OPTICAL SIGNAL-TO-NOISE RATIO ESTIMATOR AND ESTIMATION METHODOLOGY FOR OPTICAL COMMUNICATION

摘要

The present invention provides a noise estimator for determining an optical signal-to-noise ratio (OSNR) value of a QAM optical signal. The noise estimator comprises an optical detector configured to directly detect the optical signal and provide an electrical QAM signal representing an instantaneous amplitude of the detected QAM optical signal. A signal processor is configured to determine a statistical parameter value of a predetermined probability density function representing a single fit to a power amplitude distribution of the QAM electrical signal at a first timing within a power eye diagram representation.