The development of 40 Gb/s limiting-distributed modulator drivers in InP HBTs

The development of monolithic modulator drivers designed in InP SHBT technologies for 40-Gb/s optical communications is presented. The drivers consist of a differential limiting pre-driver and a differential distributed post-amplifier to achieve sufficient gain-bandwidth product, and feature cross-point control and output amplitude adjustments to ensure sufficient output extinction ratio. The drivers have achieved output swings of 2.6 Vp-p at each side with a 0.5 Vp-p single-sided input, and consume 1.72 W power.