Patents by Inventor Shimpei SHIMIZU

Shimpei SHIMIZU 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).

  • Patent number: 11929784
    Abstract: A wavelength dispersion compensating apparatus, including: a signal light generating unit which generates, from predetermined signal light, signal light having a phase correlation centered on a degenerate frequency of a phase sensitive amplifier; a dispersion compensation transmission path which compensates for a wavelength dispersion of the predetermined signal light included in the signal light; a filter which compensates for a residual wavelength dispersion after compensation by the dispersion compensation transmission path of the predetermined signal light included in the signal light; a phase sensitive amplifier which amplifies the signal light input via the dispersion compensation transmission path and the filter; a residual wavelength dispersion calculating unit which calculates a residual wavelength dispersion amount based on a measurement result of output light amplified by the phase sensitive amplifier; and a filter control unit which controls the filter so as to add a wavelength dispersion that can
    Type: Grant
    Filed: February 12, 2020
    Date of Patent: March 12, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei Shimizu, Takushi Kazama, Takayuki Kobayashi, Yutaka Miyamoto
  • Patent number: 11742950
    Abstract: A computation unit uses an assumed chromatic dispersion amount to compensate for dispersion of a coherently received optical signal and performs arithmetic of a signal power of the optical signal that is dispersion compensated. The computation unit performs computation of an evaluation function when a signal power and a delayed signal power obtained by applying a predetermined delay to the signal power satisfy a threshold condition. The evaluation function is a function for evaluating whether the assumed chromatic dispersion amount is a chromatic dispersion amount of the optical signal using the difference between the signal power and the delayed signal power. The chromatic dispersion amount calculation unit calculates a chromatic dispersion amount of the optical signal based on the computation result of the evaluation function by the computation unit when each of a plurality of different assumed chromatic dispersion amounts is used.
    Type: Grant
    Filed: November 28, 2019
    Date of Patent: August 29, 2023
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei Shimizu, Takayuki Kobayashi, Masanori Nakamura, Yutaka Miyamoto
  • Patent number: 11716144
    Abstract: An optical transmission system includes: a transmission unit configured to co-propagate a signal light in which data is modulated and an idler light having complex amplitude that is phase conjugate with the signal light via an optical transmission medium; at least one optical amplifier configured to perform a phase sensitive amplification operation through an action among the signal light, the idler light, and an excitation light in a nonlinear medium; and a reception unit configured to receive the signal light that has been amplified by the optical amplifier, coherently detect the signal light and the idler light individually, and conduct a diversity synthesis to demodulate the data.
    Type: Grant
    Filed: November 28, 2019
    Date of Patent: August 1, 2023
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei Shimizu, Takayuki Kobayashi, Yutaka Miyamoto
  • Publication number: 20230059003
    Abstract: A wavelength dispersion compensating apparatus, including: a signal light generating unit which generates, from predetermined signal light, signal light having a phase correlation centered on a degenerate frequency of a phase sensitive amplifier; a dispersion compensation transmission path which compensates for a wavelength dispersion of the predetermined signal light included in the signal light; a filter which compensates for a residual wavelength dispersion after compensation by the dispersion compensation transmission path of the predetermined signal light included in the signal light; a phase sensitive amplifier which amplifies the signal light input via the dispersion compensation transmission path and the filter; a residual wavelength dispersion calculating unit which calculates a residual wavelength dispersion amount based on a measurement result of output light amplified by the phase sensitive amplifier; and a filter control unit which controls the filter so as to add a wavelength dispersion that can
    Type: Application
    Filed: February 12, 2020
    Publication date: February 23, 2023
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei SHIMIZU, Takushi KAZAMA, Takayuki KOBAYASHI, Yutaka MIYAMOTO
  • Publication number: 20220407600
    Abstract: A computation unit uses an assumed chromatic dispersion amount to compensate for dispersion of a coherently received optical signal and performs arithmetic of a signal power of the optical signal that is dispersion compensated. The computation unit performs computation of an evaluation function when a signal power and a delayed signal power obtained by applying a predetermined delay to the signal power satisfy a threshold condition. The evaluation function is a function for evaluating whether the assumed chromatic dispersion amount is a chromatic dispersion amount of the optical signal using the difference between the signal power and the delayed signal power. The chromatic dispersion amount calculation unit calculates a chromatic dispersion amount of the optical signal based on the computation result of the evaluation function by the computation unit when each of a plurality of different assumed chromatic dispersion amounts is used.
    Type: Application
    Filed: November 28, 2019
    Publication date: December 22, 2022
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei SHIMIZU, Takayuki KOBAYASHI, Masanori NAKAMURA, Yutaka MIYAMOTO
  • Publication number: 20220399940
    Abstract: An optical transmission system includes: a transmission unit configured to co-propagate a signal light in which data is modulated and an idler light having complex amplitude that is phase conjugate with the signal light via an optical transmission medium; at least one optical amplifier configured to perform a phase sensitive amplification operation through an action among the signal light, the idler light, and an excitation light in a nonlinear medium; and a reception unit configured to receive the signal light that has been amplified by the optical amplifier, coherently detect the signal light and the idler light individually, and conduct a diversity synthesis to demodulate the data.
    Type: Application
    Filed: November 28, 2019
    Publication date: December 15, 2022
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shimpei SHIMIZU, Takayuki KOBAYASHI, Yutaka MIYAMOTO