Demodulation technique of fiber grating vibration sensor based on the edge filter method

In order to meet the needs of vibration signal monitoring on various occasions, based on long-period grating edge filtering principle, a fiber Bragg grating vibration sensor demodulation system with simple structure and low cost was designed. Dual optical path structure and low noise photoelectric conversion circuit were used in the hardware part. Demodulation system and display software were based on LabVIEW platform. After the testing on a tunable vibration bench, the demodulation of vibration signal frequency was obtained in the available range (0Hz~300Hz)of vibration sensors. The error was less than 3%. The results show that vibration acceleration analog signal volt value is a linear relationship, the fitting scale factor of the system is 0.94, the fitting extent is 0.9752 and vibration acceleration demodulation can be realized in the range of 0~4.7g of the acceleration of vibration signal.