Polarization Mode Coupling Distributed Optical Fiber Temperature Sensor

Distributed optical fiber temperature sensor by polarized modes coupling has relatively high length resolution. It can measure the temperature more exactly in some peculiar occasions. This thesis mainly introduces its operating principle, sets up experiment system, and gets the experimental result.This thesis introduces the temperature sensor head's design by using Panda fiber and presents its operating principle. The formula of radial pressure pressed on Panda fiber is deduced, which is induced by the aluminium bar's radial thermal expand. The radial pressure induces the modes coupling in the temperature sensing area. The formula of mutual interference intensity, which is formed by mode coupling singal by Michelson interferometer, is also deduced. And the result of numerical simulation is given. At last the spatial resolution and measuring precision are detailedly discussed.This thesis also introduces the polarized mode coupling distributed fiber temperature sensing system, and gives the results of the experiment and erro analysis. The experiment curve is accorded with the theory analysis. The experiment result indicates that the output singal is linear with the temperature in the range of 30℃~100℃, which accords with the theoretic analysis.The spatial resolution of this sensing system is 7cm, temperature resolution is 3℃.