Multidimensional LDPC-Coded Modulation for Beyond 400 Gb/s per Wavelength Transmission

Abstract—In this letter, we propose a multidimensional low-density parity-check-coded modulation scheme suitable for use in up to 400 Gb/s per wavelength transmission, using currently available commercial components operating at 40 gi-gasymbols/s. We show that we can achieve multiples of the current transmission speed with negligible penalty. At the same time, using this scheme, the transmission and signal processing are done at 40 gigasymbols/s, where dealing with all the nonlinear effects is more convenient and the polarization-mode dispersion is more manageable. In addition, we show that using the pro-posed technique, we can achieve an improvement ranging from 3 dB over 8-quadrature-amplitude modulation (QAM) to 14 dB over 256-QAM, and an improvement of up to 9.75 dB over the 256-3D-constellation at bit-error ratio (BER) of . We also show that we can reach the 400-Gb/s aggregate rate with a coding gain of 10.75 dB at BER of . Index Terms—High-speed optical transmission, low-density parity-check (LDPC) codes, multidimensional-coded modulation, optical communications, polarization-mode dispersion (PMD). I