Compensation apparatus and method for inter-channel nonlinear damage

Patent metadata

Field	Value
Publication number	US-9825708-B2
Application number	US-201414513689-A
Country	US
Kind code	B2
Filing date	Oct 14, 2014
Priority date	Oct 15, 2013
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A compensation apparatus and method for inter-channel nonlinear damage are disclosed where the apparatus includes: an iteration parameter determining unit configured to determine an iteration step of cross-phase modulation damage compensation performed in each channel in a multichannel optical fiber transmission link; an estimating unit configured to divide an optical fiber transmission link in each iteration step of each channel into one or more optical fiber segments, and perform cross-phase modulation damage estimation at a position in each optical fiber segment where the nonlinear damage is maximal; and a first compensating unit configured to perform cross-phase modulation damage compensation according to the result of the cross-phase modulation damage estimation. By performing cross-phase modulation damage estimation at a position in each optical fiber segment where the nonlinear damage is maximal, cross-phase modulation damage compensation may be performed effectively, and performance of the communication system may be improved.

First claim

The invention claimed is:

1. A compensation apparatus for inter-channel nonlinear damage compensation, the apparatus comprising:
an iteration parameter determining unit configured to determine an iteration step of cross-phase modulation damage compensation performed in each channel in a multichannel optical fiber transmission link model;
an estimating unit configured to divide an optical fiber transmission link model in each iteration step of each channel into at least one optical fiber segment, and perform cross-phase modulation damage estimation at an input end of each optical fiber segment according to cross phase modulation damage to a channel within a predefined distance from a current channel; and
a first compensating unit configured to perform cross-phase modulation damage compensation according to a result of the cross-phase modulation damage estimation.

2. The apparatus according to claim 1 , wherein the estimating unit comprises:
a segmenting unit configured to divide an optical fiber transmission link model in each iteration step of each channel into the at least one optical fiber segment;
a first calculating unit configured to calculate an output waveform at the input end of each optical fiber segment in each iteration step;
a second calculating unit configured to calculate cross-phase modulation damage to each optical fiber segment in each iteration step of each channel according to the output waveform;
a third calculating unit configured to sum cross-phase modulation damage of all optical fiber segments in each iteration step of each channel, to obtain cross-phase modulation damage to the optical fiber transmission link model in each iteration step; and
a fourth calculating unit configured to calculate cross-phase modulation matrices of the optical fiber transmission link model in each iteration step of each channel according to the cross-phase modulation damage to the optical fiber transmission link model in each iteration step of each channel, and calculate inverse matrices of the cross-phase modulation matrices; and
wherein the first compensating unit compensates for the cross-phase modulation damage to the optical fiber transmission link model in each iteration step of each channel according to the inverse matrices of the cross-phase modulation matrices.

3. The apparatus according to claim 1 , wherein the apparatus further comprises:
a second compensating unit configured to compensate for one of linear damage, self-phase modulation damage, or linear damage and self-phase modulation damage to each channel before the first compensating unit performs the cross-phase modulation damage compensation.

4. The apparatus according to claim 2 , wherein the first calculating unit calculates the output waveform of each iteration step of each channel according to formula (1) below:
U m,i =( W m,i ) −1 ×( U m,i−1 {circle around (×)}h LI,m1 {circle around (×)}h LI,m,2 {circle around (×)} . . . {circle around (×)}h LI,m,N i )  (1);

where, U m,i−1 and U m,i respectively denote an input signal and an output signal of an optical transmission link model of an i-th iteration step of an m-th channel, W m,i denotes a cross-phase modulation matrix corresponding to the i-th iteration step and acting on the m-th channel, and h LI,m,n =IFT(H LI,m,n ), H LI,m,n denoting a frequency characteristic of one of the linear damage, the self-phase modulation damage, or the linear damage and self-phase modulation damage compensation performed at an n-th optical fiber segment of the current iteration step of the m-th channel, and m, i and n being integers greater than 0.

5. The apparatus according to claim 2 , wherein the fourth calculating unit calculates the inverse matrices of the cross-phase modulation matrices according to formula (2) below:

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Assignees

• Fujitsu Ltd

Inventors

• Fan Yangyang
• Dou Liang
• Tao Zhenning

Classifications

• H04B10/2557 Primary

  Cross-phase modulation [XPM] · CPC title

• H04B10/0795

  Performance monitoring; Measurement of transmission parameters · CPC title