Bleaching of photodarkening in Tm-doped silica fiber with deuterium loading

We demonstrate the rapid photodarkening (PD) phenomenon in Tm-doped fiber (TDF) core pumped by a laser at 1080 nm and the bleaching effect of deuterium (${{\rm D}_2}$D₂) on PD TDF. By ${{\rm D}_2}$D₂ loading for seven days, the PD-induced excess loss (PIEL) in the visible (VIS) and near-infrared (NIR) region have been largely eliminated, and no degradation was observed within 30 days. PD resistance of the ${{\rm D}_2}$D₂ pretreated TDF has been investigated as well. The formation of color centers based on defects and precursors in the silica matrix and the mechanism of ${{\rm D}_2}$D₂ bleaching are discussed.