Zhu Wenhua, Li Danyang, Liu Jiaojiao, Wang Ruohui
Appl Opt. 2020 Feb 20;59(6):1775-1779. doi: 10.1364/AO.381002.
Traditional optical fiber acoustic sensors are mostly based on mechanical diaphragms and use indirect coupling between the acoustic and optical signals. The detectable frequency range and sound pressure range of such a sensor have limitations because they are influenced by the membrane or a mechanically deformable material. In this paper, a Mach-Zehnder interferometer-based membrane-free acoustic sensing method is developed. The sensing principle relies on direct detection of sound-pressure-induced changes of the refractive index in the open cavity. This enables an inherently flat frequency response over a broad bandwidth. Simulation and experiment were carried out to verify and demonstrate the idea. The results show that the membrane-free acoustic sensor has a flat frequency response from 500 Hz to 20 kHz.
传统的光纤声学传感器大多基于机械隔膜，并利用声学信号和光学信号之间的间接耦合。这种传感器的可检测频率范围和声压范围存在局限性，因为它们受到隔膜或可机械变形材料的影响。本文提出了一种基于马赫-曾德尔干涉仪的无隔膜声学传感方法。其传感原理依赖于直接检测开放腔中声压引起的折射率变化。这使得在宽频带上具有固有的平坦频率响应。进行了仿真和实验以验证和演示该想法。结果表明，无隔膜声学传感器在500Hz至20kHz范围内具有平坦的频率响应。
