Vibration monitor of optical fiber grating smart structure using intensity demodulation method

The long-period fiber grating(LPFG) is glued onto the experimental laminate to monitor the structure vibration and the light with a certain fixed wavelength is obtained by using the reflective characteristics of fiber Bragg grating, which acts as the input light source of LPFG. By detecting the power of the transmission at the resonance wavelength of LPFG, the vibration frequency of the laminate from 2 Hz to 2000 Hz is realized. From the vibration signal acquisition and the fast Fourier transform of the experiment, it is shown that the experimental result agrees with the exciting frequency. It is hopeful the LPFG vibration sensor is used in health monitoring of the smart material and structure.