Complexity Reduction With a Simplified MIMO Volterra Filter for PDM-Twin-SSB PAM-4 Transmission

Abstract

We propose and experimentally demonstrate a simplified multiple-input multiple-output Volterra filter (MIMO-VF) in a polarization division multiplexed (PDM) twin single side-band (SSB) scheme based on two offset carriers. The right side-band (RSB) and left side-band (LSB) signals of the twin-SSB in each polarization are separated by an optical filter, and the crosstalk between the RSB and LSB is mitigated in the receiver digital signal processing (DSP) by the proposed simplified MIMO-VF, which is combined with one two-stage equalizer, i.e., a linear 2 × 2 butterfly MIMO equalizer and two independent VFs. With the proposed simplified MIMO-VF, we experimentally demonstrate a 400-Gb/s four-level pulse amplitude modulation (PAM-4) signal transmission over an 80-km standard single mode fiber (SSMF). Compared with the traditional MIMO-VF, the proposed simplified MIMO-VF can retain the same transmission performance and reduce the computational complexity by approximately 57.9%.