Maximum probability directed blind phase search for PS-QAM with variable shaping factors.

Abstract

We report the maximum probability directed blind phase search (MPD-BPS) solution to enhance the carrier phase estimation (CPE) capability for the probabilistically shaped-quadrature amplitude modulation (PS-QAM) with variable shaping factors. We first investigate the trade-off between the shaping factor (SF) and the noise rejection window of the BPS for the PS-64/256QAM at a fixed signal to noise ratio (SNR). Next, we carry out the joint optimization of the SF and the noise rejection window, in order to obtain the maximum achievable information rate (AIR) at the fixed SNR. Then, we numerically compare the performance of the MPD-BPS and the traditional BPS for the PS-64/256QAM with variable SFs. Finally, we conduct the experimental verification of 32 Gbaud PS-64QAM with the SFs of 0.02, 0.025, 0.03, and 0.035, under scenarios of back-to-back (B2B) transmission and the standard single mode fiber (SSMF) loop transmission. The experimental results indicate that the proposed MPD-BPS can obtain an average 0.13 dB SNR enhancement under the B2B transmission and the 1.67% reach enhancement for the SSMF transmission, in comparison with the use of traditional BPS.