公开(公告)号：US20250047382A1

公开(公告)日：2025-02-06

申请号：US18708981

申请日：2021-11-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shimpei SHIMIZU ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H04B10/2507 ,  H04B10/291

Abstract: 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. The second transmission path may include one or more second optical relay units for amplifying and relaying the second optical signal.

公开(公告)号：US20240413922A1

公开(公告)日：2024-12-12

申请号：US18695580

申请日：2021-09-29

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akira KAWAI ,  Takayuki KOBAYASHI ,  Masanori NAKAMURA ,  Shimpei SHIMIZU ,  Yutaka MIYAMOTO

IPC: H04J14/04 ,  H04B10/2581 ,  H04B10/516

Abstract: 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.

公开(公告)号：US20240259095A1

公开(公告)日：2024-08-01

申请号：US18290350

申请日：2021-05-18

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akira KAWAI ,  Takayuki KOBAYASHI ,  Masanori NAKAMURA ,  Shimpei SHIMIZU ,  Yutaka MIYAMOTO

IPC: H04B10/079

CPC classification number: H04B10/0795

Abstract: 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. The time window processing unit may determine the length of the time window based on a constant multiple of the average value.

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：US20230059003A1

公开(公告)日：2023-02-23

申请号：US17797266

申请日：2020-02-12

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shimpei SHIMIZU ,  Takushi KAZAMA ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H04B10/2525

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 cancels out the calculated residual wavelength dispersion amount to the predetermined signal light.

公开(公告)号：US20220120960A1

公开(公告)日：2022-04-21

申请号：US17427248

申请日：2020-01-30

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Hirotaka ONO ,  Yutaka MIYAMOTO

IPC: G02B6/028 ,  H01S3/067

Abstract: An amplification fiber includes a core which is doped with an erbium ion and a cladding which surrounds the core and has a refractive index lower than a refractive index of the core, and a relative refractive index difference Δn51 between the core and the cladding is not more than a smaller one of values of a relative refractive index difference Δn1 expressed as a predetermined expression related to a radius a of the core and a relative refractive index difference Δn2 expressed as a predetermined expression related to the radius a of the core.

公开(公告)号：US20220029707A1

公开(公告)日：2022-01-27

申请号：US17311928

申请日：2019-12-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masanori NAKAMURA ,  Fukutaro HAMAOKA ,  Hiroshi YAMAZAKI ,  Munehiko NAGATANI ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H04B10/58 ,  H04B10/69

Abstract: An optical transmission system includes an optical transmitter and an optical receiver. The optical transmitter includes a low speed signal generation unit configured to generate, based on an input signal of a transmission data sequence and a signal obtained by cyclically shifting a spectrum of the input signal, a plurality of low speed signals, a high speed signal generation unit configured to digital-to-analog convert and synthesize the plurality of low speed signals to generate a high speed signal, and an optical modulation unit configured to transmit an optical signal obtained by modulation of the high speed signal to a transmission path. The optical receiver includes a reception unit configured to receive the optical signal from the transmission path and output the high speed signal obtained from the optical signal that is received, an optical-receiver-side high speed signal compensation unit configured to compensate, based on the high speed signal output by the reception unit and a signal obtained by cyclically shifting a spectrum of the high speed signal, for the high speed signal, and a reception data decoding unit configured to decode the high speed signal compensated by the optical-receiver-side high speed signal compensation unit to restore binary information included in the optical signal transmitted by the optical transmitter.

公开(公告)号：US20220014301A1

公开(公告)日：2022-01-13

申请号：US17294612

申请日：2019-11-13

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kazunori SENOO ,  Kenya SUZUKI ,  Keita YAMAGUCHI ,  Takayuki MIZUNO ,  Hirotaka ONO ,  Toshikazu HASHIMOTO ,  Yutaka MIYAMOTO

IPC: H04J14/02

Abstract: When a first connection number of a b-th output port in an a-th wavelength selective switch connected to paths in one side out of a Drop side and an Add side is expressed by f(a, b, k), and a second connection number of a d-th output port in a c-th wavelength selective switch connected to paths in the other side out of the Drop side and the Add side is expressed by g(c, d, k), f(a, b, k)≠g(c, d, k).

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：US20210159996A1

公开(公告)日：2021-05-27

申请号：US16967674

申请日：2019-02-01

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Hirotaka ONO ,  Mitsunori FUKUTOKU ,  Shingo KAWAI ,  Yutaka MIYAMOTO

IPC: H04J14/02 ,  H04B10/27 ,  H04B10/291 ,  H01S3/094

Abstract: An optical node device includes one or more input-side wavelength selection switches, a plurality of output-side wavelength selection switches, and an amplification unit. The input-side wavelength selection switches include a plurality of output ports, separate input light in accordance with a wavelength, and output the separated light from the output port corresponding to an output destination of the separated light. The output-side wavelength selection switches include input ports each receiving the light output from each of the one or more input-side wavelength selection switches, multiplex the light received from the input ports, and output the light. The amplification unit amplifies the light output from each of the output ports of the input-side wavelength selection switches and outputs the amplified light to the output-side wavelength selection switch at the output destination corresponding to the output port.