Photoinduced defects in Er/Al-doped optical fiber

In this work we study the mechanisms of photoinduced emergence and dissociation of defects in silica glass of Er - and Al-codoped optical fiber. Defects responsible for the degradation of amplification properties of the fiber are the main focus. Photoinduced changes in UV, visible and near IR optical range of transmission spectrum of the fiber under the 193 nm UV irradiation and the subsequent 976 nm exposure are investigated. The significant role of the interstitial molecular hydrogen in the process under study is shown. All the observed processes are explained in detail by means of photochemical reactions.