Patent ID: 8712255

Claim:
An optical receiver comprising: a compensator configured to receive an optical signal, which is modulated by at least one of an optical intensity modulation scheme and a phase modulation scheme, and to compensate for dispersion of the received optical signal with a dispersion parameter within a predetermined range of dispersion values; a memory; a compensation controller configured to instruct the compensator to compensate for dispersion of the optical signal; and a clock extractor configured to extract the received optical signal into an electric signal and to create extraction information indicating whether a clock can be extracted from the electric signal, wherein the compensation controller is configured to select a first dispersion value and a second dispersion value differing by a predetermined value from each other out of the predetermined range of dispersion values, the compensation controller is configured to store, into the memory, a stabilization time necessary to change the dispersion parameter used in the compensator from the first dispersion value to the second dispersion value, a transition time shorter than the stabilization time, and a difference between a third dispersion value used after the transition time and the second dispersion value, the compensator is configured to compensate the received optical signal using the selected first dispersion value in a case where the extraction information indicates that the clock extraction is unavailable, the clock extractor is configured to create first extraction information indicating whether the clock can be extracted from the optical signal compensated using the first dispersion value, the compensation controller is configured to change the dispersion parameter used in the compensator from the first dispersion value into the second dispersion value as a target, the compensator is configured to compensate the received optical signal using the third dispersion value after the transition time has passed since a time when the dispersion parameter was started to be changed, the clock extractor is configured to create second extraction information indicating whether the clock can be extracted from the optical signal compensated using the third dispersion value, and the compensation controller is configured to cause the compensator to compensate for dispersion of the optical signal using a dispersion value calculated based on the second dispersion value and the difference between the third dispersion value and the second dispersion value in a case where the created first extraction information indicates that the clock extraction is unavailable and the created second extraction information indicates that the clock extraction is available.