公开(公告)号：US20250055573A1

公开(公告)日：2025-02-13

申请号：US18717521

申请日：2021-12-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Etsushi YAMAZAKI ,  Yoshiaki KISAKA ,  Kengo HORIKOSHI ,  Seiji OKAMOTO ,  Masanori NAKAMURA

IPC: H04B10/61 ,  H04B10/294

Abstract: A gain adjustment method in an optical transmission system that performs communication by a digital coherent system including an optical transmission device and an optical reception device includes converting an optical signal transmitted from the optical transmission device into an electrical signal, converting the electrical signal from an analog signal to a digital signal, performing first signal processing on the digital signal, performing adaptive equalization processing on the digital signal subjected to the first signal processing using a digital filter, correcting an amplitude of an output signal of the digital filter based on information of the amplitude and a phase of the output signal of the digital filter and the amplitude of a known transmission signal, and performing second signal processing on the output signal of the digital filter whose amplitude has been corrected.

公开(公告)号：US20250038860A1

公开(公告)日：2025-01-30

申请号：US18717067

申请日：2022-01-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Masanori NAKAMURA ,  Seiji OKAMOTO ,  Yoshiaki KISAKA

IPC: H04B10/61 ,  H04B10/079

Abstract: An estimation method in an optical transmission system that performs communication by a digital coherent system including an optical transmission device and an optical reception device, the estimation method including calculating a ratio of a linearly transformed amount after converting a tap coefficient of a digital filter included in the optical reception device into a frequency domain signal by digital Fourier transform, and estimating a physical quantity related to at least a response between the optical transmission device and the optical reception device based on amplitude and phase information of the ratio of the calculated linearly transformed amount.

公开(公告)号：US20230344525A1

公开(公告)日：2023-10-26

申请号：US18025673

申请日：2020-09-14

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Hiroaki KATSURAI ,  Yoichi FUKADA ,  Tomoaki YOSHIDA

IPC: H04B10/80

CPC classification number: H04B10/807 ,  H02J7/35

Abstract: A light receiving portion of a photodiode is connected to an external light source via an optical transmission line. A power storage unit stores electrical energy generated by the photodiode. A bias circuit takes out electrical energy corresponding to the amount of stored power from the power storage unit, and applies a voltage to the cathode of the photodiode.

公开(公告)号：US20230246712A1

公开(公告)日：2023-08-03

申请号：US17925356

申请日：2020-05-18

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Kyo MINOGUCHI ,  Toshiaki SHITABA ,  Tomoaki YOSHIDA

IPC: H04B10/2519 ,  H04B10/112

CPC classification number: H04B10/2519 ,  H04B10/1127

Abstract: An optical transmission system includes a first optical communication device configured to output an optical signal, a first FBG-DCM configured to perform wavelength dispersion compensation on the optical signal output by the first optical communication device, and a second optical communication device configured to receive the optical signal wavelength-dispersion compensated by the first FBG-DCM through at first optical transmission path of an optical fiber.

公开(公告)号：US20220399942A1

公开(公告)日：2022-12-15

申请号：US17776263

申请日：2019-11-14

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Kyo MINOGUCHI ,  Tomoaki YOSHIDA ,  Toshiaki SHITABA

IPC: H04B10/564 ,  H04B10/03 ,  H04B10/272

Abstract: An optical communication system includes an optical line terminal and a plurality of optical network unit connected by optical transfer paths. The optical line terminal includes a light transmitting/receiving unit and a control unit. The light transmitting/receiving unit transmits/receives an optical signal to/from the plurality of optical network units via the optical transfer paths. The control unit performs control so as to change a launch power of an optical signal that is transmitted from the light transmitting/receiving unit, such that, when it is recognized, regarding at least one optical network unit, that a monitoring value that changes according to a receive signal quality of an optical signal transmitted from the light transmitting/receiving unit has changed to a value indicating deterioration, a receive power of an optical signal in each of the plurality of optical network units is lower than or equal to an upper limit value and a receive power of an optical signal in the optical network unit in which the monitoring value has changed to a value indicating deterioration is higher than or equal to a lower limit value.

公开(公告)号：US20230216586A1

公开(公告)日：2023-07-06

申请号：US18009600

申请日：2020-06-25

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Toshiaki SHITABA ,  Tomoaki YOSHIDA

IPC: H04B10/2513

CPC classification number: H04B10/2513

Abstract: An optical communication system includes a first optical communication device; a plurality of second optical communication devices configured to perform communication with the first optical communication device; a chromatic dispersion compensation device connected to the first optical communication device; and an optical transmission line connected to the chromatic dispersion compensation device, a path of the optical transmission line connected to the chromatic dispersion compensation device being split into a plurality of paths at a branch point, the resulting paths being respectively connected to the plurality of second optical communication devices, and the optical transmission line being configured to transmit optical signals through the paths, in which the chromatic dispersion compensation device includes a chromatic dispersion compensator configured to perform chromatic dispersion compensation corresponding to amounts of chromatic dispersion generated in optical signals propagated through respective paths between the first optical communication device and the plurality of second optical communication devices.

公开(公告)号：US20220038180A1

公开(公告)日：2022-02-03

申请号：US17278627

申请日：2019-08-27

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Etsushi YAMAZAKI ,  Seiji OKAMOTO ,  Yoshiaki KISAKA

IPC: H04B10/2513

Abstract: Provided is a chromatic dispersion compensation method including: dividing a reception signal obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands; adjusting a timing on a time axis of the reception signal for each of the divided frequency bands; performing combination processing for combining the reception signals included in the plurality of frequency bands; performing chromatic dispersion compensation on the reception signal at any timing before or after the combination processing; selecting, before the combination processing, sections in which overlapping parts determined based on lengths of overlap parts are generated; outputting the reception signal for each of the selected sections as a division processing block; and removing the overlap parts from both ends of a processing block generated by combination of the division processing blocks in the combination processing so as to be continuous on a frequency axis.

公开(公告)号：US20210211218A1

公开(公告)日：2021-07-08

申请号：US17059238

申请日：2019-05-20

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Fukutaro HAMAOKA ,  Kyo MINOGUCHI ,  Seiji OKAMOTO ,  Yoshiaki KISAKA

IPC: H04J14/02 ,  H04B10/2537 ,  H04B10/548

Abstract: An optical transmission system includes an optical transmitter, an optical receiver, and a control apparatus. The control apparatus repeatedly performs an adjustment process for adjusting power of an optical signal of a frequency band to be adjusted while switching the frequency band to be adjusted between at least two frequency bands including at least a frequency band where stimulated Raman scattering occurs among frequency bands that are multiplexed in a multiplexed optical signal transmitted by the optical transmission system. In the adjustment process, when power of an optical signal of the frequency band to be adjusted transmitted from the optical transmitter has been changed, the control apparatus determines the power of the optical signal of the frequency band to be adjusted on the basis of a signal quality measured by the optical receiver that has received the optical signal.