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 4.0 × 10⁴ and an effective mode volume V_mode of 0.67λ ³ when the gap between two cavities is 34 nm. The mechanical Q (Q_m) is determined by thermo-elastic damping and is 2.0 × 10⁶ 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.