Patents by Inventor Satoshi Sugahara

Satoshi Sugahara 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: 5345460
    Abstract: A semiconductor laser device with window regions according to the present invention is provided, in which a double hetero structure including cladding layers and an active layer sandwiched by the cladding layers is formed on a semiconductor substrate, the double hetero structure is buried in burying layers with a bandgap larger than that of the active layer, and the burying layers form window regions situated at both end facets of the double hetero structure, wherein the window regions have a waveguide structure including a plurality of semiconductor layers with different bandgaps.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: September 6, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Haruhisa Takiguchi, Seiki Yano, Kazuhiko Inoguchi, Hiroaki Kudo, Chitose Nakanishi, Toshiyuki Okumura, Satoshi Sugahara
  • Patent number: 5309472
    Abstract: A semiconductor device includes a multiple layer structure including a substantially flat active layer, and a first semiconductor layer and a second semiconductor layer adjacent to each other, the semiconductor layers having a corrugation at an interface therebetween; and a generating device which is connected to the multiple layer structure. An electromagnetic field intensity distribution is generated by use of the generating device in a waveguide region including the active layer, and the active layer includes a gain distribution having a distribution pattern corresponding to the corrugation. The multiple layer structure is produced by forming the corrugation on an upper surface of the first semiconductor layer, and forming the rest of the multiple layer structure including the second semiconductor layer and the active layer by using a vapor phase growth method once so as to make the active layer substantially flat. Then, the generating device is formed to be in contact with the multiple layer structure.
    Type: Grant
    Filed: June 24, 1992
    Date of Patent: May 3, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroaki Kudo, Kazuhiko Inoguchi, Satoshi Sugahara, Haruhisa Takiguchi
  • Patent number: 5303255
    Abstract: A distributed feedback semiconductor laser device comprising a current blocking structure having a stripe groove, and a diffraction grating formed in the bottom of the stripe groove. The current blocking structure is formed over an active layer for laser oscillation, and it includes an etch stop layer against a groove etching in a lower potion of the current blocking structure. The refractive index distribution in transverse directions inside the stripe groove is controlled by the thickness of the optical guiding layer, enabling oscillation of the fundamental transverse mode.
    Type: Grant
    Filed: June 29, 1993
    Date of Patent: April 12, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroaki Kudo, Haruhisa Takiguchi, Kazuhiko Inoguchi, Chitose Nakanishi, Satoshi Sugahara
  • Patent number: 5292685
    Abstract: In a first crystal growth step, a first cladding layer, an active layer, and an optical wave-guide layer are sequentially grown on a semiconductor substrate. A diffraction grating is formed at a surface of the optical waveguide layer. In a second crystal growth step, a current block layer is grown on the optical waveguide layer having the diffraction grating. The current block layer is selectively etched to expose the diffraction grating and thus to form a stripe groove. In a third crystal growth step, a second cladding layer is grown on the diffraction grating inside the stripe groove and on the current block layer.
    Type: Grant
    Filed: July 24, 1992
    Date of Patent: March 8, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kazuhiko Inoguchi, Satoshi Sugahara, Mototaka Taneya, Hiroaki Kudo, Chitose Nakanishi, Haruhisa Takiguchi
  • Patent number: 5280493
    Abstract: A quantum wire laser comprises a first multi-layer structure which is formed on a substrate and includes at least one first quantum well layer sandwiched by barrier layers, a second multi-layer structure which is formed on a laminated cross-section of the first multi-layer structure and is obtained by successively laminating a first barrier layer having a band gap larger than that of the first quantum well layer, a second quantum well layer having a band gap nearly equal to that of the first quantum well layer, and a second barrier layer having a band gap larger than those of the first and second quantum well layers, wherein a region for confining electrons is disposed in at least one of regions in the vicinity of the first quantum well layer and the second quantum well layer.
    Type: Grant
    Filed: March 27, 1992
    Date of Patent: January 18, 1994
    Assignees: Sharp Kabushiki Kaisha, Optoelectronics Technology Research Laboratory
    Inventors: Haruhisa Takiguchi, Hiroaki Kudo, Mototaka Taneya, Satoshi Sugahara
  • Patent number: 5070510
    Abstract: A semiconductor laser device having a mesa stripe whose side faces are facets of {111} planes is disclosed. In the laser device, a current blocking layer is formed on a semiconductor substrate whose main surface is a (100) plane, and a channel which is oriented along the <011> direction is formed in the current blocking layer. The mesa stripe is formed on the substrate within the channel by a selective growth technique. The mesa stripe has a multilayer structure including an active layer and is covered by a burying layer.
    Type: Grant
    Filed: December 10, 1990
    Date of Patent: December 3, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Fumihiro Konushi, Hiroshi Nakatu, Kazuhiko Inoguchi, Toshiyuki Okumura, Akinori Seki, Haruhisa Takiguchi, Chitose Nakanishi, Satoshi Sugahara, Hiroaki Kudo
  • Patent number: 5027368
    Abstract: A semiconductor laser device with a resonator containing an active region for laser oscillating operation is disclosed which comprises a third-order diffraction grating with a periodic corrugation for producing feedback of laser light, the corrugation being of substantially rectangular shape, wherein the ratio of the width of each convex portion of the corrugation to the periodicity of the corrugation is in the range of 0.20 to 0.25, 0.40 to 0.60, or 0.70 to 0.95.
    Type: Grant
    Filed: August 16, 1989
    Date of Patent: June 25, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroaki Kudo, Haruhisa Takiguchi, Chitose Sakane, Satoshi Sugahara
  • Patent number: 4975922
    Abstract: A multi-layered dielectric film that is coated on the end surfaces or other surfaces of optical products, wherein said multi-layered dielectric film is composed of alternate layers consisting of two kinds of dielectric layer, one of which is a first dielectric layer of TiO.sub.2 or ZnS with a high refractive index n.sub.1 and the other of which is a second dielectric layer of Al.sub.2 O.sub.3 with a low refractive index n.sub.2.
    Type: Grant
    Filed: June 19, 1989
    Date of Patent: December 4, 1990
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Chitose Sakane, Haruhisa Takiguchi, Hiroaki Kudo, Satoshi Sugahara