Optical properties of Er³⁺-doped tungsten tellurite glass waveguides by Ag⁺-Na⁺ ion-exchange

The planar waveguides of 12Na₂O · 35WO₃ · 53TeO₂ · 1Er₂O₃ glass (in mol%) were prepared by Ag⁺-Na⁺ ion-exchange at 300-360 °C for 5-30 h. The effective mode indices and propagation losses of the waveguides were measured at the wavelengths of 473, 632.8, 983.1 and 1548 nm by means of a prism coupler technique. The waveguide depths from glass surface increased with increasing ion-exchange temperature and time. The diffusion parameters such as diffusion coefficient and activation energy were calculated on the basis of an Arrhenius temperature dependence of the diffusion coefficient of Ag⁺ ions in the ion-exchanged glasses. The propagation losses of the waveguides were 5.04-6.64, 2.70-4.77, 5.44-6.73 and 7.32-8.31 dB/cm in the first half in the propagation distance from 0 to 3.0 cm and 3.52-4.82, 1.92-2.99, 3.78-5.06 and 3.91-5.15 dB/cm in the latter half at 473, 632.8, 983.1 and 1548 nm, respectively. The relationship between the optical properties of the waveguides and the ion-exchange conditions is discussed.