High-temperature treatment of hydrogen loaded GeO2:SiO2 glasses for photonic device fabrication

High-temperature treatment of hydrogen loaded silica- and germanium doped silica glass, also referred to as OH flooding, has been studied. The removal mechanism of hydroxyl groups in silica glass, during OH flooding, occurs by formation and diffusion of molecular hydrogen, while in germanium doped silica the main diffusion mechanism is attributed to diffusion of molecular water. UV exposure of OH flooded and non-treated germanium doped silica samples, from a ArF laser at 193 nm, show large changes in the asymmetric stretching vibration of Si-O-Si bridges, indicating compaction of the glass network. In addition, the thermal relaxation kinetics of the UV induced compaction are found to be similar for non-treated samples and OH flooded samples.