公开(公告)号：US20230054203A1

公开(公告)日：2023-02-23

申请号：US17800195

申请日：2020-02-18

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04J14/04 ,  H04B10/2581

Abstract: An optical transmission system includes a plurality of transmission lines through which a mode-multiplexed signal obtained by multiplexing a plurality of optical signals of different types of modes is transmitted, and one or more mode group permutation units provided between the plurality of transmission lines. The mode group permutation unit changes, on a mode-group-by-mode-group basis, an optical signal of a mode belonging to a mode group to an optical signal of another mode belonging to a mode group after permutation corresponding to the mode group in such a manner that modes are interchanged between at least some of the plurality of optical signals multiplexed into the mode-multiplexed signal input from one of the plurality of transmission lines on an input side, and outputs the mode-multiplexed signal after mode interchange to one of the plurality of transmission lines on an output side.

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：US20230421267A1

公开(公告)日：2023-12-28

申请号：US18038664

申请日：2020-12-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04B10/61 ,  H04J14/00 ,  H04B10/2581

CPC classification number: H04B10/6165 ,  H04J14/05 ,  H04B10/2581

Abstract: An interference component generated because a plurality of carrier generation units and a plurality of local oscillation units are asynchronous is used as state information, a predetermined state equation for calculating posterior state information on the basis of prior state information, and a transmission data sequence are used as observation information, a Kalman filter algorithm is applied to a predetermined observation equation for calculating the observation information in a state indicated by the posterior state information on the basis of the posterior state information calculated by the state equation, a reception data sequence, and a weight matrix to calculate a posterior state estimate of the interference component, and an estimated sequence of the transmission data sequence from which the interference component has been removed is calculated on the basis of the calculated posterior state estimate.

公开(公告)号：US20210296847A1

公开(公告)日：2021-09-23

申请号：US17258408

申请日：2019-07-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takayuki MIZUNO ,  Koki SHIBAHARA ,  Akira ISODA ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H01S3/30 ,  H01S3/067 ,  H01S3/094 ,  H04B10/293

Abstract: An optical amplifier repeater system includes an optical fiber propagating a light beam in a plurality of propagation modes and an optical amplifier repeater amplifying the light beam propagated through the optical fiber. The optical amplifier repeater includes an optical demultiplexer demultiplexing the light beam in the plurality of propagation modes propagated through the optical fiber into a plurality of single-mode light beams, an optical amplifier amplifying, by simultaneous pumping, intensities of the plurality of single-mode light beams using a light beam generated by one pumping light source, an optical multiplexer multiplexing the plurality of single-mode light beams amplified by the optical amplifier into a light beam in the plurality of propagation modes, and an optical intensity adjusting unit adjusting the intensity of each of the plurality of single-mode light beams at least one of before or after the amplification by the optical amplifier. The optical intensity adjusting unit performs the adjustment by amplifying or attenuating the optical intensity of each of the plurality of single-mode light beams in an individual optical path through which the single-mode light beam is propagated.

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：US20180252614A1

公开(公告)日：2018-09-06

申请号：US15555321

申请日：2016-10-04

Applicant: NTT ELECTRONICS CORPORATION ,  NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Etsushi YAMAZAKI ,  Tomohiro TAKAMUKU ,  Yuki YOSHIDA ,  Mitsuteru YOSHIDA ,  Koki SHIBAHARA ,  Kengo HORIKOSHI ,  Yoshiaki KISAKA

IPC: G01M11/02 ,  H04B10/079 ,  H04B10/2513 ,  H04B3/06 ,  G01M11/00

Abstract: A Fourier-transformer performs Fourier transform on a filter coefficient output from an adaptive equalizer which comprises a finite impulse response filter of N taps (N represents an integer of 2 or more) in a time direction. An eigenvalue sum calculator integrates a frequency-differentiation result of the Fourier-transformed filter coefficient and a complex conjugate of the Fourier-transformed filter coefficient to calculate a matrix, and calculates a sum of two eigenvalues of the matrix. A proportionality factor calculator calculates a proportionality factor for frequency from the sum of the two eigenvalues.

公开(公告)号：US20220329343A1

公开(公告)日：2022-10-13

申请号：US17638830

申请日：2019-09-06

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04J14/04 ,  H04B10/60

Abstract: An optical signal processing apparatus of an embodiment is an optical signal processing apparatus for separating and detecting an optical signal transmitted in a mode division multiplexing optical communication method by signal processing based on a multi-input multi-output (MIMO)-type linear filter. The device includes a signal processing unit configured to estimate weighting factors of the MIMO-type linear filter by sequential calculation based on an affine projection method. In the sequential calculation of the signal processing device, an output signal by the sequential calculation is expressed by a correlation vector indicating a correlation between the plurality of input signals, a smoothing prefilter vector indicating, of smoothing prefilter factors indicating a relationship between the weighting factors at current time and input signals from a first time being a past predetermined time to the current time, smoothing prefilter factors corresponding to each time from the first time to a second time that corresponds to an affine projection order in the affine projection method, and input signals from the first time to the second time.

公开(公告)号：US20210376924A1

公开(公告)日：2021-12-02

申请号：US17263733

申请日：2019-08-15

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akira ISODA ,  Takayuki MIZUNO ,  Koki SHIBAHARA ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H04B10/077 ,  H04J14/06 ,  H04B10/25

Abstract: A crosstalk estimation system includes: a light source unit that generates a polarization-multiplexed light, which is a polarized light having multiplexed polarizations, of each wavelength in a sideband of a modulated signal and emits the polarization-multiplexed light of each wavelength; a multiplexer that multiplexes the modulated signal with the polarization-multiplexed light for each core, which is associated with one of the wavelengths; a transmission line that transmits the modulated signal multiplexed with the polarization-multiplexed light of each wavelength through a different core; a separation unit that separates the polarization-multiplexed light from the modulated signal multiplexed with the polarization-multiplexed light for each core; a measurement unit that generates light intensity data on the polarization-multiplexed light of each wavelength; and an estimation unit that estimates a crosstalk between the cores based on a difference in light intensity between the polarization-multiplexed light of the wavelengths.

公开(公告)号：US20210013985A1

公开(公告)日：2021-01-14

申请号：US16971856

申请日：2019-02-20

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koki SHIBAHARA ,  Takayuki MIZUNO ,  Yutaka MIYAMOTO

IPC: H04J14/04 ,  H04B10/2581 ,  H04Q11/00

Abstract: An optical transmission system includes a plurality of transmission paths that transmit a mode multiplexing signal, and one or more mode permutation units provided between the transmission paths. The mode permutation unit performs mode permutation to interchange modes to be used between at least some optical signals among respective optical signals of a plurality of types of modes that are multiplexed to the mode multiplexing signal input from the transmission path on an input side, and outputs the mode multiplexing signal subjected to the mode permutation to the transmission path on an output side.