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).

  • Publication number: 20080056321
    Abstract: A vertical cavity surface emitting laser element is disclosed that includes a substrate, a first semiconductor multilayer reflector including plural pairs of layers having differing refractive indexes and thermal resistances, a resonator region including an active layer, and a second semiconductor multilayer reflector including plural pairs of layers having differing refractive indexes and thermal resistances. At least one pair of layers of the first semiconductor multilayer reflector and/or the second semiconductor multilayer reflector includes a first layer with a lower thermal resistance that has an optical thickness greater than ¼ of the oscillation wavelength and a second layer with a higher thermal resistance that has an optical thickness less than ¼ of the oscillation wavelength. The sum of the optical thickness of the first layer and the optical thickness of the second layer is equal to m/4 times the oscillation wavelength (m: even number?2).
    Type: Application
    Filed: August 27, 2007
    Publication date: March 6, 2008
    Inventors: Hiroshi Motomura, Naoto Jikutani, Shunichi Sato
  • Publication number: 20080043796
    Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 ?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: June 7, 2007
    Publication date: February 21, 2008
    Inventors: Naoto JIKUTANI, Shunichi Sato, Takashi Takahashi, Akihiro Itoh, Takuro Sekiya, Akira Sakurai, Masayoshi Katoh, Teruyuki Furuta, Kazuya Miyagaki, Ken Kanai, Atsuyuki Watada, Koei Suzuki, Satoru Sugawara, Shinji Satoh, Shuuichi Hikichi
  • Publication number: 20070280322
    Abstract: A surface-emitting laser device is disclosed that includes a substrate connected to a heat sink; a first reflective layer formed of a semiconductor distributed Bragg reflector on the substrate; a first cavity spacer layer formed in contact with the first reflective layer; an active layer formed in contact with the first cavity spacer layer; a second cavity spacer layer formed in contact with the active layer; and a second reflective layer formed of a semiconductor distributed Bragg reflector in contact with the second cavity spacer layer. The first cavity spacer layer includes a semiconductor material having a thermal conductivity greater than the thermal conductivity of a semiconductor material forming the second cavity spacer layer.
    Type: Application
    Filed: August 9, 2007
    Publication date: December 6, 2007
    Inventors: Shunichi Sato, Kei Hara, Naoto Jikutani
  • Publication number: 20070263689
    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: July 13, 2007
    Publication date: November 15, 2007
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Patent number: 7260137
    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: January 23, 2006
    Date of Patent: August 21, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Publication number: 20070171949
    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: October 16, 2006
    Publication date: July 26, 2007
    Inventor: Naoto Jikutani
  • Patent number: 7245647
    Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 ?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: Grant
    Filed: October 31, 2003
    Date of Patent: July 17, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi, Akihiro Itoh, Takuro Sekiya, Akira Sakurai, Masayoshi Katoh, Teruyuki Furuta, Kazuya Miyagaki, Ken Kanai, Atsuyuki Watada, Koei Suzuki, Satoru Sugawara, Shinji Satoh, Shuuichi Hikichi
  • Patent number: 7180100
    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: February 27, 2004
    Date of Patent: February 20, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Publication number: 20060261352
    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: April 17, 2006
    Publication date: November 23, 2006
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Patent number: 7139297
    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: June 15, 2004
    Date of Patent: November 21, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Takashi Takahashi, Shunichi Sato
  • Patent number: 7067846
    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: June 29, 2004
    Date of Patent: June 27, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Takahashi, Morimasa Kaminishi, Shunichi Sato, Akihiro Itoh, Naoto Jikutani
  • Publication number: 20060134817
    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: January 23, 2006
    Publication date: June 22, 2006
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Publication number: 20060093010
    Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to a wavelength of 1.
    Type: Application
    Filed: September 8, 2005
    Publication date: May 4, 2006
    Inventors: Takuro Sekiya, Akira Sakurai, 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: 20060093006
    Abstract: A surface emitting laser device is disclosed that is able to selectively add a sufficiently large loss to a high order transverse mode so as to efficiently suppress a high order transverse mode oscillation and to oscillate at high output in a single fundamental transverse mode. The surface emitting laser device includes a first resonance region that includes an active layer and spacer layers, two distributed Bragg reflectors that sandwich the resonance region, and a current confinement structure that defines a current injection region for the active layer. At least one of the distributed Bragg reflectors includes a second resonance region arranged in the current injection region excluding a predetermined region surrounding a center of the current injection region.
    Type: Application
    Filed: October 12, 2005
    Publication date: May 4, 2006
    Inventor: Naoto Jikutani
  • Patent number: 7022539
    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: October 1, 2003
    Date of Patent: April 4, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani, Morimasa Kaminishi, Akihiro Itoh
  • Publication number: 20060007979
    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: September 13, 2005
    Publication date: January 12, 2006
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi
  • Patent number: 6983004
    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: May 2, 2003
    Date of Patent: January 3, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Jikutani, Takashi Takahashi, Shunichi Sato
  • Patent number: 6975663
    Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 ?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: Grant
    Filed: February 26, 2002
    Date of Patent: December 13, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Takuro Sekiya, Akira Sakurai, 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
  • Patent number: 6974974
    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: August 22, 2003
    Date of Patent: December 13, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Shunichi Sato, Takashi Takahashi, Naoto Jikutani
  • Publication number: 20050238075
    Abstract: An optical semiconductor device operable in a 0.6 ?m band includes an active layer of GaInNP sandwiched by a pair of GaInP layer with a thickness of about 2 molecular layers or less.
    Type: Application
    Filed: March 16, 2005
    Publication date: October 27, 2005
    Inventors: Naoto Jikutani, Shunichi Sato, Takashi Takahashi