Transmission of 50-GHz-spaced single-carrier channels at 516Gb/s over 600km

We report the first wavelength-division-multiplexed transmission of 50-GHz-spaced single-carrier channels at 400Gb/s effective data-rate, achieving 8-b/s/Hz spectral efficiency. Twenty channels are sent over 600km with PDM-64QAM operating at 43Gbaud and received with cascaded blind equalization.