Demonstration of Real-Time DMT-WDM-PON Employing Probabilistic Shaping Based on Intra-Symbol Bit-Weighted Distribution Matching
Long Zhang, Kaihui Wang, Chen Wang, Junjie Ding, Junting Shi, Yu Chen, Yikai Wang, Yun Chen, Li Zhao, Wen Zhou, Jianjun Yu
Abstract
The probabilistic shaping (PS) technique can effectively reduce the average power of the transmitted signal by transmitting high-energy symbols with low probability and low-energy symbols with high probability, which helps to improve the tolerance of the system to the nonlinear effect of fiber. In this work, a low-complexity intra-symbol bit-weighted distribution matching (Intra-SBWDM)-based PS 16-ary quadrature amplitude modulation (PS-16QAM) scheme is implemented with a commercial off-the-shelf field programmable gate array chip for discrete multi-tone wavelength division multiplexing passive optical network (DMT-WDM-PON) communications. The Intra- SBWDM scheme, which has less computational and hardware complexity than traditional PS schemes like Gallager many-to-one mapping, hierarchical distribution matching, prefix-free code distribution matcher with framing and constant composition distribution matching, does not require look-up table or nor does it need to continuously refine the interval in order to determine the target symbol probability. As a result, it does not add a significant amount of extra redundant bits. The real-time experimental results show that the PS-DMT signals with a net rate of 131.88-Gb/s transmission over 25-km standard single-mode fiber can be achieved with the BER less than 3.8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> compared to uniformly-distributed DMT. More importantly, the BER performance measured in real-time has good stability during the one-hour measurement period for PS-16QAM DMT-WDM-PON transmission system.