Method for Determining the Resonance Frequency of a Fiber Optic Interferometric Accelerometer

A novel measurement method for the resonance frequency of a fiber optic interferometric accelerometer, one of the most important technical parameters for such a sensor, is proposed and demonstrated. First, a variable phase shift is induced by a piezoelectric fiber stretcher which also serves to ascertain that the modulation depth is unchanged while maintaining the drive amplitude and increasing the drive signal frequency within the operation frequency range. Second, the new method is compared with conventional approaches, using a compliant cylinder Michelson interferometric accelerometer mounted on a shaking table which is driven by a sweeping-frequency sinusoidal input signal; the resonance occurs at a frequency where the modulation depth shows a precipitant increase. The proposed method needs only about 10 s to obtain the resonance frequency, which is highly efficient and easy to implement, whose practicality is also attested by measurements on a number of fiber optic accelerometers and comparison with the traditional method.