Gallium-lanthanum-sulphide glasses: a review of recent crystallisation studies

Gallium-lanthanum-sulphide glasses have been proposed as rare-earth hosts f or 1.3 mu m optical amplification devices. To develop thermally stable Ga-L a-S glasses, and thus facilitate production of monomode, low optical loss, Ga-La-S glass fibre, a series of fundamental glass stability studies has be en carried out and the key results are summarised in this short review. The se results include: the critical role of oxide content in glass formation; phase identification during the crystallisation of Ga-La-S glasses; nucleat ion and crystallisation processes in Ga-La-S glasses on reheating and on co oling from above the liquidus; the effects of increased oxide content, and other sulphide and chloride additives, on glass stability. (C) 1999 Elsevie r Science B.V. All rights reserved.