Polymer Diaphragm Based Fiber Optic Fabry-Perot Acoustic Sensor

Abstract

This paper presents a polymer diaphragm based Fabry-Perot (F-P) sensor system for aeroacoustic measurement in air. The diaphragm of a novel polymer material poly phthalazinone ether sulfone ketone (PPESK) is used as the sensing element. The effective dimension of the diaphragm is 1.0mm in diameter and 6μm in thickness. Thanks to the good mechanical feature of the material and the interferometric-intensity demodulation mechanism, the sensor diaphragm shift sensitivity of 0.72 nm/Pa, correspond to an acoustic pressure to voltage sensitivity of 5.56mV/Pa has been achieved. Experimental results showed that the characteristics of the sensor system is comparable with traditional electrical microphone in frequency range 100Hz to 1kHz and the sensor has the potential to be used as an optical microphone.