Patent ID: 7734188

Claim:
A deskew device that corrects skew between at least three signals having different wavelengths, the deskew device comprising: a detector that detects a first difference in delay time between two synchronization signals having different wavelengths among synchronization signals included in received signals, and determines, upon detecting the first difference, whether the first difference is larger than a threshold, and, when the first difference is larger than the threshold, detects two synchronization signals having different wavelengths between which a second difference in delay time is smaller than the threshold; a calculator that calculates, when the first difference is not larger than the threshold, a delay compensation amount for each of the received signals based on the first difference and a signal delay characteristic in a transmission path, and calculates, when the first difference is larger than the threshold, the delay compensation amount based on the second difference and a signal delay characteristic in a transmission path; and a deskew unit that performs first deskew of the received signals based on the delay compensation amount.