Digital Pre-Distortion Employing Complex FIR Filters From Receiver Side Two Stage Dynamic Equalizer for Coherent Optical Systems

Abstract

We presented a double-stage time domain digital pre-distortion method to mitigated the degradation imposed by narrow band filtering from analog front-end for high symbol rate coherent optical communication systems. The proposed technique is based on complex finite impulse response (FIR) filters estimated from the two stage dynamic equalizer on the reception digital signal processing stack. We conducted a series of system simulations to optimize pre-distortion setup and to evaluate its performance in increasing maximum achievable symbol rates for 16QAM and 64QAM. The results indicated gains up to 3 GBd and, consequently, 32 Gb/s and 48 Gb/s, compared with the case without digital pre-distortion, for 16QAM and 64QAM, respectively.