Spectroscopic properties of 2.7 μm emission in Er³⁺ doped telluride glasses and fibers

Highlights: • Telluride glasses with high Er³⁺ doping concentration and good thermal property are prepared. • Energy transfer processes for 1.5 μm, 2.7 μm and visible emission are fully discussed. • Enhanced 2.7 μm emission is achieved from the bulk glasses. • An Er³⁺ doped fiber is successfully drawn and strong upconversion emission is observed in the fiber. - Abstract: Emissions at 2.7 μm from telluride glasses with various Er₂O₃ doping concentrations are investigated. The prepared glasses have excellent thermostability and high rare-earth solubility. Judd–Ofelt parameters are calculated based on the absorption spectra. A large emission cross section (1.12 × 10⁻²⁰ cm²) and a high spontaneous radiative coefficient (57.8 s⁻¹) are obtained at 2.7 μm. The fluorescence properties of glasses with different concentrations are analyzed and presented. An Er³⁺-doped fiber is fabricated via a rod-in-tube technique, and the loss at 1310 nm is ∼2.1 dB/m measured by using the cut-back method. Strong upconversion emission caused by intense pump absorption is observed from the Er³⁺doped fiber under excitation by a 980 nm laser diode (LD). Telluride glasses with high Er³⁺ doping concentration and good thermal property are prepared. Energy transfer processes for 1.5 μm, and 2.7 μm, as well as visible emission are fully discussed. Enhanced 2.7 μm emission is achieved from the bulk glass. An Er³⁺ doped fiber is successfully drawn, and strong upconversion emission is observed in the fiber