Field Trial of 400G Single-Carrier Ultra-Efficient 1.2Tb/s Superchannel Over 250 km

We report the first successful field trial of real-time coherent 400G single-carrier superchannel of 1.2Tb/s over distances up to 250 km using production grade 64GBaud DP - 16QAM optical transponders. Stable error-free performance has been demonstrated, co-propagating alongside multiple mixed modulation format 200G single-carrier superchannels (DP - 16QAM, DP - 8QAM, and DP - QPSK) and conventional 40G and 100G optical channels. We demonstrated the transmission of an ultra efficient 1.2Tb/s superchannel with a spectral efficiency of 6.25bit/s/Hz, which is an improvement of 56% over 200G single-carriers in a standard 50GHz grid. We have also shown the impact of optical fiber nonlinearity on both optical performance and achievable spectral efficiency, key parameters that determine the maximum capacity that can be achieved over optical fiber transmission.