A DC-51.5 GHz Electro-Absorption Modulator Driver with Tunable Differential DC Coupling for 3D Wafer Scale Packaging

Abstract

This paper presents a DC-51.5 GHz PAM-4 dual-channel electro-absorption modulator (EAM) driver realized in a 0.25-µm SiGe:C BiCMOS technology. The EAM driver is designed for 3D wafer scale packaging which integrates silicon electronics IC and InP photonics IC at wafer scale. A new asymmetric-load differential driver topology is proposed to achieve a tunable DC biasing for the EAM without extra off-chip bias-T, which significantly reduces the packaging complexity and cost. Moreover, the driver uses differential outputs to drive a single-ended EAM, which reduces the voltage swing by a factor two and reduces the power consumption. The driver has 9.4 dB gain with a 3 dB bandwidth of 51.5 GHz and −0.2 ~ −2 V tunable output DC biasing range. It delivers a differential output voltage swing of 2 Vppd at 56 Gb/s PAM-4 and consumes 219 mW per channel, resulting in a figure of merit of 3.9 pJ/bit.