Abstract: An optical modulator has, on a substrate having electro-optic effect, an optical waveguide including an input optical waveguide, two branching optical waveguides which branch a light beam incident to the input optical waveguide into two beams, two interaction optical waveguides which modulate a light beam phase by applying a voltage between a center electrode and ground electrodes, a multiplexing optical waveguide which multiplexes the light beams which propagate through the two interaction optical waveguides, and an output optical waveguide which is connected to the multiplexing optical waveguide through a multiplexing point.

Abstract: An optical modulator comprises a Z-cut lithium niobate substrate (21) on which is formed a Mach-Zehnder interferometer having two generally parallel waveguides (23, 25) lying beneath a buffer layer of dielectric material (27). First and second ground electrodes (29, 33) and a hot electrode (31) are disposed on the buffer layer (27), the first and second ground electrodes (29, 33) being spaced either side of the hot electrode (31), the hot electrode (31) and the first ground electrode (29) being proximate to at least apart of the respective waveguides (25, 23). The electrode structure is unsymmetrical in that (a) the hot electrode and the first ground electrode each have a width substantially less than that of the second ground electrode and or (b) the spacing between the first ground and hot electrodes is different from the spacing between the second ground and hot electrodes. whereby a range of chirp values can be obtained.

Abstract: An optical splitter/coupler has: a multimode waveguide having an electrooptic effect, and propagating light in a multimode; one incident waveguide propagating light in a single mode, and inputting the light to the multimode waveguide; one pair of emitting waveguides guiding-out, in a single mode, lights which have propagated-in through the multimode waveguide; at least one pair of individual electrodes provided so as to be positioned in vicinities of respective side edges on one surface of the multimode waveguide; and a ground electrode provided on another surface, wherein the multimode waveguide has a length such that 3(n+1) bright spots arise at a central portion and at both side edge portions due to incident light, the individual electrodes are provided at positions corresponding to an upstream-most one pair of the bright spots, and the emitting waveguides are connected to positions corresponding to a downstream-most one pair of the bright spots.

Abstract: A silicon-based optical modulator structure includes one or more separate localized heating elements for changing the refractive index of an associated portion of the structure and thereby providing corrective adjustments to address unwanted variations in device performance. Heating is provided by thermo-optic devices such as, for example, silicon-based resistors, silicide resistors, forward-biased PN junctions, and the like, where any of these structures may easily be incorporated with a silicon-based optical modulator. The application of a DC voltage to any of these structures will generate heat, which then transfers into the waveguiding area. The increase in local temperature of the waveguiding area will, in turn, increase the refractive index of the waveguiding in the area. Control of the applied DC voltage results in controlling the refractive index.

Abstract: An optical modulator includes a signal electrode for application of modulation signals whereby light propagated over an optical waveguide is modulated, and bias electrodes for application of a bias voltage for controlling an operating point for the modulation signals. A buffer layer is provided between a substrate exhibiting electro-optical effect and the bias electrodes, but at regions where no optical waveguide is formed beneath the bias electrodes, no buffer layer is provided, and the bias electrodes are provided directly upon the substrate. This configuration enables bias voltage to be reduced.

Abstract: An optical splitter/coupler has: a multimode waveguide having an electrooptic effect, and propagating light in a multimode; one incident waveguide propagating light in a single mode, and inputting the light to the multimode waveguide; one pair of emitting waveguides guiding-out, in a single mode, lights which have propagated-in through the multimode waveguide; at least one pair of individual electrodes provided so as to be positioned in vicinities of respective side edges on one surface of the multimode waveguide; and a ground electrode provided on another surface, wherein the multimode waveguide has a length such that 3(n+1) bright spots arise at a central portion and at both side edge portions due to incident light, the individual electrodes are provided at positions corresponding to an upstream-most one pair of the bright spots, and the emitting waveguides are connected to positions corresponding to a downstream-most one pair of the bright spots.

Abstract: A variable light controlling device comprising a substrate, an optical waveguide disposed on the substrate, a first heater and a second heater to change the optical waveguide's temperature is fabricated. And a total amount of the power supplied to the first and the second heater, or a total amount of heat emitted from both of the first and second heater, is maintained substantially constant. Then, the substrate is protected from temperature changes, thereby, stable and quick wavelength tuning operations are realized.

Abstract: A light coupling system includes a waveguide, configured to receive light from at least two light sources and to internally reflect light therein; a diffraction grating, disposed upon the waveguide; and a switchable Bragg grating, disposed upon the waveguide. The diffraction grating is configured to couple light from at least one of the light sources into the waveguide, and the switchable Bragg grating is configured to selectively couple light out of the waveguide, such that the light from the at least two light sources is selectively directed along a common projection axis.

Abstract: An electro-optical switch implemented in coupled photonic crystal waveguides is disclosed. The switch is proposed and analyzed using both a finite-difference time-domain (“FDTD”) method and a plane wave expansion (“PWM) method. The switch may be implemented in a square lattice of silicon posts in air, as well as in a hexagonal lattice of air holes in a silicon slab. Switching occurs due to a change in the conductance in the coupling region between the photonic crystal waveguides, which modulates the coupling coefficient and eventually causes switching. Conductance may be induced electrically by carrier injection or optically by electron-hole pair generation. The electro-optical switch has low insertion loss and optical crosstalk in both the cross and bar switching states.

Abstract: An electro-optic modulator having a substrate, one or more optical waveguides, at least one active electrode formed on the substrate and aligned over the optical waveguide, the active electrode operating to induce a refractive index change in the optical waveguide. The active electrode has a lower surface arranged facing the substrate, an upper surface arranged away from the substrate, substantially planar side walls, and rounded corners between the side walls and the lower surface of the active electrode. The electrode can be a bridge electrode, with two lower portions and an upper portion connected to the lower portions, the lower portions spaced apart from each other, each of the two lower portions of the active electrode extending over one of the optical waveguides. Each of the lower portions has rounded convex corners. The upper surface of the electrode can also have rounded corners or a completely rounded upper surface.

Abstract: Invention discloses an apparatus that provides linear optical modulation of light carrier signals by an electrical modulation signal. Linearized modulation is achieved through the selection of a spacing profile between two optical transmission waveguides. The spacing profile relates to a transfer function, the parameters of which are chosen to yield linear modulation within a particular dynamic range. A preferred embodiment discloses the invention being fabricated within a monolithic structure.

Abstract: An optical modulator of the Mach-Zehnder type including electrodes disposed above a substrate having a pair of linear portions of an optical waveguide includes a signal electrode to which modulating signals are applied; first and second earth electrodes; and a bias electrode to which a bias signal for controlling an operating point of the modulating signals is applied. The earth electrodes are disposed at either side of the signal electrode disposed above one of the linear portion, and the first earth electrode is disposed above the other linear portion. The bias electrode is disposed adjacent to the first earth electrode on a side opposite to the signal electrode. The bias electrode is disposed on a surface of the substrate, and a buffer layer is formed on the bias electrode. The first earth electrode has a ladder shape having the bias electrode interposed between the two long portions of the ladder.

Abstract: It is provided an optical waveguide device in which the radius of curvature of a curved part of an optical waveguide can be lowered and the radiation loss of light in the curved part can be reduced. An optical waveguide device 2 has a ferroelectric optical waveguide substrate and an optical waveguide 5 formed in or on the substrate and modulating electrodes 4A, 4B and 4C. The thickness of the optical waveguide substrate is 30 ?m or smaller at least in a region where the optical waveguide is formed. The optical waveguide has curved part having a radius of curvature of 30 mm or smaller.

Abstract: An optically coupled resonant pressure sensor includes a deformable diaphragm and an optically coupled resonator fixedly attached to the deformable diaphragm. The resonator includes a resonator body and a laterally offset photodiode adjacent to the resonator body. The resonator is driven by an electric field generated between the laterally offset photodiode and the resonator body when an incident light strikes the photodiode. Pressure applied to one side of the deformable diaphragm causes a shift in a resonant frequency of the resonator. Also disclosed are a method and system for determining pressure.

Abstract: The present photonic RF generation and distribution system provides a system and method for distributing an RF output signal. The photonic RF distribution system includes two optical sources for generating optical signals. A first optical source (42) is operable to generate a first optical signal having an operating frequency. A second optical source (44) is operable to generate a second optical signal having an operating frequency. A modulator (46) is operable to impress an RF modulation signal on a tapped portion of the first optical signal such that a modulated signal is generated. A first coupler (52) combines the modulated signal with a tapped portion of the second optical signal, thereby forming a combined signal having a difference frequency component. A control photodetector (50) is responsive to the combined signal to generate a tone signal.

Abstract: A variety of structures, methods, systems, and configurations can support plasmons for logic.

Abstract: Decrease in optical near-field intensity is prevented when an light propagating medium made of a high refractive index material, such as a waveguide or a lens, is combined with a scatterer for producing optical near-field. Near the optical near-field generating element, a second light propagating medium is disposed in contact with a first light propagating medium of a high refractive index material, such as a waveguide or a lens. The refractive index of the second light propagating medium is made smaller than the refractive index of the first light propagating medium.

Abstract: Optical arrangement comprising two parallel plates each with a through-hole forming an optical input/output with a given optical axis and one at least partly optical component placed between the plates, the component and the first plate comprising first fastening studs placed transversely in opposite relationship of the plate and connected by first bumps made of a meltable material that when molten is able to selectively wet these first fastening studs in order to optically align the component and the input/output on the first plate, and the two plates comprising second fastening studs placed transversely in opposite relationship of the plate and connected by second bumps made of a meltable material that when molten is able to selectively wet the second fastening studs in order to optically align the inputs/outputs of the two plates.

Abstract: In one embodiment, an apparatus includes a passive element including one or more first waveguides and one or more second waveguides. The apparatus also includes an active element integrated into the passive element. The active element includes one or more third waveguides that actively guide light from the first waveguides to the second waveguides. The third waveguides include polarization-independent electro-optical (EO) thin film.

Abstract: An integrated optoelectronic device includes optical waveguide elements containing InGaAlAs as a principal component, formed on an InP substrate and connected in an end-to-end fashion by butt jointing. An InGaAsP layer is formed on the InP substrate to suppress the mass transport of InP during the fabrication of the integrated optoelectronic device. The InGaAsP layer is formed before the InP substrate is heated at a crystal growth temperature on the order of 700° C. to form the InGaAlAs optical waveguide element.

Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.

Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.

Abstract: A self-electrooptic effect device (“SEED”) is integrated with waveguide interconnects through the use of vertical directional couplers. Light initially propagating in the interconnect waveguide is vertically coupled to the active waveguide layer of the SEED and, if the SEED is in the transparent state, the light is coupled back to the interconnect waveguide.

Abstract: A photoelectric composite interconnection assembly having: a flexible substrate having an electric interconnection; and an electrical interface provided at both ends of the electric interconnection. A part of the electric interconnection is replaced by an optical transmission line.

Abstract: An optical modulator includes a signal electrode for application of modulation signals whereby light propagated over an optical waveguide is modulated, and bias electrodes for application of a bias voltage for controlling an operating point for the modulation signals. A buffer layer is provided between a substrate exhibiting electro-optical effect and the bias electrodes, but at regions where no optical waveguide is formed beneath the bias electrodes, no buffer layer is provided, and the bias electrodes are provided directly upon the substrate. This configuration enables bias voltage to be reduced.

Abstract: A polarization controller includes a plurality of liquid crystal cells positioned as cladding on a waveguide that propagates a beam of light so that the evanescent field extends into the liquid crystal cells, and a ½-wave birefringent retarder for rotating the eigenstates of polarization between the liquid crystal cells. For fast response, the evanescent field preferably extends only into the surface effect region of the liquid crystal cells, where directors in the liquid crystal respond faster to changes in voltages applied across the liquid crystal cells.

Abstract: Various embodiments of the present invention are directed to photonic crystal switches. In one embodiment, a photonic crystal switch a photonic crystal switch includes a photonic-crystal-based light transmission layer that outputs an incident light beam in a selected, output direction. The photonic crystal switch may include two or more electrical contacts, positioned relative to the light transmission layer, to which a voltage is applied to select the output direction of the light beam.

Abstract: An optical device includes at least two photonic bandgap crystal (PBG) stacks that are each comprised of alternating layers of high and low index materials. A defect region is formed in a cavity region between the at least two photonic bandgap crystal stacks so as to provide the properties needed to reflect light received by the optical device.

Abstract: A wavelength selective switch device is disclosed that includes an elongated signal communication path extending from a first end of the device to a second end of the device. The signal communication path extends through a plurality of regions of varying indices of refraction, and the plurality of regions includes adjustable regions that are each coupled to an adjustable voltage source for changing a voltage potential across each of the adjustable regions such that the index of refraction of said adjustable regions may be changed by changing the voltage potential across each adjustable region.

Abstract: The invention provides an optical switch including a substrate which has conductivity or semiconductivity, an optical waveguide layer which is formed on the substrate, and a control electrode which is formed on the optical waveguide layer. The optical waveguide layer includes an incident-side channel waveguide to which a light signal is incident and plural outgoing-side channel waveguides branched from the incident-side channel waveguide. The control electrode forms a reflection plane reflecting the incident light signal near a crossover portion of the plural outgoing-side channel waveguides by applying voltage to the optical waveguide layer with the substrate to control a refractive index of the optical waveguide layer, and switches propagation paths of the light signal.

Abstract: The present invention is concerned with 1×2 thermo-optic digital optical switches known in the art as “Y-branch digital optical switches” and variable optical attenuators.

Abstract: An optical switching element comprising: a multimode waveguide having an electro-optical effect; one or a plurality of first single mode waveguides; a plurality of second single mode waveguides; a first electrode arranged in the vicinity of one edge on one side of the multimode waveguide; a second electrode arranged in the vicinity of the other edge on the same side of the multimode waveguide; and a third electrode arranged on the other side of the multimode waveguide, over the first electrode and the second electrode being arranged so as to be positioned on luminescent spots in an optical mode field generated by the light propagating through the multimode waveguide, and an optical path being switched between the first single mode waveguide and the second single mode waveguide by applying voltage between the first electrode and the third electrode and between the second electrode and the third electrode, is provided.

Abstract: An apparatus (10) and method for dynamic frequency control of a photonic band gap crystal includes an acoustic band gap crystal (12) having a defect site (14), a photonic band gap crystal (20) in the defect site of the acoustic band gap crystal (12), and a sound wave generator (40) coupled to the acoustic band gap crystal (12). Consequently, acoustic waves in the acoustic band gap crystal (12) can be used to controllably alter transmission properties of the photonic band gap crystal (20) and thereby modulate the transmission of electromagnetic radiation through the photonic band gap crystal (20). Acoustic waves in the acoustic band gap crystal (12) can squeeze the photonic band gap crystal (20) to change its properties, including one or more of lattice constant, symmetry, and optical refractive index contrast.

Abstract: A Mach-Zehnder type semiconductor device comprises electrodes for injecting carriers into first and second branch waveguides so as to change reflection indexes of the first and second branch waveguides. The device further includes electrodes which are placed above either one of the first or second branch waveguides or both of the first or second branch waveguides so as to remove the carriers. The Mach-Zehnder type semiconductor device can adjust a phase difference between first and second split lights transmitting through first and second branch waveguides, respectively, even if the lengths of the first and second branch waveguides are deviated from those designed values. The Mach-Zehnder type semiconductor device also can suppress optical loss of the first and second lights and generate an outgoing light without deterioration.

Abstract: The invention relates to an electro-optic directional coupler suitable for use as a variable optical attenuator at reduced voltages compared to those known in the prior art. The present invention has found that by careful selection of an asymmetric directional coupler geometry, the transfer function of the device can be shifted so that it has an operating point between maximum and minimum transmission. Signal electrodes driven in push pull configuration advantageously use this operating point to achieve significant reduction in operating voltages for switching to maximum or minimum transmission. Asymmetry is created in the directional coupler by forming the waveguides to have different propagation constants by a difference in waveguide width, depth, index of refraction or index profile.

Abstract: An optical fiber coupling, for example, an optical switch, for coupling a light source with a light-receiving end face of an optical waveguide comprises a lens for focusing a light beam emitted from the light source at a focal point on the light-receiving end face of the optical waveguide. An adaptive coupler positioned in the optical path is responsive to a beam steering control signal for steering and aligning the focal point relative to the light-receiving end face of the optical waveguide.

Abstract: The present invention provides a highly-integrated and compact optical element and further provides an optical element having various functions such as lower driving voltage, chirping suppression and polarization-independency. The optical element has a substrate 1 formed of a material having an electrooptic effect, a plurality of optical waveguides formed on the substrate, and a modulating electrode for applying electric field into the optical waveguides, and is characterized in that the modulating electrode has at least two branching and confluence lines on the same line for applying the same modulating signal into different optical waveguides.

Abstract: A device for transmitting modulated optical signals between a first unit and a second unit, in which the first unit is supported to be rotatable or movable linearly relative to the second unit, comprises a light guide extending along a given track on the first unit, a first light coupler for coupling light into and out of the light guide, and a second light coupler disposed on the second unit and movable relative to the light guide for coupling light into and out of the light guide. A coupling slide is provided for supporting the second light coupler, and is mechanically loosely connected to the second unit via a take-up unit so that the coupling slide is moved along the given track together with the second unit by a movement of the second unit.

Abstract: An optical mode converter comprising a slow wave electrode structure and including Schottky barriers for preventing an accumulation of free carriers in the optical waveguide region of the converter. The Schottky barriers are also used for suppressing higher order modes in the waveguide. Low refractive index insulators are used to allow efficient driving of the device without hindering the impedance or the microwave index of the optical mode converter. Two-photon absorption processes are eliminated through the use of a waveguide semiconductor material having a bandgap of at least twice the photon energy of the light beam propagating through the optical mode converter.

Abstract: A 1×N fanout waveguide detector is disclosed. The detector includes a multiple-mode interference (MMI) cavity with input and output ends. A single-mode waveguide is optically coupled to the input end of the MMI cavity so that the optical power in the guided mode is distributed over N modes. The MMI cavity forms N interference nodes at or near its output end. N waveguide detectors are optically coupled to the output end at or near the N interference nodes. The waveguide detectors each have a waveguide that is evanescently coupled to an intrinsic region of a PIN detector. The width of the detector waveguide core, which can be sub-micron, defines the carrier collection distance between the electrodes of the PIN detector. Further, the length of the detector waveguide can be selected to maximize optical absorption to provide optimum quantum efficiency. The waveguide detectors are connected in parallel to provide a high-output photocurrent.

Abstract: Optical devices are provided for optical signal modulation under the control of an electrical signal propagating along a traveling wave electrode structure. The electrode structure comprises a coplanar stripline including a control signal electrode interposed between a pair of ground plane electrodes. Each of the ground plane electrodes defines a positively or negatively biased elevated ground plane portion isolated from the control signal input and the control signal output. The present invention also contemplates provision of a coplanar stripline as described and claimed herein.

Abstract: An electro-optical modulator is disclosed that has a microwave input, chip with a thin film resistor or a lumped resistor located between an input RF connector and an RF electrode on a Lithium Niobate chip. The accessory connection chip has a broadband attenuator like a thin film resistor which is placed in a microstrip line for effecting the electrical transmission to Lithium Niobate chip. The insertion of the thin film resistor before the RF electrode lowers the electrical return loss value as a function of frequency, allowing a lower driving voltage design or a reduced chip length without degrading the performances.

Abstract: An electro-optic modulator includes a substrate, at least two parallel optical waveguides, at least one ground plane, at least one active electrode with at least two lower portions of the active electrode, and an upper portion connected to the lower portions, the lower portions spaced apart from each other, each of the two lower portions of the active electrode extending over one of the optical waveguides. An electro-optic phase modulator having at least one optical waveguide and at least one active electrode formed on a face of the substrate, the active electrode having a wider upper portion and a narrower lower portion, the lower portions of the active electrode aligned with and extending over one of the optical waveguides. A bridge electrode has at least one narrower lower portion, and a wider upper portion, the lower portion for being arranged over an optical waveguide formed in a substrate.

Abstract: The invention provides an electro-optic hybrid circuit board having an optical waveguide superposed on a wiring circuit board, the electro-optic hybrid circuit board comprising: an insulating layer; a conductor pattern formed on the insulating layer; an undercladding layer formed on the conductor pattern-having insulating layer so as to surround the conductor pattern; a core layer formed on the undercladding layer; and an overcladding layer formed to cover the core layer and the undercladding layer.

Abstract: An optical switch has an optical waveguide whose output path of an optical signal branches into two, a carrier injection section which is provided to a branch portion of the optical waveguide and to which carriers are injected, and a refractive index change section which is provided to a optical waveguide layer of the optical waveguide and in which a refractive index changes in a case that carrier are injected to the carrier injection section, wherein the refractive index change section has a quantum dot or a quantum wire.

Abstract: A method of determining the path of a projectile comprises detecting multiple time of arrivals of the projectile in multiple intersecting planes and determining the path and speed of the projectile based on the multiple times of arrivals.

Abstract: The present invention aims to provide an electromagnetic wave frequency filter capable of transmitting an electromagnetic wave having a predetermined frequency between two waveguides with a high level of efficiency. This object is achieved by the following construction: A resonator 15 that resonates with the electromagnetic wave having the predetermined frequency is located between an input waveguide 13 and an output waveguide 14 and close to the two waveguides. The output waveguide 14 is designed so that it extends parallel to the input waveguide 13 within a predetermined section 18 located in proximity to the resonator 15, and its distance from the input waveguide 13 in the other section is larger than that in the predetermined section 18.

Abstract: An optical wavelength grating coupler incorporating one or more distributed Bragg reflectors (DBR) or other reflective elements to enhance the coupling efficiency thereof. The grating coupler has a grating comprising a plurality of scattering elements adapted to scatter light along a portion of an optical path, and the one or more DBRs are positioned with respect to the grating such that light passing through the grating towards the substrate of the grating coupler is reflected back by DBRs toward the grating. The DBR comprises a multilayer stack of various materials and may be formed on the substrate of the grating coupler. The grating coupler may include a gas-filled cavity, where the cavity is formed by a conventional etching process and is used to reflect light toward the grating. The grating coupler may also incorporate an anti-reflection coating to reduce reflective loss on the surface of the grating.

Abstract: An optical waveguide is formed on a substrate and includes a curved ridge structure, a curved optical path, and a buffer layer. The curved ridge structure is formed on the substrate so as to have a curvature in a longitudinal direction of the curved ridge structure. The curved optical path is formed along the curved ridge structure. The buffer layer covers a side of the ridge structure and has a lower refractive index than a refractive index of the substrate.

Abstract: An all-optical one-by-N optical switch is provided that has fewer components, is easier to control and has fewer optical losses that prior art one-by-N optical switches. An optical switch of the present invention includes an active deflection element formed from an electro-optical material to deflect an optical input from a single input to a selected one of N outputs. In one embodiment of the present invention, a single active deflection element at the input deflects an optical signal across a waveguide that commonly connects the N outputs. The N optical outputs include passive optical elements that are aligned with the deflected optical signal to accept a signal and provide it to a selected optical output. The optical switch can either be monolithic, where the optical material are all electro-optical materials, or can be hybrid, having separately formed components, such as the common waveguide, adhered to the substrate on which the optical switch is formed.