Compared with the conventional communication fiber, the polarization maintaining fiber plays a more important role in coherent optics communication system and sensing application because of its intentional high birefringence. In recent years, microstructured optical fiber has been concerned due to its unique quality, which forms polarization maintaining ability by geometry birefringence and can achieve a high birefringence of at least one magnitude larger than conventional fiber. The features of excellent temperature stability, flexible structure design and lower cost make microstructured polarization maintaining fiber have tremendous application prospect. So the research on microstructured polarization maintaining fiber has profound significance.Based on a great number of references in domestic and abroad, firstly, this paper introduces birefringence property of light waveguide, principle of conventional polarization maintaining fiber and the relationship between birefringence and stressed zone. Secondly, the rectangle waveguide was introduced and the influence of structure parameters on waveguide birefringence was analyzed. The relationship between birefringence and structural parameters was obtained based on the principle of microstructured polarization maintaining fiber; this paper put forward a novel microstructured optical fiber and analyzed its polarization property in theory. Then comprehensively analyze the evolution of polarization states in single mode and two mode optical fibers. At last, introduce several methods for measuring beat length, and did the experimental test on multimode microstructured fiber. |