Research On The Sensitivity Enhancing Method For Fiber-optic Accelerometer

In recent years, with the rapid development of fiber optic accelerometer, its application fields are not limited to the military sphere, but also widely used in geological structure exploration, seismic monitoring, oil exploration, machine safety testing and other civilian areas,which raises high demands on the sensor performance. However, there is still a gap between the sensitivity of current fiber-optic accelerometer with the requirements of some applications, which severely restricts the further expansion of its application fields. Therefore,how to achieve high sensitivity of fiber-optic accelerometer becomes an urgent problem, and many researches are committed to solve it, which promotes the rapid development of fiber optic accelerometer.In the paper, we focused on the method to enhance the sensitivity of fiber optic flexural disc accelerometer, and the main content is as follows.Firstly, we study on the sensing method and technology of fiber optic flexural disc accelerometer. Comprehensively considering the radial strain and hoop strain, we build the theoretical model of the sensitivity and resonant frequency for fiber optic disc accelerometers,and numerically simulate the relevant structural parameters; at the same time, we build mechanical simulation model with the finite element software, and compare the theoretical model and simulation model.Secondly, we study on the sensitivity enhancing method of fiber optic flexural disc accelerometer. Discuss the influence of fiber sensing coil paste area, disc size, and fiber type to the acceleration sensitivity. Combining the three optimization results,propose an effective sensitivity enhancing method, which is with the multilayer fiber sensing coils, and simulate its sensitivity enhancement effect.Thirdly, we study on the practical technology of fiber optic flexural disc accelerometer,including the design and production of high sensitivity fiber optic flexural disc accelerometer,packaging process of one-dimension and three dimension fiber optic accelerometers.Last but not the least, we study on the performance testing program of fiber optic flexural disc accelerometer. Build the performance testing system,and conduct corresponding performance testing for one-dimension optical fiber accelerometers. Furthermore, develop field and seismic signal detection experiments for three dimension fiber optic accelerometersThe results show that, applying the multilayer fiber sensing coils in fiber optic flexural disc accelerometer can effectively realize sensitivity enhance; the one-dimension fiber optic disc accelerometer we designed is with good performance,the sensitivity is higher than 6243.4 rad/g, resonant frequency is up t0 185 Hz, resolution is better than 50.68 ng/(?),and dynamic range is greater than 113.96 dB; in the field experiments, three dimension fiber optic accelerometers perform well, and they can detect seismic signals.