Novel alkaline-free Er3+-doped fluorophosphate glasses for broadband optical fiber lasers and amplifiers

Two sets of Er3+-doped alkaline-free glass systems, MgF2–BaF2–Ba(PO3)2–Al(PO3)3 (MBBA) and Bi(PO3)3–Ba(PO3)2–BaF2–MgF2 (BBBM), have been prepared and investigated with the aim of using them as active media. Radiative lifetimes (τrad) and branching ratios (β) have been obtained for the excited states of Er3+. The absorption spectra were recorded to obtain the intensity parameters (Ωt) which are found to be Ω2 = 4.47 × 10−20 cm2, Ω4 = 1.31 × 10−20 cm2, Ω6 = 0.81 × 10−20 cm2 for the MBBA system and Ω2 = 4.03 × 10−20 cm2, Ω4 = 1.34 × 10−20 cm2, Ω6 = 0.53 × 10−20 for the BBBM system, respectively. The emission cross-section for the 4I13/2 → 4I15/2 transition is determined by the Fuchtbauer–Ladenburg method and found to be 2.35 × 10−20 cm2 and 3.54 × 10−20 cm2 for the MBBA and BBBM system, respectively. Comparison of the measured values to those of Er3+ transitions in other glass hosts suggests that our new glass systems are good candidates for broadband compact optical fiber and waveguide amplifier applications.