Low complexity fiber nonlinearity compensation scheme fusing single-channel digital back propagation with dual phase-conjugate twin waves for DSCM-WDM system
Wanxiang Bi, Chenglin Bai, Tianchi Chen, Hengying Xu, Lishan Yang, Yining Zhang, Yu Zhang, Pengfei Li, Shijie Hou
Abstract
In coherent systems combining digital subcarrier multiplexing (DSCM) and wavelength division multiplexing (WDM), signals are subject to self-subcarrier nonlinearity (SSN), cross-subcarrier nonlinearity (CSN), and cross-phase modulation (XPM) after optical fiber transmission. Most typical nonlinear compensation schemes for inter-channel and inter-subcarrier nonlinearities rely on information from neighboring channels and subcarriers, resulting in high complexity. To address the above problems, we propose a nonlinear low complexity compensation scheme that combines single-channel single-step digital back propagation (SC-DBP) with dual phase-conjugate twin waves (dual-PCTW), referred to as SC-DBP-DPCTW. This scheme efficiently compensates SSN while addressing XPM and CSN without relying on information from adjacent channels. Simulation results for a 9 × 128-GBaud transmission over a 1600-km DSCM-WDM system using dual-polarized 16QAM modulation show that SC-DBP-DPCTW achieves the same Q-factor improvement as 10-Step DSCM-DBP while reducing complexity by approximately 92.2%. Additionally, in a 3 × 28-GBaud transmission over an 806.4-km DSCM-WDM experimental system, the scheme provides the same Q-factor improvement as 5-Step DSCM-DBP with a complexity reduction of approximately 84.3%.