Enhanced adaptive DA-ML carrier phase estimator and its application to accurate laser linewidth and SNR estimation

We proposed a novel adaptive carrier phase estimator based on the phase information of the received signal only. Through eliminating the perturbation due to the amplitude of the AWGN, the proposed method outperforms the conventional adaptive filter in terms of both the carrier phase estimation and the filter gain tracking. Additionally, a dynamic tracking of both the laser linewidth and SNR is derived based on the proposed carrier phase estimator which requires no prior knowledge of the channel parameters. Numerical simulations and experiments are conducted to verify its feasibility in real applications.