On the Performance of Super-Symbol PCS-QAM Digital Subcarrier Multiplexing in Coherent Optical Fiber Systems

We experimentally assess the use of super-symbol (SUP) transmission with different distribution matching methods in a 100 GBd PCS-256QAM digital subcarrier multiplexing system. We achieve 0.1 dB SNR improvement after 900 km, a gain which comes almost for free due to the low complexity of SUP.