Patent Number: 7,711,218

Title: Optical reception apparatus and controlling method thereof

Abstract: The optical reception apparatus of the invention branches into two an RZ-DQPSK optical signal input from an optical transmission path via an optical amplifier, respectively sends this to delay interferometers and photoelectric converters on a pair of arms, separately detects a number of generated errors for the signals propagating through the arms in an error-number detection circuit, obtains a difference in the respective number of generated errors in an error-number detector, and controls phase shift in the delay interferometers so that the difference is within a preset tolerance. By so doing, it is possible to realize excellent reception performance by suppressing the occurrence of the burst error.

Inventors: Ojima; Hisayuki (Kawasaki, JP), Fukumitsu; Katsumi (Kawasaki, JP)

Assignee: Fujitsu Limited

International Classification: G02B 6/28 (20060101)

Expiration Date: 5/04/12018