Linearity Enhancement Analysis of Breakdown Voltage Doubler and Demonstration in 60 GBd SiGe BiCMOS Driver

Abstract

In this paper, we prove theoretically and experimentally the enhanced linearity behaviour of the BVD topology compared to the more well-known cascode topology in terms of THD, 1dBCP and R-LM.We present the nonlinear algebraic analysis and simulations of the topology, along with the measurements of a high-speed, large output swing, linear, four channel optical modulator driver IC using that topology. The realised driver has an electrical 3 dB-bandwidth of 30GHz and a differential output swing of 2.5 Vppd with a power consumption of 480mW per channel. It achieves an R-LM of 0.98, THD of < 2% and output referred 1dBCP of 11.4 dBm.