Effective near-infrared emission covering the fifth optical telecommunication window (1380–1525nm) has been observed in Pr 3+ -doped phosphate (LCBALP) glasses. Judd–Ofelt parameters Ω 2 (9.17×10 –20 cm 2 ), Ω 4 (16.50×10 –20 cm 2 ) and Ω 6 (2.41×10 –20 cm 2 ) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (Δλ eff ) of the corresponding 1 D 2 → 1 G 4 transition emission is obtained to be 148nm, and the maximum stimulated emission cross-section (σ em ) at 1467.5nm is derived to be 1.29×10 –20 cm 2 . The quantum efficiency of Pr 3+ : 1 D 2 level is identified to be 85.36%. The broad effective bandwidth and the large emission cross-section profile indicate that Pr 3+ -doped LCBALP glass fiber is promising in the realization of effective broadband amplification, especially at E- and S-band. As an expectation, the mature oxide glasses with Pr 3+ -doping, such as borate, phosphate and silicate glasses, are expected to be attractive candidates for broadband signal amplifiers operating at the fifth optical telecommunication window.