Nonlinear Phase Noise Mitigation With Soft-Differential Decoding and Nonredundant Error Correction for Hybrid 10G/100G Transmission

We report experimental results of 112-Gb/s po larization-division-multiplexed return-to-zero quaternary phase-shift-keying (PDM-RZ-QPSK) transmission over dis persion-managed 1200-km links embedded between 10.7-GBaud on-off keying nonreturn-to-zero (OOK-NRZ) neighbors. Taking into account implementation constraints for equalization and synchronization of the digital signal processing (DSP) by means of processing delay and parallelization, the performances without differential decoding, with hard-differential decoding, and with soft-differential decoding are evaluated. The combination of soft-differential decoding with nonredundant error correction is identified to provide the best mitigation of cross-phase modulation (XPM)-induced nonlinear phase noise.