Digital signal processing circuit and signal processing device that includes a plurality of digital signal processing circuits

Patent metadata

Field	Value
Publication number	US-2017310394-A1
Application number	US-201715490085-A
Country	US
Kind code	A1
Filing date	Apr 18, 2017
Priority date	Apr 22, 2016
Publication date	Oct 26, 2017
Grant date	—

Abstract

A signal processing device includes digital signal processing circuits. Each of the digital signal processing circuits includes: a regeneration circuit that regenerates a bit stream front an electric field information signal of an optical signal; an error correction circuit that corrects an error in the bit stream; an encoder circuit that generates an encoded bit stream from received data; and a generation circuit that generates an electric field information signal from the encoded bit stream. An electric field information signal or a bit stream is given from a regeneration circuit, an encoder circuit or a generation circuit in a first digital signal processing circuit to a second digital signal processing circuit. A regeneration circuit, an error correction circuit or a generation circuit in the second digital signal processing circuit processes the electric field information signal or the bit stream given from the first digital signal processing circuit.

First claim

What is claimed is:

1 . A signal processing device that includes a plurality of digital signal processing .circuits-, each of the plurality of digital signal processing circuits comprising:
a regeneration circuit configured to regenerate a bit stream from an electric field information signal that indicates an electric field of an optical signal; an error correction circuit configured to correct an error in the regenerated bit stream; an encoder circuit configured to add an error correction code to data so as to generate an encoded bit stream; and a generation circuit configured to generate an electric field information signal that indicates an electric field of an optical signal from the encoded bit stream, wherein an electric field information signal or a bit stream is given from a regeneration circuit, an encoder circuit, a generation circuit, or any combination thereof implemented in a first digital signal processing circuit in the plurality of digital signal processing circuits to a second digital signal processing circuit in the plurality of digital signal processing circuits, and a regeneration circuit, an error correction circuit, a generation circuit, or any combination thereof implemented in the second digital signal processing circuit processes the electric field information signal or the bit stream given from the first digital signal processing circuit.

2 . The signal processing device according to claim 1 , wherein
a first regeneration circuit implemented in the first digital signal processing circuit regenerates a bit stream from an electric field information, signal that is generated according to a received optical signal in a receiver frontend circuit, the first digital signal processing circuit distributes the bit stream regenerated by the first regeneration circuit to a first error correction circuit implemented in the first digital signal processing circuit and a second error correction circuit implemented in the second digital signal processing circuit, each of the first error correction circuit and the second error correction circuit corrects an error in the bit stream distributed from the first regeneration circuit, the first digital signal processing circuit, multiplexes a first encoded bit stream and a second encoded bit stream so as to generate a multiplexed bit stream, the first encoded bit stream being output from an encoder circuit implemented in the first digital signal processing circuit, the second encoded bit stream being output from an encoder circuit implemented in the second digital signal processing circuit, and the generation circuit implemented in the first digital signal processing circuit, generates an electric field information signal from the multiplexed bit stream, and gives the electric field information, signal to a transmitter frontend circuit.

3 . The signal processing device according to claim 1 , wherein
the regeneration circuit in each of the plurality of digital signal processing circuits includes a compensator circuit configured to compensate for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of an electric field information signal, a first compensator circuit implemented in the first digital signal processing circuit compensates for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of an electric field information signal that is generated according to a received optical signal in a receiver frontend circuit, and a second compensator circuit implemented in the second digital signal processing circuit, compensates for chromatic dispersion, non-linear distortion, or both of chromatic dispersion, and non-linear distortion of the electric field information signal that is output from the first compensator circuit.

4 . The signal processing device according to claim 1 , wherein
the regeneration circuit in each of the plurality of digital signal processing circuits includes a compensator circuit configured to compensate for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of an electric field information signal, the compensator circuit of each of the plurality of digital signal processing circuits is cascade-connected, a first compensator circuit provided at a first-stage in a plurality of compensator circuits that are cascade-connected compensates for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of an electric field information signal that is generated according to a received optical signal in a receiver frontend circuit, each of the other compensator circuits in the plurality of compensator circuits compensates for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of the electric field information signal that is output from its previous-stage compensator circuit, and in a digital signal processing circuit that includes a last compensator circuit in the plurality of compensator circuits, the regeneration circuit regenerates a bit stream from the electric field information signal in which the chromatic dispersion, the non-linear distortion, or both of chromatic dispersion and non-linear distortion is compensated for, and the error correction circuit corrects an error in the bit stream that is output from the regeneration circuit.

5 . The signal processing circuit according to claim 1 , wherein
the regeneration circuit implemented in the first digital signal processing circuit includes:
a compensator circuit configured to compensate for chromatic dispersion, non-linear distortion, or both of chromatic dispersion and non-linear distortion of an electric field information signal that is generated according to a received optical signal in a receiver frontend circuit;
a frequency offset compensator circuit configured to compensate for a frequency offset of the electric field information signal that is output from the compensator circuit; and
a carrier phase recovery circuit configured to recover a carrier phase of the electric field information signal that is output from the frequency offset compensator circuit, and the regeneration circuit implemented in the second digital signal processing circuit includes a digital filter configured to equalize the electric field information signal that is output from the carrier phase recovery circuit in the first digital signal processing circuit by using specified filter coefficients, and the regeneration circuit regenerates a bit stream from an output signal of the digital filter.

6 . The signal processing device according to claim 1 , wherein
in the first digital signal processing circuit, the encoder circuit adds an error correction code to client data so as to generate an encoded bit stream, and the generation circuit generates an electric field information signal from the encoded bit stream, the regeneration circuit implemented in the second digital signal processing circuit includes a dispersion control circuit configured to control chromatic dispersion of an electric field information signal, the dispersion control circuit controls chromatic dispersion of the electric field information signal that is generated by the generation circuit in the first digital signal processing circuit, and the first digital signal processing circuit gives, to a transmitter frontend circuit, the electric field information signal that is output from the dispersion control circuit.

7 . The signal processing device according to claim 1 , wherein
the regeneration circuit implemented in the first digital signal processing circuit generates a first regenerated bit stream from an first electric field informat

Assignees

• Fujitsu Ltd

Inventors

• Nakashima Hisao
• Nomura Yoshitaka
• Oyama Tomofumi
• Ge Yi
• Akiyama Yuichi
• Hirose Yoshio
• Hoshida Takeshi

Classifications

• H04L1/0042

  Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape (H04L1/0067 takes precedence) · CPC title

• H04B10/2513 Primary

  due to chromatic dispersion · CPC title

• H04L1/0057

  Block codes (H04L1/0061, H04L1/0064 take precedence) · CPC title

• H04B10/616 Primary

  Details of the electronic signal processing in coherent optical receivers · CPC title