Theoretical Analysis of Phase Noise in Laser With 1/fα FM Noise for Self-Homodyne Coherent System

The demand for high-speed transmission in intra- and inter-datacenter applications continues to grow, requiring a system capable of transmitting beyond 400 Gbit rates per wavelength. The self-homodyne coherent (SHC) system is a cost-effective candidate that has gained growing interest. According to this system, we rigorously examine the characterization of lasers with white and colored frequency modulation (FM) noise and investigate their impact on bit error rate (BER) performance using simulations when the carrier phase recovery (CPR) function is present and absent. Without CPR, the tolerance to mismatch length deteriorates due to linewidth broadening induced by flicker FM noise. However, in the presence of CPR, the effect of colored FM noise is alleviated, especially in high baud rate systems.The experimental results confirm the correctness of the analysis, with phase noise measurements of distributed-feedback (DFB) and distributed Bragg-reflector (DBR) lasers.