A method of recovering information bits from a modulated optical signal in which information bits are modulated using a coherent modulation technique, the method comprising: receiving the modulated signal over an optical transmission medium; generating a stream of digital samples by performing analog-to-digital conversion of the received modulated signal; processing the stream of digital samples through a first decoding stage in which carrier frequency and phase recovery is performed to obtain a stream of recovered digital samples; performing, after the first decoding stage, post-equalization on the stream of recovered digital samples, wherein the performing post-equalization includes iteratively performing: a channel equalization on the stream of recovered digital samples; a digital filtering operation on output of the channel equalization using a digital post filter, wherein an impulse or frequency response of the digital filtering operation is adjusted adaptively, and a symbol estimation operation on output of the digital post filter, wherein parameters for the symbol estimation operation are adjusted adaptively based on the response of the digital post filter; until an iteration termination criterion is satisfied; wherein an output of the symbol estimation operation is fed back into the channel equalization operation after performing symbol alignment on the output of the symbol estimation operation; and recovering, after the termination of iterations, the information bits from the output of the symbol estimation operation, wherein the termination of iterations is determined by estimating improvement in a bit error ratio over a previous iteration. receiving the modulated signal over an optical transmission medium; generating a stream of digital samples by performing analog-to-digital conversion of the received modulated signal; processing the stream of digital samples through a first decoding stage in which carrier frequency and phase recovery is performed to obtain a stream of recovered digital samples; performing, after the first decoding stage, post-equalization on the stream of recovered digital samples, wherein the performing post-equalization includes iteratively performing: a channel equalization on the stream of recovered digital samples; a digital filtering operation on output of the channel equalization using a digital post filter, wherein an impulse or frequency response of the digital filtering operation is adjusted adaptively, and a symbol estimation operation on output of the digital post filter, wherein parameters for the symbol estimation operation are adjusted adaptively based on the response of the digital post filter; a channel equalization on the stream of recovered digital samples; a digital filtering operation on output of the channel equalization using a digital post filter, wherein an impulse or frequency response of the digital filtering operation is adjusted adaptively, and a symbol estimation operation on output of the digital post filter, wherein parameters for the symbol estimation operation are adjusted adaptively based on the response of the digital post filter; until an iteration termination criterion is satisfied; wherein an output of the symbol estimation operation is fed back into the channel equalization operation after performing symbol alignment on the output of the symbol estimation operation; and recovering, after the termination of iterations, the information bits from the output of the symbol estimation operation, wherein the termination of iterations is determined by estimating improvement in a bit error ratio over a previous iteration.