Abstract: The present application provides an asymmetric Y branch optical waveguide capable of obtaining an asymmetric branching ratio stably with a low radiation loss, and a lightwave circuit and an optical transmission system both using the asymmetric Y branch optical waveguide. The asymmetric Y branch optical waveguide according to the present application has a waveguide (I) for input, two waveguides (III) for output, and a multi-mode waveguide (II) disposed between the waveguides (I) and (II). The present Y branch optical waveguide is constructed in such a manner that the width of the multi-mode waveguide, extending in the direction intersecting with an optical axis changes discontinuously at a portion where the input waveguide and the multi-mode waveguide are connected to each other, and the multi-mode waveguide is asymmetric with respect to a center line extending in the direction of the optical axis to allow optical peaks to respectively appear in each individuals of the two output waveguides.

Abstract: The present invention relates to a device for demultiplexing spectrum lines contained in an optical spectrum. This device comprises a energy separator (2a, 2b, 2c) and selective wavelength light reflectors (12), each selective wavelength light reflector having a wavelength bandpass that contains the spectral region associated with one of the lines and that, therefore, reflects only this particular line. Applications to surveying constructions, such as buildings and aircraft.

Abstract: Changing the index in the two output branches of a Y-branch optical waveguide in opposite directions, in amounts which are controlled by electrical signals applied to the branches, is used to control the chirp of the signal outputted from the Y-branch optical waveguide. In this manner, predetermined amount of chirp can be add to or subtract from an input signal to the Y-branch optical waveguide. The Y-branch optical waveguide can be fabricated using Group II-VI, Group III-V or Group IV material systems or using an insulating material, such as lithium niobate. The output branches of a semiconductor implemented Y-branch optical waveguide can be fabricated to each include a multiple quantum well for controlling the refractive index of that branch in response to an electrical signal.

Abstract: This invention discloses and optical filtering arrangement wherein a filter element having a coated substrate is disposed such that its ports on one side face the substrate instead of facing the coating upon the substrate. Hence, when the filter is positioned a distance from the ports, its coating side faces away from the ports while its substrate faces the ports. In this arrangement stress applied by adhesives or solder upon the coating can be eliminated.

Abstract: The invention relates to an optical component based on semi-conductor optical amplifiers in which the number of independent electrodes is reduced. The component has different regions (1, 2, 3, 4, 5) with the same vertical structure wherein an active waveguide (20) is buried between the upper and lower buffer layers. These regions each have lower and upper electrodes (10, E2, E4) for the purpose of injecting into them equal or different values of current density. This component is characterized in that at least one (10) of the said electrodes covers a number of regions (1, 3, 5) and has distributed resistivity which is adjusted depending on the region under consideration.

Abstract: A dynamically and chromatically variable transmissivity apparatus (e.g., a channel equalizer or an add-drop circuit) controls channel powers in wavelength-division multiplexed systems. The input WDM signal is split into two components, in one component a phase shift is added to the wavelengths needing equalizing, the two signal components are then recombined. The phase shift added at each wavelength determines the amount of equalization obtained for that wavelength. For a decrease in equalization (i.e., attenuation) range the apparatus exhibits a decrease in insertion loss.

Abstract: A multi-mode pump laser having an output, and an optical fiber coupler. The optical fiber coupler has a first section and a second section. The first section of the optical fiber coupler comprises a multi-mode fiber which is optically coupled to the pump laser output. The second section of the fiber coupler comprises a plurality of single mode optical fibers each of which has an input which is optically coupled to the multi-mode fiber. The source further comprises a pump drive which is controllable to dither the optical center frequency of the light produced by the pump laser, so as to scramble modal power distribution at the inputs of the single mode optical fibers.

Abstract: In an optical power splitter for splitting input light into N equal optical waves, and a manufacturing method therefor, a main waveguide and (N−1) branched waveguides are arranged on one side or both sides of the main waveguide. The main waveguide and the (N−1) branched waveguides form a directional coupler. In each of the directional couplers, the branched waveguide has an appropriate phase mismatch, a proper coupling coefficient, and a suitable coupling length to output 1/N of input optical power in the main waveguide. In the optical power splitter, when the main waveguide is semicircular, a circular substrate can be effectively used when the optical power splitter is manufactured.

Abstract: A substantially lossless transmissive link, such as an RF fiber optic link, that selectively employs a number of techniques to improve various link parameters. The link may be structured to comprise a high power light source, such as a laser, that provides light output having a high level of optical power. A feedback circuit may be disposed around the light source that reduces relative-intensity-noise levels produced by the light source at low frequencies. A modulator is provided that modulates the light output of the light source. Preferably, a dual output modulator may be used to provide two modulated optical signals whose respective RF modulation is “effectively” 180 degrees out of phase. An optical fiber that transmits the modulated optical signal(s). A photodetector without a load resistor directly on its output that is operable at the high level of optical power, receives the modulated light and recovers the RF signal.

Abstract: A system and method for providing a wavelength division multiplexer is disclosed. In one aspect, the system and method include providing a housing for the wavelength division multiplexer. The housing includes a first port having a first aperture therein, a second port having a second aperture and a first plurality of apertures therein, and a third port having a third aperture and a second plurality of apertures therein. The second and third apertures are coupled to the first aperture. The first plurality of apertures are disposed symmetrically around the second aperture. The second plurality of apertures are disposed symmetrically around the third aperture. In another aspect, the method and system include providing a wavelength division multiplexer. The wavelength division multiplexer includes a first port including a first collimator, a second port coupled to the first port, and a third port coupled to the first port.

Abstract: A two-way optical communication module includes a main waveguide which is optically coupled to an optical fiber and directs light incident from the optical fiber to a light-receiving element and a sub waveguide which is optically coupled to the side of the main waveguide and directs light emitted from a light-emitting element to the optical fiber so as to carry out an efficient two-way optical communication by using one optical fiber without the necessity for an optical branch device. With this arrangement, it is possible to provide an inexpensive and small-sized two-way optical communication module which readily enables an integration with other elements so as to exhibit suitability for a small-scale network, and to provide a two-way optical communication link which uses the two-way optical communication module.

Abstract: To increase its saturation threshold very strongly without degrading its gain, whilst remaining compatible with any semiconductor amplifier structure or technology, a semiconductor optical amplifier includes an input coupler having an input port and g output ports and an output coupler having g input ports and one output port. The q output ports of the input coupler are respectively connected to the q input ports of the output coupler by q semiconductor optical amplifiers having the same amplification characteristics. Applications include transmission of optical signals and to producing "all optical" switching devices.

Abstract: Digital optical switches (1) with asymmetrical wave guides (2, 3; 5, 6) and an electro-optically controllable adiabatic coupling in a central region (4) must have a degree of crosstalk suppression of better than 20 dB for use in transparent optical networks. With X or Y arrangements, the invention provides for this purpose a grid device (10) in the central region (4) which affects the wave guide's inherent modes as the main cause of the crosstalk, i.e. amplitude and phase matching of the wave guide's inherent modes at the output. The result of the solution of the invention takes the form of a "cascade" of two different physical effects, each of which, of at least 20 dB, contributes to the overall result crosstalk suppression of better than 40 dB.

Abstract: A wavelength division multiplexing optical device includes a cladding layer formed on a waveguide substrate, a first optical waveguide embedded in the cladding layer, a second optical waveguide embedded in the cladding layer and connected at one end thereof to an intermediate portion of the first optical waveguide, and an insertion groove formed in the waveguide substrate and the cladding layer so as to extend across a connected portion of the first and second optical waveguides. The wavelength division multiplexing optical device further includes first and second wide grooves formed in the cladding layer so as to cover opposite end portions of the insertion groove and open to the opposite side surfaces of the cladding layer, and a wavelength selecting filter inserted in the insertion groove.

Abstract: An optical method and apparatus particularly useful as an intensity modulation system, in which two phase modulators are placed in the loop of a Sagnac interferometer. Selective placement of the modulators, and the amplitude of any modulation signal input to the modulators, varies the bandwidth and frequency response of the system. In a preferred embodiment, the ratio of the optical distances of the modulators from interferometric midpoint, and the ratio of modulation signal amplitudes, is about 3:1, which serves to broaden and flatten the frequency response of the system.

Abstract: The invention is a photodetector device and a lightguide circuit incorporating the device. The photodetector device includes a semiconductor region for absorbing light which is incident on an edge surface of the device. The region above the absorbing region is narrow at the edge and fans out in the direction of light propagation in the device.

Abstract: A digital optical switch includes an input waveguide connected to a Y-shaped branching waveguide having two legs, each of the legs being connected to an output waveguide. Each output waveguide forms one waveguide of a directional coupler, the other waveguide of which has its output dissipated into the substrate. Electrodes are connected to voltage sources such that the switch is operative between two states. In the first state, transmission of optical energy is enhanced between the input waveguide and the first output waveguide and inhibited between the input waveguide and the second output waveguide. Coupling between the first output waveguide and the other waveguide of its respective directional coupler is inhibited and coupling between the second output waveguide and the other waveguide of its respective directional coupler is enhanced.

Abstract: Methods of using an adiabatic Y-branch digital optical modulator provide a substantially chirp-free modulator by changing the refractive index of only a first output branch of the modulator in response to a modulating signal. A second output branch of the modulator, where no refractive index change is induced, is used as the modulator output. The frequency chirp in this Y-branch modulator is negligible because the modulator output waveguide branch experiences little or no refractive index change and, therefore, little or no phase shift in operation. Substantially all of the phase shift occurs in the waveguide branch where the refractive index change is induced. According to a further embodiment, one or both of the output branches are comprised of one or more tapered waveguide sections.

Abstract: A compact, continuous-wave blue laser is developed from a fiber made from heavy metal fluorides ("ZBLAN") doped with a rare-earth ion. The footprint required to create blue laser light is reduced because the fiber can be wound into spools of radius <25 mm and stacked one atop the other without cross talk. IR diodes (.lambda..about.790 nm and .lambda..about.1050 nm) are fiber-pigtailed to silica fiber in a conventional way. The light from the IR diodes is coupled to a single fiber through a 2.times.1 fiber coupler that has silica inputs and a ZBLAN output. The IR light optically excites the electrons of the rare-earth ions in the ZBLAN fiber host. This excitation causes the electrons to emit light at 480 nm (in the blue region of the visible spectrum) as they relax to the ground state. Dielectric mirrors feed back the emitted light. A high-reflector, high-transmitter ("HRHT") is the input coupler of the pumping light; a partial reflector, the output coupler.

Abstract: A fiber optic cable comprises a plurality of packages each made up of a plurality of optical fiber ribbons. The packages are arranged in a tight structure incorporated in a polymer resin so that the packages themselves constitute reinforcements that impart strength to the cable and prevent curvature of the optical fibers due to variations in temperature. This eliminates the need to incorporate any central and/or peripheral reinforcing member into the cable.

Abstract: An interferometric semiconductor laser (YL) as well as optoelectronic arrangements with such a laser are disclosed. The laser has a special coupling segment (Z) which allows high optical output to be obtained without affecting the filtering function or significantly restricting the tuning range of the laser. Such a laser can be coupled with low loss to a subsequent optoelectronic component (e.g., a wavelength converter (WK)) which is monolithically integrated with the laser.

Abstract: A light beam (6) is applied to a waveguide (3) in order to measure properties of the beam (6), e.g. the wavelength. According to the invention, the waveguide (3) has locally and/or time-varying resonances, e.g. by suitably designed grid couplers (4, 5). A light signal (7) is thus generated in the waveguide (3) as a direct measurement of the property to be measured and can be further processed by suitable means or evaluated. It is thus possible, for example, advantageously to produce a simple and inexpensive spectrometer.

Abstract: An optical index switch including curved ridge waveguides. The cladding around the waveguides is selectively etched to produce tightly curved optical switches.

Abstract: It is the object of the invention to integrally conform functions of devices of optical fiber types with those of SiO.sub.2 waveguides, miniaturize optical devices and provide optical waveguide devices with various optical functions. A SiO.sub.2 waveguide, which is composed of a SiO.sub.2 waveguide clad with low refractive index and a SiO.sub.2 waveguide core with high refractive index, is formed on a Si substrate. The core and the clad on an area, where the direction of the core coincides with the orientation of crystallization of a Si substrate, are removed. A V-groove is formed along the orientation of crystallization of the exposed Si substrate. Both the end surfaces of an optical fiber grating, which is fitted in the V-groove, face those of the remaining SiO.sub.2 waveguide. The cores of the SiO.sub.2 waveguides and the optical fiber grating are optically coupled with each other.

Abstract: The invention disclosed is a circuit for regulating optical power levels. Electrooptic attenuators are used to control optical output intensity by means of feedback loops from the outputs of the attenuators to the electrodes of the attenuators which determine the amount of light going to the outputs. The attenuators may be used in combination with an optical switch array in a wavelength division multiplexing system.

Abstract: A system and method providing a wavelength locker is disclosed. The method and system provide a high uniformity, low polarization sensitivity optical coupler. The optical coupler further comprises a first outer fiber and a second outer fiber. The first outer fiber and the second outer fiber each have a first portion. The method and system further provide a filter coupled to the first portion of the first outer fiber. The method and system further provide a first mechanism coupled to the filter for detecting intensity and providing a first resultant. The method and system further provide a second mechanism coupled to the second portion of the second outer fiber. The second mechanism detects intensity and provides a second resultant.

Abstract: An optical filter is provided to be on a side of the output ports relative to a branch port of the first stage in an optical branch apparatus. The optical filter transmits a signal light and reflects a monitor light, so that signal lights are obtained at output ports, and the monitor light is returned to an optical transmitter to detect an abnormal state of an optical fiber transmission line.

Abstract: A polarization device is provided for splitting a transverse electric (TE) mode component and a transverse magnetic (TM) mode component into two output waveguides and for coupling the inputs of a TE mode component and a TM mode component to an output optical waveguide. The integrated optic polarization device includes, in an integrated optic substrate, a first waveguide capable of simultaneously allowing to pass through two mode components, whose polarizations are perpendicular to each other, and a second waveguide, in the same substrate, for allowing to pass through only one of the two polarization mode components. The device has a coupled area having a predetermined length and across which the first and second waveguides are parallel and separated by a predetermined distance. The device also has a non-coupled area in which the first and second waveguides are separated by a distance wider than the predetermined distance.

Abstract: A system and method for providing a wavelength division multiplexer is disclosed. In one aspect, the system and method include providing a housing for the wavelength division multiplexer. The housing includes a first port having a first aperture therein, a second port having a second aperture and a first plurality of apertures therein, and a third port having a third aperture and a second plurality of apertures therein. The second and third apertures are coupled to the first aperture. The first plurality of apertures are disposed symmetrically around the second aperture. The second plurality of apertures are disposed symmetrically around the third aperture. In another aspect, the method and system include providing a wavelength division multiplexer. The wavelength division multiplexer includes a first port including a first collimator, a second port coupled to the first port, and a third port coupled to the first port.

Abstract: An optical waveguide module having a main-line waveguide, which is excellent in optical branching properties, important properties of a bus communication network, and the reproducibility of the above branching properties and is easy to produce, and an optical transmission equipment having the above optical waveguide module. The optical waveguide module having a main-line waveguide which is connected to the optical transmission path and works as part of the optical transmission path and a pair of branch waveguides (21,22) which are unidirectionally branched from the main-line waveguide, the main-line waveguide and the branch waveguides being formed by providing an optically transparent polymer film with a refractive index distribution, a light-receiving device (25) being connected to one (21) of a pair of the branch waveguides, a light-emitting device (26) being connected to the other (22).

Abstract: An optical branching element has an input waveguide (10) and a plurality of output waveguides (20a, 20b), which are so disposed at a distance from the input waveguide (10) that a beam of light launched into the input waveguide (10) over a coupling path of a predefined length couples over with a defined intensity into the output waveguides (20a, 20b).

Abstract: The subject invention pertains to a method of apodizing interaction in spatially-coupled waveguides capable of implementing any desired interaction-strength profiles, for example, alternating functions. Wavelength filters with various types of spectral response can be synthesized. In a preferred embodiment, a Butterworth-type interaction profile is disclosed which provides a flat-top response with suppressed sidelobes. The method according to the subject invention is based on spatially offsetting a single-mode waveguide with respect to a two-mode waveguide in which the anti-symmetric mode is excited by using a Y-junction mode splitter. The method can easily be implemented in vertically-coupled structures fabricated with the use of conventional fabrication processes. Various embodiments of the method implemented. The subject invention further pertains to the device produced in accordance with the methods of the subject invention.

Abstract: A linear waveguide 12 is formed on a substrate 11. A non-linear waveguide 13 whose refractive index may vary depending on an electric field intensity of a light is formed in contact with or at a given distance from the linear waveguide 12. These waveguides form a branch structure. The linear waveguide 12 is the original optical transmission path, while the non-linear waveguide 13 is a bypass for an inicident light with an electric field intensity higher than a set value. Adjusting the refractive indices of the linear waveguide 12 and the non-linear waveguide 13 by, for example, selection of materials, can make the incident light 14 transmitted through the linear waveguide 12 when its intensity is below the set value or through the non-linear waveguide 13 when its intensity is equal to or higher than the set value.

Abstract: An extremely low-loss optical switch element includes a first waveguide segment having first and second regions longitudinally-adjacent with each other and having an index of refraction difference which is greater when the switch element is in an "on" state than when it is in an "off" state. The two regions have a common boundary which is oriented at an angle in the first waveguide so as to redirect optical energy through total internal reflection when the switch element is in the "on" state. The switch element further includes a second waveguide segment spaced from the first waveguide segment and disposed and oriented to guide optical energy redirected from the first waveguide segment when the switch element is in the "on" state.

Abstract: Methods and apparatus for performing optical signal switching or other optical routing functions in an optical device or system, in which crosstalk induced by modal interference is suppressed by providing appropriate loss, gain and/or refractive index changes in different parts of a switch structure. An exemplary optical signal switch includes first and second branches each having a refraction-controlled section and an absorption-controlled section. An optical signal path over which an optical signal propagates in passing through the switch is selected to include a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch.

Abstract: An integrated optoelectronic semiconductor component is presented, which can equally process light signals of any polarization direction. Such semiconductor components are used for digital optical telecommunications. The semiconductor component has active (A) and passive (B) waveguide sections, which comprise a number of semiconductor layers (SP) with so-called multiple quantum well structures. The semiconductor layers (SP) are deposited by a process known as selective area growth (SAG). A portion of the semiconductor layers has a lattice constant which is smaller than the lattice constant of a substrate (SUB). This creates a biaxial tensile strain in these layers. The tensile strain is optimized in the active waveguide sections (A) to attain polarization independence. Furthermore a process is described whereby such a semiconductor component can be manufactured.

Abstract: There are provided a first optical waveguide having a first curved portion, a second optical waveguide having a second curved portion that extends along and is disposed inside the first curved portion, a third optical waveguide having a third curved portion, an end portion of the third curved portion being connected to both end portions of the first and second curved portions.

Abstract: A low-loss optical 1.times.2 branching element comprises a symmetrical Y junction (4) with identical branches (4.1, 4.2) and an asymmetric Y junction (5) with different branches (5.1, 5.2). The Y junctions are coupled by means of a common trunk (6) in which two modes that are of unequal mode order can propagate. Located centrally in and/or near the trunk are optically non-linear partial areas (7, 7a, 7b). The non-linear partial areas (7 and/or 7a, 7b) and the asymmetric Y junction (5) are dimensioned so that, for a given signal power, in one signal direction (arrow D) the branching element acts as a 3 dB splitter, whereas in the other signal direction (arrow U) the loss is <<3 dB.

Abstract: An out-of-phase self-imaging waveguide integrated optical wavelength demuplexer having an input waveguide containing light of two different wavelengths. The demultiplexer has a 1-by-2 self-imaging power splitter, a first intermediate waveguide containing the two wavelengths of light, a second intermediate waveguide longer than the first intermediate waveguide, a 2-by-2 self-imaging coupler having the first and second intermediate waveguides as inputs, an output waveguide containing light of one wavelength only, and an output waveguide containing light of the other wavelength only.

Abstract: A light wavelength filtering circuit in a wavelength-division multiplexing light communication system minimizes transmission loss in the waveguide after wavelength discrimination by having a linear output waveguide added to an output end of a light wavelength discriminating element, at which a signal having a long wavelength is outputted. A curved output waveguide is added to the rear stage of the output end at which a signal having a relatively short wavelength is outputted. Hence, a radiation loss at the output waveguide at the output end is minimized, while a space between the output light waveguides is being widened. Additionally, a core layer bandgap wavelength at the output waveguide of the long wavelength signal is set to be longer than a core layer band gap wavelength in another region.

Abstract: The present invention features a rectilinear optical coupler consisting of a single optical fiber terminating in an expanded, convex portion. An array of optical fibers consisting of a central optical fiber surrounded by six additional optical fibers has an end precision-ground to receive the convex, essentially spherical portion of the first optical fiber such that radiant energy in the single, input optical fiber is uniformly transferred to each of the fibers in the array. The convex/concave topology of the interface allows for uniform distribution of radiant energy in a small, rectilinear configuration which allows combining multiple couplers in an edge-to-edge arrangement.

Abstract: An optical waveguide having a light receiving end and a propagation mode with a double-hump shaped optical field distribution at the light receiving end to receive light into the optical waveguide. The light incident on the light receiving end typically has a single-hump shaped optical field distribution. Overlap in the optical field distribution of the incident light and the optical field distribution of the propagation mode of the optical waveguide causes the light to be received by the optical waveguide. Alternatively, the optical waveguide can have a propagation mode with a single-hump shaped optical field distribution at the light receiving end, and the incident light can have a double-hump shaped optical field distribution at the light receiving end.

Abstract: An active optical circuit sheet or active optical circuit board wherein an electro optical switch or optical modulator is driven with a voltage (SIGin) from an electronic device, the electrical signal (SIGin) is converted to an optical signal, transmitted and then converted to an electrical signal (SIGout) at an optical receiver element, and an electrical connection is formed between an optical wiring board and the electronic device for transmission of signals to another or the same electronic device, separating the electrical wiring at the electronic device end and the optical wiring at the optical wiring board end, or alternatively, SIGin and SIGout electrode pads are provided on the side of the optical wiring board on which the optical device is mounted or on the opposite side, for connection with the electronic device.

Abstract: The invention concerns an integrated-optical junction splitter, in particular for applications in the wavelength range of visible light, which ensures a spatial and wideband combination of light in a wavelength spectrum .DELTA..lambda. greater than 75 nm (value given applies to short-wave visible light). In the case of a usable wavelength range comprising the entire spectrum of visible light, the junction splitter is a white light junction splitter. The junction splitter consists of at least three channel waveguides, at least one of which must be a single-mode integrated-optical wideband channel waveguide (SOWCW). Two channel waveguides each have a respective input and are combined into a common SOWCW at their outputs in a coupling point, which common SOWCW features a common light output at its end.This wideband junction splitter is used as a wavelength-selective or wavelength-independent switch or modulator, in interferometric and photometric devices, sensors, and microsystem-technical solutions.

Abstract: Disclosed is an optical transmitter-receiver module, in which an optical waveguide with an optical dividing function is formed from a first end to a second end of a waveguide substrate, and the non-branched side of the optical waveguide is optically connected to an optical fiber at the first end of the waveguide substrate, and two optical waveguides on the branched side of the optical waveguide are optically connected to an optical transmitter and an optical receiver, respectively. A first optical waveguide of the two optical waveguides is optically connected to the optical receiver at the second end of the waveguide substrate, and a second optical waveguide of the two optical waveguides comprises a turning optical waveguide which is turned back from the second end to the first end of the waveguide substrate, and the turning optical waveguide is optically connected to the optical transmitter at the first end of the waveguide substrate.

Abstract: A nonlinear Y-junction waveguide structure includes a straight linear waveguide, and a nonlinear waveguide partially joined to the linear waveguide and bent through a desired angle at an output end portion thereof, whereby incident light coming into the linear waveguide travels mainly along the linear waveguide when it has a power lower than a predetermined level while traveling mainly along the nonlinear waveguide when it has a power not lower than the predetermined level. The nonlinear Y-junction waveguide structure has an increased branching angle as compared to the conventional completely-operating optical device and exhibits an abrupt switching phenomenon. Accordingly, it is possible to achieve an easy adjustment of the critical power. In this regard, there is no difficulty in the fabrication of the waveguide structure.

Abstract: An optical planar waveguide wavelength division demultiplexer for separating multiple wavelengths received in a wavelength division multiplexed communication system is disclosed, with each wavelength launched into a separate output waveguide channel. Wavelength separation is performed by wavelength-selective angular back-reflection from Bragg gratings, which are fabricated into the channel junctions of the planar germania-enriched silica waveguide by applying short wavelength light past a mask. A second Bragg reflection, reflecting the same wavelength as the first Bragg grating, is introduced into each output channel circuit, in order to attenuate residual backscattered light at non-desired wavelengths. The Bragg grating is extended beyond the channel junctions into the merged channel for greater reflectivity, if required, for the double Bragg grating geometry.

Abstract: A branching/crossed optical waveguide circuit includes a main waveguide formed within a clad material on a substrate, and two branching waveguides and that are optically connected to the main waveguide in an optical coupling section. The main waveguide includes a contracting waveguide portion that gradually contracts along its sides while extending longitudinally in the optical coupling section, and the optical coupling is formed by arranging the contracting waveguide portion and the branching waveguides in close proximity to each other and at a prescribed spacing G.sub.gap along the sides of the contracting waveguide. The contracting waveguide portion has a tapered form along both side surfaces, and the branching waveguides in the optical coupling section have expanding waveguide portions that have a tapered form that tapers in the direction opposite that of the main waveguide and that oppose each tapered side of the main waveguide.

Abstract: Color image generation systems are disclosed for the reproduction of real or virtual, two-dimenional or three-dimensional, color, or monochrome images and their applications, in particular for television or video applications, and printing applications. Integrated-optical structures are used on a mount, in particular a substrate. An image is generated by deflecting color light beams generated into a viewing space, which deflection is effected in synchronism with color setting and intensity- or amplitude modulation of the light. All electronic and optical assemblies for color image generation may be integrated on a mount either monolithically or in hybrid fashion. The color generation system may be implemented as an encased module.

Abstract: In a waveguide type wavelength multiplexing/demultiplexing (WDM) module, a wavelength multiplexing/demultiplexing function can be realized with a half length of the conventional directional coupling device. The waveguide type WDM module is comprised of: a common waveguide for conducting first signal light having a first wavelength and second signal light having a second wavelength; common light input/output means coupled to the common waveguide; a substrate containing a WDM unit for multiplexing/demultiplexing the first signal light and the second signal light; a first waveguide for conducting the first signal light; first light input/output means optically coupled to the first waveguide; and second light input/output means for inputting/outputting the second signal light. The WDM unit includes a directional coupling type WDM device constituted by two sets of waveguides connected to the first waveguide and the common waveguide respectively.