Probabilistic Shaping 44QAM Based on Many-to-One Mapping in DMT-WDM-PON

We introduce a probabilistic shaping (PS) 44-ary quadrature amplitude modulation (44QAM) based on many-to-one (MTO) mapping into a discrete multi-tone wavelength division multiplexing passive optical network (DMT-WDM-PON) with maximum shaping gain of 0.46 dB. A low-density parity-check (LDPC) based bit-interleaved coded modulation and iterative decoding system is proposed to generate and transmit the PS-44QAM DMT signal without any extra PS redundancy. An extrinsic information (EI) is iteratively used between LDPC decoder and PS demapper to retrieve the PS-44QAM DMT signal including overlapped/ambiguous symbols. The experimental results show that the PS-44QAM DMT signal with improved receiver power sensitivity and system fiber nonlinear effect tolerance can be obtained in the power splitter based WDM-PON. Thus, the corresponding system loss budget can be significantly enlarged in the optical distribution network for the purpose of serving more optical network units.