Design investigation to improve voltage swing and bandwidth of the SiGe driver circuit for a silicon electro-optic ring modulator

Abstract. This paper reports on a new SiGe driver IC to address the low breakdown voltage level of modern BiCMOS transistors. An optical modulator driver IC in SiGe 250 nm technology with a supply voltage of 4.5 V is presented. This driver IC consists of pre- and main driver stages where a newly modified cascode topology and capacitance degeneration technique is employed to meet current application requirements; high voltage swing at high datarate. The simulation results show a differential output voltage swing of 3.9 Vp-p at 14 Gbps data rate, according to the FDR Infiniband standard.