Optical simulation of a MOEMS based tuneable Fabry-Perot interferometer

Simulation of the optical response for a tuneable Fabry-Perot interferometer fabricated using silicon MOEMS (micro-opto-electromechanical system) technology is presented. This device, which is intended to be part of an NDIR (nondispersive infrared) system, is composed of two dielectric parallel mirrors; the upper mirror is a suspended structure, electrostatically actuated, that allows tuning of the length of the resonant cavity, and therefore selection of the wavelength region corresponding to a particular absorption band. As the final spectrum of the device is directly related to the planarity of the upper mirror, once validated with measurements in small areas of the surface of the device, the optical model is used to predict the response of the whole area of the interferometer. This allows us to estimate the effect of the planarity of the device on the resulting spectra.