Radiation-induced defects in fluorine-doped silica-based optical fibers: Influence of a pre-loading with H2

We investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200–850 nm range of wavelengths (1.5–6 eV). We also studied the influence of pre-loading this kind of fibers with hydrogen on its radiation sensitivity. Our results showed that, for our experimental conditions (pre-treatment with H₂ several months before irradiation with diffusion of all the H₂ out the fiber core and cladding before X-ray exposure), this pre-treatment increases the radiation-induced attenuation in the ultraviolet part (200–300 nm) of the spectrum. A previous H₂-loading has no influence at greater wavelengths. The nature of the radiation-induced point defects is discussed from the decomposition analysis of the attenuation spectra with Gaussian bands.