Chromatic Dispersion Compensation of OOK Signals With MLSE Utilizing Diverse VSB Filtering

We present diverse vestigial-sideband-filtering maximum-likelihood sequence estimation (DVSB-MLSE), a modification of MLSE, for residual chromatic dispersion (CD) compensation in nonreturn-to-zero (NRZ) on–off keying (OOK) systems. While VSB filtering can considerably increase residual CD tolerance of MLSE receivers, the performance of MLSE can be further enhanced by diverse reception, through which the MLSE module jointly equalizes samples from upper and lower VSB filtered signals. Simulation results show that compared to conventional MLSE, DVSB-MLSE increases the residual CD tolerance at 3-dB optical signal-to-noise ratio penalty by 110% in a 42.7-Gb/s NRZ-OOK system.