Low Cost 400GE Transceiver for 2km Optical Interconnect using PAM4 and Direct Detection

A low cost 4×112Gbps PAM4 based scheme has been proposed for implementing 400GE 2km interconnect. Single channel 112Gbps PAM4 2km transmission with commercial 25Gbps devices is experimentally demonstrated to verify the feasibility of the proposed scheme. A receiver sensitivity of -7.1dBm is realized using direct-detection faster than Nyquist technique.