Patents by Inventor Naoto Jikutani

Naoto Jikutani 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: 6959025
    Abstract: A surface-emitting laser diode device that oscillates in a direction perpendicular to the substrate is provided. This surface-emitting laser diode device includes: an active layer; a resonator structure including a first distributed Bragg reflector and a second distributed Bragg reflector that face each other and sandwich the active layer; a hole passage that extends from a first electrode to the active layer; an electron passage that extends from a second electrode to the active layer; a hole restricting structure that is located in the hole passage and defines a region for confining holes to the active layer; and an optical mode control structure that includes a non-oxide region provided in the resonator structure and an oxide region surrounding the non-oxide region, each region containing Al as a constituent element. In this surface-emitting laser diode, the area of the non-oxide region is smaller than the area of the hole restricting structure.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: October 25, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi
  • Publication number: 20050147143
    Abstract: A surface-emission laser diode includes an active layer, a pair of cavity spacer layers formed at both sides of the active layer, a current confinement structure defining a current injection region into the active layer, and a pair of distributed Bragg reflectors opposing with each other across a structure formed of the active layer and the cavity spacer layers, the current confinement structure being formed by a selective oxidation process of a semiconductor layer, the pair of distributed Bragg reflectors being formed of semiconductor materials, wherein there is provided a region containing an oxide of Al and having a relatively low refractive index as compared with a surrounding region in any of the semiconductor distributed Bragg reflector or the cavity spacer layer in correspondence to a part spatially overlapping with the current injection region in a laser cavity direction.
    Type: Application
    Filed: November 24, 2004
    Publication date: July 7, 2005
    Inventor: Naoto Jikutani
  • Publication number: 20050100068
    Abstract: A surface-emitting laser diode device that oscillates in a direction perpendicular to the substrate is provided. This surface-emitting laser diode device includes: an active layer; a resonator structure including a first distributed Bragg reflector and a second distributed Bragg reflector that face each other and sandwich the active layer; a hole passage that extends from a first electrode to the active layer; an electron passage that extends from a second electrode to the active layer; a hole restricting structure that is located in the hole passage and defines a region for confining holes to the active layer; and an optical mode control structure that includes a non-oxide region provided in the resonator structure and an oxide region surrounding the non-oxide region, each region containing Al as a constituent element. In this surface-emitting laser diode, the area of the non-oxide region is smaller than the area of the hole restricting structure.
    Type: Application
    Filed: February 20, 2003
    Publication date: May 12, 2005
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi
  • Patent number: 6884291
    Abstract: An optical semiconductor device operable in a 0.6 ?m band includes an active layer of GaInNP sandwiched by a pair of GaInP layers each having a thickness of about 2 molecular layers or less.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: April 26, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi
  • Publication number: 20050040413
    Abstract: A semiconductor light-emitting device has a semiconductor layer containing Al between a substrate and an active layer containing nitrogen, wherein Al and oxygen are removed from a growth chamber before growing said active layer and a concentration of oxygen incorporated into said active layer together with Al is set to a level such that said semiconductor light-emitting device can perform a continuous laser oscillation at room temperature.
    Type: Application
    Filed: February 27, 2004
    Publication date: February 24, 2005
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Patent number: 6829271
    Abstract: A light-emitting semiconductor device for producing red color optical radiation has a cladding layer of AlGaInPAs having a lattice constant between GaAs and GaP. Further, the laser diode uses an optical waveguide layer in the system of GaInPAs free from Al. The semiconductor device may be constructed on a GaPAs substrate.
    Type: Grant
    Filed: February 3, 2003
    Date of Patent: December 7, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Publication number: 20040238832
    Abstract: A semiconductor light-emitting device has a semiconductor layer containing Al between a substrate and an active layer containing nitrogen, wherein Al and oxygen are removed from a growth chamber before growing said active layer and a concentration of oxygen incorporated into said active layer together with Al is set to a level such that said semiconductor light-emitting device can perform a continuous laser oscillation at room temperature.
    Type: Application
    Filed: June 29, 2004
    Publication date: December 2, 2004
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Publication number: 20040228381
    Abstract: A laser diode includes a substrate having a lattice constant of GaAs or between GaAs and GaP, a first cladding layer of AlGaInP formed on the substrate, an active layer of GaInAsP formed on the first cladding layer, an etching stopper layer of GaInP formed on the active layer, a pair of current-blocking regions of AlGaInP formed on the etching stopper layer so as to define a strip region therebetween, an optical waveguide layer of AlGaInP formed on the pair of current-blocking regions so as to cover the etching stopper layer in the stripe region, and a second cladding layer of AlGaInP formed on the optical waveguide layer, wherein the current-blocking regions having an Al content substantially identical with an Al content of the second cladding layer.
    Type: Application
    Filed: June 15, 2004
    Publication date: November 18, 2004
    Inventors: Naoto Jikutani, Takashi Takahashi, Shunichi Sato
  • Patent number: 6765232
    Abstract: A semiconductor light-emitting device has a semiconductor layer containing Al between a substrate and an active layer containing nitrogen, wherein Al and oxygen are removed from a growth chamber before growing said active layer and a concentration of oxygen incorporated into said active layer together with Al is set to a level such that said semiconductor light-emitting device can perform a continuous laser oscillation at room temperature.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: July 20, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Publication number: 20040065887
    Abstract: A semiconductor light emitting device is disclosed, including a semiconductor substrate, an active region comprising a strained quantum well layer, and a cladding layer for confining carriers and light emissions, wherein the amount of lattice strains in the quantum well layer is in excess of 2% against either the semiconductor substrate or cladding layer and, alternately, the thickness of the quantum well layer is in excess of the critical thickness calculated after Matthews and Blakeslee.
    Type: Application
    Filed: August 22, 2003
    Publication date: April 8, 2004
    Applicant: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Publication number: 20040065888
    Abstract: A vertical-cavity, surface-emission-type laser diode includes an optical cavity formed of an active region sandwiched by upper and lower reflectors, wherein the lower reflector is formed of a distributed Bragg reflector and a non-optical recombination elimination layer is provided between an active layer in the active region and the lower reflector.
    Type: Application
    Filed: October 1, 2003
    Publication date: April 8, 2004
    Applicant: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Patent number: 6674785
    Abstract: A vertical-cavity, surface-emission-type laser diode includes an optical cavity formed of an active region sandwiched by upper and lower reflectors, wherein the lower reflector is formed of a distributed Bragg reflector and a non-optical recombination elimination layer is provided between an active layer in the active region and the lower reflector.
    Type: Grant
    Filed: September 20, 2001
    Date of Patent: January 6, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Patent number: 6657233
    Abstract: A semiconductor light emitting device is disclosed, including a semiconductor substrate, an active region comprising a strained quantum well layer, and a cladding layer for confining carriers and light emissions, wherein the amount of lattice strains in the quantum well layer is in excess of 2% against either the semiconductor substrate or cladding layer and, alternately, the thickness of the quantum well layer is in excess of the critical thickness calculated after Matthews and Blakeslee.
    Type: Grant
    Filed: December 12, 2000
    Date of Patent: December 2, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Publication number: 20030198268
    Abstract: A laser diode includes a substrate having a lattice constant of GaAs or between GaAs and GaP, a first cladding layer of AlGaInP formed on the substrate, an active layer of GaInAsP formed on the first cladding layer, an etching stopper layer of GaInP formed on the active layer, a pair of current-blocking regions of AlGaInP formed on the etching stopper layer so as to define a strip region therebetween, an optical waveguide layer of AlGaInP formed on the pair of current-blocking regions so as to cover the etching stopper layer in the stripe region, and a second cladding layer of AlGaInP formed on the optical waveguide layer, wherein the current-blocking regions having an Al content substantially identical with an Al content of the second cladding layer.
    Type: Application
    Filed: May 2, 2003
    Publication date: October 23, 2003
    Inventors: Naoto Jikutani, Takashi Takahashi, Shunichi Sato
  • Patent number: 6614821
    Abstract: A laser diode includes a substrate having a lattice constant of GaAs or between GaAs and GaP, a first cladding layer of AlGaInP formed on the substrate, an active layer of GaInAsP formed on the first cladding layer, an etching stopper layer of GaInP formed on the active layer, a pair of current-blocking regions of AlGaInP formed on the etching stopper layer so as to define a strip region therebetween, an optical waveguide layer of AlGaInP formed on the pair of current-blocking regions so as to cover the etching stopper layer in the stripe region, and a second cladding layer of AlGaInP formed on the optical waveguide layer, wherein the current-blocking regions having an Al content substantially identical with an Al content of the second cladding layer.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: September 2, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Takashi Takahashi, Shunichi Sato
  • Publication number: 20030138015
    Abstract: A light-emitting semiconductor device for producing red color optical radiation has a cladding layer of AlGaInPAs having a lattice constant between GaAs and GaP. Further, the laser diode uses an optical waveguide layer in the system of GaInPAs free from Al. The semiconductor device may be constructed on a GaPAs substrate.
    Type: Application
    Filed: February 3, 2003
    Publication date: July 24, 2003
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Patent number: 6563851
    Abstract: An optical semiconductor device operable in a 0.6 &mgr;m band includes an active layer of GaInNP sandwiched by a pair of GaInP layers each having a thickness of about 2 molecular layers or less.
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: May 13, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi
  • Patent number: 6542528
    Abstract: A light-emitting semiconductor device for producing red color optical radiation has a cladding layer of AlGaInPAs having a lattice constant between GaAs and GaP. Further, the laser diode uses an optical waveguide layer in the system of GaInPAs free from Al. The semiconductor device may be constructed on a GaPAs substrate.
    Type: Grant
    Filed: February 11, 2000
    Date of Patent: April 1, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Publication number: 20030053501
    Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 &mgr;m or longer, wherein the distributed Bragg reflector includes an alternate repetition of a low-refractive index layer and a high-refractive index layer, with a heterospike buffer layer having an intermediate refractive index interposed therebetween with a thickness in the range of 5-50 nm.
    Type: Application
    Filed: February 26, 2002
    Publication date: March 20, 2003
    Inventors: Takuro Sekiya, Akira Sukurai, Masayoshi Katoh, Teruyuki Furuta, Kazuya Miyagaki, Ken Kanai, Atsuyuki Watada, Shunichi Sato, Koei Suzuki, Satoru Sugawara, Shinji Satoh, Shuuichi Hikichi, Naoto Jikutani, Takashi Takahashi, Akihiro Itoh
  • Publication number: 20030006429
    Abstract: A semiconductor light-emitting device has a semiconductor layer containing Al between a substrate and an active layer containing nitrogen, wherein Al and oxygen are removed from a growth chamber before growing said active layer and a concentration of oxygen incorporated into said active layer together with Al is set to a level such that said semiconductor light-emitting device can perform a continuous laser oscillation at room temperature.
    Type: Application
    Filed: March 26, 2002
    Publication date: January 9, 2003
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani