Mode-selective optical filtering and wavelength-selective switching through Fabry-Perot cavity with cylindrical reflectors

We report on Fabry-Pérot (FP) filters based on silicon cylindrical Bragg reflectors. Such filters exhibit unusual periodicity of the spectral response due to transverse resonance modes. The optical microcavities are also unusually long (L>;210μm) while maintaining reasonably high quality factors (Q), above 1000. The presented device behaves as a mode-selective filter wherein the excited mode is controlled by varying the excitation wavelength. The device can also be used as a wavelength-selective MEMS switch, with extinction ratio of 7:1. Cavities with different radii of curvature have been evaluated experimentally, their corresponding Q-factors and effective cavity lengths (L_eff) have been determined.