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

Abstract Two sets of Er 3+ -doped alkaline-free glass systems, MgF 2 –BaF 2 –Ba(PO 3 ) 2 –Al(PO 3 ) 3 (MBBA) and Bi(PO 3 ) 3 –Ba(PO 3 ) 2 –BaF 2 –MgF 2 (BBBM), have been prepared and investigated with the aim of using them as active media. Radiative lifetimes ( τ rad ) and branching ratios ( β ) have been obtained for the excited states of Er 3+ . The absorption spectra were recorded to obtain the intensity parameters ( Ω t ) which are found to be Ω 2  = 4.47 × 10 −20  cm 2 , Ω 4  = 1.31 × 10 −20  cm 2 , Ω 6  = 0.81 × 10 −20  cm 2 for the MBBA system and Ω 2  = 4.03 × 10 −20  cm 2 , Ω 4  = 1.34 × 10 −20  cm 2 , Ω 6  = 0.53 × 10 −20 for the BBBM system, respectively. The emission cross-section for the 4 I 13/2  →  4 I 15/2 transition is determined by the Fuchtbauer–Ladenburg method and found to be 2.35 × 10 −20  cm 2 and 3.54 × 10 −20  cm 2 for the MBBA and BBBM system, respectively. Comparison of the measured values to those of Er 3+ transitions in other glass hosts suggests that our new glass systems are good candidates for broadband compact optical fiber and waveguide amplifier applications.