An 80-Gbps Distributed Driver with Two-Tap Feedforward Equalization in 45-nm CMOS SOI

This paper presents an integrated differential, distributed Mach-Zehnder modulator (MZM) driver with two-tap feedforward equalization (FFE). The driver consists of two-stack, pseudo-differential FET stages capable of voltage swings exceeding the V
DD
(1V). The measured chip produces error-free (BER $\lt 10^{-11})$ NRZ transmission up to 64 Gbps with 0.3 UI sampling margin and four-level pulse amplitude modulation (PAM-4) transmission up to 80 Gbps (40 Gbaud). The total power consumption of the driver is 310 mW for an energy efficiency of 4.8 pJ/bit for NRZ and 3.9 pJ/bit for PAM-4.