Optimized Superscalar Parallelization-Based Carrier Phase Recovery for Agile Metro Optical Networks

In this paper, we present a format-transparent carrier phase recovery algorithm for the agile metropolitan optical networks based on an optimized superscalar parallelization structure. The pilot overhead and the buffer size in the superscalar parallelization can be minimized by optimizing the parallelization structure depending on the required laser linewidth tolerance of the system. The trade-off between the laser linewidth tolerance and the reduction of buffer size in the proposed superscalar parallelization is revealed in simulations for 16-QAM, 32-QAM, and 64-QAM, respectively. The results indicate that the buffer size in the superscalar parallelization can be reduced significantly when commercially available external cavity lasers (ECL) are employed for coherent detection in metro links beyond 100 Gb/s. Experiments are further conducted in a single-channel system with ECLs as the transmitter and local oscillator lasers to demonstrate the reduction of the pilot overhead and buffer size using the proposed superscalar parallelization compared with the previous superscalar structures.