Soft coded modulation for sensitivity enhancement of coherent 100-Gbit/s transmission systems
22 March 2009
Soft-decoding of a PDM-QPSK signal with 34%-FEC overhead-enabled by a symbol rate increase from 28 to 35 Gbaud-leads to 10.7-dB OSNR sensitivity. Soft-decoding is not effective for POL-QAM 6-4 modulation.