Abstract Trivalent praseodymium ions were added in bismuth-containing tellurite (LKBBT) and gallate (LKBBG) glasses to develop potential oxide glass amplifier medium operating at 1.3 μ m . Based on optical absorptions, three phenomenological Judd–Ofelt parameters Ω 2 , Ω 4 and Ω 6 of Pr 3 + have been derived to be 4.14 × 10 - 20 , 6.88 × 10 - 20 and 4.71 × 10 - 20 cm 2 in LKBBT system, and 3.85 × 10 - 20 , 7.20 × 10 - 20 and 3.10 × 10 - 20 cm 2 in LKBBG system, respectively. Large Ω 2 values indicate higher asymmetry and stronger covalent environment in them. The branching ratios for G 4 1 → H 5 3 transition of Pr 3 + in the two glass systems arrive at 60.5% and 56.9%, respectively, and the predicted spontaneous-radiative transition rates are as high as 1188 and 1112 s - 1 , which are beneficial in achieving efficient 1.3 μ m emission under the pumping of 1.03 μ m laser sources.