Patent ID: 7603042

Claim:
An optical signal receiver comprising: a photodetector configured to receive and convert an optical signal into an electrical signal; an electronic amplifier configured to amplify the electrical signal; a decision circuit configured to convert the electrical signal into logical ones and logical zeros based on a decision threshold; a forward error correction circuit configured to count a number of erred logical ones and a number of erred logical zeros; and a feedback circuit configured to: compare a first ratio to a non-unitary parameter, wherein the first ratio is a ratio of the number of erred logical ones to the number of erred logical zeros, and wherein the non-unitary parameter consists essentially of the ratio of the standard deviation of the number of logical ones probability density function to the standard deviation of the number of logical zeros probability density function; and in response to a result of said comparison, decrease the decision threshold if the comparison indicates that the first ratio is greater than the non-unitary parameter and increase the decision threshold if the comparison indicates that the first ratio is less than the non-unitary parameter.