Gallium lanthanum sulphide based glasses for mid-infrared optical fibres
Gallium lanthanum sulphide (GLS) based glasses and optical fibres have considerable potential for use in both active and passive infrared applications. These range from using it as a passive transmission medium in the mid-infrared, to a host material for mid-infrared fibre lasers. This is potentially useful for all optical gas detection systems. The purification, thermal and optical properties, and fibre drawing of GLS based optical fibre forms the content of this thesis. A successful scheme of purification of the precursors, and optimisation of the composition of the glass, has allowed the fabrication of the lowest loss GLS fibre reported to date with a loss of 1 dBm−1 at 4μm. The development of a novel preform fabrication technique for producing single mode fibres has greatly enhanced the prospects of this material for the future.