Ultrasensitive fiber optic Fabry Pérot acoustic sensor using phase detection

Abstract In this paper, a fiber optic Fabry–Perot interferometer (FPI) acoustic sensor is demonstrated based on a molybdenum disulfide (MoS2) diaphragm with a thickness of 500 nm. An air cavity-based fiber-tip FPI is implemented to detect acoustic signal frequency and corresponding pressure. Subsequently, the MoS2 is deposited on the air cavity with a fiber tip-MoS2 membrane distance of ~57 µm and ~2.52 mm dia. In fact, MoS2 nano sheets (NS) acts as a membrane sensitive to the acoustic signal. The results give out the acoustic sensitivity of the proposed sensor to be 18.8 rad/Pa at acoustic frequency of 1 kHz and 100 mPa acoustic pressure respectively. This sensor benefits a nearly flat frequency response ranging 8 Hz–10 kHz sustaining a high temperature stability over 20°−80 °C.