Patents by Inventor Takahiko Kawahara

Takahiko Kawahara 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: 9899549
    Abstract: An infrared-ray sensing device includes a support and a plurality of photodiodes disposed on the support. Each photodiode of the plurality includes a first mesa including a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type, a third semiconductor layer of a second conductivity type that is disposed between the first and second semiconductor layers, and a super-lattice region disposed on the support along a reference plane. The third semiconductor layer and the super-lattice region are provided in common for the photodiodes of the plurality. In the photodiodes, the first mesas and the second semiconductor layers are aligned along a first axis intersecting the reference plane so that each of the second semiconductor layers is provided in a position corresponding to the position of its first mesa. Each second semiconductor layer is disposed between the third semiconductor layer and the super-lattice region.
    Type: Grant
    Filed: May 3, 2017
    Date of Patent: February 20, 2018
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Kenichi Machinaga, Yasuhiro Iguchi, Takahiko Kawahara
  • Publication number: 20170358696
    Abstract: An infrared-ray sensing device includes a support and a plurality of photodiodes disposed on the support. Each of the plurality of photodiodes includes a first mesa including a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type, a third semiconductor layer of a second conductivity type that is disposed between the first and second semiconductor layers, and a super-lattice region disposed on the support along a reference plane. Each of the third semiconductor layer and the super-lattice region is provided in common for the photodiodes. The first mesas and the second semiconductor layers are aligned along a first axis intersecting the reference plane so that each of the second semiconductor layers is provided in a position corresponding to the position of first mesa. The second semiconductor layer is disposed between the third semiconductor layer and the super-lattice region.
    Type: Application
    Filed: May 3, 2017
    Publication date: December 14, 2017
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Kenichi MACHINAGA, Yasuhiro Iguchi, Takahiko Kawahara
  • Patent number: 8340147
    Abstract: A laser diode includes an n-type semiconductor region, a p-type semiconductor region, a semiconductor mesa provided between the n-type semiconductor region and the p-type semiconductor region, the semiconductor mesa including an active layer, and a semiconductor burying region located between the n-type semiconductor region and the p-type semiconductor region, the semiconductor burying region being provided on a side face of the semiconductor mesa. The semiconductor burying region includes an n-type semiconductor burying layer and a p-type semiconductor burying layer. The n-type semiconductor burying layer is provided between the p-type semiconductor region and the p-type semiconductor burying layer. The p-type semiconductor burying layer is doped with an element that forms an electron trapping level in the band gap of the p-type semiconductor burying layer.
    Type: Grant
    Filed: October 12, 2010
    Date of Patent: December 25, 2012
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Noriaki Kaida, Takahiko Kawahara
  • Patent number: 8182481
    Abstract: A PFO closing device includes a suction and hold portion at a distal portion of a catheter for sucking and holding biological tissue of a foramen ovale valve and an atrial septum secundum from one side, an electrode portion on the side contacting the biological tissue; a negative pressure supply unit for applying negative pressure to the suctional portion and hold portion, a hold mechanism adapted to protrude from the distal tip of the catheter, and be inserted into the foramen ovale to hold the foramen ovale valve while pressing it from the other side and an energy supply unit for supplying energy to the electrode portion. Energy is supplied from the energy supply unit to the electrode portion, and the foramen ovale valve and the atrial septum secundum are mutually fused together.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: May 22, 2012
    Assignee: Terumo Kabushiki Kaisha
    Inventors: Yukitoshi Kato, Yasushi Iida, Takahiko Kawahara
  • Publication number: 20110090928
    Abstract: A laser diode includes an n-type semiconductor region, a p-type semiconductor region, a semiconductor mesa provided between the n-type semiconductor region and the p-type semiconductor region, the semiconductor mesa including an active layer, and a semiconductor burying region located between the n-type semiconductor region and the p-type semiconductor region, the semiconductor burying region being provided on a side face of the semiconductor mesa. The semiconductor burying region includes an n-type semiconductor burying layer and a p-type semiconductor burying layer. The n-type semiconductor burying layer is provided between the p-type semiconductor region and the p-type semiconductor burying layer. The p-type semiconductor burying layer is doped with an element that forms an electron trapping level in the band gap of the p-type semiconductor burying layer.
    Type: Application
    Filed: October 12, 2010
    Publication date: April 21, 2011
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Noriaki KAIDA, Takahiko Kawahara
  • Patent number: 7723132
    Abstract: The present invention is to provide a semiconductor laser with a feedback grating comprised of InP and AlGaInAs without InAsP put therebetween, and to provide a method for manufacturing the DFB-LD having such grating. The LD includes an n-type InP substrate, an AlInAsP intermediate layer, an AlGaInAs lower SCH layer, an active layer, and a p-type layer for upper cladding in this order from the InP substrate. The InP substrate, the AlInAsP intermediate layer, and the AlGaInAs lower SCH layer constitute the feedback grating. The AlInAsP intermediate layer lowers a series resistance along these semiconductor stacks.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: May 25, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Takahiko Kawahara, Nobuyuki Ikoma
  • Patent number: 7627011
    Abstract: The present invention is to provide a DFB-LD with a larger coupling efficiency between the grating and the active layer. The DFB-LD of the invention provides an n-type InP substrate, an n-type InP buffer layer, an AlGaInAs layer, a intermediate layer made of a material belonging to a group III-V compound semiconductor and containing phosphorous, and an active layer. The InP substrate and the InP buffer layer form a periodic undulation of the grating. Because of the AlGaInAs layer just provided on the InP buffer layer, the AlGaInAs layer and the intermediate layer can be thinned to get a flat top surface, which enhances the coupling efficiency between the grating and the active layer.
    Type: Grant
    Filed: January 5, 2007
    Date of Patent: December 1, 2009
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Takahiko Kawahara
  • Publication number: 20090076525
    Abstract: A PFO closing device includes a suction and hold portion at a distal portion of a catheter for sucking and holding biological tissue of a foramen ovale valve and an atrial septum secundum from one side, an electrode portion on the side contacting the biological tissue; a negative pressure supply unit for applying negative pressure to the suctional portion and hold portion, a hold mechanism adapted to protrude from the distal tip of the catheter, and be inserted into the foramen ovale to hold the foramen ovale valve while pressing it from the other side and an energy supply unit for supplying energy to the electrode portion. Energy is supplied from the energy supply unit to the electrode portion, and the foramen ovale valve and the atrial septum secundum are mutually fused together.
    Type: Application
    Filed: August 28, 2008
    Publication date: March 19, 2009
    Applicant: TERUMO KABUSHIKI KAISHA
    Inventors: Yukitoshi Kato, Yasushi Iida, Takahiko Kawahara
  • Publication number: 20080299692
    Abstract: The present invention is to provide a semiconductor laser with a feedback grating comprised of InP and AlGaInAs without InAsP put therebetween, and to provide a method for manufacturing the DFB-LD having such grating. The LD includes an n-type InP substrate, an AlInAsP intermediate layer, an AlGaInAs lower SCH layer, an active layer, and a p-type layer for upper cladding in this order from the InP substrate. The InP substrate, the AlInAsP intermediate layer, and the AlGaInAs lower SCH layer constitute the feedback grating. The AlInAsP intermediate layer lowers a series resistance along these semiconductor stacks.
    Type: Application
    Filed: June 23, 2008
    Publication date: December 4, 2008
    Inventors: Takahiko Kawahara, Nobuyuki Ikoma
  • Patent number: 7460575
    Abstract: The present invention is to provide a semiconductor laser with a feedback grating comprised of InP and AlGaInAs without InAsP put therebetween, and to provide a method for manufacturing the DFB-LD having such grating. The LD includes an n-type InP substrate, an AlInAsP intermediate layer, an AlGaInAs lower SCH layer, an active layer, and a p-type layer for upper cladding in this order from the InP substrate. The InP substrate, the AlInAsP intermediate layer, and the AlGaInAs lower SCH layer constitute the feedback grating. The AlInAsP intermediate layer lowers a series resistance along these semiconductor stacks.
    Type: Grant
    Filed: January 4, 2006
    Date of Patent: December 2, 2008
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Takahiko Kawahara, Nobuyuki Ikoma
  • Patent number: 7408965
    Abstract: A semiconductor laser diode (LD) has been disclosed, where the emission efficiency is independent on a thickness of the p-type cladding layer. The LD provides a first semiconductor region made of group III-V compound semiconductor material, a mesa region and a burying region. The burying region, disposed on the first region, buries the mesa region. The mesa region includes an active layer, a cladding layer with a first conduction type, another cladding layer with second conduction type and a contact layer with the second conduction type. The LD of the invention in the contact layer thereof contains aluminum (Al) and indium (In) for group III element, while, arsenic (As) for group V element.
    Type: Grant
    Filed: April 24, 2007
    Date of Patent: August 5, 2008
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Takahiko Kawahara, Masato Furukawa
  • Publication number: 20070258498
    Abstract: A semiconductor laser diode (LD) has been disclosed, where the emission efficiency is independent on a thickness of the p-type cladding layer. The LD provides a first semiconductor region made of group III-V compound semiconductor material, a mesa region and a burying region. The burying region, disposed on the first region, buries the mesa region. The mesa region includes an active layer, a cladding layer with a first conduction type, another cladding layer with second conduction type and a contact layer with the second conduction type. The LD of the invention in the contact layer thereof contains aluminum (Al) and indium (In) for group III element, while, arsenic (As) for group V element.
    Type: Application
    Filed: April 24, 2007
    Publication date: November 8, 2007
    Inventors: Takahiko Kawahara, Masato Furukawa
  • Publication number: 20070160105
    Abstract: The present invention is to provide a DFB-LD with a larger coupling efficiency between the grating and the active layer. The DFB-LD of the invention provides an n-type InP substrate, an n-type InP buffer layer, an AlGaInAs layer, a intermediate layer made of a material belonging to a group III-V compound semiconductor and containing phosphorous, and an active layer. The InP substrate and the InP buffer layer form a periodic undulation of the grating. Because of the AlGaInAs layer just provided on the InP buffer layer, the AlGaInAs layer and the intermediate layer can be thinned to get a flat top surface, which enhances the coupling efficiency between the grating and the active layer.
    Type: Application
    Filed: January 5, 2007
    Publication date: July 12, 2007
    Inventor: Takahiko Kawahara
  • Publication number: 20060243992
    Abstract: The present invention provides a light-emitting device with a quantum well structure comprising a barrier layer containing aluminum, gallium, indium and arsenic, which reduces the leak current flowing in the buried layer. The buried layer includes first and second buried layers stacked to each other and covers the sides of the quantum well structure. The barrier layer induces a tensile stress to lower the band gap energy, to increase the band gap wavelength ?BG greater than or equal to 1.0 ?m.
    Type: Application
    Filed: June 16, 2006
    Publication date: November 2, 2006
    Inventors: Nobuyuki Ikoma, Takahiko Kawahara, Masato Furukawa
  • Patent number: 7123639
    Abstract: A semiconductor optical device 100 has an n-type semiconductor layer 2, an active layer 3, and a p-type semiconductor portion 4 provided in order on a principal surface 1a of a substrate 1. The p-type semiconductor portion 4 has a ridge portion 40 and a base portion 42, and a contact layer 5 is formed on the ridge portion 40. A first portion 60 of an insulating layer 6 extends along a plane intersecting with the principal surface 1a of the substrate 1, on a side face 4b of the ridge portion 40 and on a side face 5b of the contact layer 5. An end 6a of the first portion 60 is higher than an edge 5c of the side face 5b of the contact layer 5.
    Type: Grant
    Filed: July 2, 2004
    Date of Patent: October 17, 2006
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Takahiko Kawahara
  • Publication number: 20060159145
    Abstract: The present invention is to provide a semiconductor laser with a feedback grating comprised of InP and AlGaInAs without InAsP put therebetween, and to provide a method for manufacturing the DFB-LD having such grating. The LD includes an n-type InP substrate, an AlInAsP intermediate layer, an AlGaInAs lower SCH layer, an active layer, and a p-type layer for upper cladding in this order from the InP substrate. The InP substrate, the AlInAsP intermediate layer, and the AlGaInAs lower SCH layer constitute the feedback grating. The AlInAsP intermediate layer lowers a series resistance along these semiconductor stacks.
    Type: Application
    Filed: January 4, 2006
    Publication date: July 20, 2006
    Inventors: Takahiko Kawahara, Nobuyuki Ikoma
  • Publication number: 20060146902
    Abstract: The present invention provides a distributed feedback laser diode (DFB-LD), in which the active region may be easily flattened. The active region of the invention is optically coupled with the feedback grating made of the n-type InP layer and the n-type AlGaInAs layer. Since both layers show the n-type conduction, the n-type impurities, which are typically silicon (Si), introduced from the ambient or tools may not increase the resistivity of the layers. Moreover, the difference in the refractive index between AlGaInAs and InP is greater than that between InGaAsP and InP. Accordingly, even when the magnitude of the undulation formed in the interface between AlGaInAs and InP is small, the coupling coefficient between the grating the active layer, which is equal to the product of the magnitude of the undulation H and the difference in the refractive index An, may be prevented from the extreme decrease.
    Type: Application
    Filed: November 17, 2005
    Publication date: July 6, 2006
    Inventors: Nobuyuki Ikoma, Takahiko Kawahara
  • Publication number: 20050189552
    Abstract: A light-emitting device including an active region having a quantum well structure formed by a first barrier layer made of a first III-V compound semiconductor material that contains aluminum, gallium, indium, and arsenic, and a quantum well layer made of a second III-V compound semiconductor material. The device also includes a buried semiconductor region provided on sides of the quantum well layer. The first III-V semiconductor material has a band gap wavelength greater than 1 ?m.
    Type: Application
    Filed: December 27, 2004
    Publication date: September 1, 2005
    Inventors: Nobuyuki Ikoma, Takahiko Kawahara, Masato Furukawa
  • Publication number: 20050013335
    Abstract: A semiconductor optical device 100 has an n-type semiconductor layer 2, an active layer 3, and a p-type semiconductor portion 4 provided in order on a principal surface 1a of a substrate 1. The p-type semiconductor portion 4 has a ridge portion 40 and a base portion 42, and a contact layer 5 is formed on the ridge portion 40. A first portion 60 of an insulating layer 6 extends along a plane intersecting with the principal surface 1a of the substrate 1, on a side face 4b of the ridge portion 40 and on a side face 5b of the contact layer 5. An end 6a of the first portion 60 is higher than an edge 5c of the side face 5b of the contact layer 5.
    Type: Application
    Filed: July 2, 2004
    Publication date: January 20, 2005
    Inventor: Takahiko Kawahara
  • Publication number: 20040086015
    Abstract: An optical waveguide is provided on an n-type buffer layer. The optical waveguide is formed into a mesa form. A high resistance layer narrows a drive current path through the optical waveguide. Two trenches are formed such that their bottoms are in contact with the high resistance layer. This can effectively narrow the drive current path in the semiconductor laser device part.
    Type: Application
    Filed: October 9, 2003
    Publication date: May 6, 2004
    Inventors: Takahiko Kawahara, Michio Murata