A DC-90-GHz 4- $V_{\mathrm{ pp}}$ Modulator Driver in a 0.13- $\mu \text{m}$ SiGe:C BiCMOS Process

In this paper, a linear driver for optical modulators in a 0.13-μm SiGe:C BiCMOS technology with f
_T
/f
_max
of 300/500 GHz is presented. The design is implemented following a distributed amplifier topology in a differential manner. The driver features a small-signal gain of 12.5 dB and a 3-dB bandwidth of 90 GHz and delivers a maximum output amplitude of 4 V
_pp
to a 100-Q differential load. Delivering the maximum output swing, the large-signal gain is 10.5 dB. Time-domain measurements are performed, showing the maximum output swing with ON-OFF keying (OOK) eye-diagrams up to 64 Gb/s and pulse amplitude modulation-4 up to 45 Gbaud (90 Gb/s). Moreover, OOK eyediagrams up to 120 Gb/s are reported with an output swing of 3 V
_ppd
. Total harmonic distortion measurements are also conducted demonstrating a value of 5% at 1 and 8 GHz up to an input amplitude of 800 mV
_ppd
. Using a reduced number of stages in the design, the power dissipation of the integrated circuit is 550 mW, resulting in an output power to power dissipation ratio of 3.6%. To the best knowledge of the authors, this is the first time a linear driver for optical modulators demonstrates such high bandwidth and efficiency for the demonstrated data-rates.