Abstract
We have previously proposed a piezoelectric sensor configuration using an optical-access method. However, optical measurement of the resonance frequency is difficult. In this paper, we discuss an optical measurement method that uses the refraction index deviation caused by piezoelectric vibration. In the corresponding detection configuration, a resonator sample is inserted into the optical path of a Mach-Zehnder interferometer. The resonance frequency can be accurately measured using an optical fiber. This detection configuration is applicable to the measurement of a resonator array. Resonance frequencies of the array were optically measured simultaneously and with high accuracy.