In this work, we have applied optical low-coherence reflectometry (OLCR), implemented\nwith infra-red light propagating in fiberoptic paths, to perform static and dynamic analyses\non piezo-actuated glass micro-membranes. The actuator was fabricated by means of thin-film\npiezoelectric MEMS technology and was employed for modifying the micro-membrane curvature,\nin view of its application in micro-optic devices, such as variable focus micro-lenses. We are\nhere showing that OLCR incorporating a near-infrared superluminescent light emitting diode as\nthe read-out source is suitable for measuring various parameters such as the micro-membrane\noptical path-length, the membrane displacement as a function of the applied voltage (yielding the\npiezo-actuator hysteresis) as well as the resonance curve of the fundamental vibration mode. The\nuse of an optical source with short coherence-time allows performing interferometric measurements\nwithout spurious resonance effects due to multiple parallel interfaces of highly planar slabs,\nfurthermore selecting the plane/layer to be monitored. We demonstrate that the same compact\nand flexible setup can be successfully employed to perform spot optical measurements for static and\ndynamic characterization of piezo-MEMS in real time.
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