Enhancing 1.8 μm emission from ultra-broadband Tm-Bi-Er tri-doped fluorotellurite glasses for fiber amplifiers and near-infrared lasers

Fluorotellurite glasses tri-doped with Tm3+, Er3+ and Bi ions were investigated. The measured parameter ΔT (116 °C) confirmed that the prepared glasses had good stability. An ultra-broadband fluorescence emission (950–1670 nm) was observed with a full-width at half-maximum (FWHM) of 560 nm, which covered the entire bands of O, E, S, C, L and U. The 1800 nm fluorescence intensity of Tm3+/Er3+ co-doped and Tm3+/Er3+/Bi tri-doped glasses was enhanced compared to Tm3+ doped glass, which indicates that there is energy transfer between Tm3+, Er3+ and Bi ions. The maximum fluorescence lifetime of the prepared glasses was 7.39 ms, indicating the excellent fluorescence performance at 1800 nm. Additionally, the maximum absorption cross section (σabs = 1.77 × 10−20 cm−2) and emission cross section (σem = 7.61 × 10−20 cm−2) suggest that the Tm3+/Er3+/Bi tri-doped glasses have good optical absorption properties and high gain fluorescence emission. The above results indicate that the Tm3+/Er3+/Bi tri-doped fluorotellurite glasses have good application prospects in the field of fiber amplifiers and near-infrared lasers.