Level Equalization to Compensate for Implementation Impairments in Optical Communication Systems with High-Order Modulations

A method comprising receiving digital samples from an optical communication system, assigning the samples into bins based on signal levels of the samples, computing an average signal level for each bin, determining a level adjustment transformation function for the samples based on the average signal levels of the bins, and applying the level adjustment transformation function to the samples. Also, disclosed is an optical receiver comprising a frontend configured to receive an optical signal over an optical channel, and convert the optical signal into a plurality of sequences of digital samples, and a processor coupled to the frontend and configured to perform a channel equalization on the samples of the sequences, assign the channel equalized samples of each sequence into bins based on signal levels of the channel equalized samples, determine a level adjustment transformation function for each sequence, and apply the level adjustment transformation function to each sequence.