Optical receive device and optical transmission system
AssigneeFujitsu Limited
InventorsYo Nakamura, Hisao NAKASHIMA, GUOXIU HUANG
Life of this patent
Estimating the term…
Abstract
An optical receive device includes a coherent receiver that outputs an electrical analog signal corresponding to an optical signal, a converter that converts the electrical analog signal into a digital signal, a scrambler that scrambles a differential group delay (DGD) of the digital signal, and an adjustment unit that receives the digital signal output by the scrambler as an input and adjusts one or both of a sampling frequency and a sampling phase of the converter based on a power envelope (PE) method.
Claims14
An optical receive device comprising:
- a coherent receiver that outputs an electrical analog signal corresponding to an optical signal;
- a converter that converts the electrical analog signal into a digital signal;
- a scrambler that scrambles a differential group delay (DGD) of the digital signal;
- and
- an adjustment unit that receives the digital signal output by the scrambler as an input and adjusts one or both of a sampling frequency and a sampling phase of the converter based on a power envelope (PE) method.
An optical transmission system including:
- an optical transmit device that applies a predetermined technique for reducing intersymbol interference of a transmission line to a first digital signal and transmits an optical signal corresponding to the first digital signal, and an optical receive device that receives the optical signal,
- wherein the optical receive device includes:
- a coherent receiver that receives the optical signal and outputs an electrical analog signal corresponding to the optical signal;
- a converter that converts the electrical analog signal into a second digital signal;
- a scrambler that scrambles a differential group delay (DGD) of the second digital signal;
- and
- an adjustment unit that receives a digital signal output by the scrambler as an input and adjusts one or both of a sampling frequency and a sampling phase of the converter based on a power envelope (PE) method.
An optical transmission system including an optical transmit device that transmits an optical signal, and an optical receive device that receives the optical signal,
- wherein the optical transmit device includes:
- a coding unit that precodes an electrical first digital signal using a predetermined technique for reducing intersymbol interference of a transmission line;
- an insertion unit that inserts a training sequence including a plurality of identical patterns to the first digital signal after being precoded, and
- a modulator that modulates, into the optical signal, the first digital signal to which the training sequence has been inserted,
- wherein the optical receive device includes:
- a coherent receiver that receives the optical signal and outputs an electrical analog signal corresponding to the optical signal,
- a converter that converts the electrical analog signal into a second digital signal,
- a sampling phase compensator that compensates for a sampling phase of the optical signal based on a coefficient updated by adaptive equalization processing on the second digital signal, and
- a sampling frequency error estimation unit that determines a start position of the training sequence included in the second digital signal based on correlation of the identical patterns before compensating for the sampling phase, and estimates a sampling frequency error of the converter based on a sample number difference between a first sample number based on the start position and a second sample number of the training sequency at the optical transmit device and a sample number ratio between the first sample number and the second sample number.
Dependencies are inferred from the claim text.