Multilevel Three-Component Fiber Fabry–Perot Accelerometer Based on Dedicated Bandpass Filters

An extrinsic three-component accelerometer based on fiber Fabry-Perot (F-P) interferometer is proposed. Unlike the traditional parallel connection, a dedicated filter is proposed to realize single-channel multiplexing of accelerometers. This dedicated filter can serve as a reflective surface for an F-P cavity while also enabling wavelength selection, allowing light of a specific wavelength band to pass through and reflecting light of other bands with minimal loss to the next stage. A hinged diaphragm-type sensing element is optimized by finite element simulation. The performance of the accelerometer is explored with respect to the different free spectral ranges (FSR). The proposed three-component fiber accelerometer has a specific bandwidth of 20 nm for each stage, and the FSR for each stage is 5 nm, the natural frequency of the three-component fiber accelerometer is 680 Hz, the X-axis wavelength sensitivity is 3.01 nm/g, the Y-axis wavelength sensitivity is 3.02 nm/g, the Z-axis wavelength sensitivity is 3.21 nm/g, and the lateral interference ability is less than 6.3%. Finally, surface seismic field tests were performed for both the single-component accelerometer and the three-component accelerometer.