Spot Optical Measurements on Micromachined Mirrors for Photonic Switching

Abstract—This paper describes and compares three optical
methods for performing spot measurements on micromachined
mirrors, designed for photonic switching in fiberoptic networks.
For static characterization, two spot-position detection systems,
one based on a vidicon camera and the other based on a bidimensional
silicon position sensitive detector (PSD), are illustrated,
tested, and compared. Moreover, the dynamic behavior has been
monitored with the PSD-based detection arrangement and with
a semiconductor laser feedback interferometer. Advantages and
drawbacks of these methods are highlighted. Testing is reported on
torsional, silicon micromachined mirrors, with a single degree of
freedom. High dc voltage for static measurements, and sinusoidal
or white-noise or step excitation for dynamic characterization,
have been used for mirror driving.