A sensitive polymer diaphragm based fiber Fabry-Perot (F-P) sensor for aeroacoustic wave measurement is presented. A novel polymer material poly (phthalazinone ether sulfone ketone) (PPESK) diaphragm is used as the acoustic sensing element. The effective dimensions of the diaphragm are 4 mm in diameter and 6 \mu m in thickness. Owing to the good mechanical and optical features of the diaphragm and application of the interferometric/intensity demodulation, a system sensitivity of 31 mV/Pa is achi