Abstract
We investigate the optimal constellation size for probabilistic shaping (PS) under the constraint of different effective numbers of bits (ENOB) of the analog-to-digital converter (ADC) at the receiver. For a fixed entropy, increasing the constellation size brings a larger shaping gain, while it also leads to a higher peak-to-average-power ratio, which makes the signal more sensitive to the ENOB and fiber nonlinearity. Our experimental results show that PS-44 quadrature amplitude modulation (QAM) outperforms both PS-64 QAM and uniformly shaped 32 QAM (U-32 QAM) when the ENOB of ADC is lower than 4.5. The optimal launched power and the maximum achievable distance for U-32 QAM, PS-44 QAM, and PS-64 QAM are analyzed by simulation.
© 2019 Optical Society of America
Full Article | PDF ArticleMore Like This
Xiaojian Hong, Chao Fei, Guowu Zhang, Ji Du, and Sailing He
Opt. Lett. 44(3) 558-561 (2019)
Ahmad Fallahpour, Fatemeh Alishahi, Amir Minoofar, Kaiheng Zou, Ahmed Almaiman, Peicheng Liao, Hubin Zhou, Moshe Tur, and Alan E. Willner
Opt. Lett. 45(18) 5283-5286 (2020)
Xi Chen, Yizhao Chen, Ming Tang, Songnian Fu, and Deming Liu
Opt. Express 27(19) 26295-26306 (2019)