Fiber Bragg grating regeneration modeling and ultra-wide temperature sensing application

Three types of Fiber Bragg gratings (FBGs) were inscribed in H-2-loaded and H-2-free fiber with phase mask using 800nm femtosecond (fs) laser, ultraviolet (UV) excimer laser respectively. Their reflection spectra regenerating procedure were observed under different annealing temperature and the models of regeneration process as well as annealing temperature and time were established. Experiments and model fitting show that there were definite regeneration temperature threshold for fs FBGs written in H-2-free fiber, H-2-loaded fiber and UV FBGs in H-2-loaded fiber. The temperature sensing characteristic of RFBGs were investigated and compared experimentally under ultra-wide temperature range.