Showing papers on "Guided wave testing published in 1982"

P-Polarized nonlinear surface polaritons in layered structures

Abstract: We found an exact solution of Maxwell's equations, which describes the propagation ofp-polarized nonlinear surface polaritons and ofp-polarized nonlinear guided wave polaritons in two cases:i) in a film of a surface active material placed on a substrate described by a diagonal dielectric tensor whose elements depend on the amplitude of the electric field according to e1 1=e2 2=e⊥ + α(|E1|2 + |E2|2), e3 3=e‖, andii) in a film described by the same dielectric tensor (optically uniaxial nonlinear crystal) placed on a substrate with dielectric constant e3 (optically linear medium). The power carried in the surface waves has also been exactly calculated.

Optical guided‐wave interactions with magnetostatic waves at microwave frequencies

Abstract: Interaction of guided optical waves with microwave magnetostatic waves in yittrium iron garnet thin films has been demonstrated. TM↔TE mode conversion induced by codirectional (and contradirectional) magnetostatic waves was experimentally observed with conversion efficiencies of up to 4%. Theoretical expressions for this interaction are given and compared with observations. The thin‐film geometry demonstrated could make a practical number of optical signal processing devices in the 1–20‐GHz range.

Guided wave approaches to optical bistability

Abstract: We have analyzed four different guided wave approaches to achieving a power dependent refractive index and optical bistability. These include surface plasmons at the interface between a metal and a semiconductor, symmetric surface plasmon modes guided by thin metal films, conventional single film integrated optics waveguides, and multifilm integrated optics. The relative merits of each geometry are discussed for utilizing the large cubic nonlinearities in the semiconductors GaAs and InSb. Both the mode attenuation and the minimum power required for a nonlinear phase shift of \pi/2 are evaluated numerically and it is shown that usable propagation distances can be obtained, even for highly lossy media such as GaAs.

High Speed Guided-Wave Optical Modulators

Abstract: Design and fabrication techniques of wide-band or highspeed guided-wave electrooptic modulators are reviewed. It is shown that the traveling-wave type operation is promising because of the large bandwidth possible, even with velocity mismatching. Also the modulating electrodes, an asymmetrical planar strip line, is adequate for wide-band operation owing to the small discontinuity effect at the feeding and terminating ends.

Nonlinear waves near a cut-off frequency in an acoustic duct – a numerical study

Abstract: Cut-off frequencies are well known in acoustic ducts to be the thresholds of propagation and evanescence. If at one end of a duct the piston oscillates at very near the cut-off frequency, cross-duct resonance occurs and the linearized theory breaks down. This paper studies the nonlinear response, near a cut-off frequency of a guided wave, as an initial-boundary-value problem. The asymptotic state is shown to be governed by a modified cubic Schrodinger equation. Numerical solutions are then obtained for inputs of finite and long duration. In addition to the characteristics of the input envelope, two quantities control the transient phenomenon: frequency detuning and nonlinearity. Under certain circumstances, energy can be trapped near the piston long after a short-lived input has expired, while for a sustained input there is no sign of a steady state. Dissipation is not considered.

Integrated optical time integrating correlator

Abstract: An optical time integrating correlator is fabricated in integrated optical form. This integrated optical implementation comprises a number of integrated components including an optical waveguide on a substrate, a diode laser, a guided wave lens, an electro-optic beamsplitter, a pair of surface acoustic wave transducer for generating first and second counterpropagating surface acoustic waves, a spatial filter and a detector array.

Comparison of guided wave approaches to optical bistability

Abstract: The minimum power required for a nonlinear phase shift of π/2, and the maximum propagation distance are evaluated for the semiconductors GaAs and InSb in four guided wave geometries: surface plasmons at the interface between two semi‐infinite media and guided by a thin metal film, and single and multilayer thin‐film optical waveguides. Optimum configurations compatible with guided wave technology are identified.

Magnetometer probe using a thin-film magnetic material as a magneto-optic sensor

Abstract: A magnetometer measuring head is divided into two separate sub-units, including a first sub-unit including means for transmission and detection of polarized light is coupled via a fibre to a second sub-unit comprising a thin layer of magnetic material within which is guided the light wave transmitted by the fibre. The coupling with the fibre is established via the edge, the opposed end of the layer being provided with a mirror so that the guided wave follows an outgoing and returning path before being retransmitted to the detection means which measure the rotation of the polarization of the light caused by Faraday effect.

Coupled-beam analysis of integrated-optic Bragg reflectors

Abstract: The problem of a guided wave reflected by a thin-film grating is considered. A solution method is proposed based on a coupled-beam theory and a boundary-value iteration. The method is applied to different configurations. A focusing wavelength demultiplexer is analyzed, which could be used with stripe waveguides as input and output channels.

Equivalent network analysis of dielectric thin‐film waveguides for optical integrated circuits and its applications

Abstract: The equivalent network approach has been applied to the guided wave problems in the dielectric thin-film waveguides for optical integrated circuits. This approach utilizes transmission lines and equivalent networks which furnish physical insight, and application of the so-called transverse resonance technique yields, in very simple fashion, approximate but fairly accurate analytical expressions for the dispersion relations of the dielectric thin-film waveguides. The results computed from these relations for the optical strip waveguide and the rib waveguide which have recently received considerable attention agree well with the results of the numerical approaches.

Guided Wave Approaches to Optical Bistability

Abstract: We have analyzed four different guided wave approaches to achieving a power dependent refractive index and optical bistability. These include surface plasmons at the interface between a metal and a semiconductor, symmetric surface plasmon modes guided by thin metal films, conventional single film integrated optics waveguides, and multifilm integrated optics. The relative merits of each geometry are discussed for utilizing the large cubic nonlinearities in the semiconductors GaAs and InSb. Both the mode attenuation and the minimum power required for a nonlinear phase shift of pi/2 are evaluated numerically and it is shown that usable propagation distances can be obtained, even for highly lossy media such as GaAs.

Surface acoustic wave transducer array for a guided-wave acoustooptic device

Abstract: An optical waveguide has a multiple tilted surface acoustic wave transducer array for diffracting a wide light beam propagating through the waveguide. Adjacent transducers are relatively positioned so that at the crossover frequency, the light beams diffracted from the transducers are added in phase.

Guided-Wave Acoustooptic Interactions in GaAs-ZnO Composite Structure

Abstract: Planar guided-wave acoustooptic Bragg interactions in z-cut GaAs optical waveguides are analyzed in detail. The calculated frequency response for a 0.4 urn thick waveguide shows that both -and -propagating SAW of 1 mm beam width at a power level as low as 18.8 mW. The results of a preliminary experiment, namely, 50% diffraction at 47 mW rf drive power has demonstrated this high diffraction ef€iciency.

The influence of losses of hollow dielectric waveguides on the mode shape

Abstract: Losses of a dielectric waveguide induce a deformation of the guided wave phase fronts This mode shape is analyzed for the EH 11 mode Its influence on the coupling characteristics for the transition to free space is discussed, as it is important for waveguide lasers

Effect of guided wave analysis and surface finish on ΔHeff by magneto microwave Kerr effect

Abstract: The experimental results on magneto-microwave Kerr effect (MMKE) on seven samples of ferrites and garnets at 9.442 and 24.0 GHz have been theoretically analysed. Our earlier analysis considering only free wave propagation has been extended to take account of the guided wave nature of microwaves. Two different methods have been used to do so. It is finally found that the model in which a pure TE 11 mode is propagating in empty waveguide with a pure TEM mode in an unbound sample, explains the results best, The effect of surface polishing on MMKE has also been studied.

Intrinsic Bistable Guided-Wave Devices: Theory And Applications

Abstract: Novel all-optical signal processing devices can be realized by utilizing optical power-dependent refractive-index materials in guided-wave resonators. The resonators are channel waveguide structures that obtain their feedback by means of cleaved mirrors, a corrugation, or a ring geometry. The nonlinear material can be part of the waveguide, of the cladding, or both. As the power carried by the guided wave in the resonator is increased, the effective refractive index of the waveguide changes, the optical path length is modified, and the resonator switches between transmission and reflection states. As a result, the resonator exhibits optical hysteresis, and acts as an intrinsic bistable device. We present the general theory of power-dependent refractive-index waveguides, and apply the theory to some devices that can serve as all-optical signal processors, such as optical amplifiers, discriminators and memory devices.

Tube-contacted slab dielectric waveguide for millimeter waves

Abstract: In this paper, a tube-contacted slab dielectric waveguide for millimeter waves is proposed, and a theoretical analysis and experiments are performed to determine the propagation characteristics. This waveguide consists of a dielectric tube with its radius larger than the wavelength, placed on a guiding film. The guided wave energy is concentrated near the contact point between the tube and the film. Since the tube is easily bent due to its structure and the field distribution is similar to Gaussian, the structure can be used as a low-dispersion flexible dielectric waveguide. Also, since the tube radius is larger than the wavelength, the waveguide can be used for high power transmission. The effective dielectric constant method has been used for analysis, and the field distribution and the phase constant have been computed. A waveguide has been fabricated for 35 GHz and the field distribution, propagation loss, guide wavelength, the field distribution at a bend and the bending loss have been measured. Measured results of the field distribution, guide wavelength and bending loss have agreed well with theoretical predictions. The propagation loss is 1.52 dB/m. In addition to the bending loss, variations of the field distribution at the transition from the straight guide to the bend have been measured. Based on these measured results, it is shown that the waveguide can be used for low-dispersion flexible transmission line or for high power transmission.

Critical ray-like propagation modes along graded-index planar optical waveguides

Abstract: Graded-index planar optical waveguides and surface compression layers were formed simultaneously in the surface layer of glass plates by ion exchange. A change in the refractometer patterns was observed. Before ion exchange, only a critical ray fringe was observed, but with ion exchange a guided wave fringe appeared on the high effective refractive index side of the ‘critical ray’ fringe, and the number of guided wave fringes increased. The guided wave fringe or fringes were birefringent, whereas the ‘critical ray’ fringe was kept nonbirefringent. It was concluded that the ‘critical ray’ propagated along the bottom of a waveguide, ie at the foot of the refractive index distribution.

Transfer efficiencies in guided-wave electrooptic filters mode converters

Abstract: The influence of a spatially nonuniform electric field on the polarization Conversion efficiency of single- and multimode guided wave electrooptic filters is analyzed quantitatively, using coupled-mode theory. A single-mode graded-index surface waveguide filter is capable of essentially 100-percent transfer efficiency, with overlap integrals of field and a single TE, TM mode pair approaching 0.6 in Ti: LiNbO 3 . The thicker multi-mode slab waveguides require that spatial periods of applied field be considerably greater than the guide thickness to achieve high transfer efficiency, though never quite 100 percent; The best performance also requires focused coupling into the lowest order mode only. Experimental results with a LiTaO 3 slab waveguide filter show reasonable agreement with a multiple-coupled-mode solution.

Methods For Analyzing Optical Guided Wave Structures

Abstract: As optical fiber technology matures, complexity of optical waveguides and waveguide components also grows. Traditional techniques which may be used to analyze circular fibers are no longer adequate. An assessment of several modern analytical/numerical techniques which have been used successfully to treat problems of practical interests is given. Il-lustrative numerical examples are also presented.

An optical guided-wave dye laser and directional coupling amplifier

Abstract: The properties of a new type active thin-film optical waveguide with layers of Corning glass 7059, Pyrex, and Rh 6 G dye formed on a fused quartz substrate are discussed. It generates superradiant emission when excited by a pulsed N2UV laser. When the top layer is shaped as a square, resonant behavior is observed between the corner reflectors formed by the edges on the diagonal. When the optical path is displaced normal to the diagonal, a distinct resonance is observed. This structure was used as a directional coupler and the coupling efficiency was found to depend on the waveguide length. These properties can be treated theoretically relatively simply in terms of a complex propagation constant with a positive imaginary part.