FBG Vibration Sensing System Based on F-P Cavity Tunable Filter

In this paper, the narrow line width light source is generated by F-P cavity tunable filter and broadband light source. By adjusting F-P cavity filter, narrow line width light source works at the edge of the reflection spectrum of Fiber Bragg Grating (FBG), thus realizing the vibration sensing system based on FBG. The driving voltage of F-P cavity tunable filter is generated by STM32, the output signal of Photo detector (PD) is collected by DAQ, and the time-domain waveform and spectrum of vibration signal are displayed by PC software based on LabVIEW. By studying the dynamic drift characteristics of F-P cavity tunable filter, it is found that pre-voltage can weaken the influence of dynamic drift on system performance. Finally, by comparing the test results of the commercial electrical vibration detection system with the experimental system proposed in this paper, the results show relative error of the experimental system proposed in this paper is less than 3% when the vibration frequency is less than 100 Hz.