Patents Assigned to Photonics Electronics Technology Research Association
  • Patent number: 10911148
    Abstract: An optical transmission apparatus includes first and second optical waveguides to transmit light of multiple wavelengths; optical couplers on the waveguides, to couple the lights transmitted through the waveguides, so as to output the coupled light to the waveguides; phase shifters provided at preceding stages of part of the optical couplers, to change a phase shift amount of the light transmitted through the first and/or second optical waveguides, wherein the number of optical couplers in the part is greater than or equal to the number of the types of wavelengths; a monitor to monitor the intensity of the light output to the second optical waveguide via the optical coupler at the last stage; and a controller to control the phase shifters by changing the phase shift amount for each of the phase shifters in a direction in which the output of the monitor decreases.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: February 2, 2021
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Tomoyuki Akiyama
  • Publication number: 20200389247
    Abstract: An optical add-drop device includes optical circuits. Each of the optical circuits includes first to third sub optical circuits. Each sub optical circuit includes an input coupler, output coupler, and a phase shifter. In each of the optical circuit, two ports of the output coupler in the first sub optical circuit are respectively coupled to the input coupler in the second sub optical circuit and the input coupler in the third sub optical circuit. The output coupler in the second sub optical circuit in each of the optical circuits is coupled to a drop port or the input coupler in the first sub optical circuit in the adjacent optical circuit. The input coupler in the third sub optical circuit in each of the optical circuits is coupled to an add port or the output coupler in the third sub optical circuit in the adjacent optical circuit.
    Type: Application
    Filed: May 28, 2020
    Publication date: December 10, 2020
    Applicants: FUJITSU LIMITED, Photonics Electronics Technology Research Association
    Inventor: Tomoyuki Akiyama
  • Publication number: 20200379181
    Abstract: An optical demultiplexer is disclosed that separates light including a plurality of wavelengths into light of respective wavelengths. Unit circuits are cascaded in a tree structure. In optical demultiplexer components having the same structure, a combination of arm length differences in waveguide pairs is the same with respect to the N?1 Asymmetric Mach-Zehnder interferometers in which the phase shifters are arranged, where N equals number of 2×2 couplers. In three of the optical demultiplexer components in at least one of the unit circuits, N is three or more. Each of control circuits controls the phase shifters arranged in a corresponding optical demultiplexer component of a corresponding unit circuit in order to increase or decrease a value of a function having, as an argument, a power value acquired by a monitor from among monitors arranged at four optical waveguides at an output side of the corresponding unit circuit.
    Type: Application
    Filed: May 27, 2020
    Publication date: December 3, 2020
    Applicants: FUJITSU LIMITED, Photonics Electronics Technology Research Association
    Inventor: Tomoyuki Akiyama
  • Publication number: 20200363695
    Abstract: An optical semiconductor device including an optical waveguide; a light absorbing region coupled to the optical waveguide; a first conductive region and a second conductive region disposed at both sides of the light absorbing region so as to sandwich the light absorbing region; and a conductor coupled to the first conductive region and the second conductive region to let the first conductive region and the second conductive region short-circuit. With this configuration, the optical semiconductor device provides effects that absorption saturation less occurs even if the light intensity increases, so that reflection return light can be reliably suppressed without using an external power source.
    Type: Application
    Filed: April 17, 2020
    Publication date: November 19, 2020
    Applicants: FUJITSU LIMITED, Photonics Electronics Technology Research Association
    Inventor: Takasi Simoyama
  • Patent number: 10830950
    Abstract: An optical transmitter-receiver includes an optical integrated device in which at least an optical modulator and an optical detector are integrated as optical devices over the same substrate and an insulating layer is provided between the optical modulator and the substrate and between the optical detector and the substrate, and an electronic circuit chip that is connected to the optical integrated device and includes an electronic circuit including a ground wiring line. The optical integrated device includes a shield electrode between the optical modulator and the optical detector, and the shield electrode is provided sandwiching the insulating layer with the substrate to configure a capacitance and is connected to the ground wiring line of the electronic circuit chip.
    Type: Grant
    Filed: October 31, 2019
    Date of Patent: November 10, 2020
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventors: Shinsuke Tanaka, Tatsuya Usuki
  • Publication number: 20200264375
    Abstract: To provide an optical element that can be more easily aligned with an optical fiber, an optical element includes one grating coupler optically coupled to an optical fiber, a waveguide connected to the grating coupler, a multimode interferometer connected to the waveguide on the opposite side to the grating coupler, and a waveguide inserted between two input/output ports on the branched side of the multimode interferometer.
    Type: Application
    Filed: February 12, 2020
    Publication date: August 20, 2020
    Applicants: NEC Corporation, Photonics Electronics Technology Research Association
    Inventors: Masatoshi TOKUSHIMA, Jun USHIDA
  • Publication number: 20200150340
    Abstract: An optical transmitter-receiver includes an optical integrated device in which at least an optical modulator and an optical detector are integrated as optical devices over the same substrate and an insulating layer is provided between the optical modulator and the substrate and between the optical detector and the substrate, and an electronic circuit chip that is connected to the optical integrated device and includes an electronic circuit including a ground wiring line. The optical integrated device includes a shield electrode between the optical modulator and the optical detector, and the shield electrode is provided sandwiching the insulating layer with the substrate to configure a capacitance and is connected to the ground wiring line of the electronic circuit chip.
    Type: Application
    Filed: October 31, 2019
    Publication date: May 14, 2020
    Applicants: FUJITSU LIMITED, Photonics Electronics Technology Research Association
    Inventors: Shinsuke Tanaka, Tatsuya Usuki
  • Patent number: 10644822
    Abstract: A network system comprises a plurality of nodes and a plurality of optical amplifiers. A first node comprises a first transmitter configured to send a wavelength-division-multiplexed optical signal and a first receiver configured to receive a wavelength-division-multiplexed optical signal, and the second node comprises a second transmitter configured to send a wavelength-division-multiplexed optical signal and a second receiver configured to receive a wavelength-division-multiplexed optical signal. The first and second transmitters are optically connected to an input of the first optical amplifier and an input of the second optical amplifier, respectively, and the first and second receivers are optically connected to an output of the first optical amplifier and an output of the second optical amplifier, respectively. The receivers each comprise a photoreceiver and a reception circuit. The photoreceiver is electrically connected, by flip chip connection, to a reception circuit.
    Type: Grant
    Filed: September 6, 2017
    Date of Patent: May 5, 2020
    Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Yutaka Urino
  • Publication number: 20200132951
    Abstract: An optical device includes a light-emitting element; an electronic circuit chip; a substrate on which the light-emitting element and the electronic circuit chip are mounted; a first electrode formed on a first mounting surface of the light-emitting element on the substrate; and a second electrode formed on a second mounting surface of the electronic circuit chip on the substrate. The first electrode and the second electrode have the same structure.
    Type: Application
    Filed: October 21, 2019
    Publication date: April 30, 2020
    Applicants: FUJITSU LIMITED, NEC Corporation, Photonics Electronics Technology Research Association
    Inventors: Nobuaki HATORI, Keizo KINOSHITA
  • Publication number: 20200136729
    Abstract: An optical transmission apparatus includes first and second optical waveguides to transmit light of multiple wavelengths; optical couplers on the waveguides, to couple the lights transmitted through the waveguides, so as to output the coupled light to the waveguides; phase shifters provided at preceding stages of part of the optical couplers, to change a phase shift amount of the light transmitted through the first and/or second optical waveguides, wherein the number of optical couplers in the part is greater than or equal to the number of the types of wavelengths; a monitor to monitor the intensity of the light output to the second optical waveguide via the optical coupler at the last stage; and a controller to control the phase shifters by changing the phase shift amount for each of the phase shifters in a direction in which the output of the monitor decreases.
    Type: Application
    Filed: October 17, 2019
    Publication date: April 30, 2020
    Applicants: FUJITSU LIMITED, Photonics Electronics Technology Research Association
    Inventor: Tomoyuki AKIYAMA
  • Publication number: 20200092196
    Abstract: A parallel computer system includes: direct links that forms a direct connection between a sending node and a receiving node, one-hop links that forms a connection between a sending node and a receiving node by way of a return node that is other than the sending node and the receiving node, and a communication control unit that, when transferring data from a sending node to a receiving node, selects the link that connects the sending node and the receiving node from among a link that uses only a direct link, a link that uses only a one-hop link, and a link that forms a connection combines and uses the direct link and the one-hop link.
    Type: Application
    Filed: September 6, 2019
    Publication date: March 19, 2020
    Applicants: NEC CORPORATION, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION, FUJITSU LIMITED
    Inventors: Kenji MIZUTANI, Yutaka URINO, Tatsuya USUKI
  • Patent number: 10580923
    Abstract: A disclosed optical semiconductor device includes a first semiconductor layer having a first refractive index and a first optical absorption coefficient; and a second semiconductor layer formed on the first semiconductor layer, the second semiconductor layer having a second refractive index and a second optical absorption coefficient. The second refractive index is larger than the first refractive index, and the second optical absorption coefficient is larger than the first optical absorption coefficient. The first semiconductor layer includes a first region of p-type, a second region of n-type, a third region of p-type or n-type between the first region and the second region, a fourth region of i-type between the first region and the third region, and a fifth region of i-type between the second region and the third region. The second semiconductor layer is formed on the first region, the fourth region, and the third region.
    Type: Grant
    Filed: May 30, 2019
    Date of Patent: March 3, 2020
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Takasi Simoyama
  • Patent number: 10547406
    Abstract: An optical element includes a gain chip, a ring modulator, which is a band-pass filter, a first optical waveguide and a second optical waveguide that are optically connected to the ring modulator, and a heater, wherein the first optical waveguide and the second optical waveguide are formed to be equal in optical path length (have no difference in optical path length) between a first light coupling point and a second light coupling point and equal in shape and length between the first light coupling point and the second light coupling point (to be symmetrical with the ring modulator interposed therebetween (with respect to the ring modulator)).
    Type: Grant
    Filed: July 6, 2017
    Date of Patent: January 28, 2020
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Tomoyuki Akiyama
  • Patent number: 10535786
    Abstract: 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: Grant
    Filed: December 16, 2015
    Date of Patent: January 14, 2020
    Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventors: Kenichiro Yashiki, Jun Ushida, Masatoshi Tokushima, Kazuhiko Kurata
  • Publication number: 20190384135
    Abstract: Provided is a SIS-type electro-optic modulator capable of realizing highly efficient optical coupling with a rib-type Si waveguide, improving modulation efficiency, realizing reduction of electric capacity and lead-out resistance in stacked semiconductor layers. The modulator includes a SIS junction constituted by first and second semiconductor layers having different type of conductivity and a dielectric layer interposed therebetween, wherein an electrical signal from electrodes coupled to the first and second semiconductor layers causes free carriers accumulate, deplete or invert on both sides of the dielectric layer, thereby modulating a free carrier concentration felt by an optical signal electric filed, light having a polarization component orthogonal to the width direction of the SIS junction is incident on the dielectric layer, and the width of the SIS junction is ?/neff or less (? is the wavelength of the incident light and neff is an effective refractive index of the modulator to the incident light).
    Type: Application
    Filed: June 13, 2019
    Publication date: December 19, 2019
    Applicants: NEC CORPORATION, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventors: Shigeki TAKAHASHI, Junichi FUJIKATA
  • Patent number: 10491321
    Abstract: An optical demultiplexer has at least one unit circuit formed by three AMZs having a same arm length difference and cascaded in a tree structure in which two output ports of the 1st AMZ are connected to the 2nd AMZ and the 3rd AMZ, respectively, wherein the unit circuit has first and second monitors connected to the first and second output ports of the 2nd AMZ, and third and fourth monitors connected to the first and second output ports of the 3rd AMZ, a first control circuit controlling the transmissivity of the 1st AMZ so as to increase the monitoring result of the second and fourth monitors, a second control circuit controlling the transmissivity of the 2nd AMZ to decrease the monitoring result of the first monitor, and a third control circuit controlling the transmissivity of the 3rd AMZ to decrease the monitoring result of the third monitor.
    Type: Grant
    Filed: January 23, 2019
    Date of Patent: November 26, 2019
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Tomoyuki Akiyama
  • Patent number: 10488596
    Abstract: The invention relates to an optical fiber mounted photonic integrated circuit device, wherein the tolerance for positioning in terms of the coupling between the single mode optical fibers and the optical waveguides provided on the photonic integrated circuit device is increased. An optical waveguide core group is provided in such a manner where a plurality of optical waveguide cores having a portion that is tapered in the direction of the width within a plane are aligned parallel to each other at intervals that allow for mutual directional coupling and that are narrower than the width of the core of the single mode optical fiber, and the inclined connection end surface of the single mode optical fiber and the upper surface of an end portion of the optical waveguide cores face each other for coupling.
    Type: Grant
    Filed: August 28, 2017
    Date of Patent: November 26, 2019
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Tomoyuki Akiyama
  • Patent number: 10439729
    Abstract: A demultiplexing unit that is provided in an optical device and performs demultiplexing into a plurality of optical signals having wavelengths different from each other includes a plurality of optical filters that are coupled in multiple stages and in which a period of a peak wavelength of a transmission spectrum differs among different stages, a monitoring optical filter coupled to one of the plurality of optical filters, a monitoring photodetector coupled to the output side of the monitoring optical filter, and a plurality of wavelength adjustment units that are provided individually for the plurality of optical filters and the monitoring optical filter and cause wavelength shifts of an equal amount in a same direction.
    Type: Grant
    Filed: August 30, 2018
    Date of Patent: October 8, 2019
    Assignees: FUJITSU LIMITED, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Tomoyuki Akiyama
  • Publication number: 20190285916
    Abstract: An electro-absorption optical modulator capable of realizing optical coupling with a Si waveguide with high efficiency, improving modulation efficiency, reducing light absorption by an electrode layer and achieving low optical loss includes a substrate; a first silicon layer doped to exhibit a first type of conductivity and a second silicon layer doped to exhibit a second type of conductivity that are disposed parallel to the substrate; and a Ge1?xSix (0<x<1)/Si stack in which a Ge1?xSix layer and a Si layer are stacked on the first and second silicon layers in this order.
    Type: Application
    Filed: March 15, 2019
    Publication date: September 19, 2019
    Applicants: NEC CORPORATION, PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Junichi FUJIKATA
  • Publication number: 20190268085
    Abstract: In an embodiment, a network system comprises a plurality of nodes and a plurality of optical amplifiers. A first node comprises a first transmitter configured to send a wavelength-division-multiplexed optical signal and a first receiver configured to receive a wavelength-division-multiplexed optical signal, and the second node comprises a second transmitter configured to send a wavelength-division-multiplexed optical signal and a second receiver configured to receive a wavelength-division-multiplexed optical signal. The first transmitter and the second transmitter are optically connected to an input of the first optical amplifier and an input of the second optical amplifier, respectively, and the first receiver and the second receiver are optically connected to an output of the first optical amplifier and an output of the second optical amplifier, respectively. Each of the first photoreceiver and the second photoreceiver comprises a photoreceiver and a reception circuit.
    Type: Application
    Filed: September 6, 2017
    Publication date: August 29, 2019
    Applicant: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventor: Yutaka Urino