Gallium lanthanum sulphide glasses for mid infrared fibre applications

Gallium lanthanum sulphide glasses (GLS) are a very promising material for mid-infrared optical fibre applications. The wide transmission window of ~0.6-6µm makes it suitable for passive MIR transmission for such applications as power delivery, and remote sensing. Its low phonon energy makes it a suitable host material for rare-earth doping for use in MIR active devices; the first laser action demonstrated in chalcogenide glasses and fibre was in Nd3+ doped GLS fibres. Presented is an analysis of the impurity content of GLS glasses, which currently limits the optical performance of this material, and the latest results on single mode fibres drawn from purified precursors.