2.2-pJ/Bit 30-Gbit/s Mach-Zehnder Modulator Driver in 22-nm-FDSOI
A Mach-Zehnder modulator (MZM) driver is designed in a 22 nm FDSOI-CMOS technology. The high-voltage driving of the MZM is realized with stacked, low- impedance and loss switches which allow a voltage swing that reaches a multiple of the breakdown voltage of a single transistor. In order to use this topology the signal is transferred to the different voltage domains with level-shifters, then amplified and conditioned to rail-to-rail swing which drives the output power-stages. Shunt- and series inductive peaking is used extensively in order to increase the bandwidth. Stacking and coupling inductors results in the smallest MZM driver with 0.018 mm² active area. Measurements show 3.75 Vpp,D swing on a 50Ω load. Error-free (BER< 10-12) transmission at 30 Gbit/s is demonstrated. By using a switched output stage only a small static DC-power is consumed, resulting in the most energy-efficient MZM driver with only 2.2 pJ/bit.