication

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EVALUATION OF ELECTROLYTIC CAPACITORS FOR HIGH PEAK current PULSE DUTY

EVALUATION OF ELECTROLYTIC CAPACITORS FOR HIGH PEAK CURRENT ...

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3RD CONF ON PULSE POWER FOR LASERS

作者： HARRIS, K MCDUFF, G BURKES, TR Texas Tech Univ. (United States)

ISBN: (纸本)0819405019

Classically, electrolytic capacitors have been used for dc filter applications. However, the inherent advantages of 'electrolytics' such as self-healing and high energy density make them an attractive candidate for pulse circuitry. To this end, a new type of electrolytic capacitor has been developed specifically for high peak current applications. Preliminary results of an ongoing research effort to determine the operational characteristics of this new type of electrolytic are reported. Electrical characteristics such as equivalent series inductance (ESL) and equivalent series resistance (ESR) has been determined for the first generation test units. Along with the ESR determination, the adiabatic temperature rise per pulse was measured to assist in cooling system design as well as operation in environments where heat rejection is limited. The new electrolytic capacitors may facilitate the development of a new class of pulse generators based on high energy density components. Pulse generators for mass launchers, very low impedance loads, and space-based applications where volume and weight density are at a premium are ideal target applications for pulse electrolytics. High power flashlamp drivers for rod and slab lasers are of particular interest. With recent advances in fast solid state switching such as the dynistor, together the ultrahigh energy density capacitors can result in very compact pulsers. Compared to other energy storage alternatives, the electrolytic capacitor still offers the best source of Joules per dollar for traditional applications.

关键词： Capacitors Oxides Inductance Electrodes Resistance Capacitance Dielectrics Metals Aluminum Pulsed laser operation

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iii-V compund based heterostructure opto-thyristor for pulsed power applications

III-V compund based heterostructure opto-thyristor for pulse...

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International Conference on Pulsed Power

作者： J.H. Hur P. Hadizad H. Zhao S.G. Hummel J.S. Osinski P.D. Dapkus H.R. Fetterman M.A. Gundersen Department of Electrical Engineering Electrophysics University of Southern California Los Angeles CA USA Department of Electrical Engineering University of California Los Angeles CA USA

An analysis od iii-V compound based eterostructure opto-thyristor (HOT) for pulsed power switching application which require gate isolation, fast current rate of rise, and high gating gain is presented. design, fabrication, and performance of the device are discussed. The device has AlGaAs/GaAs heterojunction whigh allows an efficient coupling of gatin light to the critical region of the device, thus improving the gating gain and the current rate of rise.

关键词： iii-V semiconductor materials Gallium arsenide Photonic band gap Circuits Pulse measurements Diode lasers MOCVD Heterojunctions Cathodes optical fiber devices

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design OF PHOTOLITHOGRAPHIC LENSES WITH LARGE FIELD AND APPROXIMATE BITELECENTRICITY

DESIGN OF PHOTOLITHOGRAPHIC LENSES WITH LARGE FIELD AND APPR...

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CONF ON current developments IN optical engineering 4

作者： WANG, XC LIN, DJ Institute of Optics and Electronics (China) Institute of Optics and Electr (China)

ISBN: (纸本)0819403954

This paper introduced a new type of tenses with approximate bite lecentricity for *** has the quasi-diffraction Limited image quality in the range of large field size and keeps fine overlay accuracy as *** corrections of sagittal aberrations and higher order aberrations are considered in the optical design. Finaty, the MTF of two results, with NAO•2, magnification x, field diameter 140mm, and NAO•28, magnification lOX, field diameter 140mm, were given.

关键词： Monochromatic aberrations optical design Lenses optical engineering Distortion Diffraction Lens design Modulation transfer functions Semiconducting wafers Optics manufacturing

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EVALUATION OF optical-SYSTEMS designED USING THE CONCENTRIC-APLANATIC METHOD

EVALUATION OF OPTICAL-SYSTEMS DESIGNED USING THE CONCENTRIC-...

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CONF ON current developments IN optical engineering 4

作者： DESLIS, A Jet Propulsion Lab Pasadena United States

ISBN: (纸本)0819403954

The 'concentric-aplanatic' method used for lens design is described in many papers. While many shapes and forms of these lenses have been shown, performance evaluation of these lenses has never been published. How good is the method? Can one design optical systems using this technique that have acceptable image quality? This paper will deal step by step with these questions, both from first principles and by the basis of third order theory. Performance evaluations will be given for the lenses designed.

关键词： optical Systems

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DISCUSSION OF REFLECTION MICROCIRCULATION MICROSCOPE design

DISCUSSION OF REFLECTION MICROCIRCULATION MICROSCOPE DESIGN

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CONF ON current developments IN optical engineering 4

作者： ZHENG, DY CHEN, RY GE, ZF JING, FQ HU, WF WANG, BM Zhejiang Univ. (China) Hangzhou Traditional Chinese Medicine Hospital (China)

ISBN: (纸本)0819403954

Reflection microcirculation microscope has wide application value in studyiny microcirculation and microrheology , and joining with different equipment can do many ways of the studies , So research and improvement the instrument and development advanced appendant technology will produce a active sence to the study of biomedicine. In this paper , We introduce mainly the design idea of reflection microcirculation microscope which was studied by us ,and discuss some prombles.

关键词： Microscopes Objectives Blood Capillaries optical engineering Organisms Photography Illumination engineering Image analysis Image transmission

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