Cycle Slip Compensation with Polarization Block Coding for Coherent Optical Transmission: Two-dimensional phases constellation corresponds to a slip state

Cycle slip (CS) compensation is a critical technique for nondifferential coded coherent optical transmission. By monitoring the sparse, asymmetric polarization block-coded symbol mapped signal phases of two orthogonal polarizations, the CS can be estimated from a relatively short stretch of symbols (unit). Simulation shows that the polarization block coding-based method compensates CS and improves the Q-factor by 1 dB or more compared to differential coding.