State integrated Look-up table assisted BCJR scheme with significant complexity optimization in bandwidth-limited optical interconnection

A Bahl-Cocke-Jelinek-Raviv detection scheme employing a state-integrated look-up table (SiLUT-BCJR) is proposed and experimentally demonstrated in a bandwidth-efficient intensity modulation/direct detection (IM/DD) optical interconnection system. A merging approach for intermediate symbols is utilized to integrate LUT patterns, efficiently simplifying the counting paths for adjacent preceding and succeeding symbols suffering from inter-symbol interference (ISI) impairment. Consequently, the computational probabilistic load for subsequent BCJR is significantly optimized, as well as the computational complexity. The experiments validated in a 160 Git/s PAM4 interconnection system over single-mode fiber (SMF) transmission demonstrate that the proposed SiLUT-BCJR reduces computational complexity by 75% compared to traditional LUT-BCJR, with negligible optical power penalty.