Highly sensitive ZnO-doped PET diaphragm-based fiber optic microphone

Abstract

This study presents a highly sensitive Fiber Optic Microphone (FOM) based on a ZnO-doped PET (PET:ZnO) diaphragm for the first time. The FOM was first simulated and then tested experimentally. Under 14 mPa acoustic pressure and in the frequency range of 1 kHz–20 kHz, the highest SNR of 73.57 dB was measured at 5 kHz. The average signal-to-noise ratio (SNR) in the same frequency range was 51.74 dB. Based on the experimental results, the minimum detectable pressure (MDP) measured at 100 Hz resolution was calculated as low as 2 µPa/Hz1/2. The proposed FOM’s sensitivity was determined to be 150.15 mV/Pa. In addition to the static pressure analysis, a dynamic analysis using the PESQ algorithm was performed to measure the sound quality. With a sound quality score of 3.21, the proposed FOM can compete with commercial microphones. It also has advantages in terms of production and cost. Therefore, the proposed FOM has potential use in various applications, such as voice recognition, real-time communication in extreme environments, and long-distance listening in public/military/private security.