Research On Fiber Optic Accelerometer For Seismic Monitoring

Tens of thousands of lives and hundreds of billions of property can be saved by accuratein-time earthquake forecast. As one of the most important apparatus of earthquake detection,Fiber optic Accelerometer has a high sensitivity, wide frequency range, small in volume,simple structure and high capability of anti outside disturbance. This article mainly focuseson Fiber-optic Accelerometer Based on Fiber Bragg Grating.This article firstly introduced the sensing fundamental of FBG including description oftheoretical model, analysis of strain sensing model and temperature sensing model. Then, itintroduced application of fiber grating on fiber optical communication system and explainedthe manufacturing process of FBG. And after that, introduced approaches of researchingordinary earthquake accelerometer and designed a vertical Fiber-optic Accelerometer Basedon Fiber Bragg Grating which consists of FBG, brass mass block, metallic spring,Aluminium cylinder and base. In the mean time, we also designed a horizontal Glass FiberAccelerator structure which is similar to vertical ones and managed to measure3-dimensionalacceleration.We carried out sensitivity testing to vertical and horizontal Fiber optic accelerometer.And the results show that the vertical Fiber-optic Accelerometer Based on Fiber BraggGrating amounts652pm/g, The relative error is7.27%. The sensitivity of horizontal Fiberoptic accelerometer amounts2.386×105pm/g, which has two magnitudes higher in precisionthan the sensitivity of ordinary sensors. It meets the requirements of earthquake monitoring.In addition, we analyzed the problem in the experiments and gave the improving measure.