Photobleaching of UV-induced defects in Er/Al-doped glasses for fiber lasers

This work contains a study of the mechanisms of emerging and dissociation of UV-induced defects responsible for the degradation of the gain in Er- and Al- codoped silica glass. We investigate absorption spectra changes at the visible and ultraviolet range under UV irradiation at 193 nm and show the role of molecular hydrogen in this process. This includes a detailed description of the observed processes in the glass in terms of photochemical reactions. We also considered the effect of photobleaching of defects under 976 nm irradiation.