Medium-High-Frequency and High Sensitivity Fiber Optic Acceleration Sensor Based on F–P Interference

A high sensitivity fiber-optic acceleration sensor based on a Fabry-Perot Interferometer (FPI) formed by an aluminum alloy elastic mass-block structure is proposed for measuring acceleration signals in a vibrating environment. The sensing structure mainly consists of a single-mode optical fiber collimated reflector 1, reflector 2, and an elastic mass-block structure, where the optical fiber collimated reflector 1 and the reflector 2 located on the upper surface of the elastic mass block form an F-P interferometric cavity. According to the F-P interferometric sensing principle, the reflectivity of the two end faces and the cavity length parameters are simulated and optimized to produce an acceleration sensor with a high finesse reflectance spectrum (extremely narrow spectral trough). The mass block dimensions of the sensing structure were simulated and optimized and performance was analyzed using finite element software, and the sensor was fabricated according to the analysis results, and the amplitude-frequency response, sensitivity characteristics, and lateral anti-interference capability of the sensor were investigated experimentally. The experimental results show that the sensor has an intrinsic frequency of 2100 Hz, a sensitivity of 4.91 nm/g at 1300 Hz, a resolution of 0.204 mg, and a transverse immunity of less than 5% within the operating bandwidth of 0–1300 Hz. The sensor proposed in this article is characterized by high sensitivity, a large operating bandwidth range, and low lateral interference, making it suitable for monitoring medium- and high-frequency vibration signals in aerospace and other equipment structures.