Implementation of 64QAM at 42.66 GBaud using 1.5 samples per symbol DAC and demonstration of up to 300 km fiber transmission

We demonstrate 400Gbit/s data generation using 64QAM at 42.66 GBaud with a reduced oversampling ratio of 1.5 Sample/symbol including digital Nyquist filtering and spectral pre-emphasis. Even at 24% FEC overhead a successful transmission over 300 km ULAF has been shown.