公开(公告)号：US20220140906A1

公开(公告)日：2022-05-05

申请号：US17426817

申请日：2020-01-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MITSUI ,  Toshiaki SHITABA ,  Akihiro TANABE ,  Kengo HORIKOSHI ,  Hisao YOSHINAGA

IPC: H04B10/293 ,  H04B10/572

Abstract: An optical transmission system includes: a first optical transmitting unit for transmitting a first optical signal having a first wavelength; a second optical transmitting unit for transmitting a second optical signal having a second wavelength; an output adjustment unit for acquiring the first optical signal and the second optical signal, adjusting signal intensities of the acquired optical signals, and outputting the optical signals; a multiplexer for multiplexing the first optical signal and the second optical signal that have been subjected to signal intensity adjustment and outputting a multiplexed signal; an amplifier for amplifying the multiplexed signal; a first optical receiving unit for receiving the amplified first optical signal; and a second optical receiving unit for receiving the amplified second optical signal. The output adjustment unit adjusts the signal intensities of the first optical signal and the second optical signal such that the signal intensity of the first optical signal received by the first optical receiving unit is larger than or equal to a first predetermined value, and the signal intensity of the second optical signal received by the second optical receiving unit is larger than or equal to a second predetermined value.

公开(公告)号：US20250132837A1

公开(公告)日：2025-04-24

申请号：US18686829

申请日：2021-09-03

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo MIYATAKE ,  Toshiaki SHITABA ,  Tomoaki YOSHIDA ,  Yoichi FUKADA ,  Akihiro TANABE

IPC: H04B10/564 ,  H04B10/079 ,  H04B10/516 ,  H04B10/61 ,  H04J14/00

Abstract: An optical reception apparatus includes: a reception detection unit that converts an intensity-modulated optical signal transmitted from an optical transmission apparatus into a frequency modulation signal; a frequency demodulation unit that generates a multi-channel signal by performing demodulation processing on the frequency modulation signal; and a derivation unit that derives, for each channel, a difference between transmission quality and required quality of the intensity-modulated optical signal, and transmits feedback information indicating the difference for each channel to the optical transmission apparatus. The adjustment unit may give priority to a channel having high reception power in the optical reception apparatus and reduce the power of the channel, based on the feedback information. The adjustment unit may give priority to a channel having low transmission quality and increase the power of the channel, based on the feedback information.

公开(公告)号：US20230353249A1

公开(公告)日：2023-11-02

申请号：US18019280

申请日：2020-09-01

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Toshiaki SHITABA ,  Tomoaki YOSHIDA ,  Akihiro TANABE ,  Takashi MITSUI

IPC: H04B10/516 ,  H04B10/50

CPC classification number: H04B10/516 ,  H04B10/503

Abstract: An optical transmission device includes a distribution unit which generates a first modulated signal and a second modulated signal by distribution processing for an input signal; a first phase modulator which generates a first optical signal phase-modulated in accordance with the first modulated signal by using a laser beam based on a first oscillation frequency; a phase adjustment unit which generates the second modulated signal of a phase opposite to a phase of the first modulated signal; a second phase modulator which generates a second optical signal phase-modulated in accordance with the second modulated signal of the opposite phase by using a laser beam based on a second oscillation frequency; a multiplexing unit which multiplexes the first optical signal and the second optical signal; and a detection unit which generates a frequency-modulated signal by performing square-law detection processing on a result of multiplexing.

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：US20240162991A1

公开(公告)日：2024-05-16

申请号：US18281773

申请日：2021-04-01

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo MIYATAKE ,  Yoichi FUKADA ,  Toshiaki SHITABA ,  Akihiro TANABE ,  Tomoaki YOSHIDA

IPC: H04B10/516 ,  H04B10/50 ,  H04J14/00

CPC classification number: H04B10/5161 ,  H04B10/503 ,  H04J14/00

Abstract: An optical transmission device includes: a first optical phase modulator that outputs a first optical signal by phase-modulating the laser beam having a first oscillation frequency according to the first electric signal in a case where the first electric signal is output to the first transmission path, a second optical phase modulator that outputs a laser beam having a second oscillation frequency as the second optical signal in a case where the first electric signal is output to the first transmission path; an optical multiplexer/distributor that outputs a third optical signal and a fourth optical signal by multiplexing the first optical signal and the second optical signal and distributing a result of the multiplexing; a first detection unit that converts the third optical signal into a first heterodyne detection signal; a second detection unit that converts the fourth optical signal into a second heterodyne detection signal; and a first optical intensity modulator that intensity-modulates a laser beam having a third oscillation frequency according to one of the first heterodyne detection signal and the second heterodyne detection signal.

公开(公告)号：US20240063916A1

公开(公告)日：2024-02-22

申请号：US18270537

申请日：2021-01-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Toshiaki SHITABA ,  Akihiro TANABE ,  Yoichi FUKADA ,  Ryo MIYATAKE

IPC: H04B10/548 ,  H04B10/50

CPC classification number: H04B10/548 ,  H04B10/503

Abstract: An optical transmission apparatus includes:



a distribution unit configured to distribute a modulation signal to a plurality of amplification units connected in parallel; a plurality of phase modulators which are connected in cascade to generate a phase-modulated optical signal in accordance with each modulation signal of which voltage is amplified by the plurality of amplification units connected in parallel by using a laser beam based on a first oscillation frequency; a multiplexing unit configured to multiplex a laser beam based on a second oscillation frequency and the optical signal; and a detection unit configured to generate a frequency modulation signal by executing detection processing on a result of multiplexing the laser beam based on the second oscillation frequency and the optical signal.

公开(公告)号：US20240056193A1

公开(公告)日：2024-02-15

申请号：US18269491

申请日：2020-12-28

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akihiro TANABE ,  Toshiaki SHITABA ,  Yoichi FUKADA ,  Ryo MIYATAKE ,  Tomoaki YOSHIDA

IPC: H04B10/516

CPC classification number: H04B10/516

Abstract: An optical transmission device includes: an FM batch conversion unit that performs FM batch conversion on a carrier signal input from the outside, to generate an FM batch conversion signal; a signal branching unit that causes the FM batch conversion signal to branch into a first path and a second path; an optical transmission unit that is provided in the first path, converts the FM batch conversion signal into an optical signal, and transmits the optical signal to the outside; and a detection unit that is provided in the second path, and detects quality degradation of the FM batch conversion signal on the basis of the signal level of the FM batch conversion signal.

公开(公告)号：US20230370167A1

公开(公告)日：2023-11-16

申请号：US18026409

申请日：2020-09-18

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akihiro TANABE ,  Toshiaki SHITABA ,  Yoichi FUKADA ,  Tomoaki YOSHIDA

IPC: H04B10/54

CPC classification number: H04B10/54

Abstract: A signal converting apparatus includes a conversion unit, a measurement unit, and a control unit. The conversion unit performs FM batch conversion on an input signal containing a plurality of carrier signals, to generate an FM signal. The measurement unit measures the carrier levels of the plurality of carrier signals contained in the input signal, and the maximum frequency of the input signal. The control unit calculates the frequency deviation amount of the entire input signal, on the basis of the measured carrier levels of the respective carrier signals. Using the calculated frequency deviation amount and the measured maximum frequency, the control unit calculates a center frequency for the FM signal, and controls the conversion unit so that the center frequency of the FM signal to be generated by the FM batch conversion becomes equal to the calculated center frequency.

公开(公告)号：US20250080223A1

公开(公告)日：2025-03-06

申请号：US18726016

申请日：2022-01-11

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Toshiaki SHITABA ,  Tomoaki YOSHIDA ,  Yoichi FUKADA ,  Akihiro TANABE ,  Ryo MIYATAKE

IPC: H04B10/2507 ,  H04B10/079

Abstract: An optical receiving apparatus includes: a first branching unit that branches an input optical signal into a first optical signal and a second optical signal; a reception amplification unit that amplifies power of the first optical signal; a compensation unit that compensates for wavelength distortion of the first optical signal whose power has been amplified; a first detection unit that detects power of the second optical signal; a first control unit that controls an amount of compensation for the wavelength distortion on the basis of the power of the second optical signal; a second branching unit that branches the first optical signal compensated for the wavelength distortion into a third optical signal and a fourth optical signal; a second detection unit that detects power of the third optical signal; and a second control unit that controls an amplification factor of the power of the first optical signal before the compensation for the wavelength distortion on the basis of the power of the third optical signal.

公开(公告)号：US20240421910A1

公开(公告)日：2024-12-19

申请号：US18274148

申请日：2021-02-10

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Toshiaki SHITABA ,  Tomoaki YOSHIDA ,  Yoichi FUKADA ,  Akihiro TANABE ,  Ryo MIYATAKE

IPC: H04B10/516 ,  H04J14/02

Abstract: An optical transmission apparatus includes: a distributing unit which distributes a laser beam based on a first oscillation frequency; a phase modulator which generates, using the laser beam based on the first oscillation frequency, a phase-modulated signal that is an optical signal phase-modulated in accordance with a modulated signal; a multiplexing unit which multiplexes a laser beam based on a second oscillation frequency and the phase-modulated signal; a detecting unit which generates a frequency-modulated signal by performing detection processing on a result of multiplexing of the laser beam based on the second oscillation frequency and the phase-modulated signal; and an intensity modulator which generates, using the laser beam based on the first oscillation frequency, an optical signal intensity-modulated in accordance with the frequency-modulated signal.