Patents by Inventor Tsunenori Asatsuma

Tsunenori Asatsuma 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: 8520712
    Abstract: A laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: August 27, 2013
    Assignee: Sony Corporation
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Patent number: 8179941
    Abstract: A laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: May 15, 2012
    Assignee: Sony Corporation
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Patent number: 8050305
    Abstract: A semiconductor device having high reliability, a long lifetime and superior light emitting characteristics by applying a novel material to a p-type cladding layer is provided. A semiconductor device includes a p-type semiconductor layer on an InP substrate, in which the p-type semiconductor layer has a laminate structure formed by alternately laminating a first semiconductor layer mainly including Bex1Mgx2Znx3Te (0<x1<1, 0?x2<1, 0<x3<1, x1+x2+x3=1) and a second semiconductor layer mainly including Bex4Mgx5Znx6Te (0<x4<1, 0<x5<1, 0?x6<1, x4+x5+x6=1).
    Type: Grant
    Filed: June 3, 2008
    Date of Patent: November 1, 2011
    Assignees: Sony Corporation, Hitachi, Ltd., Sophia School Corporation
    Inventors: Katsumi Kishino, Ichiro Nomura, Koshi Tamamura, Kunihiko Tasai, Tsunenori Asatsuma, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa
  • Publication number: 20110206080
    Abstract: A laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Application
    Filed: May 3, 2011
    Publication date: August 25, 2011
    Applicant: SONY CORPORATION
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Publication number: 20110182313
    Abstract: A laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Application
    Filed: April 12, 2011
    Publication date: July 28, 2011
    Applicant: SONY CORPORATION
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Patent number: 7965749
    Abstract: Provided is a laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Grant
    Filed: September 25, 2008
    Date of Patent: June 21, 2011
    Assignee: Sony Corporation
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Patent number: 7907651
    Abstract: A laser diode capable of effectively inhibiting effects of feedback light is provided. A laser diode includes a substrate, and a laminated structure including a first conductive semiconductor layer, an active layer having a light emitting region, and a second conductive semiconductor layer having a projecting part on the surface thereof, on the substrate, wherein a feedback light inhibition part is provided on a main-emitting-side end face, and effects of feedback light in the vicinity of lateral boundaries of the light emitting region are inhibited by the feedback light inhibition part.
    Type: Grant
    Filed: February 17, 2009
    Date of Patent: March 15, 2011
    Assignee: Sony Corporation
    Inventors: Tsunenori Asatsuma, Yoshiro Takiguchi, Shoji Hirata
  • Patent number: 7899104
    Abstract: An n-type cladding layer structure which has good luminescence properties without the use of substances corresponding to RoHS Directive and a high Cl-doping efficiency, i.e. which facilitates the manufacture of a semiconductor optical element and device with low crystal defects and high reliability, and an active layer and a p-type cladding layer therefor are provided. The n-type layer being lattice matched to an InP substrate and containing Group II-VI compound as a main ingredient is a Group II-VI compound semiconductor, in which the Group II elements consist of Mg, Zn, and Be and the Group VI elements consist of Se and Te. The n-type layer of the present invention is characterized by a large energy gap, high energy of the bottom of a conduction band that is effective for suppressing the Type II luminescence, high carrier concentration, and low crystal defects attributed to a good quality crystallinity.
    Type: Grant
    Filed: February 27, 2008
    Date of Patent: March 1, 2011
    Assignees: Hitachi, Ltd., Sophia School Corporation, Sony Corporation
    Inventors: Katsumi Kishino, Ichiro Nomura, Tsunenori Asatsuma, Kunihiko Tasai, Koshi Tamamura, Hiroshi Nakajima, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa
  • Patent number: 7879628
    Abstract: This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: February 1, 2011
    Assignee: Sony Corporation
    Inventors: Tsunenori Asatsuma, Shoji Hirata
  • Patent number: 7668217
    Abstract: The present invention provides a Be-based group II-VI semiconductor laser using an InP substrate and having a stacked structure capable of continuous oscillation at a room temperature. A basic structure of a semiconductor laser is constituted by using a Be-containing lattice-matched II-VI semiconductor above an InP substrate. An active laser, an optical guide layer, and a cladding layer are constituted in a double hetero structure having a type I band line-up in order to enhance the injection efficiency of carriers to the active layer. Also, the active layer, the optical guide layer, and the cladding layer, which are capable of enhancing the optical confinement to the active layer, are constituted, and the cladding layer is constituted with bulk crystals.
    Type: Grant
    Filed: July 30, 2007
    Date of Patent: February 23, 2010
    Assignees: Hitachi, Ltd., Sophia School Corporation, Sony Corporation
    Inventors: Katsumi Kishino, Ichiro Nomura, Tsunenori Asatsuma, Hitoshi Nakamura, Tsukuru Ohtoshi, Takeshi Kikawa, Sumiko Fujisaki, Shigehisa Tanaka
  • Publication number: 20100040103
    Abstract: The present invention provides a semiconductor device including: a semiconductor layer including an n-type first cladding layer, an n-type second cladding layer, an active layer, a p-type first cladding layer, and a p-type second cladding layer in this order on an InP substrate. The n-type first cladding layer and the n-type second cladding layer satisfy formulas (1) to (4) below, or the p-type first cladding layer and the p-type second cladding layer satisfy formulas (5) to (8) below.
    Type: Application
    Filed: August 5, 2009
    Publication date: February 18, 2010
    Applicants: HITACHI, LTD, SOPHIA SCHOOL CORPORATION, SONY CORPORATION
    Inventors: Katsumi Kishino, Ichiro Nomura, Koshi Tamamura, Kunihiko Tasai, Tsunenori Asatsuma, Hiroshi Nakajima, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa
  • Patent number: 7656918
    Abstract: A semiconductor laser having an n-cladding layer, an optical guide layer, an active layer, an optical guide layer, and a p-cladding layer above an InP substrate, in which the active layer has a layer constituted with Be-containing group II-VI compound semiconductor mixed crystals, and at least one of layers of the n-cladding layer, the optical guide layer, and the p-cladding layer has a layer constituted with elements identical with those of the Be-containing group II-VI compound semiconductor mixed crystals of the active layer, and the layer is constituted with a superlattice structure comprising, as a well layer, mixed crystals of a Be compositions with the fluctuation of the composition being within ±30% compared with the Be composition of the group II-VI compound semiconductor mixed crystals of the active layer, whereby the device characteristics of the semiconductor laser comprising the Be-containing group II-VI compound semiconductor matched with the InP substrate.
    Type: Grant
    Filed: March 20, 2007
    Date of Patent: February 2, 2010
    Assignees: Hitachi, Ltd., Sophia School Corporation, Sony Corporation
    Inventors: Katsumi Kishino, Ichiro Nomura, Tsunenori Asatsuma, Hitoshi Nakamura
  • Publication number: 20090161716
    Abstract: A laser diode capable of effectively inhibiting effects of feedback light is provided. A laser diode includes a substrate, and a laminated structure including a first conductive semiconductor layer, an active layer having a light emitting region, and a second conductive semiconductor layer having a projecting part on the surface thereof, on the substrate, wherein a feedback light inhibition part is provided on a main-emitting-side end face, and effects of feedback light in the vicinity of lateral boundaries of the light emitting region are inhibited by the feedback light inhibition part.
    Type: Application
    Filed: February 17, 2009
    Publication date: June 25, 2009
    Applicant: Sony Corporation
    Inventors: Tsunenori Asatsuma, Yoshiro Takiguchi, Shoji Hirata
  • Publication number: 20090141763
    Abstract: There is disclosed a Be-containing II-VI group semiconductor laser that has a laminated structure formed on an InP substrate to continuously emit at room temperature without crystal degradation. A basic structure of the semiconductor laser is formed over the InP substrate by use of a lattice-matched II-VI group semiconductor including Be. An active layer and cladding layers are formed to be a double heterostructure with a type I band lineup, in order to increase the efficiency for injecting carriers into the active layer. The active layer and the cladding layers are also formed to enhance the light confinement to the active layer, in which the Mg composition of the p-type cladding layer is set to Mg<0.2.
    Type: Application
    Filed: February 27, 2008
    Publication date: June 4, 2009
    Inventors: Katsumi Kishino, Ichiro Nomura, Tsunenori Asatsuma, Sumiko Fujisaki, Hitoshi Nakamura, Takeshi Kikawa, Shigehisa Tanaka
  • Publication number: 20090137078
    Abstract: This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
    Type: Application
    Filed: December 9, 2008
    Publication date: May 28, 2009
    Applicant: Sony Corporation
    Inventors: Tsunenori Asatsuma, Shoji Hirata
  • Patent number: 7532654
    Abstract: A laser diode capable of effectively inhibiting effects of return light is provided. A laser diode includes a substrate, and a laminated structure including a first conductive semiconductor layer, an active layer having a light emitting region, and a second conductive semiconductor layer having a projecting part on the surface thereof, on the substrate, wherein a return light inhibition part is provided on a main-emitting-side end face, and effects of return light in the vicinity of lateral boundaries of the light emitting region are inhibited by the return light inhibition part.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: May 12, 2009
    Assignee: Sony Corporation
    Inventors: Tsunenori Asatsuma, Yoshiro Takiguchi, Shoji Hirata
  • Publication number: 20090092163
    Abstract: Provided is a laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
    Type: Application
    Filed: September 25, 2008
    Publication date: April 9, 2009
    Applicant: Sony Corporation
    Inventors: Shoji Hirata, Tsunenori Asatsuma, Yoshiro Takiguchi
  • Patent number: 7510887
    Abstract: This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
    Type: Grant
    Filed: April 26, 2007
    Date of Patent: March 31, 2009
    Assignee: Sony Corporation
    Inventors: Tsunenori Asatsuma, Shoji Hirata
  • Publication number: 20090059985
    Abstract: An n-type cladding layer structure which has good luminescence properties without the use of substances corresponding to RoHS Directive and a high Cl-doping efficiency, i.e. which facilitates the manufacture of a semiconductor optical element and device with low crystal defects and high reliability, and an active layer and a p-type cladding layer therefor are provided. The n-type layer being lattice matched to an InP substrate and containing Group II-VI compound as a main ingredient is a Group II-VI compound semiconductor, in which the Group II elements consist of Mg, Zn, and Be and the Group VI elements consist of Se and Te. The n-type layer of the present invention is characterized by a large energy gap, high energy of the bottom of a conduction band that is effective for suppress the Type II luminescence, high carrier concentration, and low crystal defects attributed to a good quality crystallinity.
    Type: Application
    Filed: February 27, 2008
    Publication date: March 5, 2009
    Inventors: Katsumi Kishino, Ichiro Nomura, Tsunenori Asatsuma, Kunihiko Tasai, Koshi Tamamura, Hiroshi Nakajima, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa
  • Publication number: 20080298415
    Abstract: A semiconductor device having high reliability, a long lifetime and superior light emitting characteristics by applying a novel material to a p-type cladding layer is provided. A semiconductor device includes a p-type semiconductor layer on an InP substrate, in which the p-type semiconductor layer has a laminate structure formed by alternately laminating a first semiconductor layer mainly including Bex1Mgx2Znx3Te (0<x1<1, 0<x2<1, 0<x3<1, x1+x2+x3=1) and a second semiconductor layer mainly including Bex4Mgx5Znx6Te (0<x4<1, 0<x5<1, 0<x6<1, x4+x5+x6=1).
    Type: Application
    Filed: June 3, 2008
    Publication date: December 4, 2008
    Applicants: SONY CORPORATION, HITACHI, LTD, SOPHIA SCHOOL CORPORATION
    Inventors: Katsumi Kishino, Ichiro Nomura, Koshi Tamamura, Kunihiko Tasai, Tsunenori Asatsuma, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa