Abstract
In this paper, the main features of feedback interferometry are reviewed, showing that its resolution, noise limit and bandwidth are fully adequate for the characterization of microelectromechanical devices (MEMS). Different configurations of this technique, as well as improvements of the basic scheme, are discussed.
Examples of experimental measurements at submicron resolution are reported on suspended-mass, vibrating MEMS, such as resonators and gyroscopes. Characterization includes the detection of vibration modes and of their resonance curves, the determination of the actuation efficiency and the effect of environmental parameters, such as pressure. Thanks to its very simple optical implementation, the proposed technique provides a valuable inspection tool to complement the standard electrical measurements.