Abstract: A Y-branched optical waveguide with a uniform output characteristic for use in optical communication systems is disclosed. The optical waveguide, consisting of a core section serving as a transmission medium of an optical signal and a cladding section surrounding the core section, is formed on a semiconductor substrate. An input-tapered waveguide is configured to receive the optical signal through a first ending section and to output the optical signal through a second ending section, with a symmetrical structure with respect to a centered line of the input-tapered waveguide, so that a width of the input-tapered waveguide extends more widely along the centered line.

Abstract: An optical transmission module, which can be realized at a low cost without requiring complicated adjustment of an optical axis. Sheet-type polymer optical waveguides are disposed on a substrate. On an end of each polymer optical waveguide, a transparent electrode layer serving as an anode, an organic-compound layer including a light-emitting layer, and a metal electrode layer serving as a cathode are successively overlaid via vapor deposition or the like to form an organic electro-luminescence (EL) element. When the organic EL element is used as a light source in the optical transmission module, the optical waveguide and the light source (the organic EL element) can be easily connected to each other without requiring complicated adjustment of an optical axis and complicated processing of an end surface of the optical waveguide.

Abstract: An optical waveguide device comprises at least one Y-junction integrated on a planar substrate. The junction comprises a first (1), a second (3) and a third (4) optical waveguide extending on the said substrate, and a transition portion (2), in which the second and third waveguides branch from the first waveguide, comprising a truncation (5) of predetermined width. At the position of the truncation, the width of the first waveguide is less than the sum of widths of the second waveguide, the third waveguide and the truncation. The first optical waveguide extends into the transition portion up to the bifurcation with its width essentially constant.

Abstract: The present invention relates to an optical modulator allowing appropriate interaction between signal electrodes and an optical waveguide, only by matching phases at input ends of the signal electrodes. The optical modulator includes an optical waveguide with its center part branched into two at two Y-branch waveguides, forming first and second waveguide arms, a first signal electrode transmitting a first electric signal interacting with first light propagating through the first waveguide arm in a predetermined manner, a second signal electrode transmitting a second electric signal interacting with second light propagating through the second waveguide arm in a predetermined manner, and earthed electrodes, and can match the interacting timing between the first electric signal and the first light to the interacting timing between the second electric signal and the second light, at a first input end supplying the first electric signal and a second input end supplying the second electric signal.

Abstract: A multimode optical coupler comprising a first optical fiber having a polished face on its side, and a second optical fiber having an end which is polished at an angle. The angled polished end of the second optical fiber is disposed in mating alignment with the polished face of the first optical fiber, and light energy propagating through the second fiber can pass into the first fiber. A series of such couplers may be interconnected in a network so as to combine the energy of many light sources for a desired power level in a single optical fiber.

Abstract: The present invention reduces multimoding of light generated by lasers. An asymmetric dispersion enhancer is included in a laser cavity to increase the asymmetric dispersion of the light amplified in the cavity. As a result, the side modes of the light passing through the cavity are asymmetrically disposed about the fundamental mode and, therefore, are amplified less in the cavity. Consequently, multimoding of the light is better suppressed.

Abstract: There is disclosed a waveguide-type wavelength multiplexing optical transmitter/receiver module which is composed of an optical demultiplexer having an optical waveguide substrate and a filter disposed on an optical waveguide substrate, a laser diode and a photodiode. On the optical waveguide substrate, a first optical waveguide and a second waveguide are formed. On a first end face of the optical waveguide substrate, there is a cross section in which these optical waveguides cross each other. On a second end face of the optical waveguide substrate, there is an optical fiber and ports for connecting the laser diode. The filter reflects light with a wavelength of &lgr;1 from the laser diode and allows light with a wavelength of &lgr;2 from the optical fiber to pass therethrough. The laser diode is so disposed that the location of a center axis is shifted in the direction of the first optical waveguide relative to a cross axis being normal to a first end face.

Abstract: An optical communications system and an optical transceiver used for its communications apparatus designed to realize a single core two-way full duplex type optical transceiver of a simple and low-cost structure which requires no lens, prism and any other similar item. An optical transceiver for communications apparatus which transmits signals via an optical fiber cable comprises a transmitting section, a receiving section, and a multi-core Y-shaped optical divider which is connected to the transmitting section and the receiving section .

Abstract: In order to reduce the degree to which transmission loss occurs at the branching portion in a Y-branch structure provided at an optical integrated circuit device, the Y-branch structure through which a light signal input through an input waveguide is branched and transmitted into two output waveguides adopts the following features. The Y-branch structure is provided with a tapered waveguide having an input surface with a waveguide width a equal to the width of the input waveguide which is connected flush to the input waveguide and an output surface having a waveguide width W (>2a+g) is larger than a width 2a+g achieved by adding a width g of the gap between the output waveguides to a width 2a equal to the total of the widths of the two output waveguides each having a waveguide width a equal to the width of the input waveguide, which is connected with the two output waveguides via a stage.

Abstract: An optical cavity structure for bending optical signals is provided. The optical cavity structure includes an input port for receiving input optical signals from a first waveguide. The optical cavity structure also includes an interconnecting structure that receives said input optical signals and interconnects said first waveguide to a second waveguide, the interconnecting structure further includes at least four straight edges that orthogonal and of a finite width. The optical cavity structure further includes an output port coupled to the interconnecting structure for providing the second waveguide with the input optical signals. Further, the optical cavity structure may be used to create three dimensional splitter devices and resonators.

Abstract: The present invention relates to a method and a device for modulating optical signals based on modulating bending losses in bend, quantum well semiconductor waveguide sections. The complex refractive index of the optical active semiconducting components of the waveguide section is modulated by applying a variable electric or electromagnetic field. The modulation of the complex refractive index results in a modulation of the refractive index contrast and the absorption coefficient for the waveguide at the frequency of the light. By carefully adjusting the composition of the semiconducting components and the applied electric field in relation to the frequency of the modulated radiation, the bending losses (and possibly coupling losses) will provide extinction of light guided by the bent waveguide section. The refractive index contrast may be modulated while keeping the absorption coefficient substantially constant and small, whereby the guided light can be modulated only by bending losses.

Abstract: The invention proposes a guiding structure capable of transforming a lightwave with at least one central wavelength &lgr;i with a Gaussian type propagation mode profile coming out of the introduction means into a widened type propagation mode profile, this structure comprising:

Abstract: The subject to be attained by the disclosed technique is to provide an optical unit less expensive than conventional like optical units and having a wavelength multiplexer and optical waveguides. For achieving the above subject there is provided a wavelength multiplexer wherein a light combining/branching section is constituted by a multi-mode interference type optical waveguide, and an incident-side optical waveguide and a reflection-side optical waveguide are spaced a predetermined distance from each other at their connections to the multi-mode interference type optical waveguide. An optical filter is installed in the multi-mode interference type optical waveguide and a multi-mode interference is set so that a peak in a light intensity distribution is formed in the vicinity of an inlet of each of an exit-side optical waveguide and the reflection-side optical waveguide.

Abstract: A method of producing a modulated light source including the steps of providing a modulator, fiberlessly coupling a laser diode light source to the modulator and enclosing the modulator and the laser diode light source within a housing together with output optics operative to direct modulated light from the modulator into an optical fiber extending outwardly from the housing.

Abstract: An optical waveguide is formed in an integrated optics chip that includes a substrate formed of an electrooptically active material. The optical waveguide network has an input facet where optical signals may be input to the optical waveguide network and an output facet where optical signals may be output from the optical waveguide network. A structure is located in an upper layer of the substrate to prevent surface waves that propagate in the substrate from cross coupling into the output facet.

Abstract: A fast acting, low insertion loss switch for use in an optical fiber communication system includes a small diameter waist region incorporating a Bragg grating which is precisely tuned by tensioning to be reflective at a selective wavelength band. By a small physical shift of the waist, as by lateral displacement of an attached small magnetic element with a magnetic field, the periodicity of the grating is varied so that the selected wavelength is passed through the waist with virtually no loss. The incremental motion required can be introduced by a variety of devices, selected in accordance with cost, size and response time requirements. Modules having a number of such switches in close juxtaposition offer distinct advantages for wavelength division multiplexed systems.

Abstract: A broadband partial reflector is located downstream from an optical combiner device. The partial reflector reflects a portion of the combined light back through the combiner device and back into the respective optical pump sources. There are no fiber gratings or other filters between the sources and the combiner device. Consequently, the sources are locked and/or stabilized according to the acceptance bandpass characteristics of the input ports of the combiner device. Since no gratings or other filters need to be located between the sources and the combiner device, the problem of insertion power loss due to spectral mismatch at the input ports can be avoided. In other words, self-aligned wavelength feedback stabilization is accomplished by reflecting a portion of the combined light signal back through the input ports of the combiner device.

Abstract: An illuminated interior article system (10) which can be used as a part of a vehicle interior lighting system and which includes a branching optical waveguide (12) and a vehicle interior article (14) positioned relative to waveguide such that the illuminating light exiting the waveguide at its junction (16) illuminates the vehicle interior article. The branching waveguide (12) has a stem (18), first and second branches (20,22), and the junction (16) that couples the stem to each of the branches. The first and second branches (20,22) extend away from the junction (16) at an obtuse angle relative to the stem (18) and the junction includes one or more optical features positioned at the junction such that a portion of the light traveling through one or more of the waveguide sections impinges upon the optical feature(s), with the optical feature(s) redirecting the impinging light out of the waveguide at the junction to thereby provide illuminating light from the junction.

Abstract: Apparatuses, methods, and systems are disclosed that provide for simultaneously upconverting electrical signals carrying information at electric frequencies onto optical subcarrier lightwave frequencies that are greater and less than the carrier frequency of the lightwave onto which the electrical frequencies were upconverted. The upconversion of the electrical signals can be performed with or without suppression of the optical carrier frequency.

Abstract: In order to be able to supply information signals to a number of internal system devices via light waveguides in contemporary communication systems, optical power dividers are employed. These are designed such that an optical fiber brought in at the input side is divided onto a plurality of optical fibers. In order to achieve an ordering given the plurality of light waveguides, the divided optical fibers are combined to form groups such that each group comprises a same structure as the fibers arranged at the input side.

Abstract: A hybrid and tapered waveguide coupler that has two different single-mode waveguide sections for light at two different wavelengths to couple light at the two different wavelengths into or out of an optical device located in a reach of an evanescent field of the guided optical energy in the waveguide coupler.

Abstract: Disclosed is a thermo-optic (TO) switch that reduces the difficulty in the fabrication process and has an excellent optical crosstalk. In the TO switch, variable optical attenuators utilizing higher-order mode generators are integrated to the both output ports of a conventional 1×2 digital TO switch of Y-branch type waveguide which uses mode evolution effect. Even when the Y-branch angle gets bigger, the inventive TO switch can maintain an excellent crosstalk without raising the switching power. Since a large Y-branch angle can reduce the difficulty in fabrication process, the inventive TO switch will increase the production rate. 1×2 optical switch is an essential device in an optical signal processing system such as optical communications, optical switches and optical sensors.

Abstract: An optical power divider using a beam separator and a beam expander, and a fabrication method therefor. The optical power divider includes an input optical waveguide having an input port for receiving incident light, for guiding the light incident via the input port, a plurality of output optical waveguides having at least two output ports, for outputting the light incident via the input optical waveguide to the output ports, wherein the number of output optical waveguides is equal to that of the output ports, and a beam separator located at a branch area in which the light incident on the input optical waveguide diverges toward the output optical waveguides, the beam separator being made of a material having a refractive index lower than the core of the input and output optical waveguides, for separating the light to the output optical waveguides with a predetermined ratio. Therefore, the length of the optical power divider becomes short and insertion loss can be lowered.

Abstract: An apparatus having multiple fiber terminated optical ports uses optical components such as isolators, reflectors, mirrors, and prisms to steer a beam of light to an optical port. The steered beam of light is approximately parallel to the main axis and has a small lateral offset. The optical components may be part of an integrated component or discrete. The apparatus may have multiple input fiber terminated optical ports and multiple output fiber terminated optical ports. The apparatus is especially amenable to planar packaging of optical components.

Abstract: In a digital optical switch, an input waveguide and two output waveguides form a Y-shaped splitter or switch. Electrodes are positioned on each output waveguide at the junction with the input waveguide. The electrodes extend as narrow strips across the waveguides. The inner edges of the electrodes are curved to form a smooth continuation profile to the signal paths to reduce losses.

Abstract: The invention pertains to a thermo-optical switch comprising a cascade of 1×M optical switches, gates for selectively blocking and unblocking the output paths of the cascaded switch, and means for driving the 1×M switches and the gates, which means are arranged to switch a data signal from an input path of the cascaded switch to one of the output paths, wherein the said means are also arranged to switch an unwanted signal, by means of a number of the remaining 1×M switches, to at least one of the remaining output paths. In the cascaded switch according to the invention, the generated heat is distributed evenly over the area of the switch and the overall amount of heat generated is reduced.

Abstract: Devices and methods for control of reflection and transmission of an optical wave by selective adjustment of the refractive index of a material through use of an applied electric field. In some devices, an electric field vector E is distributed in the material, where the material interfaces two optical waveguides. Since the refractive index n(E) of the material depends on the magnitude and direction of E, the electric field E can be varied to control n(E), relative to the refractive index of the interfaced waveguides, so as to make the material totally transmitting, totally reflecting, or partially reflecting of light that passes through one of the interfacing waveguides and is incident upon the material. Adjusting n(E) in such a material can also be used for selection of optical wavelengths by diffraction, wavelength selection of optical waves transmitted through mirror electrodes, and deflection of plane waves.

Abstract: Method for producing a stable, multi-port fiber optic coupler that is useful for wavelength division multiplexing (WDM). The system response is substantially independent of signal polarization and is reasonably stable against mechanical stresses and elevated temperatures. Contiguous sections of two or more fiber optic lines are alternatingly heated and elongated and are twisted according to selected process parameters for selected time intervals. The fabrication procedure uses a combination of fiber heating at two or more distinct temperatures, fiber elongation and fiber twisting, applied to two or more contiguous fiber optic lines, to produce a fused fiber optic coupler with controllable wavelength discrimination and controllable signal power coupling into each output branch of the fiber optic coupler. ITU standards for wavelength discrimination and wavelength centering in a fiber optic coupler can be met by adjustment of the process parameters.

Abstract: In an optical waveguide Y junction, comprising an input waveguide path, a split portion having one end smoothly connected to an end of said input waveguide path, and a pair of bifurcated ends, and a pair of output waveguide paths each having an end smoothly connected to a corresponding one of said bifurcated ends of said split portion, the split portion defines a modified asymmetric Y-shaped waveguide path which is defined by modifying an original symmetric Y-shaped waveguide path having a substantially constant width by removing an asymmetric wedge-shaped section from a side of the split portion interposed between the output waveguide paths. Thus, simply by changing the inner profile of the split portion, a desired uneven split ratio can be achieved without providing a spread out split portion or requiring any abrupt change in the shape of the waveguide path. This contributes to the reduction in the loss of the signal light.

Abstract: A thermo-optic switch using a small drive power while exhibiting a reduction in the coupling loss caused by the coupling to optical fibers and a switch speed of several hundred microseconds or less. A method for manufacturing the thermo-optic switch and a method for changing an optical line switching using the thermo-optic switch are also disclosed.

Abstract: A splice for crimping optical fibers includes two half-cylinders, a support block and a pressing block, which are mutually pressed by a crimping cylinder. The support block is provided with a longitudinal groove for receiving the stripped fiber and bears capped edges. The capped edges and stops are symmetrically mounted on either side of the longitudinal axis of the half-cylinders and are designed for maintaining axis of the half-cylinders and are designed for maintaining a small space between the two half-cylinders in the zone where they are located.

Abstract: A device and a method is proposed for writing on imaging material (3) with a radiation source (1) producing an electromagnetic radiation having a wavelength suitable for recording image information on the imaging material (3). The radiation produced by the radiation source (1) can be modulated with a waveguide which is integrated in a substrate material (49) and operates as a modulator (2). A modulation signal containing the image information can be received at an input (9) of the modulator (2). According to the invention, a compensator (6, 12) compensates a modulation error which occurs during modulation of the radiation.

Abstract: A waveguide element is capable of realizing acute waveguide discontinuity, such as a right angle bending, (L-shaped bending) or branching (T-shaped branching). Two single mode waveguides having the identical cross-sectional structure form a waveguide discontinuity where center axes thereof extending in the longitudinal direction intersect with each other at an angle &thgr; (0<&thgr;<90°). A leaky wave propagation region in a form of a quadrilateral shape having a length of one edge of L is located in the vicinity of a point where the center axes extended in the longitudinal directions of respective incident side and side single mode waveguides, with an effective propagation wavelength of a dominant mode there of to be cos(&thgr;/2) times of an effective propagation wavelength &lgr;G. Thus, an energy of the wave launched from an incident end of the single mode waveguide can be efficiently taken out from a end of the single mode waveguide.

Abstract: An optical switch operating on thermooptic effects has a branching section heater for heating a branching section of a core and a branched core heater for heating a branched core. The heaters are controlled separately so that the branching section and the branched core can be heated to respective temperatures so as to minimize insertion loss of inputted light and to prevent outputting light from a port not intended for light output.

Abstract: An optical circuit include a plurality of optical wave guides each having an electro-optic crystal such as LiNbO3 or LiTaO3 and a domain orientation different from the other waveguide. More specifically, in accordance with the invention, a portion of the circuit is inverted with respect to a domain. For instance, in an optical wave guide having a domain-inverted portion, if electric fields having the same orientation are applied to a plurality of portions which vary an index of refraction thereof, indexes of refraction are caused to vary in opposite polarities. Hence, it is possible to lower a voltage at which an optical device operates. If the present invention is applied to a Mach-Zehnder type phase shifter, it would be possible to accomplish push-pull operation, only if an electric field has one orientation. The invention further lower a voltage at which the phase shifter operates through a difference in an index of refraction between two optical wave guides.

Abstract: An optical device capable of detecting the intensity and wavelength of light from a light source with a high level of precision, and an optical module incorporating the optical device. The optical device has a planar lightwave circuit having a Y-branched core, a silicon substrate, a filter block, an optical fiber, and a first and a second photodiode. The end portion on the input side of the core is connected to the optical fiber. One end portion on the output side of the core is connected to the filter block, and the other on the same side is to the second photodiode. The light is divided at a predetermined ratio at the Y-branching portion. One of the branched light is sent through the filter block to be input to the first photodiode, and the other branched light is directly input to the second photodiode.

Abstract: The invention pertains to a (cascaded) optical switch at least comprising one input path, a number of output paths, one or more switch or splitter stages each comprising one or more optical switches or splitters, and at least one gate for optically disconnecting the output paths from the input path, wherein that gate is located at or near the input path. The cascaded switches according to the present invention are compact exhibit a reduced complexity and an improved insertion loss.

Abstract: A fused-fiber multi-window wavelength filter (MWF) is constructed with an unbalanced Michelson Interferometer, in which input light passing through the fused coupling region is decoupled and travels along two fibers of different optical path lengths. The two light signals travel to the end of the two fibers, where a highly reflective coating reflects the light back toward the coupling region, where the signals are coupled again and then decoupled after exiting the coupling region. By adjusting the optical path length difference, either by changing the length or refractive index, a signal at a desired wavelength can be obtained at the filter output. The MWF can be combined with other MWFs to form more compact sized multi-window wavelength division multiplexers (MWDMs) and dense WDMs. Passive thermal compensation techniques can be applied to one or both of the reflecting fibers to maintain the desired optical path length difference.

Abstract: A method is used to fabricate a wide-angle Y-branch polarization splitters on lithium niobate crystal substrate. The Y-branch polarization splitter combines a straight waveguide with a substrate prism type wide-angle waveguide branch. The straight waveguide is a random polarization nickel diffusion waveguide. The branching waveguide is a proton exchanged waveguide. The fabrication technology needs only once of nickel diffusion and once of proton exchange. Due to the inherent property of single polarization for the proton exchanged waveguide, only the extraordinary polarization wave is bent and the ordinary wave remains in the straight waveguide. This results in a polarization splitter with high extinction ratio.

Abstract: The invention pertains to a thermo-optical device comprising a waveguiding structure (1) which comprises at least one input light path (2) and at least two output light paths (3,3′) forming a first y-splitter (4), at least one output light path (3,3′) being provided with primary heating elements (5,5′), characterised in that the output light paths (3,3′) are provided with an additional branch (6) forming a second y-splitter (7), wherein at least one of the branches (6,6′) is provided with a secondary heating element (8,8′). The additional branches (6) may be positioned in the opposite direction, such that in each of the second y-splitters (7) one branch (6′) coincides with one of the output light paths (3,3′) of the first y-splitter (4).

Abstract: An optical splitter, having a stem and multiple branches integrally connected to the stem, has a junction between the stem and the multiple branches which is flexible. By controlling the angle between the stem and the multiple branches while maintaining a fixed angle between the multiple branches, i.e., by flexing the junction, the flux emitted from each of the multiple branches is adjustable based on the angle each branch makes with respect to the stem.

Abstract: This planar lightwave circuit includes a buried layer formed in a region between at least two cores branching from a branching point to decrease in thickness as the spacing between the cores increases with an increase in distance from the branching point. The planar lightwave circuit is designed to suppress scattering of light signals at the branching point.

Abstract: A method of producing a modulated light source including the steps of providing a modulator, fiberlessly coupling a laser diode light source to the modulator and enclosing the modulator and the laser diode light source within a housing together with output optics operative to direct modulated light from the modulator into an optical fiber extending outwardly from the housing.

Abstract: An optical device, has

Abstract: An optical coupler and a method of manufacturing the same are provided. The optical coupler includes an input optical waveguide and N output optical waveguides, and divides an optical signal received from the input optical waveguide into N optical signals.

Abstract: An optical module including a substrate, an optical waveguide formed on the substrate, and an optical element mounted on the substrate so as to be optically coupled to an end of the optical waveguide, for performing conversion between light and electricity. The optical module further includes a transparent resin for covering at least an optical coupling portion between the optical waveguide and the optical element, and a thermoplastic resin for covering only the optical element and its periphery including the transparent resin to seal the optical element.

Abstract: Angled unions and junctions for conduits in which fiber optic conductors are run are provided for downhole oil drilling, injection and production operations. The unions and junctions provide high pressure and adverse condition protection for the optic fibers while providing an acceptable bend radius.

Abstract: An apparatus for optically generating chaotic random numbers to obtain chaotic random numbers satisfying a chaotic dynamical system expressed by X(n+1)=F(X(n)) includes an optical signal splitting device for splitting light from a light source into a predetermined number of beams with identical optical power; an optical chaotic signal generating device comprising the same number of interferometers as the beams, each having a pair of optical paths for receiving the beams from the optical signal splitting device, splitting each of the beams, interfering the splitted beams and outputting optical chaotic signals; optical path length difference data memory device for memorizing data on a difference between the lengths of the pair of optical paths at portions thereof between splitting and interfering; optical output signal measuring device for measuring optical power of the optical chaotic signals output from the interferometers as chaotic random numbers; and an optical output signal memory device for m

Abstract: An optical switch network, for connecting P switch input waveguides to Q switch output waveguides. The switch input waveguides enter a branching subnetwork consisting of a plurality of branching cascades. In each branching cascade, an array of 1×2 splitters connects the input waveguides of the cascade to the output waveguides of the cascade, and the output waveguides of the cascade cross within the cascade so that output waveguides that connect to the same switch input waveguide emerge from the cascade P output waveguides apart. The output waveguides of the branching subnetwork connect directly to 2×1 combiners of a combining subnetwork that connects the output waveguides of the branching subnetwork to the Q switch output waveguides. The network architecture is reversible, by exchanging the roles of the input and output waveguides and the roles of the splitters and the combiners.

Abstract: An optical waveguide device having a folded waveguide structure on a semiconductor substrate. The optical waveguide device includes first and second single mode optical waveguides formed on a semiconductor substrate. The first and second optical waveguides merge together into a merging optical waveguide. A reflector is positioned so that light travelling through the first optical waveguide into the merging optical waveguide is reflected by the reflector to travel through the second optical waveguide. A total reflection complementary angle for the light traveling through the first optical waveguide is &thgr;c, and a branch angle &thgr;b of the first and second optical waveguides is less than or equal to 0.55&thgr;c.