Research On The Fabrication And Application Of Long Period Fiber Grating

Fiber grating sensor is a new sensor that is developing rapidly in recent years. It possesses many virtues that include distributing sensing, anti-electromagnetic interference, high precision and good stability, and so on. Fiber grating can be devided into three kinds: fiber bragg grating(FBG), chirp and long-period fiber grating(LPG). Specifically, LPG has particular advantages and shows outstanding superiority, which is conceivable to be used in many sensing fields far and widely.This paper study the fabrication and application of LPG. Using amplitude mask method, via choosing proper optical fiber, proper light route, proper amplitude mask, proper exposed time and frequency, proper anneal temperature and time, an applied method of LPG fabrication was designed. Then, the characteristic of LPG that shifts with temperature or axial strain was analyzed; The refraction index sensitivity and birefringence effect for LPG were also analyzed, and some conclusions have been achieved.The contributions of this paper are:1. The formation mechanism for LPG is analyzed, and the fiber photosensitive mechanism, the way to enhance the fiber photosensitivity by means of hydrogen loading and related mathematical model are studied;2. The fabrication of LPG using amplitude mask method was introduced;3. The coupled-mode theory for LPG is analyzed, the characteristic of LPG that shifts with temperature or axial strain was analyzed;4.The refraction index sensitivity and birefringence effect for LPG were analyzed, and their practical application were expound.