128 GSa/s SiGe DAC Implementation Enabling 1.52 Tb/s Single Carrier Transmission

We report a new 128 GSa/s SiGe digital to analog converter (DAC) having 8 bit physical resolution and 24 GHz 3-dB bandwidth and present its architecture and the results on fundamental converter assessment. We further integrated the DAC into a coherent optical transmission testbed allowing increase of symbol rate up to 128 GBaud. Using probabilistic constellation shaped modulation formats at an entropy of 7.5 bits per symbol and polarization multiplex we successfully transmitted at net-bit rates up to 1.55 Tb/s for a single carrier in back to back while for a typical data center interconnect (DCI) distance of 80 km a net bit rate of 1.52 Tb/s has been achieved.