Performance Tradeoffs in MEMS Sensors with High-Finesse Fabry-Perot Interferometry Detection

Keywords:
optical mems, moems, fabry-perot interferometer

Abstract:
A detailed analysis with experimental verification is presented for optical MEMS sensors based on Fabry-Perot interferometers (FPI). These sensors consist of two partially transparent parallel plates with reflective inner surfaces, forming a cavity with an optical resonance that depends on the distance between the plates. At resonant wavelengths, all of the incident light energy is transmitted through the FPI, and intensity peaks occur. By detecting the wavelength of the transmitted light, the distance between the plates can be obtained. Various optical sensors can be based on this concept, e.g. accelerometers, pressure sensors, and microphones. This paper considers factors affecting the performance of such sensors, including mechanical-thermal noise, contribution of noise in the detection system, and affects of reflectivity, surface roughness, and parallelism of mirrors. The presented experimental results confirm the feasibility of the FPI-based sensor concept.

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Nanotech 2005 Conference Program Abstract