The optical fiber air acoustic sensor has the advantages of anti-electromagnetic interference, intrinsic safety, and suitable for long-distance transmission. This paper proposes a non-metallic air acoustic sensor which is suitable for high-sensitivity concealed acoustic detection in environments such as electromagnetic interference. The sensor is based on a DFB fiber laser within an air cavity of polyimide (PI) film and poly-ether–ether–ketone (PEEK) shell. The dynamic acoustic response characteristics of the DFB fiber laser modulated by the acoustic-sensitive diaphragm is theoretically studied and numerically simulated. Based on the study and simulation results, a DFB fiber laser acoustic sensor for broadband detection covering the human auditory frequency range is designed and fabricated. An improved phase generated carrier (PGC) demodulation technique is introduced to realize high-resolution dynamic wavelength demodulation and, at the same time, to realize low sensitivity to modulation amplitude and photoelectric changes. The experimental test of the fiber laser air acoustic sensor demonstrated that, in the frequency range of 200 Hz to18 kHz, the sensitivity is − 40.39 dB re.pm/Pa, the fluctuation is less than ± 3.15 dB, and the minimum-detectable pressure (MDP) is 66.7 μPa/√Hz at 1 kHz, and the lower limit of human hearing threshold is reached.

光纤气声传感器具有抗电磁干扰、本质安全、适合远距离传输等优点。本文提出了一种适用于电磁干扰等环境下的高灵敏度隐蔽声学检测的非金属气声传感器。该传感器基于聚酰亚胺 (PI) 薄膜和聚醚-醚-酮 (PEEK) 外壳的空气腔内的 DFB 光纤激光器。对声敏膜片调制的DFB光纤激光器的动态声响应特性进行了理论研究和数值模拟。基于研究和仿真结果，设计并制作了一种覆盖人类听觉频率范围的宽带检测DFB光纤激光声学传感器。引入改进的相位生成载波(PGC)解调技术，实现高分辨率动态波长解调，同时实现对调制幅度和光电变化的低灵敏度。光纤激光空气声学传感器的实验测试表明，在200 Hz～18 kHz频率范围内，灵敏度为−40.39 dB re.pm/Pa，波动小于±3.15 dB，最小可检测压力(MDP) 在 1 kHz 时为 66.7 μPa/√Hz，达到了人类听力阈值的下限。