Position encoding and phase control of resonant MOEMS-mirrors

Assuring stable resonant oscillation with well controlled amplitude under varying environmental conditions is a major challenge for electrostatically driven MOEMS mirrors. For this reason, we developed a compact device comprising a resonant MOEMS micro-mirror, optical position sensing, and driver electronics with closed loop control, which ensures operation close to the mirror resonance. Closed loop control is realised by adjusting the driving frequency to minimize the phase offset of the mirror oscillation, which is notably applicable for high frequency devices. Here we present our position encoding and feedback scheme, and show first experimental results, which demonstrate the capability of our device.