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Showing papers on "Guided wave testing published in 1986"


Patent
20 Feb 1986
TL;DR: In this article, an optimized guided wave microwave or lightwave communication system or network is presented, where a plurality of directional couplers are disposed along a bus-like wave guiding means and a separate coupling coefficient is optimized to only couple enough of the lightwave or microwave energy onto or from the associated guiding means.
Abstract: The present invention relates to an optimized guided wave microwave or lightwave communication system or network wherein a plurality of directional couplers (14, 17) (a) are disposed along a bus-like wave guiding means (13, 16), and (b) include separate coupling coefficients which are optimized. More particularly, the present invention relates to a guided wave communication system or network including, for example, a head-end unit (15) which is coupled to one end of a bus-like wave guiding means. Separate directional couplers are disposed along the wave guiding means to couple lightwave or microwave signals either (a) into the bus-like wave guiding means (13) from separate transmitters (11), or (b) from a bus-like wave guiding means (16) to separate receivers (12). The directional couplers disposed along a guiding means each include a separate coupling coefficient which is optimized to only couple enough of the lightwave or microwave energy onto or from the associated guiding means so that either (a) the head-end unit receives a minimal signal power level from each transmitter or (b) the receivers receive a minimal signal power level from the head-end unit, respectively, to provide a predetermined bit error rate regardless of their distance from the head-end unit along the associated wave guiding means.

154 citations


Journal ArticleDOI
TL;DR: In this paper, it is shown numerically that saturation of the optically induced change in the refractive index can dramatically alter, and in some cases eliminate, the more interesting power-dependent features of the solutions.
Abstract: Guided waves with unique, power-dependent properties arise when one or more of the media bounding a guiding film exhibits an intensity-dependent refractive index. Previous theoretical work on this problem has been based formalism-limited to Kerr-type nonlinear media in which the change in refractive index is quadratic in the optical field. In this paper, a formalism recently reported by Langbein et al. is used to investigate nonlinear guided wave solutions in more realistic material systems. It is shown numerically that saturation of the optically induced change in the refractive index can dramatically alter, and in some cases eliminate, the more interesting power-dependent features of the solutions. Nonlinear wave solutions are also investigated for a larger class of media characterized by refractive indexes which depend on the optical field raised to some arbitrary power.

88 citations


Journal ArticleDOI
TL;DR: Numerical studies of the propagation of waves guided by a thin film bounded by two self-focusing media reveal a whole new class of nonstationary solutions that can propagate as guided-wave fields, some with solitonlike components.
Abstract: Numerical studies of the propagation of waves guided by a thin film bounded by two self-focusing media reveal a whole new class of nonstationary solutions that can, in their own right, propagate as guided-wave fields, some with solitonlike components.

58 citations


Journal ArticleDOI
TL;DR: The propagation of TE guided waves excited at different points of their dispersion curve has been numerically traced down a thin film bounded by two identical self-focusing media.
Abstract: The propagation of TE guided waves excited at different points of their dispersion curve has been numerically traced down a thin film bounded by two identical self-focusing media. Several types of nonstationary field evolution have been investigated and identified as transitions between or oscillations around different branches of the dispersion curve.

47 citations


Journal ArticleDOI
TL;DR: In this article, the fabrication procedure and properties of optical nonlinear guided wave structures consisting of a thin film of Corning 7059 glass deposited on the surface of CdSxSe1−x doped glass are described.
Abstract: We report the fabrication procedure and properties of optical nonlinear guided wave structures consisting of a thin film of Corning 7059 glass deposited on the surface of CdSxSe1−x doped glass. The limiting action in power‐dependent prism coupling in the structures produced is described. The nonlinear prism coupling is used to evaluate both the sign and the steady‐state value of the intensity‐dependent refractive index of the substrate. For the glass used the nonlinearity is negative and its value is in the range of 10−10 m2/W.

39 citations


Journal ArticleDOI
TL;DR: In this paper, a theoretical analysis of optical waveguiding properties of thin films with an intensity-dependent refractive index was made, and the results of numerical calculation showed that in a symmetric structure, there exist guided waves with symmetric field profiles, being the nonlinear analog of conventional guided modes.
Abstract: A theoretical investigation is made of the optical waveguiding properties of thin films that exhibit an intensity-dependent refractive index. The results of a numerical calculation show that in a symmetric structure, there exist guided waves with symmetric field profiles, being the nonlinear analog of conventional guided modes. In addition, however, there exist asymmetric guided waves that are closely related to the surface waves supported at a single nonlinear interface. Such surface waves have been studied previously. The effect of structural asymmetry on nonlinear guided waves is also investigated.

39 citations


Journal ArticleDOI
E. Murphy1, T. Rice
TL;DR: In this article, a multiple fiber-waveguide alignment technique is proposed for single-mode and multimode guided wave devices, which uses an overlap between a precision-etched silicon substrate and the top surface of the waveguide substrate to align all but one of the six degrees of freedom automatically.
Abstract: We propose and demonstrate a new multiple fiber-waveguide alignment technique suitable for single-mode and multimode guided wave devices. The method uses an overlap between a precision-etched silicon substrate and the top surface of the waveguide substrate to align all but one of the six degrees of freedom automatically. We have attached six arrays, each with twelve single mode fibers, and have measured an average excess loss of 0.9 dB at \lambda = 1.3 \mu m. The lowest loss array had an average excess loss of 0.4 dB.

37 citations


Patent
08 Apr 1986
TL;DR: In this article, a light beam scanning system consisting of a wave guide formed of a material allowing propagation of surface acoustic waves therethrough, and a means for generating the surface acoustic wave in the wave guide so that they advance along an optical path of light incident upon the wave, is described.
Abstract: A light beam scanning system comprises a wave guide formed of a material allowing propagation of surface acoustic waves therethrough, and a means for generating the surface acoustic waves in the wave guide so that they advance along an optical path of light incident upon the wave guide, and a drive circuit for periodically applying a pulsewise voltage to the surface acoustic wave generating means. The wave guided inside of the wave guide is emitted out of the wave guide at the section where the surface acoustic waves are present by a coupling action of a grating generated by the surface acoustic waves with the guided wave.

36 citations


Journal ArticleDOI
TL;DR: In this paper, an analytical solution to the field distribution for coplanar electrodes incorporating a buffer layer is obtained by using the method of images, which is applied to practical integrated optical devices incorporating waveguides with stripe geometry in order to directly estimate the overlap integral between optical and electric fields.
Abstract: An analytical solution to the field distribution for coplanar electrodes incorporating a buffer layer is obtained by using the method of images. The accuracy of the present analysis is found to be comparable to that obtained from a numerical solution, the finite element technique, The solution is applied to practical integrated optical devices incorporating waveguides with stripe geometry in order to directly estimate the overlap integral between optical and electric fields.

31 citations


Journal ArticleDOI
TL;DR: In this article, a slow-wave microstrip line made of a ferromagnetic semiconductor (FMS) substrate is proposed and its characteristics are discussed, and another possibility of a slowwave micro-strip line by a FMS substrate is also described.
Abstract: A new slow-wave microstrip line made of a ferromagnetic semiconductor (FMS) substrate is proposed and its characteristics are discussed. Another possibility of a slow-wave microstrip line by a ferromagnetic (FM) substrate is also described in this paper. It is shown that these structures have more desirable and flexible guided wave properties than the conventional metal-insulator-semiconductor (MIS) microstrip line.

28 citations


Journal ArticleDOI
02 Jun 1986
TL;DR: In this paper, a new slow-wave microstrip line made of a ferromagnetic semiconductor (FMS) substrate is proposed and its characteristics discussed, and it is shown that this structure has more desirable and flexible guided wave properties than the conventional metal-insulator-semiconductor (MIS) microstrip lines.
Abstract: A new slow-wave microstrip line made of a ferromagnetic semiconductor (FMS) substrate is proposed and its characteristics discussed. It is shown that this structure has more desirable and flexible guided wave properties than the conventional metal-insulator-semiconductor (MIS) microstrip line.

Patent
24 Mar 1986
TL;DR: In this paper, an integrated optics optical polarization conversion device comprising a guide structure formed by integrated optics in a flat substrate made from a uniaxial crystalline material having electro-optical properties in which two distinct modes may propagate.
Abstract: An integrated optics optical polarization conversion device comprising a guide structure formed by integrated optics in a flat substrate made from a uniaxial crystalline material having electro-optical properties in which two distinct modes may propagate. In accordance with the invention, the optical axis of the crystal of said substrate forms an angle with the plane of the substrate less than (π/2) radians. In one of the variants, said axis is parallel to the direction of propagation of the guided wave and the device comprises a single set of homogeneous electrodes.

Journal ArticleDOI
TL;DR: In this article, the dispersion relations for TM-polarized nonlinear waves guided by a dielectric film of thicknessd bounded on one side by a nonlinear uniaxial medium characterized by a tensor are investigated.
Abstract: We found the dispersion relations for TM-polarized nonlinear waves guided by a dielectric film of thicknessd bounded on one side by a nonlinear uniaxial medium characterized by a dielectric tensorɛ xx =ɛ y =ɛ c ,ɛ zz =ɛ c +α c |E z |2,α c >0 (self-focusing medium),E z being the electric-field component perpendicular to the surfaces. Numerical calculations are given for the power dependence of the propagation wave vector. For sufficiently larged/λ (λ: wavelength) we have found regions with multiple solutions corresponding to the same power flow. This suggests possible applications to optical devices.

Journal ArticleDOI
TL;DR: In this article, the authors examined the acoustic scattering from cylindrical shells filled with a fluid (air or liquid) by the method of isolation and identification of resonances (MIIR), which allows resonance spectra to be obtained; in addition, the mode number, n, given by the identification, makes it possible to separate the resonances into different series.

Journal ArticleDOI
TL;DR: In this paper, the theory, experimental implementation, and applications of degenerate four-wave mixing with guided waves are reviewed, and the theory and experimental implementation of the degenerate 4-wave method are discussed.
Abstract: The theory, experimental implementation, and applications of degenerate four-wave mixing with guided waves are reviewed.

Proceedings ArticleDOI
03 Nov 1986
TL;DR: In this article, the optical parametric fluorescence was observed for the first time in a guided wave structure using a cw-argon laser (λ = 514 nm) or a pulsed dye laser (580 nm < λ < 615 nm).
Abstract: The optical parametric fluorescence was observed for the first time in a guided wave structure. In contrast to bulk optics three processes occur: signal and idler photons belong both to guided modes or both to radia-ting substrate modes or one to a guided mode and the other to substrate modes. These processes were investigated experimentally in Ti:LiNb03-channel waveguides. Using a cw-argon laser (λ = 514 nm) or a pulsed dye laser (580 nm < λ < 615 nm) as pump source, the fluorescence was studied as function of the pump wavelength, the pump power, the waveguide temperature and of spatial filtering.

Book ChapterDOI
09 Jun 1986
TL;DR: In this paper, a GaAs waveguide was used to phase match the difference frequency generation in an integrated optical parametric oscillator in GaAs, and the phase matching was achieved by using the waveguide mode dispersion or material birefringence.
Abstract: In the early days of integrated optics the attractive features of nonlinear optical devices using a guided wave structure have been recognized very soon [1–4]. Due to the concentration of optical fields in a long waveguide structure with crosssection dimensions of the order of a wavelength, very efficient nonlinear interactions could be expected to generate new optical frequencies. Especially the possibility to achieve phase matching even in isotropic materials, utilizing the waveguide mode structure, stimulated the interest in integrated, nonlinear devices. Anderson and Mc Mullen [5] were the first who demonstrated experimentally phase matched difference frequency generation in a GaAs (isotropic!) waveguide. Suematsu [6] and Boyd [7] both predicted a very low threshold power for an integrated optical parametric oscillator in GaAs. Despite these promising aspects, no experimental efforts have been reported up to now, to obtain parametric oscillation in a GaAs waveguide structure. Probably the required high waveguide quality (low losses, extremely good homogeneity, no optical damage) and the need for a suitable index profile to yield a good overlap of the interacting fields prevented the development of efficient nonlinear devices in that material. Nevertheless, in a number of other material systems nonlinear effects, mainly second harmonic generation, were studied [8]. In particular, several methods to achieve phase matching in optical waveguides were demonstrated. Somekh and Yariv [9] and Tang et al. [10,11] used periodic structures; Burns, Andrews and Lee [12,13] developed a waveguide composition yielding “noncritical” phase matching; other authors used the waveguide mode dispersion or the material birefringence to get phase matching of the interacting modes.

Journal ArticleDOI
TL;DR: In this article, a theoretical study of the zero-order efficiency caused by waveguide mode excitation is carried out for the case of conical diffraction mounting, and it is shown that the coupling into the guided wave vanishes at a given polarization.

Journal ArticleDOI
TL;DR: In this article, the dependence of the leakage of the LP01 mode of a polished singlemode fiber section on the refractive index of an external medium provides nonambiguous intensity modulation of the guided wave and a single-point in situ calibration of a sensor based on this transducing mechanism.
Abstract: The dependence of the leakage of the LP01 mode of a polished single-mode fibre section on the refractive index of an external medium provides non-ambiguous intensity modulation of the guided wave and a single-point in situ calibration of a sensor based on this refractive index, or temperature, transducing mechanism. Refractive index and temperature resolution of 10m4 and 0·1°, has been obtained over an adjustable range of 0·02 and 80°, respectively.

Journal ArticleDOI
TL;DR: In this paper, the roughness-induced scattering of slab-guided modes is considered in the framework of classical electromagnetic theory, and the theory is illustrated by applying it to the case of a step-index slab waveguide.
Abstract: After generalizing a given stationary coupled-mode concept toward both arbitrary field polarization and arbitrary direction of propagation, the roughness-induced scattering of slab-guided modes is considered in the framework of classical electromagnetic theory. The theory is illustrated by applying it to the case of a step-index slab waveguide. After developing formulas for the scattered power spectral density, we discuss in detail the relationship between the roughness correlation functions and the coupling-efficiency of guided modes among themselves as well as an appropriate principle for measuring these correlation functions. Finally, a simple formula emerges for the roughness-induced attenuation rate of the primary field.

Journal ArticleDOI
TL;DR: In this article, the behavior of the radiation mode spectrum has been studied for acoustooptic conversion of a guided mode of an anisotropic waveguide to a leaky wave over a wide range of lengths of the interaction region and of acoustic power densities.

Journal ArticleDOI
TL;DR: In this article, a method to analyze the technological process role for the lithium niobate Ti diffused guide for a collinear guided wave Bragg cell is presented, where the optical slab guide plays a critical role in fulfilling the desired characteristics of the Bragg cells; it determines the optical field shape in the crystal and the overall limitation of the cell.
Abstract: High diffracted power and bandwidth in acousto‐optic guided wave Bragg cell are critically dependent on the interaction efficiency between the surface optic and acoustic waves. Through the overlapping integral, diffraction efficiency depends dramatically on the acoustic and optic field shapes in the crystal, and the surface acoustic wave penetration depth is strongly dependent on the frequency; thus, either the interaction efficiency and the acousto‐optic bandwidth are strictly related to the guide geometry. For these reasons the technological process to build an optical slab guide plays a critical role in fulfilling the desired characteristics of the Bragg cell; it determines the optical field shape in the crystal and, thus, the overall limitation of the cell. In the present work, a method to analyze the technological process role for the lithium niobate Ti diffused guide is presented for a collinear guided wave Bragg cell.

Proceedings ArticleDOI
02 Jun 1986
TL;DR: In this paper, a new interaction between the guided-wave and the leaky-wave regions in the omega-beta diagram does occur and the effect of such an interaction on the characteristics is investigated rigorously by using their network approach.
Abstract: In an open periodic structure with finite length, a new interaction between the guided-wave and the leaky-wave regions in the omega - beta diagram does occur. The effect of such an interaction on the characteristics is investigated rigorously by using our network approach already proposed. Numerical calculations show that the finite length of periodic structures significantly affects the stopband characteristics of the first Bragg reflection region, especially in producing a complicated behavior of the return loss due to radiation. This paper also shows that such a return loss behavior can be easily estimated from the radiation characteristics of only the first step discontinuity of the periodic structure.

Patent
07 Apr 1986
TL;DR: In this article, a drive circuit is provided for sequentially and selectively energizing the energy application devices, and changing the refractive index of the wave guide layer and/or the adjacent layer so that the guided wave is radiated out of the stack by interaction with the dielectric gratings at the sections where energy is applied.
Abstract: A light beam scanning system comprises a stack of a wave guide layer and adjacent layer normally exhibiting a refractive index smaller than that of the wave guide layer, the wave guide layer and/or the adjacent layer being made of a material whose refractive index changes by the application of energy. Many energy application devices are positioned at the wave guide layer and/or the adjacent layer along an optical path of wave guided inside of the wave guide layer. Dielectric gratings are positioned on the adjacent layer so as to correspond to sections where energy is applied. A drive circuit is provided for sequentially and selectively energizing the energy application devices, and changing the refractive index of the wave guide layer and/or the adjacent layer so that the guided wave is radiated out of the stack by interaction with the dielectric gratings at the sections where energy is applied.

Patent
14 Aug 1986
TL;DR: In this article, a coupler with a grating is used to permit a resonance excitation of a guided wave from a plane incident electromagnetic wave, which is controlled by a modulation voltage supplied by a generator and applied to electrodes located on either side of the guiding layer.
Abstract: The optical modulator 10 comprises a coupler with a grating 3 which permits a resonance excitation of a guided wave 9 from a plane incident electromagnetic wave 7. The guiding layer 2, superposed on the grating 3, is produced with the aid of an electrooptic material. The resonance excitation is controlled by a modulation voltage supplied by a generator 6 and applied to electrodes 4, 5 located on either side of the guiding layer 2. The amplitude modulator 10 may constitute an electrooptic modulator for guided waves as well as an electrooptic modulator for reflected waves.

Book ChapterDOI
01 Jan 1986
TL;DR: In this article, a broad class of ultrasonic transducers, called EMUS-based transducers (EMUSs), have been proposed to provide a large variety of bulk and guided wave modes including shear waves with horizontal polarization.
Abstract: Electromagnetic ultrasonic transducers (EMUS) are a broad class of ultrasonic transducers that open new possibilities in the field of nondestructive testing. The reasons are: they don!t need liquid couplants; they can be designed to operate at elevated temperatures and to scan at high speed. They can provide a large variety of bulk and guided wave modes including shear waves with horizontal polarization, and their operating characteristics are easily reproducible. All these and other advantages are faced with a general disadvantage of a larger insertion loss than conventional transducers. However proper sensor and electronic design permits sufficient signal-to-noise levels to be achieved. When properly designed and instrumented an EMUS-based ultrasonic system can be used for many practical applications.

Proceedings ArticleDOI
14 Oct 1986
TL;DR: In this article, the fabrication procedure and properties of optical nonlinear guided-wave structures are reported, which consist of a thin film of Corning 7059 glass deposited by RF planar magnetron sputtering on a surface of CdSxSe1-x doped glass.
Abstract: The fabrication procedure and properties of optical nonlinear guided-wave structures are reported. The structures consist of a thin film of Corning 7059 glass deposited by RF planar magnetron sputtering on a surface of CdSxSe1-x doped glass. The coupling of light into the waveguides characterized by a power dependent propagation constant was studied. The experiments were performed at two wavelengths λ= 0.4880 μm and λ= 0.5145 μm with a laser working in cw and mode-locked regimes of operation. It is shown that integrated optical structures fabricated exhibit strong nonlinear effect with subnanosecond response time.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Dissertation
01 Jan 1986
TL;DR: In this paper, the theoretical design and experimental evaluation of a novel type of high speed phase modulator using LiNbO3 and GaAs technology suitable for guided wave optics is described.
Abstract: This thesis encompasses the theoretical design and experimental evaluation of a novel type of high speed phase modulator using LiNbO3 and GaAs technology suitable for guided wave optics. A brief review of the development of Integrated Optics and in particular of optical modulators is given in Chapter 1, along with an outline of the aims of this project. Chapter 2 provides a comprehensive survey of the methods available for determining the theoretical propagation constant of a guided wave in a variety of dielectric waveguide configurations. A comparison between the various methods is made to provide an indication of the accuracy and complexity of each procedure for a particular waveguide geometry. The effect of metal films in close proximity to optical waveguides on the propagation characteristics is derived through the effective index method. The results obtained are then applied to minimise absorption losses due to the metal overlay in active devices. The main theoretical design of the proposed electrode structure is developed in Chapter 3. The input impedance of the device is matched to the characteristic impedance of the transmission line drive system at the operating frequency using the standard transmission line equations for low-loss lines. The response of the device is modelled by a computer program which calculates the input impedance of two short circuited transmission lines of unequal length connected in parallel. The program allows the asymmetry of the line lengths, the attenuation constant and characteristic impedance to be independently varied so that their influence upon the overall response may easily be determined. An expression is derived for the theoretical depth of modulation and the power/bandwidth ratio for such a device. Finally a description is given of the numerical methods used to obtain the characteristic impedance and attenuation constant of symmetric and asymmetric coplanar microwave waveguide. The chapter concludes with a brief mention of the analysis procedure for Schottky contacts on GaAs. The general photolithographic and fabrication procedures for forming optical waveguides in LiNbO3 and GaAs are introduced in chapter 4. This chapter also gives a detailed account of the modified lift-off technique which is successfully employed to pattern metal films up to 2mum thick - a technique which is required for the standing wave modulator electrode. The use of proton-exchange waveguides as a suitable optical waveguide for high speed active devices is explored in chapter 5. An initial experimental investigation is presented with the theoretical determination of the refractive index profile for waveguides formed in X- and Z-cut LiNbO3 from the observed optical properties. The fabrication parameters required to produce monomode stripe optical waveguides are determined and verified experimentally for a variety of exchange conditions. Other techniques are discussed which offer more control over the refractive index profile and address the problem of index stability. A brief description of the micro-analytical techniques available to monitor the hydrogen concentration is also given. Chapter 6 describes the methods available for characterising the small signal response of the modulator. A comparison is given between the experimental results and the theoretical predictions. Factors affecting the discrepancies in the response are also mentioned. In particular the uncertainties of the high frequency dielectric constants of LiNbO3 are quantified. Chapter 7 concludes the thesis with an outline of the future work required and the conclusions that may be drawn from the work carried out so far on proton exchange and the standing wave modulator.

Book ChapterDOI
01 Jan 1986
TL;DR: In this paper, nonlinear optical effects influence periodic coupling between a dielectric waveguide and a thin semiconductor cladding, and the propagation characteristics are used with distributed feedback to design a bistable switch.
Abstract: Nonlinear optical effects influence periodic coupling between a dielectric waveguide and a thin semiconductor cladding. Resulting propagation characteristics are used with distributed feedback to design a bistable switch.

Proceedings ArticleDOI
03 Nov 1986
TL;DR: In this paper, reflections off an etched vertical wall are used to provide promising low loss bends for guided wave structures with directional changes for integrated optical circuits, which will undoubtedly be required for optical circuits.
Abstract: Guided wave structures with directional changes will undoubtedly be required for integrated optical circuits. Reflections off an etched vertical wall are used to provide promising low loss bends.