Patents by Inventor Shigeru Nakagawa

Shigeru Nakagawa 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).

  • Publication number: 20150104129
    Abstract: An optical module includes: at least one optical waveguide provided on a surface of a substrate; a plurality of grooves provided in the optical waveguide on the surface of the substrate and having both a surface orthogonal to the surface of the substrate and an inclined surface; multiple pairs of light-emitting and light-receiving elements aligned with the plurality of grooves in the optical waveguide and provided so as to correspond to light of different wavelengths on the optical waveguide; and a plurality of light-selecting filters each provided on an inclined surface of the plurality of grooves in the optical waveguide and reflecting light of the wavelength corresponding to the light-emitting element in the respective pair of light-emitting and light-receiving elements towards the optical waveguide, and selectively reflecting light of the corresponding wavelength from the light propagating through the optical waveguide towards the corresponding pair of light-emitting and light-receiving elements.
    Type: Application
    Filed: September 11, 2014
    Publication date: April 16, 2015
    Inventors: Shigeru Nakagawa, Yoichi Taira, Masao Tokunari
  • Publication number: 20140147083
    Abstract: Methods for fabricating connectors for multilayered optical waveguides, as well as apparatuses for multilayered optical waveguides that embody ferrules and connectors. The method of fabricating a connector includes the steps of: stacking in a containing unit of a ferrule, a plurality of optical waveguides that are each preliminarily formed in the shape of layers; and injecting resin or adhesive through a space lying between the plurality of optical waveguides and the containing unit of the ferrule, with the plurality of optical waveguides contained in a stacked manner so that resin or adhesive reaches each of the plurality of optical waveguides.
    Type: Application
    Filed: October 10, 2013
    Publication date: May 29, 2014
    Inventors: Shigeru Nakagawa, Hidetoshi Numata
  • Publication number: 20140069382
    Abstract: A spark-ignition direct injection engine is provided. The engine includes an engine body, a fuel injection valve, a fuel pressure setting mechanism, an ignition plug, and a controller. The controller switches between a compression-ignition mode where the engine body is operated to perform compression-ignition combustion and a spark-ignition mode where the engine body is operated to perform spark-ignition combustion. Immediately after switching from the spark-ignition mode to the compression-ignition mode, the controller operates the engine body in a compression-ignition initial mode where the fuel pressure is set to be 30 MPa or above and the fuel injection valve is controlled to perform the fuel injection in a period from a late stage of the compression stroke to an early stage of the expansion stroke so that the gas mixture self-ignites to combust.
    Type: Application
    Filed: August 21, 2013
    Publication date: March 13, 2014
    Applicant: Mazda Motor Corporation
    Inventors: Kouhei Iwai, Masahisa Yamakawa, Junichi Taga, Shigeru Nakagawa, Saori Mizuno, Keiji Araki
  • Patent number: 8542963
    Abstract: An optical coupling structure that interfaces between optical devices mounted on a substrate and optical waveguides formed in the substrate. A manufacturing method includes preparing a wafer formed on an inorganic solid material on a dicing tape and cutting the back surface of the wafer to form substantially angled portions using a dicing blade having a point angle. The dicing tape is stripped from the wafer and the wafer is separated at the valleys between the substantially angled portions to obtain an optical coupling element. The obtained optical coupling element is a three-dimensional polyhedral light-reflecting member having a mirror surface corresponding to a surface of the wafer. The obtained optical coupling element is inserted into a trench that opens, substantially perpendicular to an optical waveguide of an optical transmission substrate, in the main surface of the optical transmission substrate to provide a structure for optical coupling with the outside.
    Type: Grant
    Filed: April 29, 2010
    Date of Patent: September 24, 2013
    Assignee: International Business Machines Corporation
    Inventors: Shigeru Nakagawa, Hidetoshi Numata, Kuniaki Sueoka, Yoichi Taira
  • Patent number: 8442362
    Abstract: An optical coupling structure that interfaces between optical devices mounted on a substrate and optical waveguides formed in the substrate. A manufacturing method includes preparing a wafer formed on an inorganic solid material on a dicing tape and cutting the back surface of the wafer to form substantially angled portions using a dicing blade having a point angle. The dicing tape is stripped from the wafer and the wafer is separated at the valleys between the substantially angled portions to obtain an optical coupling element. The obtained optical coupling element is a three-dimensional polyhedral light-reflecting member having a mirror surface corresponding to a surface of the wafer. The obtained optical coupling element is inserted into a trench that opens, substantially perpendicular to an optical waveguide of an optical transmission substrate, in the main surface of the optical transmission substrate to provide a structure for optical coupling with the outside.
    Type: Grant
    Filed: June 26, 2012
    Date of Patent: May 14, 2013
    Assignee: International Business Machines Corporation
    Inventors: Shigeru Nakagawa, Hidetoshi Numata, Kuniaki Sueoka, Yoichi Taira
  • Publication number: 20120267338
    Abstract: An optical coupling structure that interfaces between optical devices mounted on a substrate and optical waveguides formed in the substrate. A manufacturing method includes preparing a wafer formed on an inorganic solid material on a dicing tape and cutting the back surface of the wafer to form substantially angled portions using a dicing blade having a point angle. The dicing tape is stripped from the wafer and the wafer is separated at the valleys between the substantially angled portions to obtain an optical coupling element. The obtained optical coupling element is a three-dimensional polyhedral light-reflecting member having a mirror surface corresponding to a surface of the wafer. The obtained optical coupling element is inserted into a trench that opens, substantially perpendicular to an optical waveguide of an optical transmission substrate, in the main surface of the optical transmission substrate to provide a structure for optical coupling with the outside.
    Type: Application
    Filed: June 26, 2012
    Publication date: October 25, 2012
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Shigeru Nakagawa, Hidetoshi Numata, Kuniaki Sueoka, Yoichi Taira
  • Patent number: 7923275
    Abstract: A surface emitting laser includes a lower Bragg reflector, a resonator and an upper Bragg reflector. The resonator is provided on top of the lower Bragg reflector and includes an active layer, a lower semiconductor layer and an upper semiconductor layer. The upper Bragg reflector is provided on top of the resonator, and includes a plurality of semiconductor layers. In this surface emitting laser, the uppermost layer among the plurality of semiconductor layers in the lower Bragg reflector forms an air gap, which is larger than the aperture of the first insulating layer, while the lowermost layer among the plurality of semiconductor layers in the upper Bragg reflector forms an air gap, which is larger than the aperture of the second insulating layer.
    Type: Grant
    Filed: August 20, 2009
    Date of Patent: April 12, 2011
    Assignee: International Business Machines Corporation
    Inventor: Shigeru Nakagawa
  • Patent number: 7911686
    Abstract: An optical module, which is arranged in an optical transmission path, includes an optical amplifying unit configured with a semiconductor, wherein the optical amplifying unit amplifies light input from the optical transmission path, and an optical element configured with a semiconductor, wherein the optical element propagates the light amplified by the optical amplifying unit to the optical transmission path.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: March 22, 2011
    Assignee: FiBest, Ltd.
    Inventors: Shigeru Nakagawa, Haruhisa Soda
  • Publication number: 20100278485
    Abstract: An optical coupling structure that interfaces between optical devices mounted on a substrate and optical waveguides formed in the substrate. A manufacturing method includes preparing a wafer formed on an inorganic solid material on a dicing tape and cutting the back surface of the wafer to form substantially angled portions using a dicing blade having a point angle. The dicing tape is stripped from the wafer and the wafer is separated at the valleys between the substantially angled portions to obtain an optical coupling element. The obtained optical coupling element is a three-dimensional polyhedral light-reflecting member having a mirror surface corresponding to a surface of the wafer. The obtained optical coupling element is inserted into a trench that opens, substantially perpendicular to an optical waveguide of an optical transmission substrate, in the main surface of the optical transmission substrate to provide a structure for optical coupling with the outside.
    Type: Application
    Filed: April 29, 2010
    Publication date: November 4, 2010
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Shigeru Nakagawa, Hidetoshi Numata, Kuniaki Sueoka, Yoichi Taira
  • Publication number: 20090311812
    Abstract: A surface emitting laser includes a lower Bragg reflector, a resonator and an upper Bragg reflector. The resonator is provided on top of the lower Bragg reflector and includes an active layer, a lower semiconductor layer and an upper semiconductor layer. The upper Bragg reflector is provided on top of the resonator, and includes a plurality of semiconductor layers. In this surface emitting laser, the uppermost layer among the plurality of semiconductor layers in the lower Bragg reflector forms an air gap, which is larger than the aperture of the first insulating layer, while the lowermost layer among the plurality of semiconductor layers in the upper Bragg reflector forms an air gap, which is larger than the aperture of the second insulating layer.
    Type: Application
    Filed: August 20, 2009
    Publication date: December 17, 2009
    Applicant: International Business Machines Corporation
    Inventor: Shigeru Nakagawa
  • Patent number: 7501294
    Abstract: A method of manufacturing a coherent light generator, especially a vertical cavity surface emitting laser (VCSEL), includes a gallium based semiconductor alloy substrate, a first DBR stack over the substrate, a first n-type clad layer over the first DBR stack, an active region containing quantum wells over the first n-type clad, a tunnel junction having an n-type and a p-type material and a boundary over the active region so that there is a standing wave null at an operating wavelength at the n-type/p-type boundary in the tunnel junction, a second n-type clad layer over the tunnel junction, an oxide aperture at least partially installed in the second n-type clad layer, and the second DBR stack over the second n-type clad of the coherent light generator. The novel VCSEL provides minimized internal optical absorption and has a low electrical resistance.
    Type: Grant
    Filed: February 18, 2008
    Date of Patent: March 10, 2009
    Assignee: International Business Machines Corporation
    Inventor: Shigeru Nakagawa
  • Publication number: 20080151959
    Abstract: A surface emitting laser includes a lower Bragg reflector, a resonator and an upper Bragg reflector. The resonator is provided on top of the lower Bragg reflector and includes an active layer, a lower semiconductor layer and an upper semiconductor layer. The upper Bragg reflector is provided on top of the resonator, and includes a plurality of semiconductor layers. In this surface emitting laser, the uppermost layer among the plurality of semiconductor layers in the lower Bragg reflector forms an air gap, which is larger than the aperture of the first insulating layer, while the lowermost layer among the plurality of semiconductor layers in the upper Bragg reflector forms an air gap, which is larger than the aperture of the second insulating layer.
    Type: Application
    Filed: December 20, 2007
    Publication date: June 26, 2008
    Applicant: International Business Machines Corporation
    Inventor: Shigeru Nakagawa
  • Patent number: 7262436
    Abstract: A light emitting device includes an n-type semiconductor layer, an active layer for generating light, the active layer being in electrical contact with the n-type semiconductor layer. A p-type semiconductor layer is in electrical contact with the active layer, and a p-electrode is in electrical contact with the p-type semiconductor layer. The p-electrode includes a layer of silver. In a preferred embodiment of the present invention, the n-type semiconductor layer and the p-type semiconductor layer are constructed from group III nitride semiconducting materials. In one embodiment of the invention, the silver layer is sufficiently thin to be transparent. In other embodiments, the silver layer is thick enough to reflect most of the light incident thereon. A fixation layer may be provided. The fixation layer may be a dielectric or a conductor.
    Type: Grant
    Filed: April 11, 2005
    Date of Patent: August 28, 2007
    Assignee: Philips Lumileds Lighting Company, LLC
    Inventors: You Kondoh, Satoshi Watanabe, Yawara Kaneko, Shigeru Nakagawa, Norihide Yamada
  • Patent number: 6973238
    Abstract: A directional coupler type optical modulator with traveling-wave electrodes includes a first directional coupler region, a waveguide wave coupling region, a second directional coupler region, and a set of noncrossing traveling-wave electrodes disposed along the outside of the waveguides. The electrodes of each directional coupler are connected to the traveling-wave electrodes via air-bridges. The waveguide structures are of the P-I-N type having a common N-type conducting layer which provides delta-beta operation of the directional coupler, and both cross and bar states are controlled by a single input signal.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: December 6, 2005
    Assignee: Fibest, Ltd.
    Inventors: Haruhisa Soda, Shigeru Nakagawa
  • Publication number: 20050179051
    Abstract: A light emitting device includes an n-type semiconductor layer, an active layer for generating light, the active layer being in electrical contact with the n-type semiconductor layer. A p-type semiconductor layer is in electrical contact with the active layer, and a p-electrode is in electrical contact with the p-type semiconductor layer. The p-electrode includes a layer of silver. In a preferred embodiment of the present invention, the n-type semiconductor layer and the p-type semiconductor layer are constructed from group III nitride semiconducting materials. In one embodiment of the invention, the silver layer is sufficiently thin to be transparent. In other embodiments, the silver layer is thick enough to reflect most of the light incident thereon. A fixation layer may be provided. The fixation layer may be a dielectric or a conductor.
    Type: Application
    Filed: April 11, 2005
    Publication date: August 18, 2005
    Inventors: You Kondoh, Satoshi Watanabe, Yawara Kaneko, Shigeru Nakagawa, Norihide Yamada
  • Patent number: 6900472
    Abstract: A light emitting device is constructed on a substrate. The device includes an n-type semiconductor layer in contact with the substrate, an active layer for generating light, the active layer being in electrical contact with the n-type semiconductor layer. A p-type semiconductor layer is in electrical contact with the active layer, and a p-electrode is in electrical contact with the p-type semiconductor layer. The p-electrode includes a layer of silver in contact with the p-type semiconductor layer. A bonding layer is formed overlying the silver layer to make an electrical connection to the silver layer. The silver layer may be thin and transparent or thicker (greater than 20 nm) and reflective.
    Type: Grant
    Filed: January 16, 2001
    Date of Patent: May 31, 2005
    Assignee: Lumileds Lighting U.S., LLC
    Inventors: You Kondoh, Satoshi Watanabe, Yawara Kaneko, Shigeru Nakagawa, Norihide Yamada
  • Publication number: 20050052726
    Abstract: An optical module, which is arranged in an optical transmission path, includes an optical amplifying unit configured with a semiconductor, wherein the optical amplifying unit amplifies light input from the optical transmission path, and an optical element configured with a semiconductor, wherein the optical element propagates the light amplified by the optical amplifying unit to the optical transmission path.
    Type: Application
    Filed: November 13, 2003
    Publication date: March 10, 2005
    Applicant: FiBest, Ltd.
    Inventors: Shigeru Nakagawa, Haruhisa Soda
  • Patent number: 6841407
    Abstract: A method for aperturing a vertical-cavity surface-emitting laser (VCSEL), for increasing the external quantum efficiency and decreasing the threshold current, involves an etching mixture that is applied to the active region of the VCSEL. The etching mixture is designed in a manner to selectively etch the active region of the VCSEL at a rate substantially faster than the etch rate of at least one of the multiple DBRS associated with the VCSEL.
    Type: Grant
    Filed: August 21, 2001
    Date of Patent: January 11, 2005
    Assignee: The Regents of the University of California
    Inventors: Larry A. Coldren, Eric M. Hall, Shigeru Nakagawa, Guilhem Almuneau
  • Patent number: 6810064
    Abstract: A system and a method for reducing the temperature in a vertical-cavity surface-emitting laser (VCSEL) comprising of including at least one heat spreading layer adjecent to one of the reflecting surfaces in a VCSEL. The heat spreading layer has high thermal conductivity allowing heat to bypass said one of the reflecting surfaces, thereby efficiently removing the heat away from the device. This also reduces the serial resistance and the thermal impedance of the VCSEL.
    Type: Grant
    Filed: August 21, 2001
    Date of Patent: October 26, 2004
    Assignee: The Regents of the University of California
    Inventors: Larry A. Coldren, Eric M. Hall, Shigeru Nakagawa
  • Publication number: 20040081389
    Abstract: A directional coupler type optical modulator with traveling-wave electrodes includes a first directional coupler region, a waveguide wave coupling region, a second directional coupler region, and a set of noncrossing traveling-wave electrodes disposed along the outside of the waveguides. The electrodes of each directional coupler are connected to the traveling-wave electrodes via air-bridges. The waveguide structures are of the P-I-N type having a common N-type conducting layer which provides delta-beta operation of the directional coupler, and both cross and bar states are controlled by a single input signal.
    Type: Application
    Filed: September 5, 2003
    Publication date: April 29, 2004
    Applicant: FiBest. Ltd.
    Inventors: Haruhisa Soda, Shigeru Nakagawa