Patents by Inventor Takeshi Hoshida

Takeshi Hoshida 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: 20220109506
    Abstract: An optical transmitter includes: a modulator, square law detector, and a processor. The modulator generates an optical signal indicating transmission data. The square law detector detects an intensity of the optical signal using a photodetector and output first intensity data indicating the detected intensity. The processor calculates, based on the transmission data, an electric field of the optical signal generated by the modulator by using parameters pertaining to a state of the modulator. The processor calculates second intensity data indicating the intensity of the optical signal based on the calculated electric field. The processor updates the parameters so as to reduce a difference between the first intensity data and the second intensity data. The processor controls the state of the modulator based on the parameters.
    Type: Application
    Filed: July 1, 2021
    Publication date: April 7, 2022
    Applicant: FUJITSU LIMITED
    Inventors: Setsuo Yoshida, Shoichiro Oda, KAZUYUKI TAJIMA, Takeshi Hoshida, Takahito Tanimura
  • Publication number: 20220070555
    Abstract: A transmission device including a demultiplexer configured to demultiplex a multiplexed light obtained by multiplexing the plurality of wavelength division multiplexing (WDM) optical signals including different wavelength bands into the plurality of WDM optical signals, a plurality of optical amplifiers configured to amplify the plurality of WDM optical signals, respectively, a wavelength converter configured to convert a first wavelength band of the wavelength bands of at least a first WDM optical signal of the plurality of WDM optical signals amplified by the plurality of optical amplifiers into a second wavelength band of the wavelength bands of a second WDM optical signal of the plurality of WDM optical signals so that the second wavelength band does not overlap among the wavelength bands, and a multiplexer configured to multiplex the plurality of WDM optical signals which include the wavelength bands converted by the wavelength converter.
    Type: Application
    Filed: June 28, 2021
    Publication date: March 3, 2022
    Applicant: FUJITSU LIMITED
    Inventors: Tomohiro YAMAUCHI, Tomoyuki Kato, Shigeki Watanabe, YU TANAKA, Takeshi Hoshida
  • Publication number: 20220060273
    Abstract: An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization.
    Type: Application
    Filed: November 1, 2021
    Publication date: February 24, 2022
    Applicant: FUJITSU LIMITED
    Inventors: Tomoyuki Kato, Shigeki Watanabe, Takeshi Hoshida
  • Patent number: 11243349
    Abstract: A device includes a first excitation light source that emits first excitation light, a second excitation light source that emits second excitation light, a wavelength converter that converts signal light of a first wavelength into signal light of a second wavelength according to the first excitation light, and a measurer that measures a frequency difference between the first excitation light and the second excitation light, wherein when an abnormality of the first excitation light is detected, the second excitation light source is adjusted so that a frequency of the second excitation light is aligned with a frequency of the first excitation light before the abnormality detection, based on the frequency difference before the abnormality detection, and the wavelength converter converts the signal light of the first wavelength into the signal light of the second wavelength according to the second excitation light, after adjusting the frequency of the second excitation light.
    Type: Grant
    Filed: December 6, 2019
    Date of Patent: February 8, 2022
    Assignee: FUJITSU LIMITED
    Inventors: Tomohiro Yamauchi, Takeshi Hoshida, Shingo Hara, Hiroki Satou
  • Patent number: 11228367
    Abstract: A communication device used in an optical communication system, the communication device includes a mode change over device configured to switch between a learning mode for learning a normal state of an optical transmission path before operation and a monitoring mode for monitoring a state of the optical transmission path during operation, an anomaly detector configured to detect an anomaly of the optical transmission path using a prediction model determined by the learning mode when the monitoring mode is selected, and a data writer configured to extract waveform data including information related to the anomaly to output the extracted waveform data to an outside when the anomaly is detected.
    Type: Grant
    Filed: November 11, 2019
    Date of Patent: January 18, 2022
    Assignee: FUJITSU LIMITED
    Inventors: Takahito Tanimura, Takeshi Hoshida
  • Patent number: 11190292
    Abstract: An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization.
    Type: Grant
    Filed: October 1, 2018
    Date of Patent: November 30, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Tomoyuki Kato, Shigeki Watanabe, Takeshi Hoshida
  • Patent number: 11165502
    Abstract: An optical transmission device includes: a frontend circuit, a converter, an equalizer, a recovery, spectrum detector a correction information generator, and a transmitter. The frontend circuit converts an optical signal received via an optical network into an electric signal. The converter converts an output signal of the frontend circuit into a digital signal. The equalizer equalizes the digital signal or a second digital signal that is generated based on the digital signal. The recovery recovers a symbol from an output signal of the equalizer. The spectrum detector detects a reception spectrum of the optical signal based on the digital signal or the second digital signal. The correction information generator generates, according to the reception spectrum, correction information for correcting a shape of a transmission spectrum of the optical signal. The transmitter transmits the correction information to the source device.
    Type: Grant
    Filed: July 9, 2019
    Date of Patent: November 2, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Yi Ge, Shoichiro Oda, Yuichi Akiyama, Takeshi Hoshida
  • Patent number: 11163119
    Abstract: A method includes multiplexing signal light of first polarization and excitation light, and multiplexing signal light of second polarization, which is perpendicular to the first polarization, and the excitation light, modulating the signal light of the first polarization before the wavelength conversion, and reducing a modulation component in signal light after wavelength conversion, modulating the signal light of the second polarization before the wavelength conversion, and reducing the modulation component in the signal light after the wavelength conversion, and multiplexing the signal light of the first polarization after the wavelength conversion and the signal light of the second polarization after the wavelength conversion.
    Type: Grant
    Filed: May 27, 2020
    Date of Patent: November 2, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Tomohiro Yamauchi, Tomoyuki Kato, Goji Nakagawa, Takeshi Hoshida
  • Publication number: 20210248454
    Abstract: An optical communication element includes a plurality of slabs, an input port group, an output port group, a first waveguide group, and a second waveguide group. The plurality of slabs includes third waveguide. Each of the plurality of slabs include a predetermined number of first ports being arranged at an inlet the third waveguide at equal intervals in a lateral direction perpendicular to a light traveling direction, and input the optical signals, and a predetermined number of second ports being arranged at an outlet of the third waveguide at the equal intervals in the lateral direction so as to face the first ports, and output the optical signals. Each of the third waveguides are configured with a dimension that allows light intensity to be distributed at all traveling positions located in the lateral direction.
    Type: Application
    Filed: February 8, 2021
    Publication date: August 12, 2021
    Applicant: FUJITSU LIMITED
    Inventors: Tomoyuki Akiyama, Shinsuke Tanaka, YASUHIRO NAKASHA, Takeshi Hoshida
  • Publication number: 20210226719
    Abstract: An optical system, comprising a first wavelength conversion module to: adjust a power of a first pump wavelength; couple an input signal with the first pump wavelength to generate a first coupled signal; perform a first wavelength conversion of the first coupled signal to generate a first wavelength converted signal, the power of the first pump wavelength is adjusted such that the first wavelength conversion is performed with 0 dB conversion efficiency; the optical amplifier to amplify the first wavelength converted signal; a second wavelength conversion module to: adjust a power of a second pump wavelength; couple the amplified first wavelength converted signal with the second pump wavelength to generate a second coupled signal; perform a second wavelength conversion of the second coupled signal to generate a second wavelength converted signal with 0 dB conversion efficiency.
    Type: Application
    Filed: January 21, 2020
    Publication date: July 22, 2021
    Applicant: Fujitsu Limited
    Inventors: Youichi Akasaka, Takeshi Hoshida
  • Patent number: 10999659
    Abstract: An optical network device receives an optical signal, to which polarization information is added, from a transmitter via a transmission line. The receiver generates electric-field-information signal of the optical signal. The processor acquires, for respective polarization rotation amounts, the electric-field-information signal during a period specified by the polarization information. The processor calculates, for respective polarization rotation amounts and based on the electric-field-information signal, evaluation values corresponding to powers of the optical signal at a plurality of positions on the transmission line. The processor calculates, for respective positions, variations in the evaluation values corresponding to the polarization rotation amounts.
    Type: Grant
    Filed: July 24, 2020
    Date of Patent: May 4, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Kazuyuki Tajima, Takahito Tanimura, Setsuo Yoshida, Takeshi Hoshida
  • Publication number: 20210092498
    Abstract: An optical network device receives an optical signal, to which polarization information is added, from a transmitter via a transmission line. The receiver generates electric-field-information signal of the optical signal. The processor acquires, for respective polarization rotation amounts, the electric-field-information signal during a period specified by the polarization information. The processor calculates, for respective polarization rotation amounts and based on the electric-field-information signal, evaluation values corresponding to powers of the optical signal at a plurality of positions on the transmission line. The processor calculates, for respective positions, variations in the evaluation values corresponding to the polarization rotation amounts.
    Type: Application
    Filed: July 24, 2020
    Publication date: March 25, 2021
    Applicant: FUJITSU LIMITED
    Inventors: KAZUYUKI TAJIMA, Takahito Tanimura, Setsuo Yoshida, Takeshi Hoshida
  • Patent number: 10955727
    Abstract: A wavelength converter includes an excitation light source outputting excitation light, a beam splitter receiving an input of the excitation light and an input of the optical signal and to divide both the inputted excitation light and the inputted optical signal into a first polarization component and a second polarization component, a non-linear optical fiber as a non-polarization-maintaining fiber, an accommodation section securing and accommodating the non-linear optical fiber, a first collimator lens disposed between the beam splitter and a first end of the non-linear optical fiber, and a second collimator lens disposed between the beam splitter and a second end of the non-linear optical fiber, wherein the optical signal is inputted to the beam splitter from a direction different from the input of the excitation light.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: March 23, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Goji Nakagawa, Tomoyuki Kato, Takeshi Hoshida, Masaaki Kawai
  • Patent number: 10948802
    Abstract: A wavelength converter includes a first phase modulator configured to perform phase modulation on pump light in accordance with a first phase modulation signal, a second phase modulator configured to perform phase modulation on signal light in accordance with a second phase modulation signal, a wavelength converter configured to multiplex the signal light having undergone the phase modulation with the pump light having undergone the phase modulation, the wavelength converter configured to perform wavelength conversion on the signal light in accordance with the pump light, a detector configured to detect a modulation component from the signal light having undergone the phase modulation and the pump light having undergone the phase modulation, and a generator configured to generate the first phase modulation signal and the second phase modulation signal so as to minimize the detected modulation component.
    Type: Grant
    Filed: January 14, 2020
    Date of Patent: March 16, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Goji Nakagawa, Tomoyuki Kato, Takeshi Hoshida
  • Patent number: 10873410
    Abstract: There is provided a reception device including a receiver configured to receive a wavelength-multiplexed optical signal so as to generate a wavelength-multiplexed signal, a filter configured to pass through the wavelength-multiplexed signal having a specific wavelength and an adjacent wavelength to the specific wavelength from the wavelength-multiplexed signal, and a processor configured to detect a specific signal having the specific wavelength from the wavelength-multiplexed signal having the passed through wavelengths by the filter, and detect a first supervisory control signal having the specific wavelength and a second supervisory control signal having the adjacent wavelength from the wavelength-multiplexed signal having the passed through wavelengths by the filter.
    Type: Grant
    Filed: February 20, 2018
    Date of Patent: December 22, 2020
    Assignee: FUJITSU LIMITED
    Inventors: Yi Ge, Takeshi Hoshida, Hisao Nakashima, Tomofumi Oyama, Yuichi Akiyama
  • Patent number: 10862592
    Abstract: An optical receiver includes, a first converting circuit that converts an optical signal into an electric signal, a plurality of common circuits, each of which has a same circuit configuration and performs a digital signal processing on the electric signal, and a processor that selects and operates one or more common circuits from among the plurality of common circuits according to a transmission method.
    Type: Grant
    Filed: July 31, 2018
    Date of Patent: December 8, 2020
    Assignee: FUJITSU LIMITED
    Inventors: Hisao Nakashima, Takeshi Hoshida
  • Publication number: 20200379180
    Abstract: A method includes multiplexing signal light of first polarization and excitation light, and multiplexing signal light of second polarization, which is perpendicular to the first polarization, and the excitation light, modulating the signal light of the first polarization before the wavelength conversion, and reducing a modulation component in signal light after wavelength conversion, modulating the signal light of the second polarization before the wavelength conversion, and reducing the modulation component in the signal light after the wavelength conversion, and multiplexing the signal light of the first polarization after the wavelength conversion and the signal light of the second polarization after the wavelength conversion.
    Type: Application
    Filed: May 27, 2020
    Publication date: December 3, 2020
    Inventors: Tomohiro YAMAUCHI, Tomoyuki KATO, Goji NAKAGAWA, Takeshi HOSHIDA
  • Patent number: 10853719
    Abstract: A data collecting device includes a receiver configured to receive an optical signal; an optical-to-electrical converter configured to convert the optical signal received by the receiver into an electrical signal; an analog-to-digital converter configured to convert the electrical signal into a digital signal; a data reducing circuit configured to reduce the digital signal output from the analog-to-digital converter; and a transmitter configured to transmit, to a managing device that manages the data collecting device, a signal obtained by reducing the digital signal by the data reducing circuit.
    Type: Grant
    Filed: December 2, 2016
    Date of Patent: December 1, 2020
    Assignee: FUJITSU LIMITED
    Inventors: Takahito Tanimura, Takeshi Hoshida
  • Patent number: 10797799
    Abstract: An optical transmission apparatus includes a wavelength variable filter whose transmission light wavelength is variable; a receiver that receives light, the light being sent from another optical transmission apparatus and passing through the wavelength variable filter; a transmitter that sends to the another optical transmission apparatus, a utilization permission request for a second wavelength corresponding to a first wavelength of the light received by the receiver, the transmitter sending the utilization permission request as light of the second wavelength and in a form of a tone signal of a predetermined frequency; and a controller that, when receiving from the another optical transmission apparatus, a utilization permission notification of the second wavelength for a sender of the utilization permission request, configures a wavelength of a main signal to the second wavelength, the main signal being sent from the transmitter to the another optical transmission apparatus.
    Type: Grant
    Filed: October 25, 2018
    Date of Patent: October 6, 2020
    Assignee: FUJITSU LIMITED
    Inventors: Goji Nakagawa, Kyosuke Sone, Yoshio Hirose, Takeshi Hoshida, Setsuo Yoshida
  • Publication number: 20200264492
    Abstract: A wavelength converter includes an excitation light source outputting excitation light, a beam splitter receiving an input of the excitation light and an input of the optical signal and to divide both the inputted excitation light and the inputted optical signal into a first polarization component and a second polarization component, a non-linear optical fiber as a non-polarization-maintaining fiber, an accommodation section securing and accommodating the non-linear optical fiber, a first collimator lens disposed between the beam splitter and a first end of the non-linear optical fiber, and a second collimator lens disposed between the beam splitter and a second end of the non-linear optical fiber, wherein the optical signal is inputted to the beam splitter from a direction different from the input of the excitation light.
    Type: Application
    Filed: February 4, 2020
    Publication date: August 20, 2020
    Applicant: FUJITSU LIMITED
    Inventors: GOJI NAKAGAWA, Tomoyuki Kato, Takeshi Hoshida, Masaaki Kawai