Design And Study On The Low Frequency Triaxial Accelerometer Based On The FBG

Fiber Bragg Grating is one of the most development optical fiber passive components in recent years. Fiber Bragg Grating is produced in fiber core. It is used conveniently and Bragg reflected wavelength can be modulated by temperature, strain and so on, Fiber Bragg Grating is modulated by wavelength and easily distributed measure, So it is widely used in sensor field. In this dissertation, Based on the deeply research of triaxial accelerometer and the development of the FBG sensor, a research and design of triaxial accelerometer system based on the FBG is presented. In the first place, start with theoretic sensing model, sensing principle of fiber Bragg grating is analyzed, and the triaxial accelerometer system based on the FBG is designed, and the mathematical model of the triaxial accelerometer is analyzed in theory. Moreover,the relation between a certain axis direction acceleration and the displacement of the mass in the same direction, and between the displacement of the mass in a certain axis direction and the reflected wavelength of the two sensing FBG in the same direction is derived. Furthermore, the relation between LPG transmitted spectrum and the length, period, coupled intensity of the LPG is expounded, and the LPG is used as linear edge filter in the system, besides the chirped fiber grating is used as the band-pass filter to affirm the sensing FBG. The system can measure the direct current frequency acceleration. Next, Based on the analysis of the theory, the system of experiment is designed, and the dynamic characteristic of the system is elaborated. The resonant frequency, resolving capability, and the measuring range are also calculated in theory. Last, the error of the measuring system is being analyzed, and results show that the cross-axis sensitivity of the sensor and the temperature affect the measurement little.