Design of Automotive VCSEL Transmitter with On-Chip Feedforward Optical Power Control

We propose a novel 50Mb/s optical transmitter fabricated in a 0.6μm BiCMOS technology for automotive applications. The proposed VCSEL driver chip was designed to operate with a single supply voltage ranging from 3.0V to 5.25V. A fully integrated feedforward current control circuit is presented to stabilize the optical output power without any external components. The experimental results show that the optical output power can be stable within a 1.1dB range and the extinction ratio greater than 14dB over the automotive environmental temperature range of -40°C to 105°C.