A differential pressure fiber optic infrasound sensor based on a mechanical filter was developed, for the detection of infrasound within the frequency range of 0.01--1 Hz. The sensing unit employs a miniature polyphenylene sulfide (PPS) diaphragm which is fixed onto a glass ferrule. An extrinsic Fabry-Perot (F-P) interferometer was fabricated between the optical fiber end face and the PPS diaphragm, and a mechanical filter structure introduced to improve the minimum detectable frequency down to 0.005 Hz. Experimental results indicate that this infrasound sensor shows a favorable frequency response for infrasound signals between 0.01 and 1 Hz, and it exhibits an average minimum detectable pressure (MDP) of 88.85 mPa·Hz ^−1/2 . Our platform provides a promising solution for sensors in infrasound signal detection applications.

中文翻译：

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基于机械滤波器的压差光纤法布里-珀罗次声传感器

开发了一种基于机械滤波器的差压光纤次声传感器，用于检测0.01--1 Hz频率范围内的次声。传感单元采用固定在玻璃套圈上的微型聚苯硫醚（PPS）膜片。在光纤端面和PPS膜片之间制造了一种外在的Fabry-Perot（FP）干涉仪，并引入了机械滤波器结构以将最低可检测频率提高到0.005 Hz。实验结果表明，该次声传感器对于0.01到1 Hz之间的次声信号显示出良好的频率响应，并且其平均最小可检测压力（MDP）为88.85 mPa·Hz ^-1/2 。我们的平台为次声信号检测应用中的传感器提供了有希望的解决方案。