A low-power VCSEL driver in a complementary SiGe:C BiCMOS technology

This paper presents a driver IC for common-cathode vertical-cavity surface-emitting lasers (VCSELs) fabricated with a complementary 0.25-μm SiGe:C BiCMOS technology with f_T/f_max of 110/180 GHz for npn and 95/140 GHz for pnp transistors, respectively. By utilizing pnp transistors as an active load in the output stage, the driver exhibits a low-power and high-speed operation, consuming only 33.8 mW to drive the bias/modulation currents of 3/3 mA to the 160-Q VCSEL-equivalent circuit and demonstrating clear electrical eye diagrams up to 40 Gb/s. To the best knowledge of the authors, the reported energy efficiency of 0.84 pJ/b is the best in comparison to other state-of-the-art common-cathode VCSEL drivers.