64-Tb/s (640×107-Gb/s) PDM-36QAM transmission over 320km using both pre- and post-transmission digital equalization

Employing raised-cosine pulse-shaped PDM-36 QAM modulation and both pre- and posttransmission digital equalization, we demonstrate 12.5GHz-spaced, 640 × 107 Gbits/s DWDM transmission over 4 × 80 km of ultra-large-area fiber with a record capacity of 64 Tb/s at 8 b/s/Hz spectral efficiency.