Dynamics of infrared absorption caused by hydroxyl groups and its effect on refractive index evolution in ultraviolet exposed hydrogen loaded GeO2-doped fibers

Abstract
The growth dynamics of UV induced IR absorption and related refractive index change in hydrogen loaded GeO 2 -doped fibers have been studied. We report a higher initial rate and strong saturation for Ge–OH generation compared with Si–OH formation under UV exposure. A close correlation was found between the Ge/Si–OH groups concentration and the induced index change as a function of the UV exposure time.