Abstract: In this paper, UV photosensitivity of a hydrogen-loaded germanosilicate fiber and the relation between photosensitivity and the hydrogen-loading condition were studied experimentally. Experimental results indicate that: ① the curve of refractive index changes in the hydrogen-loaded fibers is exponential type (Δn=3.3×10^-4t^0.31689), at a certain point, refractive index changes reach saturated. This power law accords with the model proposed by Patrick H. However, the refractive index changes of the hydrogen-loading fibers continue to increase when exposed time prolongs; ② the photosensitivity changes are exponential to hydrogen-loading time until they reach saturated; ③ the photosensitivity changes are proportional to the hydrogen-loading pressure.

Key words: photosensitivity, hydrogen loading, germanosilicate fiber, fiber bragg grating