Luminescent properties of rare earth doped AlF3-based glasses

Rare earth ions can easily be incorporated into fluoride glasses in moderate to large concentrations and, due to their low phonon energy, these glasses appear to have many advantages over oxide glasses as hosts for rare earth ions used in optical amplifiers and lasers. In this paper, the authors investigate the optical properties of Pr3+, Pr3+/Yb3+ and Pr3+/Yb3+/Lu3+ doped bulk AlF3-based glass samples as a function of rare earth ion concentration. The authors find that the addition of 2 wt.% of Yb increases the fluorescence of Pr3+ at 1.32 μ by a factor of 35 when excited with 488 nm radiation. The fluorescence intensity and excited state lifetimes are found to be comparable to those measured for Pr in a ZBLAN host. since it has also been demonstrated that optical fibers drawn from AlF3-based glasses exhibit relatively low loss (<0.05 dB/m) and posses superior chemical durability compared to other fluoride glasses, it is possible that AlF3 glasses may become the fluoride glass of choice for practical fiber laser and amplifier applications