High-Spectral-Efficiency 114-Gb/s Transmission Using PolMux-RZ-8PSK Modulation Format and Single-Ended Digital Coherent Detection Technique

Employing spectrally efficient PolMux-RZ-8PSK modulation format and single-ended digital coherent detection technique, we demonstrate 8 times 114-Gb/s DWDM transmission over 640 km of SSMF on a 25-GHz grid with record spectral efficiency of 4.2 bit/s/Hz, utilizing no optical dispersion compensation or Raman amplification. We show that the distortion caused by the direct square-law detection of the signal component with single-ended photo detection can be effectively mitigated by a novel DSP algorithm.