Patents by Inventor Kazuhisa Takagi

Kazuhisa Takagi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10903619
    Abstract: A multi-wavelength integrated device (5) including plural semiconductor lasers (6) and plural modulators (7) modulating output beams of the plural semiconductor lasers (6) respectively is mounted on the stem (1). Plural leads (10) penetrates through the stem (1) and are connected to the plural semiconductor lasers (6) and the plural modulators (7) respectively. Each lead (10) is a coaxial line in which plural layers are concentrically overlapped with one another. The coaxial line includes a high frequency signal line (12) transmitting a high frequency signal to the modulator (7), a GND line (14), and a feed line (16) feeding a DC current to the semiconductor laser (6). The high frequency signal line (12) is arranged at a center of the coaxial line. The GND line (14) and the feed line (16) are arranged outside the high frequency signal line (12).
    Type: Grant
    Filed: May 17, 2017
    Date of Patent: January 26, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventor: Kazuhisa Takagi
  • Publication number: 20200220322
    Abstract: A multi-wavelength integrated device (5) including plural semiconductor lasers (6) and plural modulators (7) modulating output beams of the plural semiconductor lasers (6) respectively is mounted on the stem (1). Plural leads (10) penetrates through the stem (1) and are connected to the plural semiconductor lasers (6) and the plural modulators (7) respectively. Each lead (10) is a coaxial line in which plural layers are concentrically overlapped with one another. The coaxial line includes a high frequency signal line (12) transmitting a high frequency signal to the modulator (7), a GNU line (14), and a feed line (16) feeding a DC current to the semiconductor laser (6). The high frequency signal line (12) is arranged at a center of the coaxial line. The GND line (14) and the feed line (16) are arranged outside the high frequency signal line (12).
    Type: Application
    Filed: May 17, 2017
    Publication date: July 9, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventor: Kazuhisa TAKAGI
  • Publication number: 20200144788
    Abstract: An optical modulation device includes a first optical modulator having a first capacitance, a second optical modulator having a second capacitance larger than the first capacitance, a first feed path having a first inductance and having one end connected to the first optical modulator, and a second feed path having a second inductance larger than the first inductance and having one end connected to the second optical modulator. In a graph having an abscissa axis of inductances and an ordinate axis of capacitance values, a predetermined range between a predetermined lower limit line and a predetermined upper limit line is set. The first capacitance, the first inductance, the second capacitance, and the second inductance are determined so that a first coordinate determined by the first capacitance and the first inductance and a second coordinate determined by the second capacitance and the second inductance are contained within the predetermined range.
    Type: Application
    Filed: April 25, 2017
    Publication date: May 7, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kazuhisa TAKAGI, Kyosuke KURAMOTO
  • Patent number: 10636952
    Abstract: A flexible Peltier device in which emitting heat conversion properties between Peltier elements and an object transferring heat may be improved and a flexible heat-emitting sheet having the Peltier elements bonded thereto may be bent without worrying the separation there between. A flexible Peltier device includes a single or plural Peltier element which is disposed on one surface side of a heat-emitting sheet having flexibility made from heat-conductive rubber containing a heat conductive filler and each semiconductor element which has a heating side and a cooling side and composes the Peltier element at least one of the heating side and the cooling side is bonded integrally to the heat-emitting sheet by a direct covalent bond and/or by an indirect covalent bond through a molecular adhesive at active groups existing on each other surfaces.
    Type: Grant
    Filed: January 8, 2016
    Date of Patent: April 28, 2020
    Assignee: ASAHI FR R&D CO., LTD.
    Inventors: Kazuhisa Takagi, Koichi Abe, Nobuyoshi Watanabe, Syuhei Toyoshima
  • Patent number: 10063031
    Abstract: A diffraction grating pattern is formed in the first insulating film on the active layer by electron beam lithography, and at the same time an end facet formation pattern whose end portion corresponds to a position of an emission end facet of the optical modulator is formed in the first insulating film on the optical absorption layer by electron beam lithography. A second insulating film is formed on the end facet formation pattern. The diffraction grating formation layer is etched using the first and second insulating films as masks to form a diffraction grating, and is embedded with an embedded layer. The second insulating film is removed. A third insulating film is formed on the diffraction grating and the embedded layer not to cover the end facet formation pattern. The optical absorption layer is etched using the first and third insulating films as masks to form the emission end facet.
    Type: Grant
    Filed: March 16, 2017
    Date of Patent: August 28, 2018
    Assignee: Mitsubishi Electric Corporation
    Inventor: Kazuhisa Takagi
  • Publication number: 20180041008
    Abstract: A diffraction grating pattern is formed in the first insulating film on the active layer by electron beam lithography, and at the same time an end facet formation pattern whose end portion corresponds to a position of an emission end facet of the optical modulator is formed in the first insulating film on the optical absorption layer by electron beam lithography. A second insulating film is formed on the end facet formation pattern. The diffraction grating formation layer is etched using the first and second insulating films as masks to form a diffraction grating, and is embedded with an embedded layer. The second insulating film is removed. A third insulating film is formed on the diffraction grating and the embedded layer not to cover the end facet formation pattern. The optical absorption layer is etched using the first and third insulating films as masks to form the emission end facet.
    Type: Application
    Filed: March 16, 2017
    Publication date: February 8, 2018
    Applicant: Mitsubishi Electric Corporation
    Inventor: Kazuhisa TAKAGI
  • Publication number: 20170352794
    Abstract: A flexible Peltier device in which emitting heat conversion properties between Peltier elements and an object transferring heat may be improved and a flexible heat-emitting sheet having the Peltier elements bonded thereto may be bent without worrying the separation there between. A flexible Peltier device includes a single or plural Peltier element which is disposed on one surface side of a heat-emitting sheet having flexibility made from heat-conductive rubber containing a heat conductive filler and each semiconductor element which has a heating side and a cooling side and composes the Peltier element at least one of the heating side and the cooling side is bonded integrally to the heat-emitting sheet by a direct covalent bond and/or by an indirect covalent bond through a molecular adhesive at active groups existing on each other surfaces.
    Type: Application
    Filed: January 8, 2016
    Publication date: December 7, 2017
    Applicant: ASAHI FR R&D CO., LTD.
    Inventors: Kazuhisa TAKAGI, Koichi ABE, Nobuyoshi WATANABE, Syuhei TOYOSHIMA
  • Patent number: 9698566
    Abstract: An optical module includes: a semiconductor laser emitting laser light; an optical device having a butt joint interface; an optical amplifier amplifying the laser light passed through the optical device; an equivalent resonator length adjustor inserted between the optical amplifier and the optical device; a wavelength spectrum measuring device measuring a wavelength of light output from the optical amplifier; and a refractive index adjustment circuit controlling a current applied to the equivalent resonator length adjustor based on a result of measurement performed by the wavelength spectrum measuring device to adjust a refractive index of the equivalent resonator length adjustor. Parasitic oscillation light in a plurality of Fabry-Perot modes is generated as the butt joint interface is one of reflection ends.
    Type: Grant
    Filed: October 20, 2016
    Date of Patent: July 4, 2017
    Assignee: Mitsubishi Electric Corporation
    Inventor: Kazuhisa Takagi
  • Publication number: 20160325278
    Abstract: A three-dimensional microchemical chip having flow-path-supporting substrate sheets flow-path-retaining substrate sheets which is stacked to the flow-path-supporting substrate sheets and join and integrate therewith by a direct covalent bond or an indirect covalent bond via molecular adhesive, flow paths defined by recessing and/or piercing the flow-path-supporting substrate sheets and sterically and sequentially, in which a fluid sample is subjected to a chemical reaction and/or chemical action, a receiving hole which is pierced in the flow-path-retaining substrate sheet and is connected to the flow paths; the flow paths are sequentially and sterically connected from fluid-sample-injecting holes to fluid-sample-draining holes.
    Type: Application
    Filed: December 19, 2014
    Publication date: November 10, 2016
    Applicant: ASAHI FR R&D CO., LTD.
    Inventors: Kazuhisa TAKAGI, Tsutomu TAKANO, Yuya UBUKATA
  • Publication number: 20160184789
    Abstract: A simple and compact microchemical chip has a fine flow path formed therein through which a specimen is made to flow; is break resistance; makes it possible to flow the fluid sample to the flow path; makes it possible to analyze a useful substance and cause it to react; and can be produced with a high yield. A microchemical chip includes: a rubber sheet having a penetrated flow path which chemically reacts a pressurized fluid sample selected from a specimen and a reagent by flowing thereinto; substrate sheets which sandwich the rubber sheet and bond to both faces thereof by direct bond or by chemical bond through a silane-coupling agent and are selected from metal, ceramics, glass, and resin; and a hole for injecting the fluid sample into the flow path and a hole for draining the fluid sample flowed therefrom which are opened into the substrate sheet.
    Type: Application
    Filed: August 23, 2013
    Publication date: June 30, 2016
    Applicant: ASAHI FR R&D CO., LTD.
    Inventors: Kazuhisa TAKAGI, Tsutomu TAKANO
  • Patent number: 9147997
    Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; an optical amplifying section amplifying output light of the wave coupling section; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a light intensity lowering section located in each of the first optical waveguides and lower light intensity of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the respective semiconductor lasers; to decrease line width of the light output by the semiconductor lasers.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: September 29, 2015
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
  • Publication number: 20150229407
    Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; an optical amplifying section amplifying output light of the wave coupling section; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a light intensity lowering section located in each of the first optical waveguides and lower light intensity of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the respective semiconductor lasers; to decrease line width of the light output by the semiconductor lasers.
    Type: Application
    Filed: April 23, 2015
    Publication date: August 13, 2015
    Inventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
  • Publication number: 20150171592
    Abstract: An integrated optical modulator and laser device includes a laser section, a modulator section for modulating the intensity of a laser beam produced by the laser section, and a separation section located between the laser section and the modulator section. The laser section includes a first anode electrode and a first cathode electrode. The modulator section includes a second anode electrode and a second cathode electrode. A lower cladding layer is integral to the laser section, the modulator section, and the separation section and the width of the lower cladding layer is narrowest in the separation section.
    Type: Application
    Filed: February 24, 2015
    Publication date: June 18, 2015
    Inventors: Takeshi Yamatoya, Kazuhisa Takagi
  • Patent number: 9042008
    Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a phase regulator regulating phase of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the semiconductor lasers; a second optical waveguide optically connecting the wave coupling section to the phase regulator; an optical amplifying section amplifying output light of the phase regulator; and a third optical waveguide optically connecting an output of the phase regulator to the optical amplifying section. The phase regulator adjusts the phase of reflected light that returns to the semiconductor lasers to decrease line width of the light output by the semiconductor lasers.
    Type: Grant
    Filed: March 14, 2014
    Date of Patent: May 26, 2015
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
  • Publication number: 20140198378
    Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a phase regulator regulating phase of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the semiconductor lasers; a second optical waveguide optically connecting the wave coupling section to the phase regulator; an optical amplifying section amplifying output light of the phase regulator; and a third optical waveguide optically connecting an output of the phase regulator to the optical amplifying section. The phase regulator adjusts the phase of reflected light that returns to the semiconductor lasers to decrease line width of the light output by the semiconductor lasers.
    Type: Application
    Filed: March 14, 2014
    Publication date: July 17, 2014
    Applicant: Mitsubishi Electric Corporation
    Inventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
  • Patent number: 8780949
    Abstract: An optical semiconductor device includes: a semiconductor substrate; a semiconductor laser part on the semiconductor substrate and having a vertical ridge; and an optical modulator part on the semiconductor substrate, having an inverted-mesa ridge, and modulating light emitted by the semiconductor laser part.
    Type: Grant
    Filed: February 28, 2013
    Date of Patent: July 15, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventor: Kazuhisa Takagi
  • Patent number: 8724933
    Abstract: An optical device includes: a substrate; an optical branching filter on the substrate and dividing input light into first and second input lights; first and second Mach-Zehnder optical modulators on the substrate and respectively modulating the first and second input lights; and an optical coupler on the substrate and combining light modulated by the first Mach-Zehnder optical modulator and light modulated by the second Mach-Zehnder optical modulator. Each of the first and second Mach-Zehnder optical modulator includes two optical waveguides, a phase modulation electrode applying a modulation voltage across the optical waveguides to change phases of light in the optical waveguides, and a feed line and a terminal line respectively connected to opposite ends of the phase modulation electrode to supply the modulation voltage to the phase modulation electrode. The feed lines and the terminal lines respectively extend to peripheral portions of the substrate.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: May 13, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventor: Kazuhisa Takagi
  • Patent number: 8715533
    Abstract: There are provided a high-permittivity dielectric raw material, an antenna device using the raw material and being useful as, especially, the built-in antenna device of a portable phone; a portable phone which can be reduced in weight, thickness and size, with an antenna radiation efficiency improved, and an electromagnetic wave shielding body for effectively shielding electromagnetic wave from an electric cooker. A dielectric raw material A having carbons dispersed in a silicone rubber base material 1, wherein, in any one of dielectric raw materials A, 1) containing 150 to 300 pts.wt. of carbons per 100 pts.wt.
    Type: Grant
    Filed: December 13, 2005
    Date of Patent: May 6, 2014
    Assignee: Asahi R&D Co., Ltd.
    Inventors: Kazuhisa Takagi, Yuko Takami, Yuji Koyamashita
  • Publication number: 20140112610
    Abstract: A semiconductor optical modulator includes a substrate, which has a first conductivity type, and a first electrode on a first main surface of the substrate. A first cladding layer having the first conductivity type, a transparent waveguide layer, a second cladding layer having the first conductivity type, an optical-absorption layer, and a third cladding layer having a second conductivity type, are sequentially laminated on a second main surface of the substrate. A ridge part is formed by removing a part of the third cladding layer and a part of the second cladding layer in a laminated direction. A second electrode on the ridge part is electrically connected to the third cladding layer.
    Type: Application
    Filed: May 30, 2013
    Publication date: April 24, 2014
    Inventor: Kazuhisa Takagi
  • Patent number: 8655116
    Abstract: An optical modulator includes: a semiconductor chip; a waveguide in the semiconductor chip; a traveling wave electrode including an input portion and an output portion, to which a signal is applied for modulating light passing through the waveguide; a power supply line connected to the input portion via a first wire; and a termination resistor connected to the output portion via a second wire. Capacitance between the output portion and a grounding point is larger than capacitance between the input portion and the grounding point.
    Type: Grant
    Filed: June 9, 2011
    Date of Patent: February 18, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Eitaro Ishimura, Kazuhisa Takagi, Keisuke Matsumoto, Takeshi Saito