Abstract: An integrated acoustooptical component for frequency-shifting optical frequencies is proposed, in which two separately guided optical waveguides exhibit an optical coupling region, which is designed in the manner of a directional coupler and in which the two optical waveguides exhibit a small spacing from one another generating an optical coupling. The acoustic waves of a sound generator propagate in the longitudinal direction over the coupling region. The two optical waveguides exhibit differing propagation constants for light. If, for example, light of mode a is injected into the optical waveguide and if the sound generator is energised, then the photons of mode a are scattered at the phonons of the acoustic waves and converted into mode b of the optical waveguide, where they can propagate. This gives rise to a frequency shifting. Accordingly, the acoustooptical component includes a frequency shifter and at the same time a coupler, which can be used for beam splitting and/or as an optical switch.

Abstract: An improved optical fiber modulator producing a focused acoustic wave propagating from an acoustic transducer surrounding an optical fiber having an in-fiber reflection grating changes the core refractive index in proportion to the induced strain at the core when the focused acoustic wave arrives at the optical fiber core, and focused acoustic waves can also modulate optical carrier phase in a length of optical fiber which may lie in an arm of an interferometer. In a preferred embodiment, the index change shifts the reflection spectrum of an in-fiber grating located in the portion of optical fiber core on which the focused acoustic wave is centered with the reflection spectrum shift producing a change in the grating reflectivity for a narrow bandwidth optical signal on a skirt of the grating spectrum.

Abstract: An optical modulator device comprised of a semiconductor laser acoustically coupled to a thin film resonator is disclosed herein. The thin film resonator includes a piezoelectric crystal layer having first and second opposing surfaces, with the first opposing surface being in contact with a metallic electrode. The semiconductor laser is interposed between an acoustically reflective surface and the second surface of the thin film resonator. In a preferred implementation the acoustically reflective surface is defined by a submount underlying a substrate upon which is mounted the semiconductor laser.A frequency modulator exhibiting an improved modulation index may be achieved by integrating a superlattice structure within the active region of the semiconductor laser.

Abstract: Acousto-optic polarization converters can be used as the primary optical components in a multi-channel wavelength-routing switch (101). Switching efficiency is decreased and the polarization converted wavelength channels are shifted towards each other, however, when closely neighboring channels are selected simultaneously. This degradation has serious consequences for many applications of the acousto-optic polarization converter. By applying counterpropagating acoustic waves from opposite ends of a converter (400) and using an acoustic absorber (417) to separate the left and right sides of the converter at a defined coupler crossover length, L.sub.x, this deleterious degradation is substantially reduced.

Abstract: A wavelength-selective arrangement interacts with optical radiation propagating in a transmission medium. The arrangement includes a selector member made of a polar organic material which exhibits piezoelectric properties, the selector member having an interaction surface for interacting with the radiation. The selector member is provided with structure for propagating surface acoustic waves along the interaction surface so as to create a grating and thereby determine its interacting properties in relation to the wavelength of the radiation, in a selectively variable manner.

Abstract: A passband-flattened acousto-optic polarization converter (100) in which two acoustic waveguides (14, 20) are formed in a substrate and a separated by a small gap (18) such that the two acoustic waveguides act as a directional coupler in which acoustic power is transferred back and forth. An interdigitated transducer (12) launches a surface acoustic wave in the first acoustic waveguide, and an optical waveguide is formed in the middle of the second waveguide. A partial acoustic absorber (27) is formed over both acoustic waveguides at a crossover length at a distance from the transducer equal to the point at which the acoustic wave has transferred from the first to the second waveguides and back again. The partial absorber absorbs most of the acoustic amplitude with the attenuated acoustic amplitude being coupled back again to the second acoustic waveguide but at an opposite sign.

Abstract: Devices for controlling high frequency signals such as optic or electric signals are disclosed which utilize guided and/or reflected surface acoustic waves. The devices preferably use crystalline substrates modified (e.g., by ion exchange to increase mass density) to contain acoustic reflectors and/or continuous acoustic waveguiding channels (optionally, in combination with optical features such as optical waveguiding channels) and interdigital transducers deposited thereon to provide frequency generation (and reception where high frequency electrical signals are controlled). The preferred crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves, such as MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.

Abstract: An acousto-optic tunable filter (100) is provided with an acousto-optic interaction profile that results in a frequency response with near-ideal bandpass filter characteristics of near-unity transmission inside the passband and near-zero transmission outside the passband. The acousto-optic interaction profile which results in this frequency response has a phase polarity which alternates and is damped, i.e. the acousto-optic interaction profile has a damped oscillating shape. The physical structure to implement this filter comprises a pair of acoustical waveguides (110, 112) which taper toward each other at the beginning of the profile and then are spaced apart by a constant distance. A damping layer (132) or other damping structure is provided to achieve the damping characteristics of the profile.

Abstract: An apparatus and method for optical telecommunication includes introducing a laser beam emitted from a light source at a first station into an optical fiber, providing an ultrasonic wave obtained by modulating a voice signal by a signal-applying-device at a work section to the optical fiber, modulating a polarized light passing through the optical fiber in amplitude and frequency, receiving the polarized light with the shifted wave plane at a light-receiving section in a second station, detecting at the light-receiving section in the second station the polarized light which has been modulated by the signal-applying device in the work section, and demodulating the polarized light to obtain a voice signal.

Abstract: Apparatus and method of non-mechanical scanning a laser diode light beam by altering the wavelength of the beam through changes in current applied to the diode and applying the beam to a diffraction grating to change the position of the beam as it emerges from the grating. A second dimension is scanned by the employment of an acousto-optic deflector and electronic driving and control means to change the position of the beam as it emerges from the deflector.

Abstract: A modulator adapted to be acoustically coupled to an optical fiber for applying acoustic waves across the fiber at a spatial and phase angle with respect to one another to compress and decompress the optical fiber at said spatial angle responsive to an electrical signal whereby to modulate the polarization state of an optical wave travelling past said modulator. An optical communication system in which light waves are transmitted from a transmitting end to a receiving end and whose polarization is modulated by an acoustic modulator responsive to an input signal and the output signal is demodulated to recover the signal.

Abstract: An electronically tunable optical filter utilizing noncollinear acousto-optic interaction in an acoustically anisotropic, optically birefringent crystal. The directions of optical and acoustic waves are chosen so that the optical ray is collinear with the group velocity of the acoustic wave. The collinear beam configuration provides increased spectral resolution and reduced drive power.

Abstract: This invention disclosure describes the application of a polarization insensitive acoustically-tuned optical filter used in a multichannel WDM system to equalize variations in the power level of the WDM channels. The invention also describes a simple means for providing a low frequency control system which enables the equalizer to determine the signal levels of N optical carriers prior to equalizing the signals.

Abstract: A liquid crystal and acousto-optic based control system for phased array antennas provides independent control of scanning along two axes of the antenna. The optical control system includes a laser source providing polarized laser beams processed in an in-line interferometric optical architecture that uses two acousto-optic deflectors (AODs) driven by separate sidebands of a microwave signal that is a mixture of a drive frequency corresponding to the desired carrier frequency and a variable control frequency for determining a selected sideband frequency. The AODs and associated polarization rotators generate a plurality of optical signal pairs, each pair having one first order positive doppler shifted light beam deflected by a first sideband drive signal and one first order negative doppler shifted light beam deflected by a second sideband drive signal, the positive and negative doppler shifted beams being respectively orthogonally linearly polarized and traveling along almost collinear paths.

Abstract: A photonic switching system includes an optical link conversion board having a first end and a second end opposite to the first end, a plurality of wavelength converter elements arranged at a constant pitch along the first end of the optical link conversion board and converting input optical signals into optical signal components having different wavelengths, a combiner for combining the optical signal components received from the wavelength converter elements into an optical signal which includes optical signal components having a plurality of wavelengths, a plurality of light output parts arranged at a constant pitch along the second end of the optical link conversion board, and a deflector for sequentially deflecting the optical signal from the combiner to an arbitrary one of the light output parts in response to a control signal so that the optical signal at the arbitrary light output part includes a plurality of optical signal components having different wavelengths.

Abstract: A novel optical system is taught including an optical source, an optical modulator having at least one optical input port for receiving the optical signal from the optical source, a modulation port for receiving the optical signal from the optical source, a modulation port for receiving a modulating signal, and complementary output port signals. The complementary modulated output signals are applied to one or more optical receivers at the other end of an optical transmission link. In one embodiment, the two complementary signals are provided to two separate optical receivers, thereby allowing distribution of optically modulated signals, for example, in a cable television or other type distribution system. In another embodiment, the two complementary modulated signals are applied to a single balanced receiver, thereby providing information content to the complementary receiver twice the power level available on either one channel alone.

Abstract: An acousto-optic apparatus is described that varies the time delay of electrical signals over a continuum of delays. In the preferred embodiment, a light source, which can be either coherent or incoherent, emits an optical beam that is focused into an acousto-optic cell. An input electrical signal is used to drive the acousto-optic cell which, in turn, modulates the focused optical beam. Portions of the input optical beam are modulated and diffracted at angles proportional to the frequencies and phases contained in the input electrical signal. By appropriately choosing the cone of angles at which the light is focused into the acousto-optic cell, the diffracted optical beam can be made to overlap with portions of the undiffracted, unmodulated optical beam. All of the light exiting the acousto-optic cell is then collected onto a device for detection. Optical photomixing of the diffracted beam and the undiffracted beam is performed in order to derive the input electrical signal with a time delay.

Abstract: An apodized acousto-optic polarization converter in which two acoustic waveguides are (14, 20) are formed in a substrate and are separated by a small gap (18) such that the two acoustic waveguides act as a directional coupler in which acoustic power is transferred back and forth. An interdigitated transducer (12) launches a surface acoustic wave in the first acoustic waveguide, and an optical waveguide is formed in the middle of the second waveguide. An acoustic absorber (26) is formed over both acoustic waveguides at a distance from the transducer such that the acoustic wave is transferred from the first to the second waveguide and back again. Thereby, the optical signal in the optical waveguide is exposed to an acoustic power density that slowly increases to a maximum and then decreases with the result that the side lobes of the frequency spectrum for the converted signal are greatly reduced.

Abstract: An optical waveguide is comprised of an optical substrate and an optical thin-film optical waveguide layer and formed such that ##EQU1## where .theta. is an output angle, n.sub.o1 is an ordinary refractive index of the optical substrate for an ordinary beam, n.sub.e1 is an extraordinary refractive index of the optical substrate for an extraordinary beam, n.sub.o2 is an ordinary refractive index of the optical thin-film optical waveguide layer for the ordinary beam and n.sub.e2 is an extraordinary refractive index of the optical thin-film optical waveguide layer for the extraordinary beam, and an electrode for generating a surface acoustic wave for diffracting light is formed on the optical waveguide to construct a collinear optical deflector.

Abstract: The present invention relates to a surface acoustic wave element comprising a substrate, an optical waveguide layer formed on the aforesaid substrate to guide laser light from a laser light source, a surface acoustic wave portion for deflecting or modulating the laser light traveling through the aforesaid optical waveguide layer, a comb-shaped SAW electrode provided on the aforesaid optical waveguide layer to cause the aforesaid surface acoustic wave portion to generate surface acoustic wave, and a terminal provided on the aforesaid optical waveguide layer and connected to the aforesaid SAW electrode to apply a high-frequency alternating voltage thereto, wherein a protection cover is bonded by a viscoelastic adhesive having a refractive index smaller than that of the aforesaid optical waveguide layer to cover the aforesaid SAW electrode and surface acoustic wave portion with air space in such a manner that the aforesaid terminal is positioned outside thereof, and the manufacturing method of the surface acoust

Abstract: A light source unit comprises a laser unit for emitting a laser beam; a deflection element for deflecting the laser beam emitted from the laser unit and for outputting a deflected laser beam, a deflection angle of the deflected laser beam being controlled by a control signal supplied from an external controller to the deflection element; and a shading member for partly or entirely shading the deflected laser beam output from the deflection element, a spot size of a laser beam passing through the shading member being changed in accordance with the deflection angle of the deflected laser beam. The light source unit outputs the laser beam passing through the shading element.

Abstract: A variable wavelength light source using a semiconductor laser element suitable for use in optical communications is provided. Light emitted from one end surface of the semiconductor laser element is led along a path through a light wavefront converting element (e.g., a Fresnel lens) and a spatial light modulating element which are both formed in a waveguide layer, to a diffraction grating which is also formed in the waveguide layer. Light reflected from the diffraction grating is caused to travel back along the same path but in the opposite direction and to impinge on the semiconductor laser element. Wavelength selection of by the spatial light modulating element and the diffraction grating is utilized for generating and maintaining oscillation at a selected wavelength in the laser element. The wavelength of light is selected by selecting the wavelength of a surface acoustic wave generated the spatial light modulating element, i.e.

Abstract: An optical interconnecting device and method are disclosed for selectively directing signals from an array of optical inputs to an array of optical outputs through an optical medium. The input signals are angularly multiplexed and redirected by dynamic gratings of the appropriate spatial, or grating, frequency. Spatially periodic optical index perturbations propragated in the medium are utilized to achieve the dynamic gratings. The angles at which light is input to the gratings (input angles) and angles at which light is collected from the gratings (output angles) are selected to allow each grating frequency to connect signals at only one input angle to one output angle and thus only one optical output. The number of resolvable gratings required is the product of the number of inputs and the number of output. For the interconnection of an equal number of inputs and outputs connected in a one to one permutation, only a number of gratings equal to the number of inputs need be present simultaneously.

Abstract: Electro-optical Scanner comprising an optical waveguide (41) and an acoustic waveguide (42), arranged on a transparent substrate (40) and being colinear with respect to each other, for deflecting light waves out from the optical waveguide (41) by colinear acousto-optic interaction of the light waves (44) with a short surface acoustic wave traveling diffraction grating (43) propagating in the acoustic waveguide (42). The short traveling diffraction grating (43) is generated by a wide band transducer. Different applications of the electro-optical scanner are possible.

Abstract: A light modulator includes an interdigital transducer having a plurality of interdigital electrode fingers for generating surface elastic waves having respective different frequencies in an optical waveguide. The electrode fingers are oriented in different directions to enable the generated surface elastic waves to diffract a light beam guided through the optical waveguide, while satisfying the Bragg condition for diffraction. A driver applies high-frequency voltages having respective frequencies to the electrode fingers to generate the surface elastic waves, respectively. The application of the high-frequency voltages to the electrode fingers is turned on and off by switching circuits. The light modulator is incorporated in a recording device.

Abstract: Disclosed is an information detecting system of scanning type which comprises a substrate formed with an optical waveguide layer, a laser oscillator emitting a laser beam, a SAW type beam deflecting device formed on the optical waveguide layer, a beam irradiating section irradiating a specimen with the laser beam derived from the optical waveguide layer, a controller controlling the frequency of a high-frequency voltage applied to the SAW type beam deflecting device so as to scan the specimen with the laser beam directed from the beam irradiating section, and a detecting section detecting the position and/or the intensity of the laser beam scanning the specimen with respect to the SAW control signal controlled by the controller.

Abstract: A photo-pickup wherein a light emitting portion, a surface acoustic wave generating portion, a lens portion, a light receiving portion and a control portion are integrally integrated on a base plate formed on its surface with a light transmission path. The light emitting portion propagates a light beam to the light transmission path. The light beam propagating in the light transmission path is first deflected within a plane of the light transmission path by surface acoustic wave propagating on the light transmission path and propagated towards the lens portion. The lens portion is provided to project the light beam outside from the light transmission path and effect two-dimentional focusing of the projected beam and adjustment of focal position. The light receiving portion comprises a combination of a plurality of light receiving elements disposed at suitable intervals from the projected position of the light beam to receive a reflected light of the light beam.

Abstract: An acousto-optic modulator is described which comprises a first support layer and a second layer of piezoelectric semiconductor material disposed over the support layer. The second layer includes a plurality of active sublayers, each active sublayer having a planar surface and thickness dimension which is such as to enable the active layer to exhibit quantum-well effects. A surface acoustic wave structure is disposed on the second layer for creating an acoustic wave in the second layer. The acoustic wave induces electric field variations therein which are perpendicular to the planar surface of the active sublayers and alter an optical property thereof. An optical beam is directed through the second layer, which beam is modulated by the altered optical properties of the active sublayers.

Abstract: A waveguide type optical detection apparatus which is provided on an optical integrated circuit that has a waveguide for transmitting a light from point to point through the waveguide, one or more sets of two adjacent photodetectors provided on the waveguide, and one or more light-insensitive areas existing between the two adjacent photodetectors of each set. The waveguide type optical detection apparatus includes a waveguide focusing part and one or more reflection parts, the waveguide focusing part being provided on the waveguide for allowing a light beam passing through the waveguide to be focused on each of the two adjacent photodetectors of each set, and the reflection parts provided adjacent to each of the light-insensitive areas for reflecting each of light beams sent from the waveguide focusing means forward each of the two adjacent photodetectors of each set so that the light beams are received by the photodetectors.

Abstract: A light beam is introduced into an optical waveguide on a substrate of LiNbO.sub.3, and diffracted by a surface elastic wave generated by a tilted-finger chirped interdigital transducer on the optical waveguide. The direction in which the light beam is guided through the optical waveguide is substantially aligned with the z-axis of the LiNbO.sub.3 substrate. The light beam diffracted by the surface elastic wave and emitted out of the optical waveguide is applied to an optical member, such as a polarizing plate, a pinhole plate, or a light shield plate, which passes only a linear polarized component of the diffracted light beam.

Abstract: An optical spectrum analyzer includes a surface elastic wave generator for generating in an optical waveguide a surface elastic wave which has a continuously varying frequency and which diffracts and deflects a guided wave as it travels across the path of the guided wave, which guided wave is introduced as a measured light beam into and travels in the optical wave guide. The measured light beam which has been deflected is emitted from the optical waveguide and detected by a light detector. A modulator turns on and off or modulates the surface elastic wave by repeatedly energizing and de-energizing the surface elastic wave generator, the frequency of the modulation being lower than the continuously varying frequency. A filter receives a signal corresponding to the modulation frequency from the modulator and a signal corresponding to the measured light beam from the detector, and extracts a signal component having the same frequency as the modulation frequency from the signal received from the light detector.

Abstract: A light beam deflector employs first and second surface elastic waves to diffract guided waves split from a single light beam introduced into an optical waveguide. The surface elastic waves are generated respectively by first and second tilted-finger chirped interdigital transducers or curved-finger interdigital transducers which are arranged such that the first and second guided waves emittted out of the optical waveguide will scan a surface along respective aligned scanning lines, the ends of which scanning lines are adjacent to each other. The light beam deflector allows a large image to be recorded or read out because it has a wide deflection angle range. The first and second interdigital transducers may alternatively be arranged such that the first and second guided waves emitted out of the optical waveguide will scan the surface without overlapping each other.