公开(公告)号：US20220116121A1

公开(公告)日：2022-04-14

申请号：US17557251

申请日：2021-12-21

Applicant: NEC Corporation

Inventor： Daisaku OGASAHARA ,  Junichi ABE

IPC: H04B10/61 ,  H04B10/079

Abstract: When a frequency deviation compensation amount is compensated for by use of frequency shift, a phase offset occurs between adjacent input blocks included in a plurality of input blocks as divided, with the result that an error occurs in a reconstructed bit sequence. A frequency deviation compensation system of the invention is characterized by comprising: a frequency deviation compensation means for compensating for a frequency deviation occurring in a signal by use of frequency shift; and a phase offset compensation means for compensating for a phase offset occurring, in the signal, due to the frequency shift.

公开(公告)号：US20190296829A1

公开(公告)日：2019-09-26

申请号：US16438161

申请日：2019-06-11

Applicant: NEC Corporation

Inventor： Junichi ABE ,  Tatsuya NAKAMURA

IPC: H04B10/516 ,  H04B10/25 ,  H04L27/36 ,  H04L27/38

Abstract: If a configuration is employed in which modulation schemes used for an optical communication system can be switched depending on transmission conditions, the power consumption increases and the control becomes complex; therefore, an optical transmitter according to an exemplary aspect of the present invention includes an encoding means for encoding digital signals to be transmitted under a predetermined transmission condition over an optical carrier wave by using one of a plurality of encoding methods; an encoding control means for selecting a predetermined encoding method corresponding to the predetermined transmission condition from among the plurality of encoding methods and causing the encoding means to operate in accordance with the predetermined encoding method; a mapping means for mapping output bit signals output from the encoding means to modulation symbols; and an optical modulation means for modulating the optical carrier wave based on symbol signals output from the mapping means.

公开(公告)号：US20190140743A1

公开(公告)日：2019-05-09

申请号：US16238680

申请日：2019-01-03

Applicant: NEC Corporation

Inventor： Daisaku OGASAHARA ,  Junichi ABE

IPC: H04B10/61 ,  H04L27/26 ,  H04B10/079

Abstract: When a frequency deviation compensation amount is compensated for by use of frequency shift, a phase offset occurs between adjacent input blocks included in a plurality of input blocks as divided, with the result that an error occurs in a reconstructed bit sequence. A frequency deviation compensation system of the invention is characterized by comprising: a frequency deviation compensation means for compensating for a frequency deviation occurring in a signal by use of frequency shift; and a phase offset compensation means for compensating for a phase offset occurring, in the signal, due to the frequency shift.

公开(公告)号：US20170264372A1

公开(公告)日：2017-09-14

申请号：US15606698

申请日：2017-05-26

Applicant: NEC Corporation

Inventor： Kiyoshi FUKUCHI ,  Junichi ABE ,  Wakako YASUDA

IPC: H04B10/61

CPC classification number: H04B10/616

Abstract: The disclosed coherent optical receiver includes a local light source; a 90-degree hybrid circuit; an optoelectronic converter; an analog-to-digital converter; a skew addition unit; and a FFT operation unit. The 90-degree hybrid circuit makes multiplexed signal light interfere with local light from the local light source, and outputs multiple optical signals separated into a plurality of signal components. The optoelectronic converter detects the optical signal and outputs a detected electrical signal. The analog-to-digital converter digitizes the detected electrical signal and outputs a detected digital signal. The skew addition unit adds to the detected digital signal an additional skew amount whose absolute value is equal to, whose sign is opposite to a skew amount of a difference in propagation delay in each lane connected to each output channel of the 90-degree hybrid circuit. The FFT operation unit performs a fast Fourier transform on the output from the skew addition unit.

公开(公告)号：US20160050025A1

公开(公告)日：2016-02-18

申请号：US14779135

申请日：2013-09-19

Applicant: NEC CORPORATION

Inventor： Wakako YASUDA ,  Junichi ABE ,  Daisaku OGASAHARA

IPC: H04B10/61 ,  H04J14/06

CPC classification number: H04B10/6161 ,  H04B10/2513 ,  H04B10/25133 ,  H04B10/613 ,  H04B10/614 ,  H04B10/6163 ,  H04B10/6165

Abstract: An optical receiver (20) includes an electrical signal generation unit (200), a first phase compensation unit (101), a distortion compensation unit (102), and a first dispersion compensation unit (400). The electrical signal generation unit (200) generates an electrical signal on the basis of received signal light. The first phase compensation unit (101) performs a phase rotation compensation process on the electrical signal generated by the electrical signal generation unit (200). The distortion compensation unit (102) performs a dispersion compensation process and a phase rotation compensation process in this order, at least once, on the electrical signal after having compensation performed thereon by the first phase compensation unit. The electrical signal generation unit (200), the first phase compensation unit (101), and the distortion compensation unit (102) are incorporated into one semiconductor device.

Abstract translation: 光接收器（20）包括电信号产生单元（200），第一相位补偿单元（101），失真补偿单元（102）和第一色散补偿单元（400）。 电信号生成部（200）基于接收信号光生成电信号。 第一相位补偿单元（101）对由电信号生成单元（200）生成的电信号进行相位旋转补偿处理。 失真补偿单元（102）在通过第一相位补偿单元执行补偿之后对电信号至少一次执行色散补偿处理和相位旋转补偿处理。 电信号生成单元（200），第一相位补偿单元（101）和失真补偿单元（102）被并入到一个半导体器件中。

公开(公告)号：US20160036554A1

公开(公告)日：2016-02-04

申请号：US14782838

申请日：2014-02-19

Applicant: NEC CORPORATION

Inventor： Wakako YASUDA ,  Junichi ABE

IPC: H04J14/06 ,  H04B10/61

CPC classification number: H04J14/06 ,  H04B10/6161 ,  H04B10/6162 ,  H04B10/6163

Abstract: An optical reception device 20 includes an electric signal generation unit 200, a linear compensation unit 301, a nonlinear compensation unit 300, and a second coefficient setting unit 400. The electric signal generation unit 200 generates an electric signal based on an optical signal received over a transmission path 30. The linear compensation unit 301 performs processing for compensating for dispersion that occurs on optical signal in the transmission path 30 to the electric signal, using a first filter coefficient. The second coefficient setting unit 400 determines a second filter coefficient for compensating for a nonlinear effect that occurs on the optical signal in the transmission path 30, using an amount of dispersion that occurs in the transmission path 30. The nonlinear compensation unit 300 performs processing for compensating the electric signal for the nonlinear effect, using the second filter coefficient that is determined by the second coefficient setting unit 400.

Abstract translation: 光接收装置20包括电信号生成单元200，线性补偿单元301，非线性补偿单元300和第二系数设置单元400.电信号生成单元200基于接收到的光信号生成电信号 传输路径30.线性补偿单元301使用第一滤波器系数执行用于将传输路径30中的光信号上发生的色散补偿到电信号的处理。 第二系数设定单元400使用在传输路径30中出现的色散量来确定用于补偿发生在传输路径30中的光信号上的非线性效应的第二滤波器系数。非线性补偿单元300执行处理 使用由第二系数设定单元400确定的第二滤波器系数来补偿非线性效应的电信号。

公开(公告)号：US20150372765A1

公开(公告)日：2015-12-24

申请号：US14765908

申请日：2013-09-19

Applicant: NEC CORPORATION

Inventor： Wakako YASUDA ,  Junichi ABE

IPC: H04B10/61 ,  H04B10/2507 ,  H04B10/2543 ,  H04B10/079 ,  H04J14/06

CPC classification number: H04B10/6165 ,  H04B10/0795 ,  H04B10/2543 ,  H04B10/2572 ,  H04B10/613 ,  H04B10/614 ,  H04B10/6163 ,  H04J14/06

Abstract: A nonlinear compensation unit (300) includes a first compensation unit (350) and a second compensation unit (360). The first compensation unit (350) compensates for each of two polarization signals Ex and Ey so as to cancel a first amount of phase rotation which is the amount of phase rotation calculated based on the signal strength of the two polarization signals Ex and Ey. The second compensation unit (360) compensates for each of the two polarization signals Ex and Ey so as to cancel a second amount of phase rotation which is the amount of phase rotation calculated based on the perturbative component of the two polarization signals Ex and Ey. The first compensation unit (350) includes a strength calculation unit (302), a first filter unit (304), and a first phase modulation unit (306). The second compensation unit (360) includes a perturbative component calculation unit (316), a second filter unit (318), a second phase modulation unit (322), and a third phase modulation unit (330).

Abstract translation: 非线性补偿单元（300）包括第一补偿单元（350）和第二补偿单元（360）。 第一补偿单元（350）补偿两个极化信号Ex和Ey中的每一个，以抵消作为基于两个极化信号Ex和Ey的信号强度计算的相位旋转量的第一相位旋转量。 第二补偿单元（360）补偿两个偏振信号Ex和Ey中的每一个，以消除基于两个偏振信号Ex和Ey的扰动分量计算的相位旋转量的第二相位旋转量。 第一补偿单元（350）包括强度计算单元（302），第一滤波器单元（304）和第一相位调制单元（306）。 第二补偿单元（360）包括扰动分量计算单元（316），第二滤波单元（318），第二相位调制单元（322）和第三相位调制单元（330）。