Capacitive Silicon Modulator Design with V-shaped ${\text{SiO}_{2}}$ Gate Waveguide to Optimize ${V_{\pi}\times L}$ and Bandwidth Trade-off

This work presents a capacitive modulator design and modeling of a new waveguide architecture using silicon and poly-si technologies. We use a methodology involving the entire lumped-type modulator design process, from the optical design to the small-signal RF analysis. By means of geometric and physical parameters adjustments, the trade-offs among several figures of merit are analyzed in this paper. Due to the waveguide configuration, it is shown that the modulator can improve the trade-off between  $V_{\pi }$ and bandwidth compared to the state-of-the-art for this kind of device. For instance, the best combinations are $V_{\pi }\simeq$  1 V @ 20.4 GHz and  $V_{\pi }$  = 5.7 V @  $\sim$ 31 GHz, with equivalent optical losses of 3 dB and 1.1 dB, respectively.