Properties of Ga–La–Na sulphide glasses

Abstract A series of Ga–La–Na–S (GLNS) glasses have been investigated as candidate materials for optical fibers operating in the mid-infrared region of 2–5 μm. The GLNS system has been selected as a possible alternative to the Ga–La–S (GLS) system (based around 70Ga 2 S 3 /30La 2 S 3 ) which, due to stability criteria, has proven difficult to fiber draw. The GLNS system was derived by substituting, into the standard GLS system, Na 2 S in place of La 2 S 3 . Seven glasses in total were characterized with compositions containing 0–30 mol% Na 2 S. Two glasses have been selected that show suitable properties to form a core/clad pair for fiber fabrication. The core glass selected has a 70Ga 2 S 3 –10La 2 S 3 –20Na 2 S mol% composition in conjunction with a 70Ga 2 S 3 –5La 2 S 3 –25Na 2 S mol% glass as the cladding.