Cycle Slip-Mitigating Turbo Demodulation in LDPC-Coded Coherent Optical Communications

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Turbo demodulation for cycle-slip recovery.

We show that an iterative demodulation with soft-decision feedback information from FEC decoder can efficiently mitigate cycle slips. With 3% pilot insertion, the turbo QPSK demodulation achieves 1.05dB gain even in the presence of frequent cycle slips.