Highly sensitive fiber bragg grating accelerometer with low resonant frequency

We demonstrate a fiber optic accelerometer for low frequency vibration detection in this paper. A slider moving along a guide rail is suspended over an optical fiber into which a fiber Bragg grating (FBG) is inscribed. When acceleration signal acts on our sensing structure, the slider will vibrate vertically under the constraint of the optical fiber, inducing the change of FBG axial strain and we can therefore establish the relationship between vibrational acceleration and wavelength shift. Laboratory measurements validate the effectiveness of the derived theoretical results that the sensor owns a low natural frequency of 9.5 Hz and a high sensitivity up to 926.29 pm/g from 0.5 to 9 Hz. The sensor structure also shows a good ability to resist lateral interference that the cross-sensitivity is calculated as 0.3%.