Reaction property of diffused H2with defect Centers in GeO2-doped fiber

This paper presents the reaction property of diffused molecular hydrogen (H
2
) with irradiation-induced defect centers in a GeO
2
-doped fiber. When H
2
diffuses into an irradiated fiber, an OH loss increases even at room temperature. This loss increase is thought to be caused by chemical reaction between diffused H
2
and irradiation-induced nonbridging oxygen hole centers (NBOHC's). The hydrogen-associated defect centers having 11.9-mT hyperfine structure are formed by chemical reaction between diffused H
2
and irradiation-induced Ge-defect centers. Moreover, the irradiated fiber shows an OH loss increase at high temperatures even after diffused H
2
is removed from the fiber. The hydrogen-associated defect centers are considered to be the hydrogen source for the OH formation.