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conference on optical Manufacturing and testing ii

作者： Ai, CY Knowlden, R Lamb, J Wyko Corp Tucson AZ 85706 USA

ISBN: (纸本)0819425567

The goal of this 24 " phase shifting Fizeau interferometer design is to measure the wavefront of an optical window (780 mm x 430 mm) at Brewster's angle. There are two important requirements: a small wavefront slope error and a high optical resolution. To test the sample in transmission, each pencil of light returned from the RF must go back through the window from which it was previously transmitted (or reflected). Therefore, the slope of the wavefront transmitted through the TF has to be less than a few are seconds, especially for a long cavity length (1 meter). For example, for a 2 meter round trip, a 5 are second slope causes the beam to deviate 0.05 mm. For a 431-mm sample imaged onto a 1000 pixel array, a 0.05 mm displacement corresponds to a 0.116 pixel, which is negligible. However, when a 100 mm sub-aperture is imaged, a 0.05 mm displacement is significant. A shorter round-trip distance can effectively reduce the displacement. The deviations due to a 5-arc second wavefront slope is 0.12 pixel for 2-meter round trip in the full aperture and 0.10 pixel for 0.4-meter round trip in the sub-aperture imaging. Because the phase of the optical window is to be measured and not the amplitude or intensity, the MTF is not suitable for evaluating the interferometer's resolution. A phase object was measured to determine the system transfer function. The fidelity of the measurement is required to be within 60% amplitude for a specified spatial frequency range. For example, for a sinusoidal phase object with a phase undulation of 0.01 wave p-v, the measured result should not be less than 0.006 wave. From theory, a phase object with a smaller phase (less than or equal to 0.1 lambda) undulation can be imaged with good fidelity. Because the wavefront slope and optical resolution requirements are very tight, to ensure the interferometer meets these requirements, theoretical errors were thoroughly analyzed and the design implementation was carefully studied.

关键词： interferometer phase shifting transfer function birefringence polarization

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External photoconductive switches as generators and detectors of picosecond electric transients

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MICROELECTRONIC ENGINEERING 1996年第1-4期31卷 415-426页

作者： Heiliger, HM Pfeifer, T Roskos, HG Kurz, H Institut für Halbleitertechnik II Rheinisch-Westfälische Technische Hochschule Aachen Sommerfeldstraße 24 D-52056 Aachen Germany

We report on external photoconductive switches utilized as both detectors and generators of picosecond electric transients. The probes were manufactured on transparent silicon-on-sapphire substrate with two types of contacting tips, titanium tips and conductive-epoxy tips. Such a contacting tip enables to connect the switches with arbitrary points on a circuit. We investigated the behavior of detectors with a titanium tip in the time-domain concerning time resolution, sensitivity, linearity and invasiveness. As pulse generators we used probes of different design based on single strips and coplanar waveguides. Signals generated by probes with and without tips were injected into a coplanar waveguide and detected electrooptically. The influence of the tips on the shape of the electric transients is analyzed.

关键词： optical switches

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optical wireless ethernet

Optical wireless ethernet

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conference on All-optical Communication Systems - Architecture, Control, and Network Issues ii

作者： Nicholls, PJ Greaves, SD Sibley, MJN UNIV HUDDERSFIELD DEPT ELECT ENGNHUDDERSFIELD HD1 3DHW YORKSHIREENGLAND

ISBN: (纸本)0819423211

This paper details the design and testing of an optical wireless Ethernet system. This system is a demonstration unit that grants the user of a mobile computer access to network services usually only available to wired users. The system operates at the full Ethernet rate of 10Mbit/s and has a range of approximately four meters in a typical office environment. Issues concerning the safety of the transmitters has been presented along with details of how the commercial LEDs used in the transmitter were switched at the high speeds and powers required. Also the transmitter/receiver link has been modeled and simulated. These simulations compare well to measurements taken in a test room, the layout of which matches that of a typical office environment.

关键词： optical wireless optical transmitters eye safety wireless Ethernet

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Analysis and design of solid corner cube reflectors for a space navigation application

Analysis and design of solid corner cube reflectors for a sp...

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conference on Spaceborne Sensors ii

作者： Granade, SR LeCroy, J Adv Opt Syst Inc Huntsville AL 35806 USA

ISBN: (纸本)0819457833

Proximity operations between orbital vehicles require precise knowledge of relative navigation states. Retro-reflectors may be used by proximity operations navigation sensors as part of the navigation sensor system, to indicate the position of fixed points on one of the vehicles so that relative state data may be calculated. Use of corner cube retro-reflectors in an orbital navigation sensor required detailed ray-tracing analysis to define the expected return signal levels, signal/noise ratios, and predicted error effects due to reflector geometry and optical characteristics. Conventional corner cube reflector images would have displayed image artifacts due to corner cube bevels, interfering with software interpretation of sensor image data. This design avoided software errors due to bevel effects. Special optical design features were required to permit use of multiple target sets, enabling successful tracking over a I to 200 meter effective range. We have used this mounting scheme to create corner cube targets for use with the Advanced Video Guidance Sensor (AVGS) on the Orbital Express mission. We discuss our design, the finite-element analysis done on the design, and the results of sensor performance testing with the targets.

关键词： corner cube retro-reflectors space optics optics mounting guidance and navigation

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Reliability improvement methodology for cockpit high voltage power supplies

Reliability improvement methodology for cockpit high voltage...

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conference on Cockpit Displays ii

作者： CHOW, D ARDUSSI, J ELDEC CORP DIV POWER CONVERSLYNNWOODWA 98046AUSTRALIA

ISBN: (纸本)0819418153

High voltage power supplies (HVPS) have traditionally been among the least reliable components in airborne display electronics. NAVMAT P- 4855-1A, a power supply design manual adopted by the U.S. Navy in 1989, highlighted the source of these problems in industry's failure to apply appropriate methods for high voltage design, development and materials selection. Also, the nature of airborne HVPS is such that MTBF prediction using MIL-HDBK-217 has shown very little correlation to actual field performance. These problems continue today. In recent years, ELDEC has developed a methodology to systematically evaluate and improve the design and long term reliability of high voltage power supplies. This methodology has been successfully applied under a recent Air Force CRT PRAM contract to improve HVPS reliability in AWACS aircraft situation displays. The accelerated testing portion of the methodology has been recommended to the Air Force for adoption as a standard to be used in procurement of future high voltage power supplies. Elements of the methodology are described in this paper.

关键词： HIGH VOLTAGE POWER SUPPLY PACKAGING RELIABILITY FAILURE MECHANISMS design OF EXPERIMENT ACCELERATED testing THERMAL CYCLING STEP STRESS

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Making mirrors for giant telescopes 2

Making mirrors for giant telescopes

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Symposium on Astronomical Optics - design, Manufacture, and Test of Space and Ground Systems ii held at SPIE optical Engineering + Applications conference

作者： Martin, H. M. Univ Arizona Steward Observ Tucson AZ 85721 USA Univ Arizona Coll Opt Sci Tucson AZ 85721 USA

ISBN: (数字)9781510629264

ISBN: (纸本)9781510629257;9781510629264

Advances in our understanding of the Universe depend on improvements in sensitivity and angular resolution that can come only with larger telescopes. Telescope diameters increased by almost an order of magnitude in the last century, but that growth has been sporadic, limited mainly by the ability to make bigger mirrors that hold their shape against the dynamic effects of gravity, wind and temperature. Three major advances in mirror technology occurred in the 1980s, including the lightweight honeycomb mirrors made at the Richard F. Caris Mirror Lab at the University of Arizona. In this informal paper, I will describe these technologies and show how they enabled the current generation of 8- to 12-m telescopes and how they are now being used to build telescopes of 25 to 39 m.

关键词： telescopes ELTs Giant Magellan Telescope optical fabrication optical testing

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Experience in estimating fixed-base modal parameters from testing in flexible support configuration

Experience in estimating fixed-base modal parameters from te...

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17th International Modal Analysis conference (IMAC) on Modal Analysis - Reducing the Time to Market

作者： Soucy, Y Humar, JL Canadian Space Agcy Space Technol St Hubert PQ J3Y 8Y9 Canada

ISBN: (纸本)091205364X

Test-derived modal parameters of a structure in fired-base or constrained configuration are often required to verify and update the mathematical model of the structure in the same configuration. However, fixed-base modal testing of large structures can be very challenging and expensive. The paper presents an approach for estimating the fixed-base modal parameters of a structure based on modal testing on the same structure supported by supports of arbitrary stiffness. The simplicity of the procedure and of the hardware used in this approach could lead to considerable cost saving in testing. potential applications include verification of mathematical model of shuttle payloads in a constrained configuration. The theorical formulation for the suggested approach is outlined. The design of flexible support system is described Effectiveness of the test procedure is verified through experiments on lest articles of increasingly complex configuration.

关键词： Flexible structures

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Portable optical actuator for photodynamic therapy

Portable optical actuator for photodynamic therapy

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conference on Smart Medical and Biomedical Sensor Technology

作者： Charamisinau, I Happawana, G Evans, G Rosen, A Hsi, RA So Methodist Univ Dept Mech Engn Dallas TX 75275 USA

ISBN: (纸本)0819451509

This paper presents a low cost semiconductor red laser light delivery system for esophagus cancer treatment. The system is small enough to slide inside the patient's body and it produces up to 4 Watts of optical power from several semiconductor lasers. Specifically, the paper presents optimized high power 635 nm semiconductor laser array design with testing results. The laser array is more powerful than conventional ridge waveguide and more reliable than the broad area lasers at this wavelength. The design optimization is based on i) thermal analysis using finite element analysis as well as analytical calculations for minimizing laser array temperature, and ii) specially designed scattering elements with nanoparticles, to achieve uniform illumination.

关键词： semiconductor lasers photodynamic therapy optical systems design Mie theory scattering particles high power laser arrays

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The DEIMOS spectrograph for the Keck ii telescope: integration and testing

The DEIMOS spectrograph for the Keck II telescope: integrati...

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conference on Instrument design and Performance for optical/Infrared Ground-based Telescopes

作者： Faber, SM Phillips, AC Kibrick, RI Alcott, B Allen, SL Burrous, J Cantrall, T Clarke, DA Coil, AL Cowley, DJ Davis, M Deich, WTS Dietsch, K Gilmore, DK Harper, CA Hilyard, DF Lewis, JP McVeigh, MM Newman, J Osborne, J Schiavon, RP Stover, RJ Tucker, D Wallace, V Wei, MZ Wirth, GD Wright, CA Univ Calif Santa Cruz Univ Calif Observ Lick Observ Santa Cruz CA 95064 USA

ISBN: (纸本)0819446203

The DEIMOS spectrograph is a multi-object spectrograph being built for Keck ii. DEIMOS was delivered in February 2002, became operational in May, and is now about three-quarters of the way through its commissioning period. This paper describes the major problems encountered in completing the spectrograph, with particular emphasis on optical quality and image motion. The strategies developed to deal with these problems are described. Overall, commissioning is going well, and it appears that DEIMOS will meet all of its major performance goals.

关键词： astronomical spectrographs multi-object spectrographs astronomical cameras ground-based instrumentation CCDs mosaic detectors flexure compensation optical testing

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design, fabrication and testing of polysilicon microheaters in silicon

Design, fabrication and testing of polysilicon microheaters ...

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2nd Annual SPIE conference on Microlithography and Metrology in Micromachining

作者： George, N Srivastava, A ALLIANCE SEMICOND SAN JOSECA 95327

ISBN: (纸本)0819422789

We report the technology for the design, fabrication and testing of polysilicon microheaters in silicon using a standard 2 micrometers n-well CMOS technology. The polysilicon microheaters are realized in two steps: layout design for CMOS process and post processing etching. An additional layer in CMOS technology called `open' was incorporated. The `open' layer creates a direct opening to the substrate. Post processing is done on the fabricated CMOS chips using isotropic etchant like xenon difluoride (XeF₂) or anisotropic etchant like ethylenediamine pyrocatechol (EDP) to create a `cavity' in the silicon substrate. The cavity provides thermal isolation from the polysilicon microheaters to the circuits and other devices. These microheaters can reach incandescence at very low power. Several test devices incorporating arrays of polysilicon microheaters were designed and fabricated. Measurements are presented that verify the design and performance of the microheater.

关键词： polysilicon heaters microheaters micromachined heaters MEMS-CMOS process

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