Eur. Phys. J. AP 11, 107-110 (2000)
https://doi.org/10.1051/epjap:2000151

Cr⁴⁺-doped silica optical fibres: absorption and fluorescence properties

Laboratoire de Physique de la Matière Condensée (UMR CNRS UNSA 6622), Université de Nice Sophia Antipolis, parc Valrose, 06108 Nice Cedex 2, France

Corresponding author: Bernard.Dussardier@unice.fr

Received: 22 December 1999
Revised: 8 June 2000
Accepted: 20 June 2000
Published online: 15 August 2000

Abstract

Chromium-doped silica-based optical fibres emit infrared fluorescence at 77 K near 1250 nm (500 nm band-width) under 860−980 nm excitation. Visible and near-infrared absorption spectra of fibres were analysed using the Tanabe-Sugano formalism. It is shown that although the fibre core is codoped with only 1 mol% of aluminium, chromium is preferentially stabilized as Cr⁴⁺ in Al-rich regions of the glassy matrix in distorted tetrahedrally coordinated sites. The infrared fluorescence is assigned to Cr⁴⁺ along a transition from the ³T₂ state down to the ³A₂ ground state.