In the search for suitable glass hosts for 1300 nm amplification, the
field has been narrowed to Pr-doped fluorozirconate, fluoroindate, cad
mium mixed halide and sulphide glasses. This paper presents data ident
ifying the cadmium mixed halide system as a leading candidate, based o
n the lifetime and quantum efficiency of the (1)G(4) --> H-3(5) fluore
scence of Pr3+ in this system. Compositional studies to develop claddi
ng and core glasses suitable for high numerical aperture fiber, as wel
l as relevant physical and optical properties, are also discussed.