Low-complexity absolute-term based nonlinear equalizer with weight sharing for C-band 85-GBaud OOK transmission over a 100-km SSMF

• DOI: 10.1364/ol.454715
• Publication Date: 2022-02-28T16:31:33Z
• Authors: Xiong Wu; Junwei Zhang; Alan Pak Tao Lau; Chao Lu
• Keywords: 0202 electrical engineering, electronic engineering, information engineering; 02 engineering and technology; 01 natural sciences; 0105 earth and related environmental sciences

A low-complexity absolute-term based nonlinear feed-forward equalizer (FFE) combined with a decision-feedback equalizer (DFE) with weight sharing (AT-NLE-WS) is proposed and experimentally performed in a C-band 85-GBaud on-off keying (OOK) transmission system over a 100-km standard single-mode fiber (SSMF). By applying the k-means clustering algorithm to reduce weight redundancy, the required number of real-valued multiplications per symbol (RNRM) of the proposed AT-NLE-WS is only 14 for a bit error ratio (BER) under a KP4-forward error correction (FEC) threshold of 2.4 × 10−4. Compared with FFE-DFE, polynomial based nonlinear FFE-DFE (P-NLE), and AT-NLE, the proposed AT-NLE-WS saves >93% real-valued multiplications under the KP4-FEC threshold. In addition, compared with FFE-DFE, the proposed AT-NLE-WS can simultaneously achieve an approximately 2-dB improvement of receiver sensitivity and reduce the complexity by >80%. All experimental results show that AT-NLE-WS is a very attractive approach for practical implementation of low-cost optical interconnections with a data rate beyond 50 Gb/s and transmission distance up to 100 km.