The effect of GaSe on Ga–La–S glasses

Abstract Gallium–lanthanum–sulphide (GLS) glasses have been investigated as candidate materials for fabrication of IR transmitting optical fibres. Previously, significant oxide additions have been used to increase glass stability and also to allow the tailoring of the RI the produce compatible core/clad pairs. However, oxide additions have a detrimental effect on the IR transparency and suitability for rare-earth doping. A method of extrusion has been proposed that can be used to produce core/clad optical fibre performs. In this work a new method of altering the RI of the GLS glasses is investigated which can be used in conjunction with extrusion to produce optical fibre preforms. Variation of refractive index has been achieved using small additions of GaSe to the standard GLS composition, producing GLSSe glasses, avoiding the need for unfavourable oxide additions.