High-purity glasses for optical-fibre communication

High-purity soda-lime-silicate glasses have been prepared by coupling power radio frequencies directly into the glass, held in a `cold¿ silica crucible. Optical losses were measured at 1.06 ¿m, and the glasses were analysed for transition-metal impurities. The loss results approach the target of 20 dB/km required for a Commercial optical-communication system.