C-Band 112-Gb/s PAM-4 Transmission Employing Cluster-Pruning LUT-Based Volterra DFE

We propose a low-complexity cluster-pruning look-up-table-based Volterra decision-feedback equalizer (CPLUT-VDFE) to substantially reduce the computational complexity associated with compensating for chromatic dispersion (CD) and nonlinear distortions in intensity modulation and direct detection (IM/DD) transmission systems. By employing CPLUTs, the proposed CPLUT-VDFE not only eliminates all multiplication operations required for the implementation of the VDFE, but also significantly reduces the overall table size. The performance of the proposed CPLUT-VDFE is evaluated after Volterra feed-forward equalization in a C-band 112-Gb/s PAM-4 50-km transmission system. Experimental results demonstrate that the proposed CPLUT-VDFE, with 82 cluster centers, achieves comparable equalization performance to the cluster-assisting LUT-VDFE (CLUT-VDFE) with 110 cluster centers, while reducing the total table size by 71.1% and the number of real-valued additions by 25.7%. Furthermore, the proposed CPLUT-VDFE, with 42 cluster centers, can achieve a 99.9% reduction in total table size and a 62.4% decrease in the number of real-valued additions compared to the CLUT-VDFE with 110 cluster centers, at the expense of a 1-dB power penalty.