Abstract: An opto-electronic semiconductor device including a variable strained layered quantum well structure having at least two superimposed heavy- and light-hole triangular bottom valance band quantum wells with mutually opposite slopes. Upon the application of a bias potential across a thickness dimension of the quantum wells, an electric field is generated therethrough which produces an interchange of the confined energy levels of heavy-holes and light-holes in the quantum wells which causes a change in the transmission characteristics of light passing through the device as a result of the heavy- and light-hole energy bands having different light absorption anisotropy.

Abstract: An optical article exhibits effects attributable to the nonlinear second order polarizability of electromagnetic radiation and comprises a polymer containing within its repeating units polar aligned noncentrosymmetric molecular dipoles having an electron donor moiety linked through a conjugated .pi. bonding system to an electron acceptor moiety to permit oscillation of the molecular dipoles between a ground state exhibiting a first dipole moment and an excited state exhibiting a different dipole moment, characterized in that the molecular dipoles include as an acceptor moiety a vinyl group geminally substituted by two strong electron withdrawing groups, at least one of which is a sulfonyl moiety.

Abstract: An optical guided-wave device with an electro optic effect is comprised of first and second substrates having first and second refractive indices wherein the second refractive index is larger than the first one. These substrates are made of a single crystal dielectric material such as lithium tantalate or lithium niobate and, if they are made of the same material, they have different crystal orientations resulting in different refractive indices. These substrates are physically bonded directly or via a thin film such as glass, silicon, silicon oxide or silicon nitride and then, the second substrate is thinned and worked to form a wave guide therein.

Abstract: This invention aims at providing an optical waveguide device capable of stably operating for an extended period of time. The optical waveguide device comprises an optical waveguide path formed inside a surface of an electro-optical substrate, a buffer layer formed on the optical waveguide path, and a driving electrode for impressing an electric field so as to change a refractive index of the optical waveguide path, wherein the buffer layer is made of a transparent dielectric or insulator of a mixture between silicon dioxide and an oxide of at least one element selected from the group consisting of the metal elements of the Groups III to VIII, Ib and IIb of the Periodic Table and semiconductor elements other than silicon, or a transparent dielectric or insulator of an oxide between silicon and at least one of the metal elements and semiconductor elements described above.

Abstract: An optical modulation device includes a substrate. An optical waveguide is formed on the substrate. The optical waveguide exhibits an electro-optical effect. Parallel lines electromagnetically coupled with each other are formed on the substrate. The parallel lines extend at opposite sides of the optical waveguide respectively. The parallel lines are of a microstrip line structure. The parallel lines may alternatively be of a strip line structure or a coplanar line structure.

Abstract: A wavelength-division-multiplexed transmitter has a single modulator modulating the output of an array of individually actuable semiconductor lasers integrated onto the same substrate as the modulator. An optical combiner integrated onto the same substrate between each of the lasers and the single modulator combines the outputs of the lasers. One or more of the lasers are activated as desired for wavelength division multiplexing.

Abstract: An interferometric modulator comprising a substrate of titanium-doped lithium niobate (Ti:LiNbO.sub.3) having top and bottom surfaces and a waveguide formed in the top surface is disclosed. A conductive layer is formed on the bottom surface of the substrate and electrically coupled to a top-surface ground plane or simply to ground potential. The bottom surface conductive layer functions to thermally stabilize the modulator during operation.

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: An optical modulator is disclosed. The modulator is based upon an ARROW waveguide, consisting of a substrate, a lower cladding, an interference layer, and a core layer. An electronic element is formed in the structure to control the free-carrier concentration in the interference layer. The light is coupled by grating into the interference layer, where the free-carrier concentration is controlled by the element, which in turn controls the modulation of the light in the interference layer before it is coupled back to the core layer.

Abstract: An electro-optical modulator system obtained by linking a modulator incorporating a Y-junction coupler having a length Ll(101-108) to a passive coupler (104,105) whose length L2 in relation to the coupling length LC2 is determined so as to cancel substantially the third order distortions of the modulator. The resulting modulator has all of its even distortions cancelled and its uneven distortion is substantially zero. Furthermore, the rate of decay can potentially be zero.

Abstract: An optical modulator in which waveguide regions are disposed at opposite ends of a modulation region to reduce the capacitance of the device and prevent pn junctions from exposure to air. On an n-side electrode there are laminated a substrate, an n-type clad layer and an optical modulation waveguide layer. A modulation region lies at the center of the optical modulation waveguide layer along the direction of travel of light, and two waveguide regions are disposed at opposite ends of the modulation region, respectively. On the optical modulation waveguide layer which constitutes the modulation region there are laminated a non-doped layer, a p-type clad layer and a p-side electrode, and a semi-insulating semiconductor is formed on the optical modulation waveguide layer which forms the two waveguide regions.

Abstract: A broadband optical modulator having a light waveguide and modulating electrodes incorporated into an output or drain transmission line of a distributed amplifier driver. The modulator has a distributed gain mechanism which overcomes the electrical losses in the modulating electrodes and provides broadband velocity matching between the driving electrical signal and the modulated lightwave signal.

Abstract: An optical modulating element has a core layer and first and second cladding layers sandwiching the core layer. The core layer is made of one or semiconductors belonging to a point group 43m or 42m, and has TM.sub.00 and TE.sub.00 propagation modes. The direction of light of said TM.sub.00 and TE.sub.00 propagation modes is parallel to the [110] or [-110] direction of crystal orientation. The change amount of an index of refraction of the core layer caused by the application of an electric field to the core layer in the direction parallel to the [001] direction is different for the two propagation modes.

Abstract: Optical device including an optical waveguide composed of a LiTaO.sub.3 monocrystalline substrate and a LiNbO.sub.3 monocrystalline thin film waveguide formed on the surface of the substrate, with the lattice length of the LiNbO.sub.3 monocrystalline thin film waveguide and the LiTaO.sub.3 monocrystalline substrate being matched with each other, and an electrode provided on at least one of the branched sections of the waveguide extending along the optical axis thereof for changing a refractive index of the waveguide. The optical device having the optical waveguide has excellent electro-optic effects and a resistance to optical damage as well as an advanced modulation efficiency and a stable amplitude modulation.

Abstract: An intelligent opto-bus including an optical/electrical connector with a display. An array of photonic components is mounted on a base and coupled to external electrical connections of the base. Electronics are mounted on the base and coupled to the array for sensing the operation of the array and the status of optical signals supplied to optical ports of the array. A display is coupled to the electronics to provide a visual indication of the operation of the array and the status of optical signals supplied to the optical ports of the array. The base is molded with a well and grooves. The electronics and display are positioned in the well and the grooves form optical waveguides that communicate with a fiber ribbon.

Abstract: A wavelength conversion element includes a substrate made of LiTaO.sub.3 of non-linear medium, a three-dimensional waveguide formed in the substrate and a second harmonic generation portion for defining a change in refractive index in the waveguide with a period .LAMBDA. and generating a second harmonic of a fundamental wave introduced into the wave guide, where .LAMBDA.=2m.pi./{.beta.(2.omega.)-2.beta.(.omega.)}, m is a natural number, .omega. is a frequency of fundamental harmonic, .beta.(.omega.) is a propagation constant of the fundamental wave, and .beta.(2.omega.) is a propagation constant of second harmonic.

Abstract: In an optical fibre system, an optical fibre is monitored to determine if a transmitted signal is being received at a receiving end. A bi-modal optical switch located between the laser transmitter and receiver operates in a first transmitting mode to allow a transmitted signal to pass through and in a second reflecting mode to reflect back the transmitted signal to the transmitting end. A monitor at the transmitting end monitors the fibre for the absence or presence of the reflected signal. The switch can be used to remotely monitor the receiver in an optical fibre link, to control handshaking between two computers, to remove idle sections from an optical fibre communications network, and to control the reflectance of a laser mirror.

Abstract: An optical integrated circuit comprises an optical substrate and an optical waveguide supported by the substrate. A transducer is incorporated into the optical integrated circuit and coupled to the optical substrate. The transducer comprises a region of piezo-electric material and a set of electrodes for applying a voltage to the piezo-electric material for selectively causing the deformation of the piezo-electric material so as to alter the optical path length of the waveguide.

Abstract: An optically bidirectional electrically controlled optical switch having reduced light loss includes an electro-optic crystal having one set of fast and slow optical axes and having at least two light paths for receiving light beams through the crystal, the crystal exhibiting electric field induced birefringence such that a light beam passing through the crystal along a light path and having a plane of polarization oriented in a first direction may have its plane of polarization switched from the first direction to a plane of polarization oriented in a second direction. Beam splitting polarizers are disposed at each end of the electro-optic crystal and optically aligned with the two light paths. The beam splitting polarizers split the optical beam into two light beams having planes of polarization oriented in the first and second directions when transmitting light to the two light paths and combine the two light beams into a single light beam when receiving light beams from the two light paths.

Abstract: External modulation is accomplished in a dual waveguide device wherein substantially identical input optical beams are supplied to the waveguides and wherein each waveguide through its electrode is subject to individual, mutually exclusive control. Modulation signals are applied to each waveguide via its separate electrode. Control signals are applied to each waveguide for adjusting the modulation chirp parameter to a desired fixed, non-zero value. Typically, the desired value of the chirp parameter is one which provides the lowest fiber dispersion penalty for the system. Modulated lightwave signals emerging from the waveguides are combined to form a single output signal suitable for transmission over an optical fiber. In one embodiment, Mach-Zehnder interferometer having separately controllable waveguides has its input coupled to a CW laser. Both III-V semiconductor and Ti:LiNbO.sub.

Abstract: An electro-optic waveguide deflector appropriate for use in an optical pickup head uses any film exhibiting high second order susceptibility such as nonlinear optic organic Langmuir-Blodgett films or nonlinear optic organic poled polymer films, or a liquid-crystal overlay cell. The deflector comprises a base support, a planar electrode layer disposed on the base support, a first buffer layer atop the first electrode layer, and an optical waveguide layer overlying the first buffer layer and planar electrode. When nonlinear optic films are used to form the waveguide layer, a second buffer layer is disposed atop the waveguide layer, and a pair of spaced electrodes is disposed atop the second buffer layer. When a nematic-type liquid-crystal overlay cell is used, it is disposed atop a passive dielectric waveguide, and a pair of spaced electrodes is disposed on the under surface of the liquid-crystal cell cover plate.

Abstract: The total internal reflection modulator has an electrode array distributed across an area of the reflecting surface of the electro-optic material. The electrode array has multiple sets of electrodes forming an outer rectangle interdigitated with at least one reference set of electrodes forming a inner diamond. A diamond-shaped area with no electrodes is preferably symmetrically within the inner electrodes of the electrode array on the reflecting surface. The uniform voltage difference between the electrodes and the varying lengths of the electrodes creates a fringe electrical field in the electro-optical material and an optical phase grating to diffract the incident light on the reflecting surface. The zero order nondiffracted light becomes the output beam. The optical phase grating will control the incident beam's optical profile at the modulator (near field) and hence the imaged spot size at a focus at the image plane (far field).

Abstract: In a variable density scanning apparatus, a variable focal distance device is provided in a scanning optical system. This variable focal distance device is formed of a light waveguide having a plurality of electrodes provided of which the lengths along the direction of incident laser beam are decreased or increased with the increase of the distance from the central electrode. The voltage to be applied between the electrodes is controlled in accordance with a desired dot pattern so as to change the refractive index of the light waveguide through which the laser beam is passed, thereby effectively changing the focal distance so that the diameter of the scanning laser beam spot can be changed in one dimension.

Abstract: An optical modulation system having cascade-coupled electro-optic modulator stages in either dual tandem or split tandem configurations. An electrical splitter derives multiple electrical drives for the multiple stages from a single modulating input signal. The multiple drive signals are linearly related in magnitude and preferably induce simultaneous antiphase (180.degree. out-of-phase) optical modulation in the tandem stages. While a double Mach-Zehnder cascade configuration could be used, at least one modulator stage might instead be a balanced-bridge interfometer-type modulator having at least one directional coupler. At least one directional coupler in such a configuration may be a .DELTA..beta. coupler. Application of bias voltages to the interferometer sections and to coupler sections by means of a parametric feedback loop is done in order to simultaneously enhance the linear modulation coefficient, minimize odd order distortions and null the even order distortions that are associated with biased .

Abstract: An integrated optical head has first and second channels forming an interferometer. A electro-optically phase-shiftable waveguide channel is associated with one of the first and second channels of the interferometer for electro-optical phase shifting of one channel with respect to the other channel. The interferometer is formed on a silicon substrate and the phase-shiftable waveguide channel is formed of Langmuir-Blodgett thin-film electro-optic polymers described on the silicon substrate.

Abstract: An electro-optic device, such as a Mach-Zehnder interferometer or a directional coupler, has a power dissipating electrode structure and a ground plane electrode, and is switchable between first and second distinct states by the application of respective first and second potentials to the power dissipating electrode. Thermally induced instabilities are minimized by biasing the ground plane electrode such that the first and second potentials are of substantially equal magnitude but of opposite sign. The power dissipating electrode may be a travelling-wave electrode connected to a 50 ohm transmission line.

Abstract: An integrated electro-optic waveguide device has a substrate, an optically transparent lower buffer layer positioned atop the substrate, an optically transparent nonlinear optic (NLO) organic poled polymer waveguide positioned atop the lower buffer layer, and a GaAs laser diode optically coupled to the waveguide. The NLO material has a higher refractive index than the buffer layer. A ridge waveguide section forms an extended resonator cavity for the laser diode and combines a modulation function and an in-cavity quasi-phase matched second harmonic generation function. A grating coupled ridge-to-planar waveguide section combines a beam expansion function, a TE-TM conversion function, and a beam turning function. A planar surface prism electrode section provides electro-optic waveguide beam deflection. A dual linear grating coupler section performs the output/input coupling. Beam turning is accomplished by a planar waveguide mirror section.

Abstract: An optical modulator is disclosed. The modulator is based upon an ARROW waveguide, consisting of a substrate, a lower cladding, an interference layer, and a core layer. An electronic element is formed in the structure to control the free-carrier concentration in the interference layer. The light is coupled by grating into the interference layer, where the free-carrier concentration is controlled by the element, which in turn controls the modulation of the light in the interference layer before it is coupled back to the core layer.

Abstract: A 1-input/2-output or 2-input/2-output directional coupler type optical device comprising a junction including two optical waveguides arranged parallel to each other and each fitted with an electrode for controlling a propagation constant, the incidence end or ends of one or both of the optical waveguides being connected to curved or straight optical waveguides, thus forming an incidence-side lead section, and the respective emergence ends of the two optical waveguides being optically connected to curved or straight optical waveguides, thus forming an emergence-side lead section. An electrode for suppressing the mode coupling is mounted on each optical waveguide of the emergence- or incidence-side lead section. A high extinction ratio of 30 dB or more can be obtained in either of cross and through modes by activating a required one of the mode coupling suppressing electrodes while applying an electrical signal to each propagation constant control electrode.

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: A method for fabricating a conformal optical waveguide on a semiconductor bstrate which results in an improved conformal processing method of producing ferroelectic ceramic waveguides that is integratable with conventional electronic and optoelectronic devices. First, a patterning of a desired waveguide configuration is made on a desired semiconductor substrate. A conformal confinement layer is fabricated in the pattern of the desired waveguide configuration on the semiconductor substrate. The conformal confinement layer has an index of refraction. Next, the method calls for a placing of a sol-gel waveguide precursor in the conformal confinement layer. Next the spin casting of a sol-gel waveguide precursor shapes a sol-gel conformal waveguide layer in the conformal confinement layer on the semiconductor substrate.

Abstract: An electro-optic waveguide device (10) comprises an assembly of waveguides (30) connected to a common light input region (41) and forming a common far field diffraction pattern (44). The device (10) comprises an n.sup.+ GaAs substrate (14) bearing a waveguide lower cladding layer (16) of n.sup.+ Ga.sub.0.9 Al.sub.0.1 As, which is in turn surmounted by a waveguide core layer (18) of n.sup.- GaAs. The layer (18) has grooves (20) defining the waveguides (30), each of which has a respective Schottky contact (32). Each contact (32) is biased negative with respect to the substrate (14), which reverse biases the respective Schottky diode waveguide structure. The waveguide core layer (18) has electro-optic properties, and its refractive index varies with electric field. The phase of light emerging from each waveguide is therefore independently variable by means of its applied bias voltage.

Abstract: A neural plane, which can form the basis of a neural network or a component thereof, is comprised by an optical modulator, an electrical non-linearity circuit and an optical detector interconnected whereby in use the non-linearity circuit controls the modulator in dependence on the detector output. There are parallel arrays (10, 11, 12) of such modulators, non-linearity circuits and detectors (M, T, D, 30, 33, 34). The modulator, non-linearity circuits and detectors have components formed in a common semiconductor substrate (20), for example by VLSI techniques with a silicon substrate, the modulators (30) may be comprised by liquid crystal on silicon in that case (FIGS. 4, 7).

Abstract: The present invention relates to a high performance nonlinear optical device by utilizing an optical medium of large second order nonlinear optical effects, which has acceptable processability and stability. The second-order nonlinear optical device of the present invention comprises an optical element of a monoclinic crystal of 4-hydroxy-3-methoxy-4'-nitrostilbene represented by the formula (I): ##STR1## said crystal belonging to space group P2.sub.1, point group #4, said optical element having at least one substantially optically smooth surface.

Abstract: An optical waveguide device includes an optical waveguide formed on a surface of a substrate having an electrooptical effect, and a pair of electrodes formed on corresponding regions above the optical waveguide and receiving a driving electric signal thereacross. By applying the electric signal to the electrodes, an electric field is formed in a vicinity of the optical waveguide. By changing a distribution of the electric field in accordance with a change in a frequency of the electric signal, it is possible to suppress a DC drift of the device to effectively compensate a fluctuation in operational characteristics due to the DC drift, stress of the like.

Abstract: The voltage signal applied between a conductive thin film (2) and a transparent conductive thin film (6) changes the aligning direction of a liquid crystal layer (5) near the surface of a waveguide layer (4) so that the refractive index of the liquid crystal (5) for waveguide light (8) is changed thereby to change the equivalent refractive index for the waveguide light (8), and thus the diffraction angle of the radiated light (9) from the waveguide layer (4) including the cyclic structure (3G) formed therein is also changed to deflect the radiated light.

Abstract: Method for optically measuring submicron dimensions of an object or covering between two objects, and device implementing such method, wherein a light beam (23) is emitted by means of an arc lamp (22) into a system (21) with an optical monofibre (8) having a diameter larger than 500 .mu.m and a length longer than 3 m, the beam (23) is focussed to the object to be measured through the lens (32) of a microscope, the reflected beam passing through the microscope lens is separated from the incident beam in order to direct it towards the sensors of the matrix cameras (41, 42) of the charge coupling type and the spatial signals thus obtained are processed in order to reconstitute the contours of the object or to measure the covering between the two objects.

Abstract: There is disclosed a new superfluorescent source comprising a long fiber doped with a lasing material presenting three-level transitions, such as Erbium. Due to the ground state signal absorption present in three-level systems, the source of the present invention can achieve backward signal quantum efficiencies well in excess of the limit of 0.5 exhibited by four-level systems. The source can be used in a Sagnac interferometer which may comprise an optical isolator because of possible high feedback.

Abstract: A semiconductor structure for a light-interactive semiconductor device includes first and second crystalline semiconductor cladding layers having a first lattice constant and a strained superlattice structure disposed in contact with and between the first and second cladding layers and including alternating first crystalline semiconductor quantum barrier layers having a first and second crystalline semiconductor quantum well layers having a second energy band gap less than the first energy band gap and a third lattice constant wherein the first lattice constant is approximately equal to the average of the second and third lattice constants and the second lattice constant differs from the third lattice constant by at least 0.5 percent of the second lattice constant.

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: There is provided a magnetooptic device including a substrate; a semiconductor layer having a quantum well structure formed on the substrate, in which the semiconductor layer is formed by alternately laminating a well layer and a barrier layer and at least the barrier layer in those layers contains magnetic ions; and electrodes to apply an electric field to the semiconductor layer. A light which was polarized in a predetermined direction is input to the semiconductor layer. A magnetic field is applied to the semiconductor layer. An electric field is applied to the semiconductor layer by the electrodes. The light which was transmitted in the semiconductor layer is extracted. A degree of leakage of a wave function of the carrier in the well layer into the barrier layer changes. An effective magnetic field which a carrier spin feels changes by an exchange interaction between the carrier spin and a magnetic moment associated with the magnetic ions.

Abstract: A semiconductor heterojunction, guided-wave, electroabsorption modulator. The device includes a rib waveguide fabricated on a substrate. The waveguide includes a relatively thin and off-center undoped electroabsorbing layer within a light-guiding region. Electrodes configured for interconnection to an external voltage source produce an electric field within the waveguide. Heavily doped field confining layers on opposite sides of the electroabsorbing layer confine the electric field within the electroabsorbing layer to cause the electroabsorption of radiation in accordance with the Franz-Keldysh effect.

Abstract: A waveguide-type optical device of the invention has a dielectric substrate, wave-guiding paths formed in the dielectric substrate, and electrodes for forming an operation-controlling electric field for the wave-guiding paths. A carrier capture layer is provided in a region into which carriers are injected from at least one of the electrodes.

Abstract: An article is manufactured from a substrate of a material that exhibits the pyroelectric effect by depositing a film containing a selected material in a first state over a front surface of the substrate. At least one electrode is formed on the film, portions of the film being exposed around the electrode. The exposed portions of the film are subjected to a treatment such that they are converted from the first state to a second state, in which the material has a resistivity that lies within a desired range of values.

Abstract: An optical waveguide device for polarization rotation comprises a substrate, a waveguide path arranged on the substrate, a mode converting element arranged at an intermediate region of the waveguide path, and a polarization rotating element arranged at a location in the waveguide path between a place where light is incident and the mode converting element. The mode converting element includes a phase shifter for relatively shifting a phase between TE and TM components of light transmitted through the waveguide path, in response to an applied voltage, and also includes a mode converter for converting modes between the TE and TM components. The polarization rotating element rotates a polarization plane of the light transmitted through the waveguide path by (90+180 .times.n) degrees, where n is zero or an integer.

Abstract: An optical switch for arbitrarily polarized light having low cross-talk is made in which an input beam is split into its TE (s wave) and TM (p wave) polarization components, the TM component is converted to TE by total internal reflection, the two beams are either reflected or transmitted by liquid crystal cells, one of the beams is then converted to TM polarization, again by total internal reflection, and the two beams are recombined and outputted from one of two ports.

Abstract: In one embodiment this invention provides a frequency doubling optical waveguide consisting of a substrate-supported polymeric thin film which exhibits second order nonlinear optical response and is thickness variation insensitive, and which has a periodic structure for quasi-phase matching of propagating laser wave radiation. In a preferred embodiment the waveguide has a two-dimensional channel structure for intensified single mode wave transmission.

Abstract: An optical deflection device for manipulating optical beams employs a set of layers having the configuration NUPUN . . . , where the N and P symbols refer to N-type and P-type dopants and the U symbol refers to an electrooptically active optical guide layer having an index of refraction sufficiently higher than that of the N- and P- layers that light is guided within it and a free electron concentration low enough that the guide layers are depleted, so that light is guided within the layers with low loss, while the N- and P- layers have an appropriate bias applied to establish a differential phase shift between layers to deflect emitted radiation along a desired angle.

Abstract: An electro-optical transducer module assembly has a substrate on which is secured a guided-wave transducer having an optical waveguide and electrode structure formed on one surface thereof with the waveguide surface in a facing relationship with the substrate. Spacers are provided to position the transducer above the substrate surface and means are provided to electrically connect the electrode structure with the substrate. Optical waveguides are affixed to the substrate adjacent to the transducer for coupling an optical signal into and out of the transducer.

Abstract: An optical directional coupler switch is fabricated from a semiconductor substrate having a (111) plane. Thus, refractive indexes are changed for TE and TM modes by electrooptic effect, although the change amount is different between TE and TM modes. Therefore, a switching operation is realized for an incident light having any polarization. A device length L is preferrably set to meet an equation of "L.sub.TE .ltoreq.L.ltoreq.L.sub.TM " (L.sub.TE and L.sub.TM are coupling lengths for TE and TM modes) to decrease a cross-talk, even if the coupling lengths are different between TE and TM modes, considering that the difference is small.