8 × 320-Gb/s transmission over 5600 km using all-ETDM 80-Gbaud polarization multiplexed QPSK transmitter and coherent receiver

WDM transmission over 5600 km of ultra-large-area fiber is achieved using an 80-Gbaud all-electronically multiplexed polarization-division multiplexed quadrature phase-shift-keyed (PDM-QPSK) transmitter and off-line intradyne detection with four synchronized 120-GSamples/s, 45-GHz inputs of an oscilloscope prototype.