A novel fiber Bragg grating vibration sensor

A novel fiber Bragg grating vibration sensor system was presented based on the demodulation by a mechanical-induced long period fiber grating(MLPFG).The stainless steel grooved board which was fabricated by mechanical line processing technology (MLPT),was used to make MLPFG with period of 600 μm,length of 60 mm.The MLPFG was adopted as filter in system,and its center wavelength is 1 539.820 nm,the length of the slope is larger than 6 nm.The vibration sensor was made by a special chosen FBG,whose center wavelength is 1 542.400 nm,3 dB bandwidth is 0.3 nm.Through adding electromagnetic damping,the sensitivity of signal detection was improved and the range of frequency measurement was expanded.It is proved in the experiment that the FBG sensor has a good dynamic response,and its frequency spectrum agree with the excitation signal exactly. Its testing frequency domain is between 10 Hz and 3 kHz,and it also has good impact vibration response.