Demonstration and performance analysis of 4 Tb/s DWDM metro-DCI system with 100G PAM4 QSFP28 modules

We demonstrate a 4-Tb/s metro-DCI system with commercial QSFP28 modules (40×100G dual-wavelength 56-Gb/s PAM4). We detail system performance over 80km and quantify tolerance to chromatic dispersion and nonlinearity over a wide range of fiber types.