Research On The Fiber Grating Vibration Sensing System Based On Erbium-doped Fiber Laser

In recent years,fiber Bragg grating vibration sensor has wide application prospects in the field of power equipment and civil engineering structural health online diagnosis,fault location and other fields.Among them,the fiber Bragg grating(FBG)vibration sensor based on erbium doped fiber laser has become the main research direction because of its excellent sensing performance.This paper first introduced the basic structure,classification and the research status of fiber grating laser sensor and its research progress in vibration sensing,and the basic principle of the fiber grating laser sensor,erbium-doped fiber laser,the basic principle of fiber grating strain,temperature,vibration sensing and demodulation technology research,put forward a fiber grating vibration sensor system based on erbium doped fiber laser with double edge filter demodulation of the vibration signal,and analyzes the characteristics of the system.The output characteristics of the erbium-doped fiber laser are simulated by OptiSystem,the parameters that affect the output power of the laser was optimized,the optimal light ratio of the output coupler and the optimal length of the erbium-doped fiber are obtained.Changed the wavelength of FBG,the simulation research on the relationship between the central wavelength of sensing grating and the output power of the vibration demodulation system,the results show that the two was linear in a certain range sensing and determine the feasibility of the system.The fiber grating vibration sensing system based on erbium-doped fiber laser using edge filter demodulation is built.Cantilever type fiber Bragg grating sensor was used to provide vibration signal,by changing the length of erbium-doped fiber,the laser has a large output power at 15 m,and achieved the vibration signal detection at the low-frequency of 10 Hz,20 Hz,30 Hz.