Patents by Inventor Kazutaka Takeda

Kazutaka Takeda 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: 20160099549
    Abstract: A surface-emitting semiconductor laser device includes a substrate and a semiconductor layer disposed on the substrate. The semiconductor layer includes a first semiconductor multilayer film of a first conductivity type, a first spacer layer, an active layer, a second spacer layer, and a second semiconductor multilayer film of a second conductivity type. The first semiconductor multilayer film and the second semiconductor multilayer film form a cavity. A peak of a pattern of a standing wave formed by the cavity and the center of the active layer are located at different positions.
    Type: Application
    Filed: August 17, 2015
    Publication date: April 7, 2016
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Naoki JOGAN, Jun SAKURAI, Akemi MURAKAMI, Takashi KONDO, Kazutaka TAKEDA, Junichiro HAYAKAWA
  • Publication number: 20160064900
    Abstract: A surface-emitting semiconductor laser includes a first semiconductor multilayer film reflector, an active region, a second semiconductor multilayer film reflector, and a current confinement layer including an oxidized region formed by selective oxidation. The current confinement layer includes a first semiconductor layer having a relatively high Al content, a second semiconductor layer that is adjacent to the first semiconductor layer on an active-region side of the first semiconductor layer and has a lower Al content than the first semiconductor layer, and a composition-gradient layer adjacent to the first semiconductor layer on a side of the first semiconductor layer which is opposite to the active-region side. A portion of the composition-gradient layer which faces the first semiconductor layer has a lower Al content than the first semiconductor layer.
    Type: Application
    Filed: July 28, 2015
    Publication date: March 3, 2016
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka TAKEDA, Junichiro HAYAKAWA, Akemi MURAKAMI, Naoki JOGAN, Takashi KONDO, Jun SAKURAI
  • Publication number: 20160064899
    Abstract: Provided is a surface-emitting semiconductor laser including a substrate; a first semiconductor multilayer reflector of a first conductivity type formed on the substrate, the first semiconductor multilayer reflector including plural pairs of a low-refractive-index layer and a high-refractive-index layer; a cavity region formed on the first semiconductor multilayer reflector; a second semiconductor multilayer reflector of a second conductivity type formed on the cavity region, the second semiconductor multilayer reflector including plural pairs of a low-refractive-index layer and a high-refractive-index layer; a columnar structure extending from the second semiconductor multilayer reflector to the cavity region; and a current confinement layer formed inside the columnar structure by selective oxidation of a semiconductor layer containing Al. The cavity region includes an active region; and a cavity extension region interposed between the active region and the first semiconductor multilayer reflector.
    Type: Application
    Filed: July 10, 2015
    Publication date: March 3, 2016
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Junichiro HAYAKAWA, Akemi MURAKAMI, Takashi KONDO, Kazutaka TAKEDA, Naoki JOGAN, Jun SAKURAI
  • Patent number: 9252562
    Abstract: A surface emitting semiconductor laser includes a substrate, a first conductivity-type first semiconductor multilayer reflector, an active layer, a semiconductor layer, a second conductivity-type second semiconductor multilayer reflector that includes a current confinement layer, and a heat dissipating metal member. At least the first semiconductor multilayer reflector, the active layer, the semiconductor layer, and the second semiconductor multilayer reflector are stacked in this order on the substrate. A columnar structure having a top portion, a side surface, and a bottom portion is formed from the second semiconductor multilayer reflector to the semiconductor layer. The heat dissipating metal member is connected to the semiconductor layer exposed at the bottom portion of the columnar structure.
    Type: Grant
    Filed: May 12, 2014
    Date of Patent: February 2, 2016
    Assignee: FUJI XEROX CO., LTD.
    Inventors: Junichiro Hayakawa, Kazutaka Takeda, Akemi Murakami
  • Publication number: 20160006214
    Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector on the substrate including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; an active region on or above the first reflector; a second semiconductor multilayer reflector on or above the active region including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; and a cavity extending region formed between the first reflector and the active region or between the second reflector and the active region, having an optical film thickness greater than an oscillation wavelength, extending a cavity length, including a conductive semiconductor material, and including an optical loss causing layer at at least one node of a standing wave of a selected longitudinal mode.
    Type: Application
    Filed: September 15, 2015
    Publication date: January 7, 2016
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka TAKEDA, Takashi KONDO
  • Patent number: 9219349
    Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector on the substrate including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; an active region on or above the first reflector; a second semiconductor multilayer reflector on or above the active region including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; and a cavity extending region formed between the first reflector and the active region or between the second reflector and the active region, having an optical film thickness greater than an oscillation wavelength, extending a cavity length, including a conductive semiconductor material, and including an optical loss causing layer at at least one node of a standing wave of a selected longitudinal mode.
    Type: Grant
    Filed: May 6, 2013
    Date of Patent: December 22, 2015
    Assignee: FUJI XEROX CO., LTD.
    Inventors: Kazutaka Takeda, Takashi Kondo
  • Patent number: 9166370
    Abstract: A vertical cavity surface emitting laser includes a first semiconductor multilayer reflector, a resonator, and a second semiconductor multilayer reflector. The first semiconductor multilayer reflector is formed on a substrate and is configured by stacking a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively low refractive index. The resonator includes an active layer formed on the first semiconductor multilayer reflector. The second semiconductor multilayer reflector is configured by stacking the high refractive index layer and the low refractive index layer. The resonator includes a pair of spacer layers disposed vertically on the active layer and a resonator extension area formed at one side of the pair of spacer layers. The resonator extension area contains a material in which an energy level with a crystal defect is higher than a general energy level without the crystal defect.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: October 20, 2015
    Assignees: FUJI XEROX CO., LTD., TOKYO INSTITUTE OF TECHNOLOGY
    Inventors: Takashi Kondo, Hideo Nakayama, Kazutaka Takeda, Fumio Koyama
  • Patent number: 9059362
    Abstract: A light emitting element includes a semiconductor substrate, and an island structure formed on the semiconductor substrate. The island structure includes a light-emitting-unit thyristor and a current confinement structure. The light-emitting-unit thyristor includes stacked semiconductor layers having a pnpn structure. The current confinement structure includes a high-resistance region and a conductive region, and confines carriers in the conductive region.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: June 16, 2015
    Assignee: FUJI XEROX CO., LTD.
    Inventors: Taku Kinoshita, Takashi Kondo, Kazutaka Takeda, Hideo Nakayama
  • Publication number: 20150099317
    Abstract: A surface emitting semiconductor laser includes a substrate, a first conductivity-type first semiconductor multilayer reflector, an active layer, a semiconductor layer, a second conductivity-type second semiconductor multilayer reflector that includes a current confinement layer, and a heat dissipating metal member. At least the first semiconductor multilayer reflector, the active layer, the semiconductor layer, and the second semiconductor multilayer reflector are stacked in this order on the substrate. A columnar structure having a top portion, a side surface, and a bottom portion is formed from the second semiconductor multilayer reflector to the semiconductor layer. The heat dissipating metal member is connected to the semiconductor layer exposed at the bottom portion of the columnar structure.
    Type: Application
    Filed: May 12, 2014
    Publication date: April 9, 2015
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Junichiro HAYAKAWA, Kazutaka TAKEDA, Akemi MURAKAMI
  • Publication number: 20150043605
    Abstract: A vertical-cavity surface-emitting laser diode includes: a first resonator that has a plurality of semiconductor layers comprising a first current narrowing structure having a first conductive region and a first non-conductor region; a first electrode that supplies electric power to drive the first resonator; a second resonator that has a plurality of semiconductor layers comprising a second current narrowing structure having a second conductive region and a second non-conductive region and that is formed side by side with the first resonator, the second current narrowing structure being formed in same current narrowing layer as the layer where the first current narrowing structure is formed; and a coupling portion as defined herein; and an equivalent refractive index of the coupling portion is smaller than an equivalent refractive index of each of the first resonator and the second resonator.
    Type: Application
    Filed: August 5, 2014
    Publication date: February 12, 2015
    Applicants: FUJI XEROX CO., LTD., TOKYO INSTITUTE OF TECHNOLOGY
    Inventors: Fumio KOYAMA, Hamed DALIR, Takashi KONDO, Naoki JOGAN, Kazutaka TAKEDA, Hideo NAKAYAMA
  • Patent number: 8842709
    Abstract: A surface emitting semiconductor laser includes a first semiconductor multilayer reflector of a first conductivity type, an active area, a second semiconductor multilayer reflector of a second conductivity type, a current confinement layer having a conductive area and a surrounding high-resistance area, each provided on a substrate, and a higher-order transverse mode suppressing layer formed on an emission surface from which laser light is emitted and in an area in which higher-order transverse mode is induced. The higher-order transverse mode suppressing layer includes first to third insulation films having first to third refractive indices, respectively, formed on each other, and capable of transmitting an oscillation wavelength. The second refractive index is lower than the first refractive index. The third refractive index is higher than the second refractive index. The optical film thickness of the first to third insulation films is an odd number times one-fourth of the oscillation wavelength.
    Type: Grant
    Filed: June 5, 2013
    Date of Patent: September 23, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazutaka Takeda, Takashi Kondo
  • Patent number: 8824520
    Abstract: A laser includes: a substrate; a first reflector including pairs of high and low refractive index layers; an active region forming a resonator; a second reflector including an emission surface and pairs of high and low refractive index layers; an extending region thicker than oscillation wavelength, extending the length of the resonator, and including a conductive semiconductor material; a confining layer including a high refractive index region and a surrounding low refractive index region; and an additional film allowing the oscillation wavelength to transmit therethrough. The first and second reflectors, the extending region, and the active region determine a reflection band including resonance wavelengths, in one of which oscillation occurs. The additional film includes central and outer circumferential portions having different thicknesses to suppress resonance in the high refractive index region and the extending region.
    Type: Grant
    Filed: May 21, 2013
    Date of Patent: September 2, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takashi Kondo, Kazutaka Takeda
  • Patent number: 8759859
    Abstract: Disclosed is a light-emitting element including a semiconductor substrate, an island structure formed on the semiconductor substrate and including at least a current confining layer and p-type and n-type semiconductor layers, a light-emitting thyristor formed in the island structure and having a pnpn structure, and a shift thyristor formed in the island structure and having a pnpn structure, wherein a groove portion having a depth such that the groove portion reaches at least the current confining layer is formed between a formation region of the shift thyristor of the island structure and a formation region of the light-emitting thyristor, and an oxidized region that is selectively oxidized from a side surface of the island structure and a side surface of the groove portion is formed in the current confining layer.
    Type: Grant
    Filed: July 31, 2012
    Date of Patent: June 24, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Taku Kinoshita, Kazutaka Takeda, Takashi Kondo, Hideo Nakayama
  • Patent number: 8731012
    Abstract: A surface emitting semiconductor laser includes a substrate; a first semiconductor distributed bragg reflector of a first conductive type; an active region; a second semiconductor distributed bragg reflector of a second conductive type; a current confinement layer that confines current in the active region; an optical confinement layer that confines light in the active region; and an optical loss unit including center and periphery portions in a predetermined direction, and gives a larger optical loss to the periphery portion than that of the center portion. Also, Do1<Do2 and Dn<Do2 are satisfied, where Do1 is a width of an optical confinement region of the optical confinement layer in the predetermined direction, Do2 is a width of a current confinement region of the current confinement layer in the predetermined direction, and Dn is a width of the center portion of the optical loss unit in the predetermined direction.
    Type: Grant
    Filed: October 17, 2012
    Date of Patent: May 20, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takashi Kondo, Kazutaka Takeda
  • Publication number: 20140112364
    Abstract: A laser includes: a substrate; a first reflector including pairs of high and low refractive index layers; an active region forming a resonator; a second reflector including an emission surface and pairs of high and low refractive index layers; an extending region thicker than oscillation wavelength, extending the length of the resonator, and including a conductive semiconductor material; a confining layer including a high refractive index region and a surrounding low refractive index region; and an additional film allowing the oscillation wavelength to transmit therethrough. The first and second reflectors, the extending region, and the active region determine a reflection band including resonance wavelengths, in one of which oscillation occurs. The additional film includes central and outer circumferential portions having different thicknesses to suppress resonance in the high refractive index region and the extending region.
    Type: Application
    Filed: May 21, 2013
    Publication date: April 24, 2014
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Kazutaka TAKEDA
  • Patent number: 8692264
    Abstract: Provided is a light-emitting element including a semiconductor substrate, an island structure formed on the semiconductor substrate and including at least a current confining layer and p-type and n-type semiconductor layers, a light-emitting thyristor formed in the island structure and having a pnpn structure, and a shift thyristor formed in the island structure and having a pnpn structure, wherein the island structure includes a first side surface having a first depth such that the first side surface does not reach the current confining layer in a formation region of the shift thyristor and a second side surface having a second depth such that the second side surface reaches at least the current confining layer in a formation region of the light-emitting thyristor, and an oxidized region selectively oxidized from the second side surface is formed in the current confining layer in the formation region of the light-emitting thyristor.
    Type: Grant
    Filed: August 1, 2012
    Date of Patent: April 8, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Taku Kinoshita, Michiaki Murata, Takashi Kondo, Kazutaka Takeda, Hideo Nakayama
  • Patent number: 8659035
    Abstract: Provided is a light-emitting device including a semiconductor substrate of a first conductivity type, a semiconductor multilayer reflection mirror of the first conductivity type, formed on the semiconductor substrate, a first semiconductor layer of the first conductivity type, formed on the semiconductor multilayer reflection mirror, a second semiconductor layer of a second conductivity type, formed on the first semiconductor layer, a third semiconductor layer of the first conductivity type, formed on the second semiconductor layer, a fourth semiconductor layer of the second conductivity type, formed on the third semiconductor layer, a first electrode formed on a rear surface of the semiconductor substrate, and a second electrode formed on the fourth semiconductor layer, wherein the semiconductor multilayer reflection mirror includes a first selectively oxidized region and a first conductive region adjacent to the first oxidized region, and the first conductive region electrically connects the semiconductor s
    Type: Grant
    Filed: May 21, 2012
    Date of Patent: February 25, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takashi Kondo, Taku Kinoshita, Kazutaka Takeda
  • Publication number: 20140044438
    Abstract: A surface emitting semiconductor laser includes a first semiconductor multilayer reflector of a first conductivity type, an active area, a second semiconductor multilayer reflector of a second conductivity type, a current confinement layer having a conductive area and a surrounding high-resistance area, each provided on a substrate, and a higher-order transverse mode suppressing layer formed on an emission surface from which laser light is emitted and in an area in which higher-order transverse mode is induced. The higher-order transverse mode suppressing layer includes first to third insulation films having first to third refractive indices, respectively, formed on each other, and capable of transmitting an oscillation wavelength. The second refractive index is lower than the first refractive index. The third refractive index is higher than the second refractive index. The optical film thickness of the first to third insulation films is an odd number times one-fourth of the oscillation wavelength.
    Type: Application
    Filed: June 5, 2013
    Publication date: February 13, 2014
    Inventors: Kazutaka Takeda, Takashi Kondo
  • Publication number: 20140022326
    Abstract: A surface-emitting semiconductor laser includes a substrate, a first n-type semiconductor multi-layer reflecting mirror that is formed on the substrate and includes a pair of a high refractive index layer with a relatively high refractive index and a low refractive index layer with a low refractive index which are laminated, an n-type semiconductor layer that is formed on the first semiconductor multi-layer reflecting mirror, has an optical film thickness greater than an oscillation wavelength, and includes Al and Ga, an active region formed on the semiconductor layer, and a second p-type semiconductor multi-layer reflecting mirror that is formed on the active region and includes a pair of a high refractive index layer with a relatively high refractive index and a low refractive index layer with a low refractive index which are laminated, wherein an n-type impurity dopant injected into the semiconductor layer is a group VI material or Sn.
    Type: Application
    Filed: June 14, 2013
    Publication date: January 23, 2014
    Inventors: Takashi KONDO, Kazutaka TAKEDA, Hideo NAKAYAMA
  • Publication number: 20140023380
    Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector on the substrate including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; an active region on or above the first reflector; a second semiconductor multilayer reflector on or above the active region including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; and a cavity extending region formed between the first reflector and the active region or between the second reflector and the active region, having an optical film thickness greater than an oscillation wavelength, extending a cavity length, including a conductive semiconductor material, and including an optical loss causing layer at at least one node of a standing wave of a selected longitudinal mode.
    Type: Application
    Filed: May 6, 2013
    Publication date: January 23, 2014
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka TAKEDA, Takashi Kondo