Patents Examined by MinSun Harvey
  • Patent number: 8000364
    Abstract: The present invention provides a nitride semiconductor light emitting device having an n-type ohmic electrode with an Au face excellent in ohmic contacts and in mounting properties, and a method of manufacturing the same. The device uses an n-type ohmic electrode having a laminate structure that is composed of: a first layer containing Al as a main ingredient and having a thickness not greater than 10 nm or not less than 3 nm; a second layer containing one or more metals selected from Mo and Nb, so as to suppress the upward diffusion of Al; a third layer containing one or more metals selected from Ti and Pt, to suppress the downward diffusion of Al; and a fourth layer being made of Au, from the side in contact with an n-type nitride substrate in order of mention, and after the laminate structure is formed, the n-type ohmic electrode is annealed.
    Type: Grant
    Filed: August 19, 2008
    Date of Patent: August 16, 2011
    Assignee: Opnext Japan, Inc.
    Inventors: Aki Takei, Akihisa Terano
  • Patent number: 8000363
    Abstract: The present invention relates to a solid state laser device with a solid state gain medium between two resonator end mirrors (3, 5) and a GaN-based pump laser (1) arranged to optically pump the solid state gain medium. The solid state gain medium is a Pr3+-doped crystalline or polycrystalline host material (4) which has a cubic crystalline structure and highest phonon energies of ?600 cm?1 and provides a band gap of ?5.5 eV. The proposed solid state laser can be designed to emit at several visible wavelengths with the emitted power showing a reduced dependence on the temperature of the GaN-based pump laser (1).
    Type: Grant
    Filed: February 22, 2008
    Date of Patent: August 16, 2011
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Ulrich Weichmann, Jaione Bengoechea Apezteguia, Patrice Jean-Pierre Camy, Jean-Louis Doualan, Richard Moncorge
  • Patent number: 8000361
    Abstract: The higher efficiency and lower power consumption are realized in a laser system for generating a high-power short-pulse laser beam. The laser system includes a laser oscillator for generating a pulse laser beam by laser oscillation, plural amplifiers for sequentially inputting the pulse laser beam generated by the laser oscillator and amplifying the pulse laser beam, and a control unit for controlling the laser oscillator to perform burst oscillation and halting an amplification operation of at least one of the plural amplifiers in a burst halt period between burst oscillation periods.
    Type: Grant
    Filed: March 9, 2009
    Date of Patent: August 16, 2011
    Assignees: Komatsu Ltd., Gigaphoton Inc.
    Inventors: Tamotsu Abe, Hideo Hoshino, Akira Endo, Osamu Wakabayashi, Kouji Kakizaki
  • Patent number: 8000374
    Abstract: A polarization pinned vertical cavity surface emitting laser (VCSEL). A VCSEL designed to be polarization pinned includes an upper mirror. An active region is connected on the upper mirror. A lower mirror is connected to the active region. A grating layer is deposited to the upper mirror. The grating layer includes a low index of refraction layer formed by deposition on the upper mirror. The grating layer further includes a high index of refraction layer formed by deposition on the low index of refraction layer. A grating is formed into the grating layer.
    Type: Grant
    Filed: December 12, 2005
    Date of Patent: August 16, 2011
    Assignee: Finisar Corporation
    Inventors: Ralph H. Johnson, James K. Guenter
  • Patent number: 7995630
    Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise control of optical frequency and phase, including the ability for broadband electronic tunability of optical signals and the cascading of multiple lasers for enhanced tunability and coherent combining for increased output power.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: August 9, 2011
    Inventor: George A. Rakuljic
  • Patent number: 7995633
    Abstract: A method for producing a multiplicity of semiconductor lasers (100) comprising the steps of providing a carrier wafer (30), producing an assembly (70) by applying a multiplicity of semiconductor laser chips (4) to a top side (31) of the carrier wafer (30), and singulating the assembly (70) to form a multiplicity of semiconductor lasers (100). Each semiconductor laser (100) comprises a mounting block (3) and at least one semiconductor laser chip (4). Each mounting block (3) has a mounting area (13) which runs substantially perpendicular to a top side (12) of the mounting block (3), on which top side the semiconductor laser chip (4) is arranged. The mounting area (13) is produced during the singulation of the assembly.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: August 9, 2011
    Assignee: OSRAM Opto Semiconductors GmbH
    Inventors: Juergen Dachs, Stefan Illek, Roland Schulz, Thomas Schwarz, Frank Singer, Heiko Unold
  • Patent number: 7995637
    Abstract: One aspect of the disclosed subject matter describes a gas discharge laser chamber. The gas discharge laser chamber includes a discharge region formed between a first electrode and a second electrode, a tangential fan for circulating gas through the discharge region, wherein the fan is proximate to an input side of the discharge region, an input side acoustic baffle proximate to the input side of the discharge region. The input side acoustic baffle includes a vanishing point leading edge, a vanishing point trailing edge, a gas flow smoothing offset surface aligning a gas flow from a surface of the input side acoustic baffle to an input side of a cathode support in the discharge region, a plurality of ridges separated by a plurality of trenches, wherein the plurality of ridges and the plurality of trenches are aligned with a direction of gas flow through the discharge region and wherein the plurality of ridges have a random pitch between about 0.3 and about 0.7 inch.
    Type: Grant
    Filed: October 21, 2009
    Date of Patent: August 9, 2011
    Assignee: Cymer, Inc.
    Inventors: Richard L. Sandstrom, William N. Partlo, Daniel J. W. Brown, Bryan G. Moosman, Tae H. Chung, Thomas P. Duffey, James J. Ferrell, Terance Hilsabeck
  • Patent number: 7995634
    Abstract: A nitride semiconductor laser element exhibits high-speed responsiveness by largely reducing the capacitance of the nitride semiconductor laser element. The nitride semiconductor laser element includes an n-type semiconductor layer, an active layer and a p-type semiconductor layer each laminated on the main surface of the substrate. The nitride semiconductor laser element further includes a striped ridge portion formed in the p-type semiconductor layer, and pn-junctions of the semiconductor layer in the peripheral region remote from the ridge portion are broken by ion implantation to form an insulative region for reducing the capacitance of the element.
    Type: Grant
    Filed: March 10, 2005
    Date of Patent: August 9, 2011
    Assignee: Nichia Corporation
    Inventors: Akira Kitano, Ken Katsuragi, Hiroaki Matsumura
  • Patent number: 7991024
    Abstract: In an external cavity wavelength tunable laser device including an external cavity (20) which includes a semiconductor optical amplifier (2) and performs laser oscillation operation by feeding back external light, a wavelength tunable mirror (7) having at least a single-peak reflection spectrum characteristic within a laser wavelength tuning range is placed on one end of the external cavity (20), and a Fabry-Perot mode interval determined by the effective length of the external cavity (20) is not less than 1/10 times and not more than 10 times the reflection band full width half maximum of the wavelength tunable mirror (7).
    Type: Grant
    Filed: June 29, 2006
    Date of Patent: August 2, 2011
    Assignee: NEC Corporation
    Inventors: Kenji Sato, Jan De Merli, Kenji Mizutani, Koji Kudo, Shinya Sudo, Mads. L Nielsen
  • Patent number: 7991025
    Abstract: Techniques and devices that stabilize a laser to a whispering gallery mode optical resonator.
    Type: Grant
    Filed: June 13, 2008
    Date of Patent: August 2, 2011
    Assignee: OEwaves, Inc.
    Inventors: Lutfollah Maleki, Vladimir Ilchenko
  • Patent number: 7991030
    Abstract: A method for deriving precise control over laser power of an optical pickup unit (OPU) includes: providing an analog-to-digital converter (ADC) within an automatic power calibration (APC) circuit to derive a path gain and/or a path offset from the APC circuit; and selectively performing compensation according to the gain and/or the path offset, in order to maintain precision of a relationship between the laser power and a target command utilized for controlling the laser power. An associated APC circuit comprising an ADC and at least one compensation module is further provided. The ADC is utilized for deriving a path gain and/or a path offset from the APC circuit. The compensation module is utilized for selectively performing compensation according to the path gain and/or the path offset, in order to control the laser power by a target command.
    Type: Grant
    Filed: August 21, 2008
    Date of Patent: August 2, 2011
    Assignee: Mediatek Inc.
    Inventors: Hsiao-Yuan Chi, Chih-Ching Chen, Chia-Wei Liao
  • Patent number: 7991028
    Abstract: A high-powered diffraction limited diode pumped solid-state source optically end pumps a compact, widely tunable solid state material. Imaging of the collimated pump beam into the tunable medium produces ideal volumetric overlap producing high conversion efficiencies. Fully integrated pump source provides pump energy at or near the peak absorption wavelength. Birefringent elements placed intracavity are used for linewidth narrowing and tuning of the laser wavelength. Tunable active medium is placed in linear cavity arrangement utilizing a confocal or hemispherical arrangement. Mode waist is minimized in crystal such that there is optimal overlap with pump source while simultaneously maximizing extraction efficiency.
    Type: Grant
    Filed: March 17, 2010
    Date of Patent: August 2, 2011
    Inventor: Thomas Bruno
  • Patent number: 7991023
    Abstract: A multi-band (multi-color) multiwavelength mode locked laser diode is provided by dynamic phase compensation of a quantum dot active medium. The laser diode is provided with a PIN diode structure where the active medium consists of a plurality of layers of quantum dots such as those produced by self-assembly from known chemical beam epitaxy methods. The multiplicity of bands may be produced by AC Stark splitting, frequency selective attenuation, or by the inclusion of multiple different layers having different, respective, peak ASE emissions. Dispersion compensation within laser facets, waveguides, and the optically active media permit the selection of a fixed dispersion within the cavity. A dynamic group phase change induced by the AC Stark effect permits compensation of the fixed dispersion sufficiently to produce an intraband mode-locked laser. Even interband mode locking was observed.
    Type: Grant
    Filed: September 25, 2009
    Date of Patent: August 2, 2011
    Assignee: National Research Council of Canada
    Inventors: Jiaren Liu, Zhenguo Lu, Sylvain Raymond, Philip Poole, Pedro Barrios, Daniel Poitras
  • Patent number: 7991022
    Abstract: Techniques and apparatus for using stimulated Raman scattering in an optical gain medium to produce amplified laser pulses.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: August 2, 2011
    Assignee: Calmar Optcom, Inc.
    Inventors: Daniel Beom Soo Soh, Anthony Hong Lin
  • Patent number: 7991032
    Abstract: Disclosed herein is a laser driver including a light emission controlling section configured to stop generation of a control voltage by a control voltage generating section, causing a given voltage corresponding to a magnitude of a reference current to be outputted to an input node of a first emitter follower to operate the first emitter follower for a first time period from start of a light emission time period, release stop of the generation of the control voltage by the control voltage generating section, causing the control voltage to be outputted to the input node of the first emitter follower to operate the first emitter follower until end of the light emission time period of the laser, and operate a second emitter follower to discharge electric charges accumulated in the laser for a second time period after the end of the light emission time period of the laser.
    Type: Grant
    Filed: March 4, 2010
    Date of Patent: August 2, 2011
    Assignee: Sony Corporation
    Inventors: Katsuhisa Daio, Takahiro Tsukada
  • Patent number: 7991036
    Abstract: A two-dimensional photonic crystal plane emission laser of the invention includes a two-dimensional photonic crystal which has a two-dimensional photonic crystal area and a light reflecting area, and which selects a wavelength of light to be generated in an active layer. The light reflecting area is formed in such a manner that when light leaking from the two-dimensional photonic crystal area and reflected on a reflecting surface of the light reflecting area is returned to the two-dimensional photonic crystal area, the reflection light is combined with a standing wave residing in a propagating direction of the reflection light without disturbing its resonant state.
    Type: Grant
    Filed: June 16, 2008
    Date of Patent: August 2, 2011
    Assignee: Konica Minolta Holdings, Inc.
    Inventor: Mitsuru Yokoyama
  • Patent number: 7991031
    Abstract: In a method of controlling an injection-seeded laser, a response of the laser is sampled at a plurality of different laser current values. A threshold current and a slope efficiency of the sampled response are then estimated, and a bias current and a modulation current calculated based on the estimated threshold current and a slope efficiency.
    Type: Grant
    Filed: August 21, 2009
    Date of Patent: August 2, 2011
    Assignee: LG-Ericsson Co., Ltd.
    Inventor: John D. Bainbridge
  • Patent number: 7991302
    Abstract: A method and apparatus for optical signaling. In one embodiment, a laser driver converts a digital voltage sequence to a current signal having a bias mode adjustable by a bias control and a modulation mode adjustable by a modulation control. A laser generates an optical signal responsive to the current signal of the laser driver. In one embodiment, a photo-detector receives an optical signal and generates a single ended current signal. A transimpedance amplifier circuit converts the single ended current signal to a differential voltage signal. A clock recovery circuit generates an aligned clock signal and a sampler circuit uses the aligned clock signal to retrieve a digital voltage sequence.
    Type: Grant
    Filed: March 31, 2004
    Date of Patent: August 2, 2011
    Assignee: Intel Corporation
    Inventors: Jianping Xu, Fabrice Paillet, Tanay Karnik, Donald S. Gardner
  • Patent number: 7991033
    Abstract: A vertical cavity surface emitting laser (VCSEL) includes a semiconductor substrate, a lower reflecting mirror formed on the semiconductor substrate, and a mesa structure. The mesa structure includes an active layer, a selective oxidization layer that includes a current confined structure, and an upper reflecting mirror. A lower electrode is connected to the semiconductor substrate, and an upper electrode is connected to the upper reflecting mirror. The VCSEL emits laser light perpendicularly to the plane of the semiconductor substrate when an electric current flows between the upper electrode and the lower electrode. The semiconductor substrate is inclined with respect to (100) plane. The active layer includes a quantum well layer having a compressive strain with respect to the substrate, and a spacer layer. The spacer layer has either a compressive strain or a tensile strain with respect to the semiconductor substrate.
    Type: Grant
    Filed: June 2, 2009
    Date of Patent: August 2, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Kei Hara, Morimasa Kaminishi
  • Patent number: 7986720
    Abstract: A circuit for driving a light-emitting element such as a laser diode LD has a boost circuit for boosting an input voltage to supply it to the light-emitting element, a photoreceptor such as a photodiode PD for monitoring light from the light-emitting element; and a boost control circuit for controlling a boost voltage of the boost circuit based on a monitored amount of the photoreceptor. In the method for driving a light-emitting element by boosting an input voltage to supply the voltage to the light-emitting element, light from the light-emitting element is monitored and its monitored amount is used as a basis to control a boost voltage to the light-emitting element. A control circuit may be provided to control a driving current that passes through the light-emitting element based on the monitored amount of the photoreceptor.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: July 26, 2011
    Assignee: NEC Corporation
    Inventor: Masashi Tachigori