Abstract: A semiconductor modulator is disclosed which exhibits a negative alpha parameter at low operating bias. The device includes at least two barrier layers with a quantum well layer therebetween. An additional layer is formed adjacent to the quantum well layer, the additional layer having a bulk bandgap energy greater than the quantum well layer so as to form a stepped well between the barrier layers.

Abstract: An apparatus and method for high speed phase modulation of optical beam with reduced optical loss. In one embodiment, an apparatus includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus also includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type opposite to the first conductivity type. A first contact is included in the apparatus and is coupled to the optical waveguide at a first location in the first region outside an optical path of an optical beam to be directed through the optical waveguide. The apparatus also includes a first higher doped region included in the first region and coupled to the first contact at the first location to improve an electrical coupling between the first contact and the optical waveguide. The first higher doped region has a higher doping concentration than a doping concentration within the optical path.

Abstract: A method and apparatus are provided for driving an electro-optic converter assembly with an information signal. The method includes the steps of disposing a resistor having a resistance substantially equal to a resistance of the electro-optic converter adjacent the electro-optic converter, coupling the electro-optic converter and resistor together, in series, to form a current loop, driving the electro-optical converter end of the current loop with the information signal and driving the resistor end of the current loop with an opposite polarity of the information signal.

Abstract: The present invention has an object to provide a Mach-Zehnder optical modulator with the excellent productivity and reliability, which can obtain a favorable optical response characteristic even if a high frequency electric signal is applied to a signal electrode. To this end, the present optical modulator is configured such that, in a Mach-Zehnder optical modulator in which an optical waveguide and a coplanar electrode are formed on a surface of a substrate having an electro-optic effect, floating electrodes formed using a conducting material, are provided on side faces along parallel waveguides, among side faces substantially perpendicular to the surface of the substrate. Thus, even when a high frequency electric signal is applied to the signal electrode, a phenomenon is suppressed in which a particular frequency resonates within the substrate, and an occurrence of dip in a particular frequency is avoided.

Abstract: A color filter substrate for a liquid crystal display device includes a polarizing substrate, a black matrix positioned on the polarizing substrate, a color filter layer positioned on the black matrix, and a common electrode positioned on the color filter layer.

Abstract: An optical modulator includes a p- or n-type semiconductor layer that is provided at an upper part of an optical waveguide path, and modulating electrodes that are provided at intervals on the semiconductor layer in an extension area of the optical waveguide path. The semiconductor layer has first regions located immediately under the modulating electrodes, and second regions located between the first regions. The second regions have separators that electrically separate the first regions from one another.

Abstract: An optical transmitter architecture has a return-to-zero (RZ) laser modulator coupled in cascade with a non-return-to-zero (NRZ) laser modulator. Modulator bias and electronic phase delay bias are controlled using dither-based feedback, so as to align the phase of the RZ clock signal with that of the NRZ data. A first method uses an RZ quadrature AM dither or an RZ “hillclimber” bias dither, to apply a relatively low frequency dither signal to a variable RF delay for the RZ clock signal applied to the RZ modulator or NRZ data signal applied to the NRZ modulator. A second method is an RZ quadrature AM dither or “hillclimber” bias dither scheme that applies equal amplitude and opposite phase dither signals to perform complementary modulation of both the RZ and NRZ MZ modulators simultaneously.

Abstract: An apparatus and method for modulating a phase of optical beam. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of semiconductor material having a first polarity. The apparatus further includes a second region of semiconductor material having a second polarity. The second region is disposed proximate to the first region such that an interface between the first and second regions defines interdigitated regions of the first and second regions of semiconductor material. The first and second regions are adapted to be reversed biased in response to a signal to modulate a depletion region in response to the signal at the interface between the first and second region. Accordingly, an optical beam directed through the interface between the first and second regions through the modulated depletion region is adapted to be phase shifted in response to the signal.

Abstract: A variable semiconductor all-optical buffer and method of fabrication is provided where buffering is achieved by slowing down the optical signal using a control light source to vary the dispersion characteristic of the medium based on electromagnetically induced transparency (EIT). Photonic bandgap engineering in conjunction with strained quantum wells (QWs) and quantum dots (QDs) achieves room temperature operation of EIT. Photonic crystals are used to sharpen the spectral linewidths in a quantum well structure due to its density of states and in a quantum-dot structure caused by the inhomogeneity of the dot size, typically observed in state-of-the-art QD materials. The configuration facilitates monolithic integration of an optical buffer with an amplifier and control laser to provide advantages over other material systems as candidates for optical buffers.

Abstract: Electroabsorption modulator (100) having a layer sequence of at least five sequential layers, having at least one light absorption layer (106) which is arranged between the first layer (101) and the third layer (102) and is set up to generate charge carriers upon irradiation of light (108) of a specific wavelength, and having at least one storage layer (104) which is arranged between the third layer (102) and the fifth layer (103) and is set up to store charge carriers.

Abstract: This invention pertains to a spintronic device for emitting light and to a method for its operation. The device includes a cathode electrode capable of producing spin-polarized charge carrier electrons under the influence of an electric field; an anode electrode spaced from the cathode for producing spin-polarized charge carrier holes; an intermediate medium disposed between the electrodes into which the carriers are injected under the influence of an electric field and which serves as a transport medium for the carriers wherein the carriers are transported and within which the carriers react and form excitons; and a circuit between the electrodes for imparting en electric field which serves as the motive force for the carriers.

Abstract: The inventive photoreactive device has a semiconductor and an oxidation-reduction material. The semiconductor has a conduction band with a potential and being capable of producing electrons under the irradiation of light on the semiconductor. The oxidation-reduction material has a redox potential being positive compared with the potential of the conduction band. The semiconductor supplies electrons into the oxidation-reduction material to reduce it under the irradiation of light for storing the electrons. The stored electrons are discharged from the oxidation-reduction material into a metal material to prevent the corrosion of the metal material.

Abstract: The present invention discloses an optical printed circuit board assembly with multi-channel block-type optical devices packaged therein, the printed circuit board assembly including a plate type heat spreader, a driving printed circuit board die bonded to a top of the heat spreader to convert electrical and optical signals to optical and electrical signals, respectively, a driving integrated circuit, die bonded to the top of the heat spreader and wire bonded to the driving printed circuit board.

Abstract: A capacitive structure including single crystal silicon and an insulating layer in a semiconductor substrate. One embodiment of the present invention includes an optical switching device having one or more capacitive structures including single crystal silicon in a substrate such as a silicon-on-insulator (SOI) wafer and can be used in a variety of high bandwidth applications including multi-processor, telecommunications, networking or the like. In one embodiment, a capacitive structure includes single crystal silicon disposed in a first semiconductor material with an insulating layer disposed between the single crystal silicon and the semiconductor material. In one embodiment, a capacitive structure may be formed by laterally growing single crystal silicon through an opening in a trench adjacent to a trench where the capacitive structures is formed.

Abstract: A semiconductor optical modulator, a Mach-Zehnder optical modulator employing the same, and a method of manufacturing a semiconductor optical modulator that are suitable for high-speed baseband communication are provided. An optical waveguide core layer is formed in such a manner that it alternately crosses micro optical modulator elements and gap regions, which are formed by placing electrically insulating material at predetermined intervals on an electrically conductive substrate. The core layer is connected to a signal electrode portion via a conductive semiconductor portion in each micro optical modulator element. A ground electrode is connected to the core layer via the conductive substrate. Further, the signal electrode portions are connected in a series to form a signal electrode by means of in-between metal wirings. Conductive semiconductor material is located between the core layer and the electrodes. In the gap regions, the core layer is sandwiched between insulating semiconductor layers.

Abstract: An electro-optical device 101 is provided with an electro-optical panel 102 in which a liquid crystal material L is held between a pair of opposed electrodes 114a and 114b, and a dot is formed in each of regions where the pair of opposed electrodes 114a and 114b is opposed to each other, and with a light source 106 for irradiating the electro-optical panel 102 with light. The device further comprises a transflective film 112 having a light-transmitting region 113 provided for each of the dots to transmit light from the light source 106 and a light-reflecting region for reflecting the external light, a colored layer 118 provided corresponding to the dots, and a colored layer 121 provided opposite to the colored layer 118 with the liquid crystal material L held therebetween corresponding to the light-transmitting region 113.

Abstract: An exemplary monolithic stabilized monolithic transmissive active optical device, such as an electroabsorption modulator (EAM), a variable optical attenuator (VOA), or a semiconductor optical amplifier (SOA), with an output optical tap, is formed from: a substrate; a waveguide layer; a semiconductor layer. The waveguide layer is coupled to the substrate and includes an active medium, which interacts with a predetermined wavelength of light, and is responsive to an electric signal. The electric signal is applied between the substrate and the semiconductor layer. The waveguide layer includes an output optical tap section and an active section adjacent to the output optical tap section. These sections include portions of the active medium. Further embodiments of the present invention incorporate temperature as well as bias control to improve performance of exemplary monolithic transmissive active optical devices.

Abstract: A quantum-confined Stark effect quantum-dot optical modulator includes an interferometer having a beam splitter, first and second parallel optical branches fed by the beam splitter and a beam combiner fed by the first and second parallel optical branches and a laser for feeding a laser beam to the beam splitter. First and second optical phase shifters are provided in respective ones of the first and second parallel optical branches. Each optical phase shifter includes an intrinsic semiconductor crystalline planar layer and p-type and n-type planar semiconductor layers on opposite faces of the intrinsic semiconductor crystalline planar layer, the intrinsic layer lying in a plane parallel to a direction of propagation of the laser beam in the respective optical branch. The intrinsic layer has plural layers of planar arrays of quantum dots therein. A reverse bias D.C. voltage source is connected across the p-type and n-type layers.

Abstract: Drive circuitry to provide a DC bias voltage and a high frequency modulation current to an electroabsorption modulator (EAM), including a high frequency modulation current source, a coupling capacitor, and a first DC lead. The drive circuitry may include termination circuitry. One lead of the high frequency modulation current source is electrically coupled to the first semiconductor type contact of the EAM and the other lead of the high frequency modulation current source is electrically coupled to an AC ground. The coupling capacitor includes a first electrode electrically coupled to the second semiconductor type contact of the EAM, a second electrode electrically coupled to the AC ground, and a dielectric layer between the electrodes. The first DC lead is electrically coupled to the EAM-side capacitor electrode and configured to be coupled to a first DC potential.

Abstract: An optical modulator having a good reflection characteristic over a broad band is provided, with a small semiconductor chip area, by use of a semiconductor chip on which a semiconductor optical modulator is mounted. A typical example of the optical modulator has a structure in which a semiconductor chip provided with an electro-absorption semiconductor optical modulator comprising an electrode of traveling wave modulator is mounted on a dielectric substrate provided with a transmission line, and the characteristic impedance of at least a part of the transmission line is set to be greater than the output impedance of a modulator driver circuit and the impedance of an optical modulator portion. By this, a broad band optical modulator with excellent reflection characteristic can be provided by use of a semiconductor chip which is small in area.

Abstract: The present application is directed to high speed optical system. In one embodiment, the optical system includes a photodiode which is sensitive to a wavelength of light, an image source irradiating a wavefront of a first wavelength on the photodiode to which the photodiode is sensitive, the wavefront containing an optical path difference induced phase-shift, a read source of photons irradiating photons of a second wavelength to which the photodiode is insensitive, an electric field across the photodiode in excess of the breakdown voltage thereof and configured to result in an avalanching of electrons in the photodiode when the photons from the first source strike the photodiode, the avalanching electrons resulting in a photorefractive response which changes the index of refraction in the photodiode, and a capture device in optical communication with and configured to capture light reflected from the photodiode.

Abstract: Drive circuitry to provide a DC bias voltage and a high frequency modulation current to an electroabsorption modulator (EAM), including a high frequency modulation current source, a coupling capacitor, and a first DC lead. The drive circuitry may include termination circuitry. One lead of the high frequency modulation current source is electrically coupled to the first semiconductor type contact of the EAM and the other lead of the high frequency modulation current source is electrically coupled to an AC ground. The coupling capacitor includes a first electrode electrically coupled to the second semiconductor type contact of the EAM, a second electrode electrically coupled to the AC ground, and a dielectric layer between the electrodes. The first DC lead is electrically coupled to the EAM-side capacitor electrode and configured to be coupled to a first DC potential.

Abstract: In order to obtain an optical transmitter module for converting an input electric signal to a light signal with fidelity and outputting it therefrom, a terminal resistor Rt and an optical modulator MD are connected in parallel within a package including a laser diode with a monolithically integrated optical modulator for obtaining the light signal according to the electric signal. One thereof is grounded and the other thereof is connected to a wire inductance (L1) and an impedance matching resistor Rd in series with this parallel connection. Further, a high frequency transmission line (micro-strip line) MSL for the transmission of the electric signal is connected to the other end of the impedance matching resistor Rd.

Abstract: An optoelectronic component has at least one monolithically integrated laser diode and at least one monolithically integrated optical waveguide. At least one of the optical waveguides is functionally coupled to at least two electro-absorption modulators, and at least one electro-absorption modulator is assigned at least one optical amplifier. The assembly forms an active electro-optical device that can be driven efficiently.

Abstract: A spatial light modulator is disclosed which includes an electro-optic wafer, such as lithium niobate (LiNbO3) or PLZT, formed as an asymmetric Fabry-Perot cavity with a totally reflecting dielectric mirror on its bottom face and a partially reflecting dielectric mirror on its top face. The electro-optic wafer is sandwiched between a transparent top electrode that forms a solid ground plane and a bottom electrode that is formed on a circuitry wafer and segmented into an array of electrode pads. Voltage source circuitry for each electrode is located immediately beneath the electrode in the circuitry wafer, which is bonded to the electro-optic wafer. Because the bottom electrode is segmented, a different voltage can be applied to each electrode so that the refractive index, and therefore the phase of an exiting light wave, can be spatially modulated.

Abstract: A device comprising movable micro-structures configured to contact a substrate is disclosed. The substrate has a metal-insulator-metal construction with an upper metal layer and an insulator being patterned to provide substrate contact regions to a lower metal layer. The micro-structures have metal under layers for providing ribbon contact regions and non-contact regions. In use, a bias voltage is applied across the micro-structures and the top metal layer of the substrate causing the micro-structures and the substrate to contact through the contact regions. During contact, the contact regions are maintained at a potential that is substantially less than the applied bias voltage, thereby reducing the formation of asperities and/or sticking between contacting parts. The micro-structures are preferably ribbon structures in an optical MEM device configured to modulate light.

Abstract: A waveguide having a periodic structure and the excitation of exciton polariton as one form of interactions between radiation fields and matter systems are applied to light switching to provide an optical switch that is excellent in light intensity extinction ratio and operable at a speed in the terahertz order. The optical switch includes a polariton and photon interacting region (5) made of a grating (3) formed on a top face of a transparent substrate (2) and a semiconductor layer (4) with which the grating (3) is covered. The polariton and photon interacting region (5) is irradiated from a free space with a controllable light (7) having a preestablished wavelength and also from a free space with a control light (6) having a preselected wavelength to control the transmissivity of the controllable light (7) through the polariton and photon interacting region (5).

Abstract: An apparatus and method for modulating a phase of optical beam with reduced contact loss. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus further includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type, which is opposite to the first conductivity type. A first contact is coupled to the optical waveguide at a first location, which is outside an optical path of an optical beam that is to be directed through the optical waveguide. A first buffer of insulating material is disposed along the optical waveguide between the first contact and the optical path of the optical beam. A buffer plug of insulating material disposed in the optical waveguide on a same side as the first location.

Abstract: This invention pertains to a spintronic device for emitting light and to a method for its operation. The device includes a cathode electrode capable of producing spin-polarized charge carrier electrons under the influence of an electric field; an anode electrode spaced from the cathode for producing spin-polarized charge carrier holes; an intermediate medium disposed between the electrodes into which the carriers are injected under the influence of an electric field and which serves as a transport medium for the carriers wherein the carriers are transported and within which the carriers react and form excitons; and a circuit between the electrodes for imparting en electric field which serves as the motive force for the carriers.

Abstract: A band discontinuity reduction layer having a band gap energy larger than that of that of an MQW (multiple quantum well) absorption layer and smaller than that of a p-InP clad layer is provided between the MQW absorption layer and the p-InP clad layer. In addition, a band discontinuity reduction layer having a band gap energy larger than that of the MQW absorption layer and smaller than that of an n-InP clad layer is provided between the MQW absorption layer and the n-InP clad layer. Consequently, as a pile-up of carriers is suppressed, a semiconductor light modulator with an enhanced response speed can be obtained.

Abstract: A modulator formed with a solid state electro-optic material having a pixellated structure interconnected to a circuit on a semiconductor substrate. Silicon CMOS integrated circuit that can include random access memories (RAMs) are used as a substrate and interfaced to solid state electro-optic materials coated thereon. In particular, the electro-optic modulators are controlled by RAM cells to produce a modulation of reflected light. SRAMs can be used with connection to the SRAM cell flip-flop. DRAMs can be used with the modulator replacing the DRAM storage capacitor. The SLM thus formed can be connected to a digital computer and controlled as if were a being written to as a memory, but other IC structures can also be used. In order to enhance the modulation effects, the electro-optic material is used as the spacer for a Fabry-Perot etalon structure that is also deposited on the semiconductor substrate. PLZT is a suitable electro-optic material.

Abstract: An exemplary optical isolator, such as a magnetic-semiconductor composite optical isolator, and method for making the same, is provided that includes a semiconductor waveguide and a magnetic-semiconductor composite layer. The semiconductor waveguide includes a guide layer, a first clad layer and a second clad layer. The guide layer includes one or more layers with a first end, a second end, a top, and a bottom, the guide layer allows a light wave incident the first end of the guide layer to propagate in a positive propagation direction, and allows a light wave incident the second end of the guide layer to propagate in a negative propagation direction. The first clad layer and the second clad layer are provided, respectively, relative to the bottom and the top of the guide layer, and the second clad layer has a thickness to allow an optical field penetration through the second clad layer.

Abstract: A resonance type optical modulator includes an optical path having electro-optical effect characteristics, a modulation electrode formed along the optical path for applying an electric field to the optical path, a common electrode formed in opposition to the modulation electrode, a feeding line that is connected to the modulation electrode and stubs connected to the feeding line, wherein the feeding line, stubs and common electrode are provided on one side of a region that is divided by the modulation electrode.

Abstract: A semiconductor optical device includes a substrate, an optical waveguide layer on the substrate and having well and barrier layers. The semiconductor optical device also includes an optical absorbing layer on the substrate and adjacent to the optical waveguide layer so that incident light having an incident wavelength &lgr;LD is guided into the optical absorbing layer. Each of the well layers has a wavelength &lgr;g corresponding to the band gap of the well layers and that is larger than the incident wavelength &lgr;LD. Also, the band gap energy between base levels of a conduction band and a valence band of the optical waveguide layer is larger than the energy of the incident light having the incident wavelength &lgr;LD.

Abstract: An optoelectronic module has a laser diode configured on a substrate. The laser diode is drivable using an electronic drive device. At least one electrode of the laser diode is connected or coupled to the substrate. In order to match the impedance of the laser diode to the assigned electronic drive device, the substrate is designed as an electric line coupled to one electrode of the laser diode, and the impedance is matched by setting the specific electric conduction properties of the substrate. In this way, in addition to the mechanical function as carrier of the laser diode and the thermal function of dissipating the heat produced in the laser diode, the substrate additionally fulfills an electric function of impedance matching between the laser diode and the assigned electronic drive system. The optoelectronic module therefore offers improved EMC properties.

Abstract: A method and apparatus for modulating light with an array of nanocrystals. First photons are directed onto an array of nanocrystals and at least a portion of the first photons ate directed by the array of nanocrystals. In one embodiment, the array of nanocrystals emit second photons. A wavelength of the second photons is modulated responsive to a signal. In one embodiment, dopants are formed proximate to the array of nanocrystals and energy from the absorbed portion of the first photons is coupled to the dopants to cause the to emit third photons. An intensity of the third photons is modulated responsive to a signal.

Abstract: An electroabsorption semiconductor optical modulator includes a light absorption layer for generating a modulated light beam by absorbing an incident light beam. A well layer in the light absorption layer, accumulates charge carriers generated by the light absorption layer. The charge carriers are guided and released from the well layer upon receipt of an incident excitation light beam having a wavelength corresponding to the bandgap energy of the well layer. The incident light beam is modulated by changes in absorption coefficient in response to an externally applied voltage. The modulator responds to a high-intensity incident light beam at high frequency, free from deterioration of extinction characteristics, and has good transmission characteristics.

Abstract: An apparatus and method for modulating a phase of optical beam. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of semiconductor material disposed in a second region of semiconductor material. An insulating region is disposed between the first and second regions of semiconductor material defining a plurality of interfaces between the insulating region and the first and second regions of semiconductor material. An angle of incidence between an optical beam and the plurality of interfaces is substantially equal to Brewster's angle. A plurality of charge modulated regions proximate to the plurality of interfaces in the first and second regions of semiconductor are included such that the optical beam directed through the plurality of interfaces and the plurality of charge modulated regions is phase shifted in response to the plurality of charge modulated regions.

Abstract: A quasi-optical system is provided. More specifically, a quasi-optical system is provided comprising various embodiments of quasi-optical grids (such as arrays or layers and the like) with reconfigurable quasi-optical unit cells. The quasi-optical system, grids and unit cells are configured to control an incident beam in a variety of ways.

Abstract: Disclosed is a high speed optical signal processor which includes a saturable absorber area including a substrate, an active layer, a clad layer and a first upper electrode which are sequentially formed on one face of the substrate, and a first lower electrode formed on the other face of the substrate; and a gain-clamped optical amplifier area including a substrate having a diffraction grating for generating a laser beam, an active layer, a clad layer and a second upper electrode which are sequentially formed on one face of the substrate, and a second lower electrode formed on the other face of the substrate, the second upper electrode being isolated from the first upper electrode of the saturable absorber area.

Abstract: The invention discloses phase-shifters, modulators, and method that produces a smaller &pgr; by means of a field excitation using multiple electrodes. A negative signal is introduced that travels with the positive signal, which enhances the electric field significantly. The field enhancement is provided by the superposition of the fields accumulated from each electrode. A base or substrate material can be made from any compound having linear electro-optic properties, such as lithium niobate, lithium tantalite, potassium lithium niobate, potassium titanyl phosphate or gallium-arsenide. For lithium niobate, there are two possible orientations of electric field, z-cut orientation or x-cut orientation.

Abstract: To enhance the emission output of the light emitting device including an active layer made of nitride semiconductor containing In, the light emitting device having an active layer between the n-type semiconductor layer and the p-type semiconductor layer, characterized in that the active layer comprises an well layer made of Inx1Ga1−x1N (x1>0) containing In and a first barrier layer made of Aly2Ga1−y2N (y2>0) containing Al formed on the well layer.

Abstract: A solid-state light source apparatus includes a first excitation laser light source for outputting a laser beam of a first wavelength, a second excitation laser light source for outputting a laser beam of a second wavelength, a difference frequency between the laser beam of the first wavelength and the laser beam of the second wavelength being in a terahertz band, and a semiconductor pseudo phase matching device which is disposed at a place where a first optical axis of the laser beam of the first wavelength overlaps with a second optical axis of the laser beam of the second wavelength, and generates a terahertz beam in a direction coaxial with the first and second optical axes on the basis of irradiation of the laser beams of the first and second wavelengths. Thus, high output and high efficiency terahertz wave generation can be easily and certainly realized while a narrow line width characteristic is maintained.

Abstract: A moveable micromirror includes a supporting structure, a flexible post extending from the supporting structure, and a table extending radially from the end of the post along a plane generally perpendicular to the post, the table having a reflective surface facing away from the supporting structure. The post, preferably formed of single-crystal silicon, is dimensioned to be sufficiently flexible to allow the reflective surface to be selectively moveable and positionable, with at least two degrees of freedom, when urged by a suitable actuating force. A method of making an array of moveable micromirrors of this type includes deep etching a silicon substrate so as to form posts surrounded by trenches, etching back the surface of the substrate around the posts so as to allow the posts to protrude beyond the surface of the substrate, and affixing a table with a reflective surface thereon to the tops of a plurality of the posts.

Abstract: When manufacturing a recording medium, a material layer 12 formed on a substrate 11 that composes the recording medium is exposed to a laser beam in accordance with a recording pattern. The material layer 12 has a predetermined reflectivity for the laser beam 13 so as to produce return light for the laser beam 13. By detecting this return light, the focusing of the laser beam on the material layer is adjusted. By doing so, a laser beam can be easily and accurately focused on a material layer during a process in which a laser beam is shone, in accordance with a recording pattern, onto a material layer formed on a recording medium or a production plate used when manufacturing a recording medium.

Abstract: An optical gate according to the invention comprises a polarization divider to divide an optical signal into two orthogonal polarization components and to output them as a first polarization component which precedes in the time base and a second polarization component which follows the first one in the time base; a semiconductor optical amplifier to modulate the phase of the second polarization component output from the polarization divider according to a control light; an assist light supplier to supply to the semiconductor optical amplifier an assist light to help the recovery of the refractive index variation of the semiconductor optical amplifier caused by the control light; a polarization combiner to combine the first and second polarization components of the optical signal transmitting on the semiconductor optical amplifier so as to adjust them in the same time location; and a polarization extractor to extract a predetermined polarization direction component from the output from the polarization combine

Abstract: An electroabsorption modulator (10) includes at least one quantum well (26) in a conduction band and a corresponding quantum well (26) in a valence band. A barrier made from InGaAlAs or InGaAsP is formed within each of the quantum wells in the conduction and valence bands.

Abstract: A forming method and a structure of a high efficiency electro-optics device are disclosed. In the present invention, the cell-fixing surface between the die carrier and the electro-optics cell is decreased to increase the light emitting and absorbing regions of the electro-optics device. Thus, the operating efficiency and the sensitivity of the electro-optics device is increased substantially. Especially, the present invention has the advantage of fully showing the efficacy of device using the transparent substrate. Furthermore, when the electro-optics cell is fixing on the cell-fixing surface by utilizing the eutectic or metal-melting bonding method, a result of self-alignment can be achieved. Thus, the accuracy of the packaging device is increased substantially, thereby reducing the loss caused by the failure of poor cell-fixing while in mass production and meanwhile increasing the accuracy of fixing cell. Therefore, the present technology is quite suitable for use in the packaging of high precision.

Abstract: An electro absorption modulator in which the photocurrent generated by the absorption of light is monitored and the bias voltage applied to the electro absorption modulator is varied in order to vary the photocurrent and thence the extinction ratio of the electro absorption modulator.

Abstract: An electro-modulating device for modulating light from a light source, as part of an opto-electronic communication network has a modulating medium for modulating light passing therethrough by varying an electric field applied across the modulating medium, an optical input-output surface, a light reflector, and electrodes for applying the varying electric field across the modulating medium. The input-output surface, the medium and the reflector are arranged so that light enters the medium through the input-output surface, travels through the medium towards the reflector, is reflected by the reflector to travel back through the medium towards the input-output surface, and exits the medium through the input-output surface. The electric field is transverse to light traversing the medium between the input-out surface and the reflector, to make it easier to couple an optic fiber to the input-output surface of the modulating medium.