基于MEMS声敏结构的光纤声波传感器

Fiber Optic Acoustic Sensor Based on MEMS Acoustic Sensing Structure

基于微机电系统(Micro Electro Mechanical System,MEMS)工艺加工声波敏感结构,将声波敏感结构与光纤端面构成非本征型光纤法布里-珀罗干涉仪(Extrinsic Fabry-Perot Interferometer,EFPI)感知声波。研究了不同厚度和不同增敏环数的声压敏感薄膜结构对声波探测性能的差异,对比了信噪比测试结果。实验结果表明,针对400 nm和1000 nm厚度的声敏薄膜,在相同的测试条件下,前者的声敏结构位移更大、频率响应的信噪比更高。在相同薄膜厚度条件下,具有增敏结构的MEMS薄膜可以释放薄膜的初始应力,降低薄膜的刚性,相比无增敏结构的MEMS薄膜具有更高的灵敏度。

Based on Micro Electro Mechanical System(MEMS)technology,the acoustic sensitive structure and the end face of optical fiber form an Extrinsic Fabry-Perot Interferometer(EFPI)to sense acoustic waves.The differences of sound detection performance of sound pressure sensitive film structures with different thickness and different number of sensitizing rings are studied,and the signalto-noise ratio test results are compared.The experimental results show that,under the same test conditions,for acoustic sensitive films with thickness of 400 nm and 1000 nm,the displacement of acoustic sensitive structure of the former is larger and the signal-tonoise ratio of frequency response is higher.Under the condition of the same film thickness,the MEMS film with sensitization structure can release the initial stress of the film and reduce the rigidity of the film,which has higher sensitivity than the MEMS film without sensitization structure.