MECHANICAL RESONATOR SENSOR

摘要

A transducer 10 comprising a mechanical resonator 14 exhibiting a resonant frequency dependent upon one or more properties of a fluid 12 also has a temperature sensing optical cavity whose path difference varies with transducer temperature changes. The transducer may further comprise a substrate 15; the optical-cavity may be a reflective optical-cavity; a fluid property may be pressure; there may be a detector of the path-difference and the resonant-frequency; a diaphragm 16 may be coupled to the resonator; the detector, which may indicate a fluid property compensated for temperature variations, may also comprise a spectral engine where the path-difference corresponds to a Fourier transform peak and/or cross-correlation of the interference spectrum. A sensor comprising a transducer comprising a mechanical-resonator with a resonant-frequency dependent upon one or more fluid properties; an optical-cavity varying in optical path-difference with the vibration of the resonator; a resonator driver; and a detector of the resonant-frequency and of the resonators amplitude of vibration; the detector may be arranged to compensate fluid property indications for detected changes in vibration amplitude; the sensor may further comprise a photo-detector and possibly at least one Mach Zehnder interferometer; the resonator vibration may be driven optically along an optical fibre.