Patents by Inventor Yoshifumi Sasahata
Yoshifumi Sasahata 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).
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Patent number: 10553742Abstract: A substrate has a front surface and a back surface opposite from the front surface. An n-type layer, a multiplication layer, a p-type electric field control layer, a light absorption layer, and a window layer are layered in order on the front surface. A p-type region is provided in part of the window layer. An anode electrode is provided on the p-type region and connected to the p-type region. An anode pad and a cathode pad are provided on the back surface. First and second connecting holes penetrates the substrate. A third connecting hole penetrates from the window layer to the n-type layer. The cathode pad is electrically connected to the n-type layer via the first connecting hole. The anode pad is electrically connected to the anode electrode via the second and third connecting holes. A light-receiving region is provided on the back surface.Type: GrantFiled: October 28, 2016Date of Patent: February 4, 2020Assignee: Mitsubishi Electric CorporationInventors: Ryota Takemura, Nobuo Ohata, Yoshifumi Sasahata, Kazuki Yamaji
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Publication number: 20190296175Abstract: A substrate has a front surface and a back surface opposite from the front surface. An n-type layer, a multiplication layer, a p-type electric field control layer, a light absorption layer, and a window layer are layered in order on the front surface. A p-type region is provided in part of the window layer. An anode electrode is provided on the p-type region and connected to the p-type region. An anode pad and a cathode pad are provided on the back surface. First and second connecting holes penetrates the substrate. A third connecting hole penetrates from the window layer to the n-type layer. The cathode pad is electrically connected to the n-type layer via the first connecting hole. The anode pad is electrically connected to the anode electrode via the second and third connecting holes. A light-receiving region is provided on the back surface.Type: ApplicationFiled: October 28, 2016Publication date: September 26, 2019Applicant: Mitsubishi Electric CorporationInventors: Ryota TAKEMURA, Nobuo OHATA, Yoshifumi SASAHATA, Kazuki YAMAJI
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Patent number: 9804330Abstract: According to the present invention, a semiconductor device includes a substrate comprising a front end face, a rear end face and side faces, a plurality of semiconductor lasers provided on the substrate, a forward optical multiplexer to multiplex forward output light of the plurality of semiconductor lasers and output the multiplexed light to the front end face, a backward optical multiplexer to multiplex backward output light of the plurality of semiconductor lasers and output the multiplexed light to the rear end face and a plurality of backward waveguides connected to an output section of the backward optical multiplexer, wherein the plurality of backward waveguides includes a main waveguide disposed at a center of the output section and a plurality of lateral waveguides disposed on both sides of the main waveguide to bend toward the side faces and output light from the side faces diagonally to the side faces.Type: GrantFiled: January 9, 2017Date of Patent: October 31, 2017Assignee: Mitsubishi Electric CorporationInventors: Ryosuke Nagao, Yoshifumi Sasahata, Eitaro Ishimura
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Patent number: 9147997Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; an optical amplifying section amplifying output light of the wave coupling section; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a light intensity lowering section located in each of the first optical waveguides and lower light intensity of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the respective semiconductor lasers; to decrease line width of the light output by the semiconductor lasers.Type: GrantFiled: April 23, 2015Date of Patent: September 29, 2015Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
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Publication number: 20150229407Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; an optical amplifying section amplifying output light of the wave coupling section; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a light intensity lowering section located in each of the first optical waveguides and lower light intensity of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the respective semiconductor lasers; to decrease line width of the light output by the semiconductor lasers.Type: ApplicationFiled: April 23, 2015Publication date: August 13, 2015Inventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
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Patent number: 9042008Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a phase regulator regulating phase of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the semiconductor lasers; a second optical waveguide optically connecting the wave coupling section to the phase regulator; an optical amplifying section amplifying output light of the phase regulator; and a third optical waveguide optically connecting an output of the phase regulator to the optical amplifying section. The phase regulator adjusts the phase of reflected light that returns to the semiconductor lasers to decrease line width of the light output by the semiconductor lasers.Type: GrantFiled: March 14, 2014Date of Patent: May 26, 2015Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
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Publication number: 20140198378Abstract: An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a phase regulator regulating phase of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the semiconductor lasers; a second optical waveguide optically connecting the wave coupling section to the phase regulator; an optical amplifying section amplifying output light of the phase regulator; and a third optical waveguide optically connecting an output of the phase regulator to the optical amplifying section. The phase regulator adjusts the phase of reflected light that returns to the semiconductor lasers to decrease line width of the light output by the semiconductor lasers.Type: ApplicationFiled: March 14, 2014Publication date: July 17, 2014Applicant: Mitsubishi Electric CorporationInventors: Takeshi Saito, Masakazu Takabayashi, Eitaro Ishimura, Tohru Takiguchi, Kazuhisa Takagi, Keisuke Matsumoto, Yoshifumi Sasahata
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Publication number: 20140056556Abstract: An optical semiconductor device includes: semiconductor lasers separated into two groups; an optical coupler combining light output from the semiconductor lasers; an optical amplifier amplifying light output from the optical coupler; and waveguides respectively connecting the semiconductor lasers to the optical coupler. Each of the waveguides includes a respective bent waveguide. The bent waveguides have the same radius of curvature.Type: ApplicationFiled: March 15, 2013Publication date: February 27, 2014Applicant: Mitsubishi Electric CorporationInventors: Yoshifumi Sasahata, Tohru Takiguchi, Keisuke Matsumoto, Masakazu Takabayashi
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Patent number: 8659053Abstract: A semiconductor light detecting element includes: an InP substrate; and a semiconductor stacked structure on the InP substrate and including at least a light absorbing layer, wherein the light absorbing layer includes an InGaAsBi layer lattice-matched to the InP substrate.Type: GrantFiled: August 28, 2012Date of Patent: February 25, 2014Assignee: Mitsubishi Electric CorporationInventors: Yoshifumi Sasahata, Eitaro Ishimura
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Publication number: 20130207160Abstract: A semiconductor light detecting element includes: an InP substrate; and a semiconductor stacked structure on the InP substrate and including at least a light absorbing layer, wherein the light absorbing layer includes an InGaAsBi layer lattice-matched to the InP substrate.Type: ApplicationFiled: August 28, 2012Publication date: August 15, 2013Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Yoshifumi SASAHATA, Eitaro ISHIMURA
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Publication number: 20120299141Abstract: An avalanche photodiode including a semiconductor substrate of a first conductivity type, an avalanche multiplication layer, an electric field control layer, a light absorption layer, and a window layer wherein the layers are laid one on another in this order on a major surface of the semiconductor substrate, an impurity region of a second conductivity type in a portion of the window layer, and a straight electrode on the impurity region and connected to the impurity region, the straight electrode being straight as viewed in a plan view facing the major surface of the semiconductor substrate.Type: ApplicationFiled: December 15, 2011Publication date: November 29, 2012Applicant: Mitsubishi Electric CorporationInventors: Yoshifumi Sasahata, Masaharu Nakaji
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Publication number: 20110303949Abstract: A semiconductor light-detecting element includes: a semiconductor substrate of a first conductivity type; a light absorption recoupling layer of the first conductivity type, a multilayer reflection film of the first conductivity type, a light absorbing layer, and a window layer, which are laminated, in that order, on the semiconductor substrate; a doped region of a second conductivity type in part of the window layer; a first electrode connected to the doped region; and a second electrode connected to an underside of the semiconductor substrate. The band gap energy of the window layer is larger than the band gap energy of the light absorbing layer, and the band gap energy of the light absorption recoupling layer is smaller than the band gap energy of the semiconductor substrate.Type: ApplicationFiled: January 28, 2011Publication date: December 15, 2011Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Yoshifumi Sasahata, Masaharu Nakaji
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Publication number: 20090225804Abstract: A semiconductor laser comprises an active section for generating light, and a peripheral section as resonator for producing laser light from the generated light, and includes an InP substrate. The active section has a lower cladding layer formed of AlInAs or AlGaInAs, a core layer including an active layer formed of AlGaInAs or InGaAsP, and an upper cladding layer formed of AlInAs or AlGaInAs. The peripheral section has a first cladding layer formed by oxidizing AlInAs or AlGaInAs, a core layer, and a second clad layer formed by oxidizing AlInAs or AlGaInAs, and a two-dimensional photonic crystal defined by an array of regularly spaced apart holes the peripheral section.Type: ApplicationFiled: February 25, 2009Publication date: September 10, 2009Applicants: MITSUBISHI ELECTRIC CORPORATION, OSAKA UNIVERSITYInventors: Yoshifumi Sasahata, Keisuke Matsumoto, Toshitaka Aoyagi, Masahiko Kondow, Masato Morifuji, Hideki Momose