Noise considerations on hybrid optical MEMS displacement sensors

Light flux modulators based on micro-opto-electromechanical systems (MOEMS) enable high resolution displacement based inertial sensors. To unveil the resolution limiting mechanisms, we investigated the performance of modulators with a rectangular aperture design. The two major noise sources for such devices are the Brownian noise originating from the surrounding air and the noise emerging from the opto-electronic photodetector. The experimental data suggests that the noise equivalent displacement is determined by the transmitive aspect ratio of the aperture.