Generation and FEC-decoding of a 231.5-Gb/s PDM-OFDM signal with 256-iterative-polar-modulation achieving 11.15-b/s/Hz intrachannel spectral efficiency and 800-km reach

A 231.5-Gb/s PDM-OFDM signal with 256-iterative-polar-modulation, outperforming 256-QAM by 1.2 dB in required OSNR after soft-FEC decoding, is generated, FEC-decoded, and transmitted over a record distance of 800 km with 11.15-b/s/Hz intrachannel spectral efficiency.