Tunable Fabry-Perot surface micromachined interferometer-experiments and modeling

Abstract

We present an optical tunable Fabry-Perot micromachined interferometer. The device is monolithically integrated with a p⁺-n photodiode on a silicon substrate, providing an adequate positioning of the photonic and microoptical components. The Fabry-Perot micro-interferometer consists of two parallel mirrors and lets the light with a particular wavelength pass through. The wavelength depends on the gap between the mirrors. We can change the gap of the micro-mechanical Fabry-Perot interferometer by applying a voltage to the mirrors, an electrostatic force inducing an attraction between the substrate and the top mirror. A simulation of the mechanical behavior was performed based on finite elements, using CoventorWare software. The method included an electro-mechanical simulation for a square parallel plate actuation with four connecting beams. The finite elements method (FEM) simulations of the device (the Fabry-Perot tunable filter) are performed for optimizing the design parameters in order to model the overall system performance, both the steady-state behavior and dynamic response.