A two-segment optical DAC 40 Gb/s PAM4 silicon microring resonator modulator transmitter in 65nm CMOS

Abstract

A two-segment silicon photonic microring modulator implements an optical DAC for PAM4 modulation. Independent level and edge-rate control is achieved using segmented MSB/LSB pulsed-cascode drivers. The 65nm CMOS transmitter achieves 40Gb/s operation at 4.38mW/Gb/s while driving each microring modulator segment with 4.4V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ppd</sub> swing.