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STUDY OF UV-BLEACHED CHANNEL-wave-GUIDE PERFORMANCE IN NONLINEAR-OPTICAL POLYMER-FILMS

APPLIED OPTICS 1995年第30期34卷 6885-6891页

作者： FENG, W LIN, SH HOOKER, RB MICKELSON, AR []The authors are with the Department of Electrical Computer Engineering University of Colorado at Boulder Boulder Colorado 80309.

We report studies on UV-photobleached optical channel waveguides in nonlinear optical polymer films. The nonlinear optical polymer used is poly(methyl methacrylate)/DR1 side-chain polymer. The effective indices of the channel waveguides are measured with the prism-coupling technique, along with the effective indices of bleached and unbleached polymer films. The effective-index method was used to predict the effective indices of the channel waveguides from measurements of the slab waveguides, without detailed knowledge of the index distributions in the polymer films. Some local stress-related effects on the boundaries of the channel waveguides caused by the UV-bleaching process are identified by comparison between direct channel measurement and prediction. It is found that the technique used in this study can be employed to predict the performance of channel waveguides processed such that they have no excessive internal stress distributions.

关键词： wave-guides Index profiles index profile Polymeric membranes internal stress distribution slab waveguide channel waveguide waveguide Device Component optical polymers

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DIRECT MEASUREMENT OF HUMAN-CONE-PHOTORECEPTOR ALIGNMENT

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 1995年第10期12卷 2329-2338页

作者： BURNS, SA WU, S DELORI, F ELSNER, AE []The Schepens Eye Research Institute 20 Staniford Street Boston Massachusetts 02114

We have developed an imaging reflectometer to measure cone-photoreceptor alignment. One makes measurements by bleaching the cone photopigment and imaging the distribution of light returning from the retina, which is illuminated from a small source imaged in the plane df the eye's pupil. If the source is near the optimal entry pupil position as determined psychophysically, the distribution of light returning from the retina is peaked, and the magnitude of the peak depends on the location of the source in the pupil. of the eye. If the source is far from the optimal entry pupil position, then there is no measurable peak. The location of the peak varies across individuals and coincides with the reported location of best visibility of the measuring light and with previous psychophysical and reflectometric measurements of the Stiles-Crawford peak. The source of this directionality must arise either from the photoreceptors or from behind the photoreceptors because the peak is not present if measurements are made when the cone photopigments have high optical density.

关键词： PHOTORECEPTORS COLOR VISION wave-guides VISUAL SENSITIVITY STILES-CRAWFORD EFFECT

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AN FD-BPM WITH ADAPTIVE MESH FOR LONGITUDINALLY VARYING OPTICAL STRUCTURES

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OPTICAL AND QUANTUM ELECTRONICS 1995年第10期27卷 951-959页

作者： MASSINI, C BELLANCA, G BASSI, P SORRENTINO, R UNIV BOLOGNA DIPARTIMENTO ELETTRON INFORMAT & SISTEMISTI-40136 BOLOGNAITALY

A finite difference beam propagation method (FD-BPM) algorithm using an adaptive mesh is proposed for optimal use of computer memory and minimization of CPU times in three-dimensional longitudinally varying guiding structures. Preliminary results confirming its feasibility and the advantages of the new algorithm both in CPU and computer memory requirements are described in a 2D case using a Y-junction.

关键词： Beam propagation method Finite-difference wave-guides computer memory Finite differences Beam propagation method central processing units waveguide Device Component Y junction

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PRACTICAL USE OF THE SPATIAL COHERENCE FUNCTION FOR DETERMINING LASER TRANSVERSE-MODE STRUCTURE

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OPTICAL ENGINEERING 1995年第11期34卷 3323-3328页

作者： PELZ, LJ ANDERSON, BL Univ. of Dayton (USA) Ohio State Univ. (USA)

The spatial coherence function of a beam exiting from a waveguiding device can be used to determine the transverse modal composition of the fields which are supported within the structure. The strength of the spatial coherence technique is that it directly yields the relative modal weights which exist within the cavity. While this technique has received little attention in the past due to the experimental difficulties in measuring spatial coherence, a recently developed technique overcomes several of these problems. We demonstrate how the relative modal amplitudes may be extracted from the spatial coherence function for the case where the field distribution is described by Hermite-Gaussian polynomials, We point out some limitations of this method and discuss how these may be circumvented.

关键词： SPATIAL COHERENCE TRANSVERSE MODES LASERS wave-guides

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SCATTERING FROM A FOLDED SHORT IN PARALLEL-PLATE wave-GUIDE

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IEICE TRANSACTIONS ON COMMUNICATIONS 1995年第10期E78B卷 1424-1426页

作者： LEE, JW EOM, HJ Korea Advanced Inst of Science and Technology Taejon South Korea

A folded short in parallel-plate waveguide is investigated using the Fourier transform and the mode-matching. A fast-converging series solution for scattering from the folded short is obtained and its characteristics are presented. Our solution for the E-plane short agrees well with measurement and is numerically more efficient than the existing moment-method solution. The presented scattering characteristics are useful for the design of the E- and H-plane shorts in rectangular waveguide.

关键词： COMMUNICATION CABLE wave-guides ELECTROMAGNETIC THEORY SCATTERING

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A NUMERICAL PROCEDURE FOR SOLITON GENERATION

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OPTICAL AND QUANTUM ELECTRONICS 1995年第9期27卷 799-803页

作者： GLASNER, M YEVICK, D QUEENS UNIV DEPT ELECT ENGNKINGSTONON K7L 3N6CANADA

We present a simple method for obtaining stationary solutions to the perturbed nonlinear Schrodinger equation from a random input field. In particular, we propagate the initial field while both renormalizing to ensure that the maximum field value remains constant and absorbing the field at increasingly large distances from the centre of the computational window in position and wavevector space. Our algorithm, which results in near-perfect lowest-order solitons for a wide range of absorber and computational parameters, should be equally applicable to other nonlinear equations.

关键词： wave-guides Propagation Schrodinger equation waveguide Device Component Random inputs

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wave-GUIDE CARS - A METHOD TO DETERMINE THE 3RD-ORDER POLARIZABILITY OF THIN-LAYERS APPLIED TO A SIOXNY wave-GUIDE

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APPLIED SPECTROSCOPY 1995年第9期49卷 1326-1330页

作者： KANGER, JS OTTO, C GREVE, J UNIV TWENTE BMTIDEPT APPL PHYSAPPL OPT GRP7500 AE ENSCHEDENETHERLANDS

waveguide coherent anti-Stokes Raman spectroscopy (WCARS) can be used to measure Raman-active vibrations of thin (mono, submono) layers deposited on dielectric, waveguides. In these experiments, surface sensitivity and background-free spectra are obtained by using asymmetric mode combinations. The degree of suppression then depends upon the waveguide parameters (thicknesses, refractive indices, and third-order polarizabilities), the wavelengths used, and the selected propagating modes. With knowledge of the refractive indices and the third-order polarizabilities, the other parameters can be used to tune into a background-free region. The refractive indices of many waveguide materials are known or can easily be measured. Unfortunately, the third-order polarizabilities are most often not known and should therefore be determined experimentally. In this paper a method is outlined to measure the third-order susceptibility (chi(NR)((3))) of a waveguide,vith the use of WCARS experiments. The value chi(RA)((3)) of SIOxNy is determined experimentally and is found to be 0.22 +/- 0.03 10(-12) electrostatic units.

关键词： wave-guides RAMAN CARS

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MODAL APPROACH TO wave-GUIDE COUPLING WHEN GAPS, OFFSETS AND ROTATIONS OF ONE wave-GUIDE WITH RESPECT TO THE OTHER ARE PRESENT

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OPTICS AND LASER TECHNOLOGY 1995年第2期27卷 113-123页

作者： GAUTHIER, RC The author is in the Department of Physics and Astronomy Laurentian University Sudbury Ontario Canada P3E-2C6

In this paper, optical power coupling when waveguide separations, translations and rotations are present is addressed using a modal expansion technique. Numerical results are presented and discussed for Hermite-Gaussi... 详细信息

关键词： wave-guides COUPLING ALIGNMENT

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MULTILAYER DIELECTRIC MATERIALS OF SIOX/TA2O5/SIO2 FOR TEMPERATURE-STABLE DIODE-LASERS

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MATERIALS CHEMISTRY AND PHYSICS 1995年第3期42卷 214-216页

作者： CHU, AK LIN, CJ CHENG, WH Institute of Electro-Optical Engineering National Sun Yat-Sen University Kaohsiung 80424 Taiwan

A novel athermal waveguide for temperature-stable diode lasers was investigated. The waveguide consisted of SiOX, Ta2O5 and SiO2 dielectric layers deposited on a Si substrate. A theoretical calculation shows that the optical path (defined by the product of the effective index of the waveguide and the waveguide length) of the waveguide can be independent of temperature if the thicknesses of Ta2O5 and SiOX layers are properly chosen. The Ta2O5 and SiOX layers were deposited using the magnetron sputtering technique. The indices of SiOX and Ta2O5 films are 1.5 and 2.12, respectively. The SiO2 layer was fabricated by flame hydrolysis deposition with a thickness of 4 mu m. Good surface morphology and thickness uniformity of the SiO2 layer were obtained. The index-temperature drift of SiO2 was measured to be 3 X 10(-5)/degrees C which is about 10 times less than that of a III-V semiconductor. A comparison of the temperature dependence of the SiOX/Ta2O5/SiO2 waveguide and Ta2O5/TiO2/SiO2 waveguide is also presented.

关键词： DIELECTRICS DIODE LASERS wave-guides SILICON TANTALUM

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SENSORS FOR MONITORING THE PROCESSING OF CARBON-CARBON COMPOSITES

SENSORS FOR MONITORING THE PROCESSING OF CARBON-CARBON COMPO...

引用

Smart Structures and Materials 1995: Smart Sensing, Processing, and Instrumentation Conference

作者： TITTMANN, BR YEN, CE PENN STATE UNIV UNIVERSITY PKPA 16802

ISBN: (纸本)0819417939

Carbon-carbon composite are used in many applications including aircraft disk brakes, space shuttle leading edges, rocket inlet nozzles and exit cones, and are currently being considered for future aircraft structural components, because of their mechanical stability under adverse temperature conditions. Unfortunately, the processing of carbon-carbon composites, especially the first carbonizations, has a relatively low yield, because of in-process interply failure leading to catastrophic delaminations. Considerable amount of man-power, equipment time and material are lost. Here we report on the progress in the development of sensors for monitoring these catastrophic events during the first carbonization. Specifically, acoustic emission sensors and gas sensors are singled out as the most promising ones for monitoring the evolution of micro and macro-structural changes during the first carbonization. Analysis of the high temperature waveguide was undertaken to determine the optimum waveguide geometry so that only a single mode is allowed to propagate in the waveguide.

关键词： ACOUSTIC EMISSION SENSORS GAS SENSORS wave-guides CARBONIZATION C/C COMPOSITES PROCESS MONITORING

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