Design of a 40 GHz bandwidth slow-wave silicon modulator

We present the design of a carrier depletion silicon modulator with series push-pull diode configuration and slow-wave transmission line for the 1550 nm wavelength range. The electro-optical bandwidth is 40 GHz at −2.5 V diode bias and 35 Ω termination resistance in a 3.15 mm long device. The modulation efficiency V π L π is 2.2 V.cm and optical loss is 12.8 dB/cm for the same bias. The steps in the design process are detailed and simulation results are presented.