Liu Kaijun, Luo Binbin, Zou Xue, Deng Ou, Wang Zhihua, Wu Decao, Zou Xianglong, Fan Junhao, Wu Taojiang, Zhao Mingfu
Appl Opt. 2021 Apr 1;60(10):2886-2892. doi: 10.1364/AO.420171.
An optic-fiber vibration sensor based on the reflected 81° tilted fiber grating (81° TFG) integrated with a symmetrical flexible hinge is proposed and experimentally demonstrated in this paper. The vibration sensor is composed of a symmetrical flexible hinge and a reflected 81° TFG, the ends of which are simply fixed on the upper surface of the mass. The theoretical model of the proposed vibration sensor is analyzed, by which the important parameters related to the resonant frequency of the sensor are simulated and discussed; then, the vibration sensing experiments are conducted. Experiment results show that TE/TM mode of the 81° TFG can provide the maximal acceleration sensitivity of 338.28 and 299.94 mV/g at 400 Hz in the flat area of the amplitude-frequency response (50-400 Hz), which is increased by 9.95 and 11.5 times as compared with the optical fiber cantilever beam structure, respectively. Further, the signal-to-noise ratio in the flat area (50-400 Hz) is about ∼66.275 under the acceleration of 2 g, which is increased by ∼20. Furthermore, it can be used for detecting mechanical vibration of medium-high frequency ranging from 50 to 3500 Hz. The proposed 81° TFG vibration sensor has the characteristics of small volume, simple package, high acceleration sensitivity, and wide vibration signal response range, which will ensure it has broad application prospects in the field of mechanical vibration.
本文提出并通过实验验证了一种基于反射式81°倾斜光纤光栅（81°TFG）与对称柔性铰链集成的光纤振动传感器。该振动传感器由对称柔性铰链和反射式81°TFG组成，其两端简单固定在质量块的上表面。分析了所提出的振动传感器的理论模型，通过该模型模拟并讨论了与传感器谐振频率相关的重要参数；然后进行了振动传感实验。实验结果表明，81°TFG的TE/TM模式在幅频响应的平坦区域（50 - 400 Hz）中，在400 Hz时可提供最大加速度灵敏度分别为338.28和299.94 mV/g，与光纤悬臂梁结构相比分别提高了9.95倍和11.5倍。此外，在2 g加速度下平坦区域（50 - 400 Hz）的信噪比约为66.275，提高了约20。而且，它可用于检测50至3500 Hz的中高频机械振动。所提出的81°TFG振动传感器具有体积小、封装简单、加速度灵敏度高和振动信号响应范围宽的特点，这将确保其在机械振动领域具有广阔的应用前景。
