Low-loss compound-glass optical fibre

Progress has been made in reducing the losses of optical fibres made from multicomponent glasses by using the doublecrucible technique. This has been achieved by reducing the absorption loss caused by water and transition-metal impurities. The intensity of the OH absorption peak at 960 nm has been reduced to 5 dB/km, and a minimum total loss in fibre form of 3.4 dB/km at 840 nm has been achieved.