A pre-relaxed FBG accelerometer using transverse forces with high sensitivity and improved resonant frequency

Abstract

Fiber Bragg grating (FBG) accelerometers using transverse forces have higher sensitivity but lower resonant frequency than ones using axial forces. By shortening the distance between the two fixed ends of the FBG, the resonant frequency can be improved without lowing the sensitivity. Here, a compact FBG accelerometer using transverse forces with a slightly pre-relaxed FBG and 25mm distance between the two fixed ends has been demonstrated with the crest-to-trough sensitivity 1.1nm/g at 5Hz and the resonant frequency 42Hz. It reveals that making the FBG slightly pre-relaxed rather than pre-stretched also improves the tradeoff between the sensitivity and resonant frequency.

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