Long-distance effectiveness of MLSE IMDD receivers

We present numerical evidence that maximum-likelihood sequence estimation (MLSE)-based receivers, assuming ideal implementation, could operate over as much as 11 000 ps/nm of chromatic dispersion (700 km of G.652 fiber), keeping the total penalty with respect to back-to-back within approximately 3 dB. We argue that these results suggest that the penalty of an MLSE-based receiver versus total chromatic dispersion could be bounded to an asymptotic value, provided that enough trellis states are used to properly deal with the channel memory.