Stable, high-Q fabry-perot resonators with long cavity based on curved, all-silicon, high reflectance mirrors

For the first time, we demonstrate experimentally high optical quality factor Q ~9000 in MEMS-compatible silicon Fabry-Pérot (FP) resonators based on free space propagation of light and direct coupling to optical fiber. This result is obtained on long cavity resonators (L >; 250 μm), a usually difficult case in terms of power loss. The resonator design includes two multilayered silicon-air Bragg mirrors of cylindrical shape, combined with a Fiber Rod Lens (FRL). Dimensions are chosen according to stability criteria imposed on the optical resonator. The core of the presented device is entirely made of single-crystal silicon. It is obtained by DRIE using an optimized single step process.