The field of heavy metal halide glasses (namely fluorides) is only ten
years old now, but it has developed rapidly since the discovery of
fluorozirconate glasses by the group at the University of Rennes
(France). The main reason for this was the early demonstration of the
enormous potential of such glasses for use as long-haul ultra-low loss
middle infrared waveguide materials, aided in part by the scientific
interest held by their unusual short range structures. As a result,
significant research efforts were initiated in the academic, government
and industrial sectors in Europe, the United States and Japan. However,
the search for a finished product has per- haps led to a partial
overlooking of some of the more funda- mental aspects by the scientific
community. After the initial excitement, the workers in this field are
perhaps at a crossroads where attenuations lower than 1 dB/Km need to be
obtained for long lengths of fiber of good chemical and thermal
stability, in order to guarantee continual R&D sUE ports. Therefore,
there is a strong need for a critical asses- sment of the potential of
halide glasses for infrared fiber- optics and the formulation of
recommendations for future re- search in this area and other related
fields.