Luminescence spectroscopy of hydrogen-associated defects in hydrogen-loaded and heated germanosilicate optical fibres

We report experimental results on the luminescence spectroscopy of hydrogen -loaded-germanosilicate optical fibres annealed in air at various temperatu res, up to 500 degrees C, excited at 488 nm. Two kinds of Ge-H defect are i dentified by their emission bands at 650 or 740 nm. Precursors of the forme r are drawing-induced GeE' defects, whereas the latter are due to the react ion of H-2 molecules at the Ge-O-Si site. Another band, centred at 390 nm, is also observed in high-temperature-heated fibres and is proposed to be du e to germanium-lone-pair-centre luminescence.