This paper presents a chipset with a multichannel vertical-cavity-surface-emitting laser (VCSEL) driver and a trans-impedance amplifier (TIA) in a 180-nm SiGe BiCMOS process. With the target of 400G-1.6T short-reach applications, a high-speed linear gain is developed for fourlevel pulse amplitude modulation (PAM-4). The VCSEL driver employs a second-order continuous-time linear equalizer to compensate for non-linear input channel loss, while exploiting an RC-degenerated output stage with inductive shunt peaking to extend the bandwidth. The TIA uses the resistive feedback topology along with a series-peaking inductor to improve its input bandwidth. The measurements show that the VCSEL driver operates up to 100 Gb/s with a 280-mVpp PAM-4 signal. The TIA scores a 61.5-dBΩ trans-impedance gain, a 36-GHz BW and a 16-pA/√Hz averaged input-referred noise.