Optical properties of Nd3+-doped and Er3+-Yb3+ codoped borotellurite glass for use in NIR lasers and fiber amplifiers

The optical properties of borotellurite glasses doped with Nd3+ ions or codoped with Er3+-Yb3+ ions are investigated, in order to evaluate the potential application of these types of glass in laser systems and amplifier materials. The Judd-Ofelt (JO) model is used to determine the absorption intensities of both types of glass so as to establish the J-O intensity parameters (Ωλ). The J-O intensity parameters are then used to determine the various radiative parameters viz., the radiative transition probabilities (AR), branching ratios (βR), stimulated emission cross-sections (σe), full width half maxima (Δλp) and radiative lifetimes (τR) of both types of glass, which are also compared to the equivalent parameters for other host glasses. It has been shown that Yb3+ acts as an Er3+ sensitizer and contributes largely to the improvement of the spectroscopic properties of the glasses that is codoped with Er3+-Yb3+. The obtained values ofAR, βR, τR, σe and Δλp for the Nd3+- and Er3+-doped glass show that both the 4F3/2→4I11/2 transition at 1.06 μm in the Nd3+ case and the 4I13/2→4I15/2 transition at 1.56 μm for the Er3+ case exhibit better NIR luminescence at a level suitable for photonic device applications. The potential of the glasses examined in this study, due to their promising gain media, is also discussed in terms of the development of solid state NIR lasers and optical amplification for telecommunication applications.