Reduction of the radiation-induced absorption in hydrogenated pure silica core fibres irradiated in situ with γ-rays

We studied the efficiency of a hydrogen-treatment in different pure silica core fibres irradiated by γ-ray in an attempt to decrease the radiation-induced absorption (RIA). It is observed that the effect of hydrogen already reduces the drawing-induced band commonly observed in low-OH fibres. During irradiation we observe a large increase of the radiation-induced OH growth with a corresponding significant reduction of the radiation-induced absorption at 0.63 μm. The presence of hydrogen also reduces the transient radiation-induced absorption at 0.7 μm sometimes observed in low-OH/low-chlorine fibres and believed to pertain to self-trapped holes (STHs).