Joint-symbol MLSE receiver for phase-shift keying to mitigate PMD by polarization diversity

The proposed joint-symbol MLSE receiver employs another delay interferometer (DI) based on cross polarization interference together with a traditional DI to mitigate PMD impairment to phase-shift keying. Applied to an 80-Gbit/s DQPSK demonstration system, this MLSE receiver shows better performance.