公开(公告)号：US20230163552A1

公开(公告)日：2023-05-25

申请号：US17921681

申请日：2020-05-08

Applicant: NEC Corporation

Inventor： Hitoshi TAKESHITA ,  Keiichi Matsumoto ,  Hidemi Noguchi

IPC: H01S3/067 ,  H01S3/094 ,  H01S3/16

CPC classification number: H01S3/06737 ,  H01S3/094011 ,  H01S3/094015 ,  H01S3/06733 ,  H01S3/1608 ,  H01S3/094007

Abstract: The present invention addresses the problem that, when an optical amplification device having a plurality of optical transmission paths, such as multi-core optical fibers, is used for bidirectional communication, it is difficult to construct an optical transmission system optimized for all of signal lights having different transmission directions. The optical amplification device of the present invention comprises: an optical guide means having a plurality of optical transmission paths including an optical amplification medium having a gain in the wavelength band of a signal light; an excitation light introducing means for introducing excitation light for exciting the optical amplification medium into the optical guide means from both ends of the optical guide means; and a residual excitation light introducing means for introducing residual excitation light output from both ends of the optical guide means and having a wavelength component of the excitation light into the optical guide means.

公开(公告)号：US11632184B2

公开(公告)日：2023-04-18

申请号：US17440420

申请日：2020-02-04

Applicant: NEC Corporation

Inventor： Hidemi Noguchi ,  Junichi Abe ,  Masaki Sato

IPC: H04J14/02 ,  H04B10/2507 ,  H04B10/50 ,  H04B10/61

Abstract: To suppress the deterioration of the characteristics of a MIMO equalizer as well as minimizing an increase in circuit size in spite of the occurrence of signal spectrum narrowing and asymmetric spectrum degradation, a wavelength-division multiplexing optical transmission system (10) according to an embodiment includes a transmitter (1) that generates one channel signal by wavelength-division multiplexing a plurality of subcarrier signals so as to overlap each other and transmits the channel signal, and a receiver (2) that separates a received channel signal into subcarrier signals, and performs equalization using an MIMO equalizer (3) including a FDE-MIMO equalizer (4) and a TDE-MIMO equalizer (5) on each of the separated subcarrier signals.

公开(公告)号：US11435477B2

公开(公告)日：2022-09-06

申请号：US16982021

申请日：2018-03-28

Applicant: NEC Corporation

Inventor： Hidemi Noguchi

IPC: G01B9/02 ,  G01S17/34 ,  G01B9/02003

Abstract: A distance measurement device (2000) generates transmission light by modulating an optical carrier wave. The distance measurement device (2000) transmits the generated transmission light, and receives reflected light acquired by the transmission light being reflected by a measured object (10). The distance measurement device (2000) generates a first beat signal by causing the transmission light to interfere with reference light. The distance measurement device (2000) generates a second beat signal by causing the reflected light to interfere with the reference light. The distance measurement device (2000) calculates a distance to the measured object (10), based on a difference between the first beat signal and the second beat signal.

公开(公告)号：US10819443B2

公开(公告)日：2020-10-27

申请号：US16490632

申请日：2018-03-05

Applicant: NEC Corporation

Inventor： Hidemi Noguchi

IPC: H04B10/67 ,  H04B10/079 ,  H04B10/61 ,  H04J14/02 ,  H04B10/60 ,  H04B10/50

Abstract: The receiving-side system (10) includes a smaller number of optical reception front ends (12) than the number of a plurality of wavelength-multiplexed subcarrier signals. Each of the optical reception front ends (12) is configured to receive two or a plurality subcarrier signals of the plurality of subcarrier signals. A frequency offset monitoring unit (22) monitors frequency offsets of the respective subcarrier signals received by the optical reception front end (12). A light source frequency control unit (24) controls at least one of a light source frequency of the transmitting-side system (2) and a light source frequency of the receiving-side system (10) based on a result of the monitoring performed by the frequency offset monitoring unit (22).

公开(公告)号：US10171177B2

公开(公告)日：2019-01-01

申请号：US15534120

申请日：2015-12-15

Applicant: NEC Corporation

Inventor： Wakako Yasuda ,  Hidemi Noguchi

IPC: H04B10/03 ,  H04B10/69 ,  H04B10/2507 ,  H04B10/61 ,  H04J11/00 ,  H04L25/03

Abstract: It is difficult to obtain a demodulated signal with high signal quality in a digital optical receiver because it is difficult to compensate for each of different types of waveform distortion by a high-performance equalization process; therefore, a digital signal processor according to an exemplary aspect of the present invention includes a fixed equalization means for performing a distortion compensation process based on a fixed equalization coefficient on an input digital signal; an adaptive equalization means for performing an adaptive distortion compensation process based on an adaptive equalization coefficient on an equalized digital signal output by the fixed equalization means; a low-speed signal generation means for generating a low-speed digital signal by intermittently extracting one of the input digital signal and the equalized digital signal; a low-speed equalization coefficient calculation means for calculating a low-speed equalization coefficient to be used for a distortion compensation process of the low-speed digital signal; and a fixed equalization coefficient calculation means for calculating the fixed equalization coefficient by using at least a predetermined coefficient out of the low-speed equalization coefficient and the predetermined coefficient.

公开(公告)号：US20150280831A1

公开(公告)日：2015-10-01

申请号：US14433713

申请日：2013-07-31

Applicant: NEC CORPORATION

Inventor： Hidemi Noguchi

IPC: H04B10/548

CPC classification number: H04B10/548 ,  G02F1/0121 ,  H04B10/5051 ,  H04B10/508 ,  H04B10/516 ,  H04B10/5561

Abstract: The optical transmission system incudes signal output means (11S) for outputting a drive signal according to an input signal to the first optical modulator (11a), first waveform shaping signal output means (12S) for outputting a first waveform shaping signal to the second optical modulator (10A), and second waveform shaping signal output means (13S) for outputting a second waveform shaping signal to the third optical modulator (13a). The first waveform shaping signal is output to the second optical modulator (10A) at a timing relatively later than a timing of an output of a signal by the first optical modulator (11a). The second waveform shaping signal is output to the third optical modulator (13a) at a timing relatively earlier than the timing of the output of the signal by the first optical modulator (11a).

Abstract translation: 光传输系统包括用于根据到第一光调制器（11a）的输入信号输出驱动信号的信号输出装置（11S），第一波形整形信号输出装置（12S），用于将第一波形整形信号输出到第二光 调制器（10A）和用于向第三光调制器（13a）输出第二波形整形信号的第二波形整形信号输出装置（13S）。 第一波形整形信号在比由第一光调制器（11a）输出信号的定时更晚的定时输出到第二光调制器（10A）。 第二波形整形信号在比由第一光调制器（11a）输出信号的定时更早的时间被输出到第三光调制器（13a）。