A silicon cantilever-based fiber-optic acoustic sensor (FOAS) is presented in this work. A rectangular cantilever is fabricated upon a silicon-on-insulator (SOI) wafer using a micro-electro-mechanical system (MEMS). The length, width and thickness of the silicon cantilever are 530 μm, 200 μm and 3 μm, respectively. The resonant frequency of the silicon cantilever is 14820 Hz with a sensitivity of 950 nm/Pa. An ultra-high speed absolute cavity length demodulation method is adopted using a complementary metal oxide semiconductor (CMOS) spectrometer and an 850 nm superluminescent light emitting diode (SLED). A modified Buneman frequency estimation and total phase demodulation algorithm is adopted. The frequency response curve shows a relatively flat trend from 20 Hz to 13 kHz. The sensor exhibits good linearities at different frequencies while the applied acoustic pressure is increased from 0 Pa to 2.5 Pa. Experimental results indicate that the minimum detectable pressure (MDP) of the proposed FOAS is calculated to be 25.68 μPa/Hz1/2 at the frequency of 13 kHz. The silicon cantilever-based FOAS achieves broad operating bandwidth, high sensitivity, small size, and good stability.

中文翻译：

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采用超高速频谱解调的微型光纤硅悬臂梁声学传感器


这项工作提出了一种基于硅悬臂梁的光纤声传感器（FOAS）。使用微机电系统 (MEMS) 在绝缘体上硅 (SOI) 晶圆上制造矩形悬臂梁。硅悬臂梁的长度、宽度和厚度分别为530μm、200μm和3μm。硅悬臂梁的谐振频率为14820 Hz，灵敏度为950 nm/Pa。采用互补金属氧化物半导体（CMOS）光谱仪和850 nm超辐射发光二极管（SLED）的超高速绝对腔长解调方法。采用改进的Buneman频率估计和全相位解调算法。频率响应曲线在 20 Hz 至 13 kHz 范围内呈现出相对平坦的趋势。当施加的声压从0 Pa增加到2.5 Pa时，传感器在不同频率下表现出良好的线性。实验结果表明，所提出的FOAS的最小可检测压力（MDP）在该频率下计算为25.68 μPa/Hz1/2 13kHz。基于硅悬臂梁的FOAS具有宽工作带宽、高灵敏度、小尺寸和良好的稳定性。