The role of hydrogen as a radiation protection agent at low temperature in a low-OH, pure silica optical fiber

It is demonstrated in a low-OH, pure-silica-core fiber waveguide that hydrogen plays a significant role in both suppressing the in situ steady-state radiation-induced optical attenuation near 850 nm reducing the subsequent recovery time at low temperature (-55°C). The natural beneficial effects of radiolytic hydrogen formed from hydroxyl groups in silicas containing OH are here provided by externally impregnated molecular hydrogen. SiH was observed to form during both low-temperature irradiation and the subsequent recovery up to 10⁴ s; radiolytic SiOH was not observed to form. Spectroscopic analysis of the radiation-induced loss in the visible and near-infrared demonstrates that there is more than one simple absorption band involved. However, these bands are not all equally suppressed by hydrogen impregnation