Electrical Dispersion Compensation Equalizers in Optical Direct- and Coherent-Detection Systems

We study the performances of several electrical dispersion compensation (EDC) equalizers in the presence of chromatic dispersion and polarization mode dispersion for optical coherent- and direct-detection on–off keying systems. The EDCs that are analyzed include decision-feedback equalizer, linear equalizer, and maximum-likelihood sequence estimator (MLSE). We present an inclusive quantitative analysis of the performance difference between the various techniques. The MLSE gives a good indication of the best possible performance.