A 40-Gb/s Modulator Driver Using Cascade Swing Compensation in 90 nm CMOS

Abstract

This letter presents a high-speed optical modulator driver with a large output swing in 90-nm CMOS technology. A new topology of cascade swing compensation (CSC) output stage is proposed for protecting the transistors from breakdown using dynamic gate biasing without extra <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> networks. To enhance the bandwidth and gain, the active feedback with T-coil peaking and the negative capacitance with series peaking are employed in the preamplifier and main driver, respectively. Under a power consumption of 767 mW, the measured results demonstrate an operating data rate up to 40 Gb/s with a maximum differential output swing of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5~V_{\mathrm {ppd}}$ </tex-math></inline-formula> obtained at 32 Gb/s.