Binary-LDPC-coded DP-QDQ Transmission Scheme and its Performance Analysis

Dual-polarized quadrature duobinary (DP-QDQ) has so high spectral efficiency that it can realize super-Nyquist-wavelength-division-multiplexing (super-Nyquist-WDM) transmission. In order to promote BER performance, binary Low-density parity-check (LDPC) codes are used in DP-QDQ systems. Two detection methods for DP-QDQ, which can be combined with corresponding LDPC decoding, are presented. LDPC-coded DP-QDQ systems based on these two detection methods are investigated at 128Gb/s five-channel WDM systems by simulations.