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

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 RC 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 4.5 $V_{{ppd}}$ obtained at 32 Gb/s.