Radiation hardening of sol gel-derived silica fiber preforms through fictive temperature reduction
Résumé
The impact of fictive temperature (T f ) on the evolution of point defects and optical attenuation in non-doped
and Er3-doped sol-gel silica glasses was studied and compared to Suprasil F300 and Infrasil 301 glasses before
and after γ-irradiation. To this aim, sol-gel optical fiber preforms have been fabricated by the densification of
erbium salt-soaked nanoporous silica xerogels through the polymeric sol-gel technique. These γ-irradiated fiber
preforms have been characterized by FTIR, UV-vis-NIR absorption spectroscopy, electron paramagnetic resonance,
and photoluminescence measurements. We showed that a decrease in the glass fictive temperature leads
to a decrease in the glass disorder and strained bonds. This mainly results in a lower defect generation rate and
thus less radiation-induced attenuation in the UV–vis range. Furthermore, it was found that γ-radiation “hardness”
is higher in Er3+-doped sol-gel silica compared to un-doped sol-gel silica and standard synthetic silica
glasses. The present work demonstrates an effective strategy to improve the radiation resistance of optical fiber
preforms and glasses through glass fictive temperature reduction