Complexity curtailed MLSE equalizer based on a compact look-up-table for C-band DSB IM/DD transmission

• Published in: Optics letters Vol. 47; no. 21; p. 5606
• Main Authors: Chen, Zhuo, Dai, Xiaoxiao, Nie, Junyuan, Zhang, Shenmao, Zhou, Jiahao, Zhang, Jing, Qiu, Ying, Luo, Ming, Yang, Qi, Deng, Lei, Cheng, Mengfan, Qiu, Kun, Liu, Deming
• Format: Journal Article
• Language: English
• Published: United States 01.11.2022
• ISSN: 1539-4794
• DOI: 10.1364/OL.475764

Chromatic dispersion appears to be a major performance limiting problem in optical intensity modulation direct detection (IM/DD) transmission systems, especially for a double-sideband (DSB) signal. We propose a complexity-reduced look-up-table based maximum likelihood sequence estimation (LUT-MLSE) for DSB C-band IM/DD transmission based on pre-decision-assisted trellis compression and a path-decision-assisted Viterbi algorithm. To further compress the size of the LUT and reduce the length of the training sequence, we proposed a finite impulse response (FIR) and LUT hybrid channel model for the LUT-MLSE. For PAM-6 and PAM-4, the proposed methods can compress the size of the LUT into 1/6 and 1/4, and reduce the number of multipliers by 98.1% and 86.6% with slight performance degradation. We successfully demonstrate a 20-km 100-Gb/s PAM-6 and a 30-km 80-Gb/s PAM-4 C-band transmission over dispersion-uncompensated links.