Thermal Stability and Spectroscopic Properties of Yb:Zinc-Tungsten-Tellurite Glass

New multi-component Yb:zinc--tungsten--tellurite glasses (70TeO₂-(20-x) ZnO-xWO₃-5La₂O₃-2.5 K₂O-2.5Na₂O-1.0 Yb₂O₃ (x = 0, 15 mol%) have been presented. Thermal stability and spectroscopic properties of Yb³⁺ ions have been measured. The results show that TZW2 glass (x = 15 mol%) has thermal stability (T_x - T_g > 160°C with T_x being the onset crystallization temperature and T_g the glass transition temperature) better than TZN glass and that the stimulated emission cross-section of 1.32 pm² for the ²F_5/2 → ²F_7/2 transition is higher than other laser glasses (QX, ADY, LY and FP), with the measured fluorescence lifetime of 0.93 ms and the broad fluorescence effective linewidth of 74.5 nm. Evaluated from the good potential laser parameters, TZW2 glass with both the minimum pump intensity (0.92 kW/cm²) and gain parameter (1.23 pm²ms) is promising for miniature solid fibre lasers or high-peak power lasers, as well as tunable lasers.