Carrier Phase Estimation Softwarized on GPU Using Decision-Aided Phase Unwrapping for Flexible Optical Coherent Access Systems

We present a unique carrier phase recovery algorithm which permits the softwarization of optical coherent receiver digital signal processing (DSP). The proposed algorithm with decision-aided phase unwrapping overcomes the serial dependency issue that has, up to now, prevented the softwarization of optical coherent systems. Its performance is verified through extensive Monte Carlo (MC) simulations and hardware experiments on quadrature phase-shift keying (QPSK) signaling. The proposed algorithm is implemented on a general-purpose graphic processing unit (GPU) and achieves 5-Gbit/s throughput for real-time streaming signals, as well as -44.5-dBm receiver sensitivity. The softwarization of carrier phase recovery function is demonstrated for the first time; our enhancement of disaggregated optical coherent receivers will significantly improve system flexibility and scalability, towards the realization of a new access networking that exploits general purpose hardware and virtualized transport layer functions.