CMOS DAC Supported 1.1 Tb/s/λ DWDM Transmission at 9.8 bit/s/Hz Over DCI Distances

We report on a 16-nm CMOS DAC based transmitter optimization enabling bitrates up to 1.1 Tb/s. We describe the transmitter optimization and derive the maximization of the net bitrate. Based on back-to-back experiments we optimize the entropy of the probabilistically shaped QAM format, which we further apply for subsequent transmission experiments over data center interconnect distances. Finally, we successfully demonstrate DWDM transmission of 17 channels in a 112.5 GHz grid operated at 105 GBaud over 80 km up to 118 km achieving a net bitrate of 1.1 Tb/s and spectral efficiencies of 9.8 bit/s/Hz.