Broadband Vibration Sensor Using Reflected Excessively Tilted Fiber Grating With Clamped Beam

A broadband vibration sensor using reflected excessively tilted fiber grating (ExTFG) with clamped beam was proposed. The two ends of reflected ExTFG were fixed, and the fiber grating part was suspended, thus forming a clamped beam structure. The resonance frequency and vibration mode of the proposed sensor were calculated and analyzed by numerical calculation and software simulation. Axial strain, acceleration response and vibration frequency detection experiments were designed and conducted. Experimental results showed that the axial strain sensitivity of TE/TM mode was -2.57 pm/ με and -1.6 pm/ με, respectively. The first-order resonant frequency of the sensor was 1900Hz with a flat region ranging from 100 Hz to 800 Hz, and the maximum acceleration sensitivity of TE/TM mode in the flat region was 38.79 mV/g and 31.43 mV/g at 800Hz, respectively. In addition, it could detect the vibration frequency range of 100-10000 Hz, and provide a highest signal-to-noise ratios (SNR) of 55.1 dB at 1900 Hz. The proposed sensor possessed a wide response frequency range, and was able to realize dual-parameter detection for acceleration and vibration frequency, which would make its good application prospects in the mechanical vibration detection for large-scale projects.