Rare-earth doped tellurite glass optical fibre for visible light sources

We report on the fabrication of three tellurite glass compositions co-doped with Yb³⁺/Er³⁺, Yb³⁺/Tm³⁺ and Yb³⁺/Pr³⁺, respectively. The thermal properties of the glasses are presented and discussed. We investigated the intense upconversion photoluminescence generated at visible wavelengths by the samples when excited by a commercial infrared (IR) laser operating at 978 nm. With the aim to exploit this emission for biomedical, optical sensing or display applications, we discuss the fabrication of a microstructured fibre whose core consists in three concentric rings made of the three active glasses mentioned above. Morphological and optical characterisations of the optical fibre are presented and preliminary conclusions on the prospect of such device are also drawn.