A Simple, High Sensitive Fiber Optic Microphone Based on Cellulose Triacetate Diaphragm

We present a high sensitive fiber-optic microphone (FOM) with a wide measuring range based on a cellulose triacetate diaphragm in this work. The average signal-to-noise ratio (SNR) of the proposed FOM is measured 50.86 dB in at the frequency range of 100 Hz-20 kHz. In the same spectrum range, the highest SNR for the 2-kHz frequency under 103.16 mPa acoustic pressure is measured at 72.20 dB with 2 Hz resolution bandwidth, which corresponds to a noise-limited minimum detectable acoustic pressure level of 17.91 μPa/√Hz. The proposed sensor has advantages of high sensitivity, low cost, and easy fabrication. According to the assessments based on the obtained results, the FOM can be used for medical spectroscopy, imaging applications, and for long-distance listening and voice recognition in the military-public security.