Luminescence spectra of germanosilicate optical fibres I - radioluminescence and cathodoluminescence

Abstract

Data are reported on the luminescence spectra generated by X-ray and electron irradiation of optical fibres, fibre preforms and silica. The impurities and imperfections in the fibre core have a higher luminescence efficiency than those in the substrate material. The core luminescence provides a major fraction of the total light emission, despite the fact that the core is a small fraction of the total fibre volume. A wide variety of overlapping emission bands are reported. The spectra are strongly temperature dependent but the component emission bands can generally be linked to either Ge impurities, giving the 400 nm band, exciton emission near 460 nm or other blue/UV bands linked to E'-type defects. Overall, the study of the fibre luminescence provides a sensitive technique for analysis d changes and repeatability of fibre fabrication