High-Q silica zipper cavity for optical radiation pressure driven MOMS switch

We design a silica zipper cavity that has high optical and mechanical Q (quality factor) values and demonstrate numerically the feasibility of a radiation pressure driven micro opto-mechanical system (MOMS) directional switch. The silica zipper cavity has an optical Q of 6.0x10^4 and an effective mode volume Vmode of 0.66{\lambda}^3 when the gap between two cavities is 34 nm. We found that this Q/V_mode value is five times higher than can be obtained with a single nanocavity design. The mechanical Q (Q_m) is determined by thermo-elastic damping and is 2.0x10^6 in a vacuum at room temperature. The opto-mechanical coupling rate g_OM is as high as 100 GHz/nm, which allows us to move the directional cavity-waveguide system and switch 1550-nm light with 770-nm light by controlling the radiation pressure.