Synthesis And Application Of Interferometric Fiber Optic Sensor Based On Fused-silica Capillary

The research about optical fiber has been attracting the attention of people greatly. Compared with the early sensors, optical fiber sensor has the advantages of light weight, small volume, high sensitivity, real-time detection, fast response speed, less sample without tags, anti-electromagnetic interference and so on, and has been widely applied in biological, chemical and other fields. In this paper, a high-performance interferometric fiber optic sensor based on fused-silica micro capillary (FSC) is proposed and experimentally investigated. Specific content is as follows:First of all, the research background and the classification of optical fiber sensor have been introduced. Also, the sensor mechanism and the current development situation of all kinds of sensors are expounded.Second, theory model of fused-silica capillary optical fiber sensing system is set up, and the sensing mechanism and related basic concepts is introduced. Based on theoretical model, we find the factors influencing the sensing element. In order to understand the operation principle of the sensor, we simulated the optical field distribution in the sensing region, using the three-dimensional beam propagation method (BPM) and the transparent boundary condition with commercial photonic analysis software (Rsoft). Optical fiber sensor has a good response to the solution of different refractive index in simulation.Then, the fused-silica capillary optical fiber sensor detection system is built, and we introduced the performance and parameters in all parts of this sensing system and the welding and production process of capillary sensing element. To find out the optimal sensor length, the contrasting experiment with different lengths of capillary optical fiber sensors has been done. We have done the basic performance test to fused-silica capillary sensing element, including the test to solution of different refractive index and the measurement of different temperature. The results show that the capillary optical fiber sensor has high sensitivity.Finally, based on the basic sensing system, three applications of fused-silica capillary optical fiber sensor system are presented in this paper. One is the high sensitivity temperature sensor based on fused-silica capillary, and we use alcohol as a medium, which can greatly improve the sensitivity of the system for temperature measurement. The second one is the gas experiment based on fused-silica capillary, using the metal palladium to complete the research on the measurement of the gas. In order to verify the application value of the system in biochemical tests, the third one is the specificity of DNA testing. Through the discussion and analysis of experimental results, a good fused-silica capillary optical fiber sensing system has been got, and this kind of sensor based on capillary wall will become a small biological fiber optic sensor in further development.