A 64 Gb/s PAM4 Two-Segment Silicon Microring Resonator Modulator Transmitter with Integrated 28nm CMOS Driver

This paper presents a CMOS quarter-rate transmitter (TX) co-packaged with a two-segment silicon based microring resonator (MRM). The AC-coupled MSB/LSB drivers implemented using the pulsed-cascode topology, achieve 4.2Vpp differential swing, provide independent level-tuning, edge-rate control, and asymmetric pre-emphasis on the rising and falling edges. Designed in 28nm CMOS process, the driver operates at 64Gb/s PAM4 data-rate while exhibiting power efficiency of 4.8pJ/bit.