公开(公告)号：US20250150194A1

公开(公告)日：2025-05-08

申请号：US18832739

申请日：2022-02-10

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masanori NAKAMURA ,  Takayuki KOBAYASHI ,  Fukutaro HAMAOKA ,  Yutaka MIYAMOTO

IPC: H04J14/06

Abstract: A signal processing method of converting a real number component and an imaginary number component of each polarization of a sub-carrier-multiplexed and polarization-multiplexed received signal into a frequency domain signal; selecting a frequency domain signal corresponding to a sub-carrier; receiving, as input signals, a real number component and an imaginary number component of each polarization of each sub-carrier and frequency inversion and phase conjugation, performing a first equalization process of multiplying, for each sub-carrier and polarization, the real number component and the imaginary number component of each polarization included in the input signal by a complex transfer function and then adding them and performing inverse conversion from a frequency domain signal into a time domain signal and a second equalization process of performing a signal of a real number component obtained by subjecting the real number component of each polarization included in the input signal to frequency inversion and taking complex conjugation and a signal of an imaginary number component obtained by subjecting the imaginary number component to frequency inversion and taking complex conjugation by a complex transfer function and then adding them, and performing inverse conversion from a frequency domain signal into a time domain signal, and adding or subtracting the transmission data bias correction signal to or from the signal obtained by adding the first addition signal and the second addition signal.

公开(公告)号：US20240388376A1

公开(公告)日：2024-11-21

申请号：US18691536

申请日：2021-09-16

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Koki SHIBAHARA ,  Takayuki KOBAYASHI ,  Fukutaro Hamaoka ,  Shimpei SHIMIZU ,  Yutaka MIYAMOTO

IPC: H04J14/04

Abstract: 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.

公开(公告)号：US20230057448A1

公开(公告)日：2023-02-23

申请号：US17800201

申请日：2020-02-19

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04B10/2581 ,  H04B10/61 ,  H04B10/2507

Abstract: An optical transmission system including: N transmitters, each of the N transmitters being configured to convert one of N electrical signals indicating data sequences different from one another into an optical signal; a signal generator configured to cause N optical splitters to split the N optical signals output from the N transmitters to convert the N optical signals into M optical signals; a multiplexer configured to convert the M optical signals converted by the signal generator into one mode-multiplexed signal that is excitable in at least M modes; a demultiplexer configured to convert the mode-multiplexed signal converted by the multiplexer into M optical signals; M receivers, each of the M receivers being configured to convert one of the M optical signals converted by the demultiplexer into the electrical signal; and a signal detector configured to perform signal separation on the M electrical signals converted by the M receivers to extract the N data sequences.

公开(公告)号：US20210218477A1

公开(公告)日：2021-07-15

申请号：US17197754

申请日：2021-03-10

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kohki SHIBAHARA ,  Takayuki MIZUNO ,  Akira ISODA ,  Yutaka MIYAMOTO

IPC: H04B10/69 ,  H04B1/10 ,  H04B10/2581 ,  H04J14/04 ,  H04J14/06

Abstract: A signal receiving apparatus includes at least one signal separating apparatus that separates a specific signal from a plurality of received signals. Each of the at least one signal separating apparatus includes a spatial filtering unit that separates at least one equalized signal and a decision signal outputting unit that generates a first decision signal by deciding the equalized signal and outputs the generated first decision signal. The spatial filtering unit separates the at least one equalized signal by multiplying at least the plurality of received signals among the plurality of received signals and either the first decision signal output from the decision signal outputting unit or a second decision signal output from another signal separating apparatus by predetermined weighting coefficients.

公开(公告)号：US20200381888A1

公开(公告)日：2020-12-03

申请号：US16640242

申请日：2018-08-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takayuki MIZUNO ,  Akira ISODA ,  Kohki SHIBAHARA ,  Mitsunori FUKUTOKU ,  Yutaka MIYAMOTO

IPC: H01S3/23 ,  H01S3/30 ,  H01S3/0941 ,  H01S3/094 ,  H01S3/067 ,  H01S3/16 ,  H04B10/297

Abstract: An optically amplified repeater system includes optical transmission paths, a multi-channel optical amplifier, one or more Raman amplification pumping light sources, and a wavelength multiplexer. The multi-channel optical amplifier includes K simultaneous pumping light sources, N optical amplification media, and one or more optical couplers, and simultaneously amplifies, with the K simultaneous pumping light sources, light intensities of optical signals that pass through the N optical amplification media and propagate through the optical transmission paths. Light intensities of the wavelength band of the optical signals is Raman amplified by the Raman amplification pumping light. A light intensity of the Raman amplification pumping light output from the one or more Raman amplification pumping light sources is determined in accordance with characteristic differences between the optical signals passing through the optical transmission paths.

公开(公告)号：US20200014469A1

公开(公告)日：2020-01-09

申请号：US16492917

申请日：2018-03-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kohki SHIBAHARA ,  Takayuki MIZUNO ,  Akira ISODA ,  Yutaka MIYAMOTO

IPC: H04B10/69 ,  H04B1/10 ,  H04B10/2581 ,  H04J14/06 ,  H04J14/04

Abstract: A signal receiving apparatus includes at least one signal separating apparatus that separates a specific signal from a plurality of received signals. Each of the at least one signal separating apparatus includes a spatial filtering unit that separates at least one equalized signal and a decision signal outputting unit that generates a first decision signal by deciding the equalized signal and outputs the generated first decision signal. The spatial filtering unit separates the at least one equalized signal by multiplying at least the plurality of received signals among the plurality of received signals and either the first decision signal output from the decision signal outputting unit or a second decision signal output from another signal separating apparatus by predetermined weighting coefficients.

公开(公告)号：US20180375579A1

公开(公告)日：2018-12-27

申请号：US15775658

申请日：2016-11-22

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takuya ODA ,  Tetsuro INUI ,  Akira HIRANO ,  Wataru IMAJUKU ,  Shoukei KOBAYASHI ,  Takafumi TANAKA ,  Yutaka MIYAMOTO ,  Hidehiko TAKARA

IPC: H04B10/2581 ,  H04J14/02 ,  H04B10/29

Abstract: A communication system includes three or more nodes and a multi-core fiber having a plurality of cores and being used in at least a partial segment of the connection between the nodes. One node of the nodes is connected to the multi-core fiber and includes a connector configured to add and drop a signal to and from an allocated core exclusively allocated for communication between the one node and another node of the nodes and/or configured to relay a signal transmitted through another core allocated to communication between the other nodes in multi-core fibers connected to the one node.

公开(公告)号：US20250085608A1

公开(公告)日：2025-03-13

申请号：US18580660

申请日：2021-08-13

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shimpei SHIMIZU ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: G02F1/39 ,  G02F1/35

Abstract: An aspect of the present invention is a transmission system for transmitting an optical signal which includes a phase conjugate light generation part which generates phase conjugate light of the optical signal whose frequency is within a first band in a second band different from the first band and an optical phase-sensitive amplifying part which phase-sensitively amplifies the optical signal and the phase conjugate light and in which the first band is a frequency band in which the sensitivity of light reception of a receiver which receives the optical signal is a predetermined level or more among the frequency bands in which a transmitter which outputs the optical signal is able to output the optical signal with a predetermined intensity or more and the second band is a higher or lower frequency band than the first band.

公开(公告)号：US20230216589A1

公开(公告)日：2023-07-06

申请号：US18019013

申请日：2020-08-20

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04B10/2581 ,  H04J14/04 ,  H04B10/60

CPC classification number: H04B10/2581 ,  H04J14/04 ,  H04B10/60

Abstract: The signal detection device includes the signal detection unit that derives the estimation vector of the transmission signal vector,
the first conversion unit that converts the estimation vector of the transmission signal vector to the estimation vector of the transmission signal vector based on the reduced basis, the first determination unit that converts the estimation vector of the transmission signal vector based on the reduced basis to the determination value vector of the transmission signal vector, the first update unit that updates the separation matrix, the second conversion unit that converts the first error signal vector to the second error signal vector based on the reduced basis, the second update unit that updates the error covariance matrix based on the reduced basis, the second determination unit that determines whether or not the predetermined condition is satisfied, and a third update unit that updates the unimodular matrix, the inverse matrix of the unimodular matrix, and the error covariance matrix based on the reduced basis when it is determined that the predetermined condition is established.

公开(公告)号：US20210096440A1

公开(公告)日：2021-04-01

申请号：US16981651

申请日：2019-03-19

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Hiroto KAWAKAMI ,  Hiroshi YAMAZAKI ,  Yutaka MIYAMOTO

IPC: G02F1/21 ,  G02F1/225

Abstract: An optical modulator according to embodiments includes a first MZI and a second MZI each including a first optical coupler that splits CW light into two, a second optical coupler that couples the CW light split by the first optical coupler and outputs the CW light, and a bias electrode that adjusts a phase of the CW light split by the first optical coupler, a third optical coupler that couples outputs of the first MZI and the second MZI with at a predetermined ratio and outputs the light, and a bias adjustment circuit that adjusts an output voltage of a bias power supply applied to a bias electrode so that an optical path length difference between the CW light beams split by the first optical coupler is a predetermined times a carrier wavelength under a condition that an output of a differential output amplifier is a zero level, in accordance with an operating mode of the own apparatus.