Determination of a discrimination threshold in an optical transmission system

摘要

A method to determine a discrimination threshold of a received signal, input from an optical transmission line, comprises steps of measuring a bit error rate of the received signal at each of a plurality of discrimination thresholds, by changing the polarization of an optical signal entering the optical transmission line, detecting the worst bit error rate at each discrimination threshold, and searching a predetermined bit error rate from the plurality of the detected worst bit error rates, and searching a discrimination threshold of the received signal according to the predetermined bit error rate.