Single-Carrier 800-Gb/s 32 RZ/QAM Coherent Transmission Over 225 km Employing a Novel RZ-CW Conversion Technique

We report the single-carrier 800-Gb/s coherent transmission of polarization-multiplexed 32 return-to-zero (RZ)/quadrature amplitude modulation signals at 10 Gsymbol/s × 8 optical time-division multiplexing (OTDM). Transmission over 225 km was achieved by adopting an RZ-continuous-wave conversion scheme in a coherent receiver, which made it possible to demodulate and demultiplex ultra high-speed multilevel OTDM signals with a high signal-to-noise ratio.