We present a study of chalcogenide glass fiber lasers doped with Dy 3+ , Pr 3+ or Tb 3+ that would operate in the mid-infrared wavelength range. A set of chalcogenide glass samples doped with different concentrations of rare earth ions is fabricated. The modeling parameters are directly extracted from FTIR absorption measurements of the fabricated bulk glass samples using Judd-Ofelt, Füchtbauer-Ladenburg theory and McCumber theory. The modeling results show that, for all the dopants considered, an efficient mid-infrared laser action is possible if optical losses are kept at the level of 1dB/m or below.

A simple Dy 3+ -doped chalcogenide glass fibre laser design for mid-infrared light generation is studied using a one dimensional rate equation model. The fibre laser design employs the concept of cascade lasing. The results obtained demonstrate that efficient cascade lasing may be achieved in practice without the need for fibre grating fabrication, as a sufficient level of feedback for laser action is provided by Fresnel light reflection at chalcogenide glass fibre-air interfaces. Further enhancement of the laser efficiency can be achieved by terminating one of the fibre ends with a mirror. A numerical analysis of the effect of the Dy 3+ doping concentration and fibre loss on the laser operation shows that with 5 W of pump power, at 1.71 µm wavelength, output powers above 100 mW at ∼ 4.5 µm wavelength can be achieved with Dy 3+ ion concentrations as low as 3 × 10 19 cm −3 , when fibre loss is of the order 1dB/m.

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