Parameter passing master–slave carrier phase recovery for frequency comb-based long-haul coherent optical communication systems

Abstract

Replacing a large number of individual lasers with frequency comb in coherent optical communication systems is a current research focus, which has great potential in realizing low-cost, high-capacity communication. Parameter passing master–slave carrier phase recovery (PPMS-CPR) with low complexity for frequency comb-based long-haul coherent optical communication systems is proposed in this paper. For the wavelength division multiplexed (WDM) signals modulated from a frequency comb, chromatic dispersion (CD) causes relative time delays between channels at different wavelengths, which weaken the phase coherence of these channels. Conventional master–slave carrier phase recovery (MS-CPR) uses the phase noise of the master channel to compensate all slave channels. The proposed PPMS-CPR implements coarse phase pre-recovery using the phase noise parameters passed from the master channel and inner slave channels, and uses maximum likelihood estimation (MLE) to compensate the residual phase noise. Consequently, the PPMS-CPR can well solve the problem of weakened phase coherence between the master and slave channels and maintain low computational complexity (CC) requirements. The simulations show that the proposed PPMS-CPR has a good tolerance for the linewidth of the frequency comb and transmission distance, and its performance is comparable to the independent carrier phase recovery (ICPR), while its complexity is just about 7.1% of ICPR when the number of channels is 101.