Beyond 100 Gb/s Optical Transmission Based on Polarization Multiplexed Coded-OFDM With Coherent Detection

We propose a coded-modulation scheme suitable for beyond 100 Gb/s transmission and 100 Gb/s Ethernet. It is based on polarization multiplexed coded-orthogonal frequency division multiplexing (OFDM). By using 32-QAM-based polarization multiplexed coded-OFDM, we are able to achieve the aggregate rate of 100 Gb/s, while the OFDM signal bandwidth is only 10 GHz, resulting in a spectral efficiency of 10 bits/s/Hz. The spectral efficiency of the proposed scheme is twice higher than that of the polarization diversity OFDM scheme. We show that the proposed multicarrier scheme is insensitive to polarization mode dispersion (PMD), while the PMD represents a major source of performance degradation in single carrier systems, in addition to fiber nonlinearities. We also describe how to determine the symbols' log-likelihood ratios in the presence of laser phase noise.