Patents by Inventor Kenichiro Yashiki
Kenichiro Yashiki 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: 10535786Abstract: Provided is a light receiving element with high light receiving sensitivity. The light receiving element comprises: a light absorbing layer that absorbs light to generate a carrier; and a diffraction element that converts the optical path of first polarized light, which is obliquely incident on a plane formed by the light absorbing layer, so that the first polarized light propagates in a first direction along the light absorbing layer, and that converts the optical path of second polarized light incident from the same direction as the first polarized light so that the second polarized light propagates in a second direction, opposite the first direction, along the light absorbing layer.Type: GrantFiled: December 16, 2015Date of Patent: January 14, 2020Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Kenichiro Yashiki, Jun Ushida, Masatoshi Tokushima, Kazuhiko Kurata
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Patent number: 10353225Abstract: The purpose of the present invention is to allow a silicon photonics modulator to be operated at high speed with high frequency by providing an electrode structure for the small multichannel high-density silicon photonics modulator. This electrode structure for a silicon photonics modulator includes, on the planar surface of a silicon substrate, a first layer for forming a plurality of bias electrical wirings, and a second layer formed by aligning each of a plurality of ground electrode portions and each electrical wiring in the first layer.Type: GrantFiled: August 11, 2015Date of Patent: July 16, 2019Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Kenichiro Yashiki, Yasuyuki Suzuki
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Publication number: 20180231809Abstract: The purpose of the present invention is to allow a silicon photonics modulator to be operated at high speed with high frequency by providing an electrode structure for the small multichannel high-density silicon photonics modulator. This electrode structure for a silicon photonics modulator includes, on the planar surface of a silicon substrate, a first layer for forming a plurality of bias electrical wirings, and a second layer formed by aligning each of a plurality of ground electrode portions and each electrical wiring in the first layer.Type: ApplicationFiled: August 11, 2015Publication date: August 16, 2018Inventors: Kenichiro Yashiki, Yasuyuki Suzuki
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Publication number: 20170345952Abstract: Provided is a light receiving element with high light receiving sensitivity. The light receiving element comprises: a light absorbing layer that absorbs light to generate a carrier; and a diffraction element that converts the optical path of first polarized light, which is obliquely incident on a plane formed by the light absorbing layer, so that the first polarized light propagates in a first direction along the light absorbing layer, and that converts the optical path of second polarized light incident from the same direction as the first polarized light so that the second polarized light propagates in a second direction, opposite the first direction, along the light absorbing layer.Type: ApplicationFiled: December 16, 2015Publication date: November 30, 2017Applicant: Photonics Electronics Technology Research AssociationInventors: Kenichiro Yashiki, Jun Ushida, Masatoshi Tokushima, Kazuhiko Kurata
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Patent number: 9772461Abstract: A semiconductor integrated circuit that reduces a loss in an electrical signal and a method for manufacturing the semiconductor integrated circuit are provided. The semiconductor integrated circuit comprises a first region on which an optical circuit is to be formed and a second region on which an electrical signal wiring is to be formed. The first region comprises an Si substrate (502), a BOX layer (504) formed on the Si substrate (502), a first SOI layer (506) formed as an optical circuit on the BOX layer (504), and a first SiO2 layer (508) formed on the first SOI layer (506). The second region comprises the Si substrate (502), the BOX layer (504), a second SiO2 layer (508) formed on the BOX layer (504), and an electrical signal wiring (510) formed on the second SiO2 layer (508).Type: GrantFiled: October 1, 2014Date of Patent: September 26, 2017Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Yasuyuki Suzuki, Kenichiro Yashiki, Kazuhiko Kurata
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Patent number: 9775245Abstract: A pad-array arrangement structure on a substrate for mounting an IC chip on the substrate, wherein a structure with which it is possible to maximally avoid an increase in the number of wiring layers on the substrate is obtained by devising the pad arrangement in an IC pad-array region. A embodiment of the present invention provides a pad-array structure on a substrate for mounting an IC chip on the substrate. The present invention is characterized in that: a plurality of ground pads arrayed equidistantly in a first row, and a plurality of signal pads arrayed equidistantly in a second row on the inside of and parallel to the first row, are provided on a first circumferential edge in the pad-array region; each of the signal pads passes between two adjacent ground pads in the first row and is connected to an external circuit on the substrate; and electrical signals are input to and output from the external circuit.Type: GrantFiled: March 18, 2015Date of Patent: September 26, 2017Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Takeshi Akagawa, Kenichiro Yashiki
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Publication number: 20170105284Abstract: A pad-array arrangement structure on a substrate for mounting an IC chip on the substrate, wherein a structure with which it is possible to maximally avoid an increase in the number of wiring layers on the substrate is obtained by devising the pad arrangement in an IC pad-array region. A embodiment of the present invention provides a pad-array structure on a substrate for mounting an IC chip on the substrate. The present invention is characterized in that: a plurality of ground pads arrayed equidistantly in a first row, and a plurality of signal pads arrayed equidistantly in a second row on the inside of and parallel to the first row, are provided on a first circumferential edge in the pad-array region; each of the signal pads passes between two adjacent ground pads in the first row and is connected to an external circuit on the substrate; and electrical signals are input to and output from the external circuit.Type: ApplicationFiled: March 18, 2015Publication date: April 13, 2017Inventors: Takeshi AKAGAWA, Kenichiro YASHIKI
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Patent number: 9577407Abstract: This present invention is provided with: a semiconductor laser for emitting laser light in a plurality of channels; optical waveguides optically coupled in a corresponding manner to the semiconductor lasers, the optical waveguides propagating laser light as input light for each channel; optical modulators for modulating the input light and generating an optical signal; and an optical signal output unit coupled to the optical modulators, the optical signal output unit outputting the optical signal propagated from the optical modulators to the exterior. The present invention is characterized in that the semiconductor laser is arranged on the opposite side from an optical branching unit and the optical modulators, with the optical signal output unit interposed therebetween, in the plane of an opto-electric hybrid board.Type: GrantFiled: July 18, 2014Date of Patent: February 21, 2017Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Kenichiro Yashiki, Kazuhiko Kurata
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Patent number: 9519115Abstract: An optical circuit, wherein the effects of reflected light generated by an optical component are reduced. The optical circuit (100) is provided with an optical branching (110) for branching light, an optical coupler (114) for coupling a first portion of branched light to an optical waveguide (118) for transmission, and an optical reflecting unit (116) for reflecting a second portion of the branched light, the phase difference between the reflected light from the optical coupler (114) and the reflected light from the optical reflecting unit (116) being (2m?1)? (where m is an integer) on an input side of the optical branching (110).Type: GrantFiled: March 19, 2014Date of Patent: December 13, 2016Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATIONInventors: Kenichiro Yashiki, Masatoshi Tokushima
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Publication number: 20160266333Abstract: A semiconductor integrated circuit that reduces a loss in an electrical signal and a method for manufacturing the semiconductor integrated circuit are provided. The semiconductor integrated circuit comprises a first region on which an optical circuit is to be formed and a second region on which an electrical signal wiring is to be formed. The first region comprises an Si substrate (502), a BOX layer (504) formed on the Si substrate (502), a first SOI layer (506) formed as an optical circuit on the BOX layer (504), and a first SiO2 layer (508) formed on the first SOI layer (506). The second region comprises the Si substrate (502), the BOX layer (504), a second SiO2 layer (508) formed on the BOX layer (504), and an electrical signal wiring (510) formed on the second SiO2 layer (508).Type: ApplicationFiled: October 1, 2014Publication date: September 15, 2016Applicant: Photonics Electronics Technology Research Associat ionInventors: Yasuyuki Suzuki, Kenichiro Yashiki, Kazuhiko Kurata
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Publication number: 20160164251Abstract: Provided is a transmission unit for an optical transmitter/receiver or an optical transmitter provided with an optical integrated circuit, characterized in the arrangement of a single-channel or multichannel semiconductor laser and the placement of a plurality of optical waveguides. This present invention is provided with: a semiconductor laser for emitting laser light in a plurality of channels; optical waveguides optically coupled in a corresponding manner to the semiconductor lasers, the optical waveguides propagating laser light as input light for each channel; optical modulators for modulating the input light and generating an optical signal; and an optical signal output unit coupled to the optical modulators, the optical signal output unit outputting the optical signal propagated from the optical modulators to the exterior.Type: ApplicationFiled: July 18, 2014Publication date: June 9, 2016Inventors: Kenichiro Yashiki, Kazuhiko Kurata
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Publication number: 20160054529Abstract: An optical circuit, wherein the effects of reflected light generated by an optical component are reduced. The optical circuit (100) is provided with an optical branching (110) for branching light, an optical coupler (114) for coupling a first portion of branched light to an optical waveguide (118) for transmission, and an optical reflecting unit (116) for reflecting a second portion of the branched light, the phase difference between the reflected light from the optical coupler (114) and the reflected light from the optical reflecting unit (116) being (2m?1)? (where m is an integer) on an input side of the optical branching (110).Type: ApplicationFiled: March 19, 2014Publication date: February 25, 2016Inventors: Kenichiro Yashiki, Masatoshi Tokushima
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Patent number: 7974328Abstract: The present invention provides a surface-emission type semiconductor laser wherein an effective length of a cavity is reduced, thereby enabling to realize a higher-speed direct modulation. In the surface-emission type semiconductor laser according to the present invention, when supposing the optical path length (L) of a resonator part relative to a lasing wavelength ?0 to be given as 0.9×?0?L?1.1×?0, and denoting the refractive indexes of a high refractive index layer and a low refractive index layer of a dielectric DBR by nH1 and nL1; the average refractive index within an optical path length ?0/4 in the semiconductor in contact with the dielectric DBR by nS1; and the refractive indexes of the high refractive index layer and the low refractive index layer of a semiconductor DBR by nH2 and nL2, respective materials to be used are selected so as to satisfy the following conditions (1) and (2): nH1>f(nS1)nL12+g(nS1)nL1+h(nS1),??(1) where f(nS1)=0.0266 nS12?0.2407 nS1+0.6347; g(nS1)=?0.0508 nS12+0.Type: GrantFiled: March 14, 2008Date of Patent: July 5, 2011Assignee: NEC CorporationInventors: Naofumi Suzuki, Masayoshi Tsuji, Takayoshi Anan, Kenichiro Yashiki, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takeshi Akagawa
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Patent number: 7940828Abstract: An optical communication system for performing data transmission with optical signals comprises a first optical transmitter and a first optical receiver. The first optical transmitter has a first surface-emitting laser including an active layer of a multiple quantum well structure having a quantum well layer of InxGa1-xAs (0.15?x?0.35), the first surface-emitting laser having an oscillation wavelength ranging from 1000 nm to 1100 nm inclusive. The first optical transmitter transmits an optical signal generated by the first surface-emitting laser. The first optical receiver is connected to the first optical transmitter by a first optical transfer path, and receives the optical signal transmitted from the first optical transmitter through the first optical transfer path.Type: GrantFiled: December 27, 2006Date of Patent: May 10, 2011Assignee: NEC CorporationInventors: Masayoshi Tsuji, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takayoshi Anan, Naofumi Suzuki, Kenichiro Yashiki
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Patent number: 7881358Abstract: A surface emitting laser is provided with a first multilayer Bragg reflecting mirror including a first layer, a second multilayer Bragg reflecting mirror including a second layer, and an optical resonator unit that is held between these multilayer Bragg reflecting mirrors and includes an active layer. Further, the optical resonator unit contacts with the first layer and second layer respectively. The effective refraction index neff of the resonator unit is larger than either the first layer or the second layer, and an optical length neffL of the optical resonator unit has a relationship with an oscillating wavelength ? of the surface emitting laser to satisfy the following relationship: 0.5?<neffL?0.7?.Type: GrantFiled: December 18, 2007Date of Patent: February 1, 2011Assignee: NEC CorporationInventors: Takayoshi Anan, Naofumi Suzuki, Kenichiro Yashiki, Masayoshi Tsuji, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takeshi Akagawa
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Publication number: 20100034233Abstract: The present invention provides a surface-emission type semiconductor laser wherein an effective length of a cavity is reduced, thereby enabling to realize a higher-speed direct modulation. In the surface-emission type semiconductor laser according to the present invention, when supposing the optical path length (L) of a resonator part relative to a lasing wavelength ?0 to be given as 0.9×?0?L?1.1×?0, and denoting the refractive indexes of a high refractive index layer and a low refractive index layer of a dielectric DBR by nH1 and nL1; the average refractive index within an optical path length ?0/4 in the semiconductor in contact with the dielectric DBR by nS1; and the refractive indexes of the high refractive index layer and the low refractive index layer of a semiconductor DBR by nH2 and nL2, respective materials to be used are selected so as to satisfy the following conditions (1) and (2): nH1>f(nS1)nL12+g(nS1)nL1+h(nS1),??(1) where f(nS1)=0.0266 nS12?0.2407 nS1+0.6347; g(nS1)=?0.0508 nS12+0.Type: ApplicationFiled: March 14, 2008Publication date: February 11, 2010Inventors: Naofumi Suzuki, Masayoshi Tsuji, Takayoshi Anan, Kenichiro Yashiki, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takeshi Akagawa
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Publication number: 20100020835Abstract: A surface emitting laser is provided with a first multilayer Bragg reflecting mirror including a first layer, a second multilayer Bragg reflecting mirror including a second layer, and an optical resonator unit that is held between these multilayer Bragg reflecting mirrors and includes an active layer. Further, the optical resonator unit contacts with the first layer and second layer respectively. The effective refraction index neff of the resonator unit is larger than either the first layer or the second layer, and an optical length neffL of the optical resonator unit has a relationship with an oscillating wavelength ? of the surface emitting laser to satisfy the following relationship: 0.5?<neffL?0.7?.Type: ApplicationFiled: December 18, 2007Publication date: January 28, 2010Inventors: Takayoshi Anan, Naofumi Suzuki, Kenichiro Yashiki, Masayoshi Tsuji, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takeshi Akagawa
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Publication number: 20090080488Abstract: A surface emitting laser including a semiconductor substrate, a semiconductor substrate, a first reflector formed on the semiconductor substrate, an active layer formed on the first reflector, a tunnel junction layer formed above a part of the active layer, a semiconductor spacer layer which covers the tunnel junction layer, a second reflector formed on the semiconductor spacer layer in a region above the tunnel junction layer, a first electrode formed in the periphery of the second reflector on the semiconductor spacer layer, and a second electrode electrically connected to a layer lower than the active layer, wherein a layer thickness of the semiconductor spacer layer in the region directly above the tunnel junction layer is thinner than the layer thickness of the semiconductor spacer layer in the region directly below the first electrode.Type: ApplicationFiled: September 24, 2008Publication date: March 26, 2009Applicant: NEC CORPORATIONInventors: Hiroshi HATAKEYAMA, Naofumi SUZUKI, Kenichiro YASHIKI, Takeshi AKAGAWA, Takayoshi ANAN, Masayoshi TSUJI, Kimiyoshi FUKATSU
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Publication number: 20090028201Abstract: An optical communication system for performing data transmission with optical signals comprises a first optical transmitter and a first optical receiver. The first optical transmitter has a first surface-emitting laser including an active layer of a multiple quantum well structure having a quantum well layer of InxGa1-xAs (0.15?x?0.35), the first surface-emitting laser having an oscillation wavelength ranging from 1000 nm to 1100 nm inclusive. The first optical transmitter transmits an optical signal generated by the first surface-emitting laser. The first optical receiver is connected to the first optical transmitter by a first optical transfer path, and receives the optical signal transmitted from the first optical transmitter through the first optical transfer path.Type: ApplicationFiled: December 27, 2006Publication date: January 29, 2009Applicant: NEC CORPORATIONInventors: Masayoshi Tsuji, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takayoshi Anan, Naofumi Suzuki, Kenichiro Yashiki
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Publication number: 20080317476Abstract: A vehicle-mounted optical communication system, which uses an optical signal to perform data transmission, comprises a first optical transmitter and an optical receiver. The first optical transmitter, which is mounted on a vehicle, has a multiple quantum well structure, in which an active layer has a quantum well layer of InxGa1-xAs (where 0.15?x?0.35), and includes a first surface emitting laser the oscillation wavelength of which is between 1000 nm and 1100 nm inclusive. The first optical transmitter transmits an optical signal generated by the first surface emitting laser. The optical receiver, which is mounted on the vehicle and connected to the first optical transmitter via a first optical transmission path, receives the optical signal, which was transmitted by the first optical transmitter, via the first optical transmission path.Type: ApplicationFiled: December 28, 2006Publication date: December 25, 2008Applicant: NEC CORPORATIONInventors: Masayoshi Tsuji, Hiroshi Hatakeyama, Kimiyoshi Fukatsu, Takayoshi Anan, Naofumi Suzuki, Kenichiro Yashiki