A Low-Distortion Modulator Driver With Over 6.5-V_pp Differential Output Swing and Bandwidth Above 60 GHz in a 130-nm SiGe BiCMOS Technology

Optimizing a modulator driver for linear and high-speed operation, while simultaneously achieving high output voltage swing is very challenging. This paper investigates the design of highly-linear, high-bandwidth yet power-efficient Mach-Zehnder based on breakdown doubler concept, which overcomes transistors’ physical limitations enables swings twice as conventional differential pair amplifiers can provide. The low-power was enabled by use an open-collector topology stage well employing resistors instead current mirrors in order to provide bias currents emitter-follower (EF) stages. We show that means this EF implementation approach, power consumption be reduced 19% without sacrificing circuit’s bandwidth linearity. achieves peak-to-peak above 6.5 Vpp,d consumes 670 mW DC power, being one most drivers literature. 3-dB 61.2 GHz total harmonic distortion 1%, measured at 1 Vpp,d. To best authors’ knowledge, these are highest linearity reported literature with bandwidths 40 GHz.