<title>MOEMS integrated optical monitoring</title>

Abstract

For certain classes of MEMS, implementation of closed loop feedback control and system model-based fault detection offer significant performance advantages. Such systems include those in safety critical applications and systems in which dynamic loads are anticipated. Detailed continuous knowledge of the positional state of the microstructure is needed in order for accurate system models to be developed and experimentally verified, control techniques to be effectively applied, and model based fault detection evaluated. Moreover, this positional state information must be fully decoupled from the microstructure voltage drive signal. This paper reviews the group's current efforts exploring the use of integrated optics to provide this MEMS state feedback information and the merits and challenges of its application for microstructure control and fault detection. Modeling and experimental results using a 1.3 micron wavelength coherent optical probe for optical state monitoring will be presented including work integrating the probe optics within a folded diffractive optical element coplanar with MEMS die. Use of this signal in system model parameter estimation and real-time position control of a lateral comb resonator stage will be demonstrated and the potential for application to MEMS model-based fault detection discussed.