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).
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Publication number: 20250047382Abstract: An optical transmission system, comprising: a transmission unit that maximizes a frequency interval between a plurality of channel components within a transmission band, and generates a first optical signal that is an optical signal in which the plurality of channel components are wavelength-division multiplexed, a first transmission path for transmitting the first optical signal, a phase conjugate conversion unit that generates a second optical signal by inverting a spectrum of the first optical signal, and a second transmission path for transmitting the second optical signal. The first transmission path and the second transmission path wavelength-disperse the plurality of channel components of the first optical signal and the second optical signal. The first transmission path may include one or more first optical relay units for amplifying and relaying the first optical signal.Type: ApplicationFiled: November 17, 2021Publication date: February 6, 2025Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takayuki KOBAYASHI, Yutaka MIYAMOTO
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Publication number: 20240413922Abstract: One aspect of the present invention is an optical transmission system including a transmitter connected to a transmission line having M spatial channels, and a receiver that receives a signal transmitted from the transmitter via the transmission line, wherein the transmitter includes: an allocator that allocates a transmission bit string transmitted to the transmission line into a bit string serving as a basic signal and a bit string serving as spatial channel information; a generator that generates N (M>N) signals from the bit string serving as the basic signal allocated by the allocator; and a selector that selects N spatial channels, through which the N signals generated by the generator are transmitted, from the M spatial channels on the basis of the bit string serving as the spatial channel information allocated by the allocator.Type: ApplicationFiled: September 29, 2021Publication date: December 12, 2024Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Akira KAWAI, Takayuki KOBAYASHI, Masanori NAKAMURA, Shimpei SHIMIZU, Yutaka MIYAMOTO
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Publication number: 20240388376Abstract: One aspect of the present invention is a signal detection device including a mode demultiplexer configured to convert N (N is a natural number) spatial mode signals including a plurality of higher modes excited in a transmission path fiber into N base modes and output the N basis modes, a frequency conversion unit configured to convert N optical signals into frequencies different from each other, a multiplexing unit configured to multiplex the N optical signals having frequencies that have been converted, and a reception unit configured to photoelectrically convert a multiplexed optical signal while maintaining modulation information for a phase and polarization, perform digital signal conversion and signal processing, and demodulate an original information sequence.Type: ApplicationFiled: September 16, 2021Publication date: November 21, 2024Inventors: Koki SHIBAHARA, Takayuki KOBAYASHI, Fukutaro Hamaoka, Shimpei SHIMIZU, Yutaka MIYAMOTO
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Publication number: 20240259095Abstract: A waveguide estimation device includes: a time window processing unit that multiplies time-series tap coefficients of an adaptive filter by a time window function; and an estimation unit that estimates at least one of a differential group delay in a frequency series or a time series and a polarization dependent loss in a frequency series or a time series based on the time-series tap coefficients in a time window. The estimation unit may estimate at least one of the differential group delay in a frequency series or a time series and the polarization dependent loss in a frequency series or a time series based on a tap coefficient exceeding a lower limit threshold value or falling below an upper limit threshold value among the time-series tap coefficients in a time window. The estimation unit may estimate the average value of the differential group delays in a frequency series or a time series.Type: ApplicationFiled: May 18, 2021Publication date: August 1, 2024Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Akira KAWAI, Takayuki KOBAYASHI, Masanori NAKAMURA, Shimpei SHIMIZU, Yutaka MIYAMOTO
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Publication number: 20240248369Abstract: An optical amplification device includes: a polarization demultiplexing unit that separates an optical signal into a first polarized wave and a second polarized wave; a first optical amplification unit that amplifies the first polarized wave by using a first amplification medium; a second optical amplification unit that amplifies the second polarized wave by using a second amplification medium; a first band demultiplexing unit that demultiplexes the first polarized wave into a band component of the first polarized wave and a band component of first phase conjugate light; a second band demultiplexing unit that demultiplexes the second polarized wave into a band component of the second polarized wave and a band component of second phase conjugate light; a signal monitoring unit that measures a first optical power value of either the band component of the first polarized wave or the band component of the first phase conjugate light and a second optical power value of either the band component of the second polarType: ApplicationFiled: May 20, 2021Publication date: July 25, 2024Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takushi KAZAMA, Takayuki KOBAYASHI, Yutaka MIYAMOTO, Takeshi UMEKI
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Publication number: 20240250768Abstract: The present invention provides an optical amplification system (1) having a plurality of cascade-connected optical amplification units (11), wherein the optical amplification units (11) comprise: a band division unit (111) that divides an optical signal into optical signals of two different bands; a polarized wave division unit (112) that divides the divided optical signals into two polarized wave components orthogonal to each other, an excitation light multiplexing unit (113) that multiplexes excitation light and the optical signals divided by the polarized wave division unit (112); an amplification medium (115) that generates an optical parametric amplification and amplifies the optical signals; an excitation light division unit (117) that divides the excitation light and the optical signals amplified by the amplification medium (115); a polarized wave synthesis unit (118) that synthesizes the two divided polarized wave components; and a band multiplexing unit (119) that multiplexes the two divided bands.Type: ApplicationFiled: May 21, 2021Publication date: July 25, 2024Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takushi KAZAMA, Takayuki KOBAYASHI, Yutaka MIYAMOTO, Takeshi UMEKI
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Patent number: 11929784Abstract: 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 canType: GrantFiled: February 12, 2020Date of Patent: March 12, 2024Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei Shimizu, Takushi Kazama, Takayuki Kobayashi, Yutaka Miyamoto
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Patent number: 11742950Abstract: 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: GrantFiled: November 28, 2019Date of Patent: August 29, 2023Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei Shimizu, Takayuki Kobayashi, Masanori Nakamura, Yutaka Miyamoto
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Patent number: 11716144Abstract: 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: GrantFiled: November 28, 2019Date of Patent: August 1, 2023Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei Shimizu, Takayuki Kobayashi, Yutaka Miyamoto
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Publication number: 20230059003Abstract: 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 canType: ApplicationFiled: February 12, 2020Publication date: February 23, 2023Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takushi KAZAMA, Takayuki KOBAYASHI, Yutaka MIYAMOTO
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Publication number: 20220407600Abstract: 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: ApplicationFiled: November 28, 2019Publication date: December 22, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takayuki KOBAYASHI, Masanori NAKAMURA, Yutaka MIYAMOTO
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Publication number: 20220399940Abstract: 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: ApplicationFiled: November 28, 2019Publication date: December 15, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shimpei SHIMIZU, Takayuki KOBAYASHI, Yutaka MIYAMOTO