Showing papers on "Guided wave testing published in 1990"
TL;DR: In this article, magneto-optic (MO) Bragg diffraction of guided-optical waves from the MSFVW in a noncollinear coplanar geometry is analyzed.
Abstract: Realization of magnetostatic forward volume wave (MSFVW)-based guided-wave magneto-optic (MO) Bragg cells and their applications to communications and signal processing are reported. Bragg diffraction of guided-optical waves from the MSFVW in a noncollinear coplanar geometry is analyzed. The design of microstrip line transducers that facilitate wideband MO Bragg diffraction with electronically tunable microwave carrier frequencies (2.0 to 12.0 GHz) are briefly discussed. Experimental results obtained with the resulting Bragg cells in both pure and bismuth-doped yttrium-iron-garnet (YIG) waveguides and a comparison to the theoretical predictions are presented. Applications of the Bragg cells to light beam modulation, scanning/switching, and RF spectral analysis are presented in detail. >
76 citations
TL;DR: In this article, the authors extended coupled mode techniques for guided wave propagation to 2D stochastic heterogeneity superimposed on a stratified medium, which requires the variations to be smoothly varying and of modest size (less than ± 2 per cent).
Abstract: SUMMARY
Coupled mode techniques for guided wave propagation are extended to 2-D stochastic heterogeneity superimposed on a stratified medium. This approach requires the variations to be smoothly varying and of modest size (less than ±2 per cent). By averaging over an ensemble of statistically similar models, coupled equations for the modal energy transport can be generated. The intermode coupling depends on the horizontal correlation functions for the heterogeneity in the crust and mantle, and the integrated effect of the vertical variations in velocity and the modal eigenfunctions.
For a particular stochastic model, the attenuation of a single mode as a function of distance can be calculated as a superposition of intrinsic attenuation and scattering loss by energy transfer to other modes of propagation. These statistical estimates of attenuation can be compared with observations of regional phases travelling over a variety of paths in a single region. For Lg and Sn phases, intermode scattering may represent up to 30 per cent of the apparent loss.
57 citations
01 Jan 1990
TL;DR: In this paper, an overview of the theory of the near-zone Doppler effect is presented. But, the authors do not consider the effect of near-zones on the spectrum of the reflector and Horn antennas.
Abstract: 1 Electromagnetic Waves in Chiral Media.- 2 Norms of Time-Domain Functions and Convolution Operators.- 3 An Overview of the Theory of the Near-Zone Doppler Effect.- 4 Analysis of Channeled-Substrate-Planar Double-Heterostructure Lasers Using the Effective Index Technique.- 5 Correlation Theory of Electromagnetic Radiation Using Multipole Expansions.- 6 On Fractal Electrodynamics.- 7 Fringing Field Effects in VLSI Structures.- 8 Some Methods of Reducing the Sidelobe Radiation of Existing Reflector and Horn Antennas.- 9 Group Symmetries of Antenna Arrays.- 10 Many-Body Problems in Electromagnetic Theory.- 11 Electromagnetic Shielding.- 12 Coherence Effects in Guided Wave Optical Systems.- 13 How Scattering Increases as an Edge Is Blunted: The Case of an Electric Field Parallel to the Edge.- 14 Electromagnetic Fields Determined from Two-Dimensional Infrared Thermal Patterns.- 15 Dielectric Waveguide Theory.- Author Index.
49 citations
TL;DR: In this article, the coupling between the guided modes and between guided and radiation modes of two parallel slab waveguides forming a directional coupler was computed to determine the radiation losses introduced by the coupling grating.
Abstract: The coupling between the guided modes and between guided and radiation modes of two parallel slab waveguides forming a directional coupler in order is computed to determine the radiation losses introduced by the coupling grating. The problem is solved in two stages. First, the guided modes for each waveguide are computed separately and the radiation modes are only determined for the more complicated of the two waveguides, the one that is nearer to the grating. Modifications caused by the presence of the opposite waveguide are then taken into account by computing first-order correction terms. For a practical example of slab waveguides defined in GaInAsP, the authors find that the radiation losses per power exchange length remain below 0.02 dB for a rectangular grating depth of 0.01 mu m. >
41 citations
TL;DR: In this article, a method for enhancing guided-wave second-harmonic generation (SHG) phase matched by a Cerenkov radiation scheme by tailoring the transverse (y direction) nonlinear susceptibility profile in the waveguide channel is proposed.
Abstract: A method for enhancing guided‐wave second‐harmonic generation (SHG) phase matched by a Cerenkov radiation scheme by means of tailoring the transverse (y direction) nonlinear susceptibility profile in the waveguide channel is proposed. Specifically, linear and domain‐inverted (poled) channels embedded in a nonlinear substrate are considered, and the SHG efficiency for each structure is compared with that for the conventional nonlinear channel without domain inversion. Through electromagnetic field analysis, a significant enhancement of SHG is demonstrated, particularly with the domain inverted channel.
37 citations
TL;DR: In this article, the nonlinear properties of a distributed feedback grating in a waveguide characterized by a diffusive thermal nonlinearity were investigated experimentally, and all-optical tuning of the reflectivity was achieved either by a guided wave incident onto the distributed feedback gating near its Bragg condition, or by a second guided beam tuned far from the Bragg conditions.
Abstract: The nonlinear properties of a distributed feedback grating in a waveguide characterized by a diffusive thermal nonlinearity were investigated experimentally. Reflection and transmission were measured in an InSb planar structure, and all‐optical tuning of the reflectivity was achieved either by a guided wave incident onto the distributed feedback grating near its Bragg condition, or by a second guided beam tuned far from the Bragg condition.
35 citations
TL;DR: In this article, a linearly focusing grating coupling (LFGC) was proposed and discussed for parallel pickup of 8-μm-sized marks, and it was experimentally confirmed that the virtual images of the marks can be formed in the waveguide.
Abstract: Parallel pickup of optical digital data is attractive in optical memory applications. In order to construct a parallel pickup device with integrated optics, the use of a linearly focusing grating coupling (LFGC) was proposed and discussed. A guided wave in a slab waveguide is diffracted by the LFGC to be focused to a line in the air. The linearly focused wave is reflected by a recorded medium, such as an optical card, and is coupled by the same LFGC back into the waveguide. The backcoupling of the LFGC was discussed for parallel pickup of 8-μm-sized marks, and it was experimentally confirmed that the virtual images of the marks can be formed in the waveguide.
33 citations
TL;DR: In this article, the current state of the art of nonlinear optics to optical waveguides is reviewed, with emphasis on recent progress in the area of third-order interactions.
Abstract: The current state of the art of applications of nonlinear optics to optical waveguides is reviewed, with emphasis on recent progress in the area of third-order interactions. In the last few years, various groups have reported calculations and experiments on degenerate four-wave mixing, and a variety of effects that depend on an intensity-dependent refractive index including power-dependent field distributions, nonlinear coherent directional couplers, nonlinear prism couplers, and nonlinear grating phenomena.
29 citations
TL;DR: In this article, the optical response behavior of dielectric multifilm systems containing an arbitrary number of film components with self-focusing Kerr nonlinearity has been investigated for an oblique s-polarized incident wave.
29 citations
TL;DR: In this article, a quasi-TEM analysis using the method of lines is implemented to calculate the electric field anywhere within a layered guided wave structure at appropriately low frequencies, and the analysis provides the electric fields and transmission line parameters for a shielded structure having any number of coplanar electrodes within an arbitrary number of anisotropic dielectric layers, the principal axes of which are parallel to the axes of the structure.
Abstract: A quasi-TEM analysis using the method of lines is implemented to calculate the electric field anywhere within a layered guided wave structure at appropriately low frequencies. The analysis provides the electric fields and transmission-line parameters for a shielded structure having any number of coplanar electrodes within an arbitrary number of anisotropic dielectric layers, the principal axes of which are parallel to the axes of the structure. The practical application considered is the calculation of the phase shift of a guided optical wave within an electrooptic modulator that has a dielectric buffer layer between the electrodes and electrooptic substrate. >
TL;DR: In this paper, the elliptically polarized nonlinear beam propagation in a two-dimensional optical guided-wave system that contains isotropic Kerr media is solved numerically by using the finite-element method.
Abstract: The elliptically polarized nonlinear beam propagation in a two-dimensional optical guided-wave system that contains isotropic Kerr media is solved numerically by using the finite-element method. Computed results for the nonlinear substrate exhibit novel transverse effects, such as spatial modulational instabilities for solitons emitted from the film. Since soliton emission can be interpreted in terms of self-induced Cerenkov radiation, these instabilities can be classified as Cerenkov instabilities. The sensitivity of the beam propagation to the initial state of polarization suggests the possibility of constructing new photonic devices.
Patent•
28 Dec 1990TL;DR: In this article, a scattered light Moire-Brillouin guided wave gyroscope includes a coherent light source for providing two counter-rotating primary waves and an optical waveguide, responsive to the two primary waves.
Abstract: A scattered light Moire-Brillouin guided wave gyroscope includes a coherent light source for providing two counter-rotating primary waves; an optical waveguide, responsive to the two primary waves, for generating a Moire fringe from a primary fringe and a Brillouin fringe derived respectively from the counter-rotating primary waves and from the counter-rotating Brillouin waves produced from the primary waves; and means for detecting the rotation of the Moire fringe relative to the waveguide.
TL;DR: In this article, an exact formulation for the boundary value problem of a class of doubly periodic structures, each of which is composed of a uniform dielectric layer sandwiched between two gratings with two different periods, is presented.
Abstract: An exact formulation is presented for the boundary-value problem of a class of doubly periodic structures, each of which is composed of a uniform dielectric layer sandwiched between two gratings with two different periods. The general dispersion properties of doubly periodic structures as waveguides are rigorously established and both global and local behaviors of the Brillouin diagram are analyzed to illustrate the guiding characteristics of doubly periodic structures, regardless of the grating profiles. The effects of the commensurability of the two grating periods are carefully studied; in particular, it is shown that the commensurate case will still support purely bounded waves, but the noncommensurate case will not. Furthermore, it is shown that, in a doubly periodic structure, strong couplings may involve two or more space harmonics that may come from more than one mode. Numerical results are given for the special case of a dielectric layer with rectangular corrugations of different periods on its two boundary surfaces. The stop-band behaviors are examined in detail for various cases involving one, two, and three modes.
TL;DR: In this article, one-to-30 guided wave optical interconnections are demonstrated at 632.8 nm using a highly multiplexed waveguide volume hologram, and the theoretical limit of the fanout number is addressed and experimentally confirmed.
Abstract: One‐to‐30 guided wave optical interconnections are demonstrated at 632.8 nm using a highly multiplexed waveguide volume hologram. This technology is capable of providing intrachip and intrawafer optical interconnections. The theoretical limit of the fanout number is addressed and experimentally confirmed. The measured data show that the diffracted beams have an average diffraction efficiency of 2.3% with ±0.2% variation. The demonstrated results can save surface space of electronic chips and also provide a large fanout capability due to the high index modulation of the volume hologram. Further applications based on this technology are very promising. Head‐up display, high‐speed optical data bus, surface enhanced Raman spectrometer, and optical sensors are some of the attractive ones.
TL;DR: In this paper, it was shown that the slowly-varying approximation usually adopted in the frame of coupled-mode theory is actually unnecessary, and the slowly varying approximation is not necessary.
04 Dec 1990
TL;DR: In this article, a simple AO coupling weighting technique for sidelobe suppression that involves only variation of the width of the surface acoustic wave (SAW) slot waveguide is presented.
Abstract: A simple acoustooptic (AO) coupling weighting technique for sidelobe suppression that involves only variation of the width of the surface acoustic wave (SAW) slot waveguide is presented. Calculations on single-stage and multistage acoustooptic tunable filters (AOTFs) consisting of an optical channel waveguide and a SAW slot waveguide in LiNbO/sub 3/ have shown that waveguide width coupling using the Hanning weighting function provides significant improvement in sidelobe suppression. Specifically, using the Hanning function a sidelobe level of -26 dB is predicted as compared to that of -9 dB with the conventional uniform coupling. Calculated results together with the design, fabrication, and preliminary measured performance characteristics of a single-stage guide-wave AOTF in YX-LiNbO/sub 3/ substrates at the optical wavelengths of 0.6328 and 1.55 mu m are reported. >
TL;DR: In this paper, the effect of the metal-cladding thickness on the guided-mode optical characteristics of the asymmetric metal-clad four-layer waveguide is analyzed by a simplified method, and the expressions for the propagation constant and the absorption loss coefficient are derived for the TE modes.
Abstract: The effect of the metal-cladding thickness on the guided-mode optical characteristics of the asymmetric metal-clad four-layer waveguide is analyzed by a simplified method, and the expressions for the propagation constant and the absorption loss coefficient are derived for the TE modes. For the air/Au/GaAs/AlGaAs waveguides the results computed from this method are in good agreement with the numerical results of the mode complex transcendental eigenvalue equation, except in the regions near mode cutoff.
TL;DR: In this article, a new principle for optimising wavevector conservation and phase-matching in organic-based guided wave devices is proposed and demonstrated using controlled changes in the refractive index by photobleaching.
Abstract: A new principle for optimising wavevector conservation and phase-matching in organic based guided wave devices is proposed and demonstrated. Fine tuning of grating coupling into a poly-4BCMU waveguide is demonstrated using controlled changes in the refractive index by photobleaching.
TL;DR: In this article, a numerical method for the study of reflection, transmission, and conversion into volume electromagnetic fields of surface polaritons or radiation fields incident onto the end face of a surface polariton active medium or from one polaritonactive medium to another separated from it by barrier of variable width is presented.
TL;DR: In this article, all-optical limiting and bistability of zinc sulfide waveguides excited by distributed grating couplers is demonstrated. But the results are consistent with the presence of a diffusive nonlinearity through the optothermal effect, and a simplified model of the nonlocal traveling-wave interaction between radiation and guided modes is in agreement with the experimental data.
Abstract: All‐optical limiting and bistability are experimentally demonstrated in zinc sulfide waveguides excited by distributed grating couplers. The results are consistent with the presence of a diffusive nonlinearity through the optothermal effect, and a simplified model of the nonlocal traveling‐wave interaction between radiation and guided modes is in agreement with the experimental data.
TL;DR: The present method gives accurate results with limited computational effort and can analyze a wide variety of integrated optical components ranging from single waveguides of arbitrary cross-sectional profile to multiple coupled guides of arbitrary widths and spacings.
Abstract: A modular equivalent circuit representation for modeling and analyzing open guided-wave structures, which takes into account both the guided and the continuous spectra, is discussed. In the development of the technique approximations that are valid for integrated optics in III-V compound semiconductors are utilized. The validity of these approximately was assessed on the basis of both physical arguments and numerical simulations. Results obtained with the present method are compared with the results of other methods of analysis for rectangular fiber and rib guides with sloped rib sides. The present method gives accurate results with limited computational effort and can analyze a wide variety of integrated optical components ranging from single waveguides of arbitrary cross-sectional profile to multiple coupled guides of arbitrary widths and spacings. >
12 Mar 1990
TL;DR: In this paper, the surface characteristics of HgCdTe infrared detectors were examined to determine the source of performance-limiting dark current in those detectors, where the primary goal of the project was to examine the surface properties of the detectors.
Abstract: : The primary goal of this project is to examine the surface characteristics of mercury cadmium telluride (HgCdTe) infrared detectors, to determine the source of performance-limiting dark current in those detectors This report discusses research progress in the Optica Sciences, including the areas of: scanning tunneling microscopy in the evaluation of HgCdTe material; optical elements for x-ray and uv wavelengths; interaction of a single semiconductor cluster with intense laser beams; coherent and nonlinear effects in semiconductors; nonlinear organics for guided wave devices; nonlinear propagation and wave mixing in sodium vapor; gain/feedback approach to optical instabilities; conical emission; kaleidoscopic spatial instability; nonlinear dynamics and chaos in cavity QED; origin and application of four-wave mixing in semiconductors; theory of the semiconductor laser; nonlinear theory of phase conjugate optics; polishing of diamond films with argon and oxygen ion beams; and chemical vapor deposition of diamond and diamond-like films
01 Sep 1990
TL;DR: In this paper, the authors examined the anomalous or nonlinear responses of two coupled waveguide devices when exposed to the particular adverse condition of ionizing radiation consisting of protons and electrons.
Abstract: The ability of coupled waveguide devices to perform in adverse environments is of increasing concern for application in photonic systems. The intent of this paper is to examine the seemingly anomalous or nonlinear responses of two guided wave devices when exposed to the particular adverse condition of ionizing radiation consisting of protons and electrons. Physical models are presented explaining the different responses, and a possible method for partially controlling or mitigating these responses is discussed. The guided wave devices examined include: a polarization maintaining silica fiber and a titanium in-diffused lithium niobate channel waveguide directional coupler.
Patent•
15 Aug 1990
TL;DR: In this article, a guided wave light-beam deflector enabling variation of laser light transmission direction with a large deviation is proposed, which has means for deflecting light in a plane parallel to an optical waveguide and a grating as an output section disposed on the surface of or inside the waveguide.
Abstract: A guided wave light-beam deflector enabling variation of laser light transmission direction with a large deviation, which has means for deflecting light in a plane parallel to an optical waveguide, and a grating as an output section disposed on the surface of or inside the waveguide and having an inclination with respect to a direction crossing at right angle to transmission direction of the guided wave, whereby light is deflected out of the plane parallel to the waveguide.
TL;DR: In this paper, the influence of diffusion on stationary nonlinear surface-guided TM waves is investigated numerically and a detailed description of the finite element method used for solving this problem is presented.
05 Jan 1990
TL;DR: In this paper, a variety of guided-wave devices such as multi/demultiplexers for 1.3 and 1.55 μm wavelength, 2 x 8 couplers, ring resonators, and Mach-Zehnder interferometers are presented.
Abstract: Silica-based single-mode waveguides, fabricated on silicon substrates by a combination of flame hydrolysis deposition and reactive ion etching, have low propagation loss and low fiber coupling loss. High controllability in the silica-based waveguide fabrication leads to directional couplers with an accurate coupling ratio can be fabricated. Based on these advantageous features, we have successfully constructed a variety of guided-wave devices such as multi/demultiplexers for 1.3 and 1.55 μm wavelength, 2 x 8 couplers, ring resonators, and Mach-Zehnder interferometers which operate as optical switches or multi/demultiplexers with various channel spacings from 0.008 nm to 0.25 μm.
TL;DR: In this paper, deegenerate four-wave mixing was used to evaluate third-order nonlinearities in Ag-Na exchange waveguides, and guided wave linear absorption analysis was employed to correlate metallic Ag content with nonlinear properties.
Abstract: Degenerate four‐wave mixing was used to evaluate third‐order nonlinearities in Ag‐Na exchange waveguides. Guided wave linear absorption analysis was used to correlate metallic Ag content with nonlinear properties. Measured conjugate reflectivities approached 4%.
01 Jan 1990
TL;DR: In this article, a detailed investigation of the cylinder frequency equation is in order in the sizing process for bolt and pump-shaft inspections, and the wave scattering at the circumferential crack can be formulated in terms of the guided cylindrical waves which mathematically result from the cylinder frequencies equation.
Abstract: The propagation of a longitudinal wave in an isotropic cylinder has been used in the inspections of pumps and shafts of a nuclear power plant [1]. An ultrasonic technique called the “cylindrically guided wave technique” (CGWT) has been developed that can detect simulated circumferential defects through long metal paths in metallic materials being used for bolts and studs [1]. In the recent development of the sizing process for the cylindrically guided wave technique, the wave scattering at the circumferential crack can be formulated in terms of the guided cylindrical waves which mathematically result from the cylinder frequency equation. Therefore, a detailed investigation of the cylinder frequency equation is in order in the sizing process for bolt and pump-shaft inspections.
TL;DR: In this paper, a guided-wave lens structure is realized by embedding a low-index lens-shaped waveguide region in a surrounding higher-index planar waveguide, making it possible to fabricate low f-number lenses with low spherical aberration.
Abstract: A guided-wave lens is reported. The present lens structure is realized by embedding a low-index lens-shaped waveguide region in a surrounding higher-index planar waveguide. Very large index differences between the lens region and host waveguide are realizable using this technique, making it possible to fabricate low f-number lenses with low spherical aberration. The lens exhibits excellent off-axis performance, low chromatic aberration, and high polarization independence. A prototype f/2 lens in a GaAs/Ga/sub 0.97/Al/sub 0.03/As waveguide has been designed and fabricated using Corning 7059 glass and SiO/sub 2/ for the lens waveguide structure. >