LAUSR

Abstract Structural and fluorescence properties of Ho 3+ /Yb 3+ co-doped germanosilicate glasses have been modified by tailoring the composition using lanthanide additive Lu 2 O 3 . Raman spectra and X-ray Photoelectron spectra reveal that the addition of Lu 2 O 3 can change the structure by increasing non-bridging oxygens (NBO) in this glasses. Meanwhile, an improved thermal stability (ΔT: from 110 to 187 °C) has also been obtained via Lu 3+ ‘lanthanide contraction’. Futhermore, the positive effect of changed glass structure gives excellent fluorescence properties by the decreasing cross relaxation process which are proved by the experimental upconversion, near-infrared and mid-infrared fluorescence spectra. Additionally, a double enhancement of a 2.0 μm emission has been achieved successfully in this silica-germanate glass with 7 mol% Lu 3+ addition, which possesses a larger emission cross section (4.41 × 10 −21  cm 2 ) at 2022 nm. These results indicate that the optimized emission of Ho 3+ for optical fiber laser can be achieved by tuning the glass structure using lanthanide additive Lu 2 O 3 .