Judd–Ofelt analysis and improvement of thermal and optical properties of tellurite glasses by adding P2O5

Er³⁺ and Er³⁺/Yb³⁺ co-doped tellurite glasses, suitable for developing optical fiber laser and amplifier, have been elaborated from the conventional melt-quenching method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P₂O₅. Absorption spectrum from near infrared to visible was obtained and the Judd–Ofelt (J–O) intensity parameters (Ω₂, Ω₄, and Ω₆) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er³⁺ have been predicted using intensity J–O parameters. Absorption cross-section and calculated emission cross-section, using the McCumber method, for the ⁴I_13/2→⁴I_15/2 transition, were determined and compared for the doped and co-doped glasses. Energy transfer (ET) and effect of changing concentration of P₂O₅ and Yb³⁺ ions on spectroscopic properties were investigated. It was found that the addition of P₂O₅ can increase the symmetry of the Er³⁺ ion. As a consequence, PL lifetime becomes more longer.The spectroscopic properties and the efficient infrared luminescence indicate that Er³⁺ doped TeO₂–ZnO–Na₂O–Er₂O₃(TZNE) is a promising laser and amplifier materials and may be a potentially useful material for developing upconversion fiber optical devices.