A new method of developing ultralow-loss glasses.

A new and effective method for developing ultralow-loss glasses for long-distance optical fiber systems is presented. The idea is based on the observed strong effect of a very small amount of alkaline or alkaline-earth impurities on structural relaxation of “frozen-in” density fluctuations. Efficiency of this method is demonstrated in the case of silica glass with Na[sub 2]O of less than 50 wt. ppm, where the light scattering loss was reduced by 13% by the addition of only 10 wt. ppm (≈ 1 × 10[sup −3] mol %) Na[sub 2]O. Various problems in developing ultralow-loss fiber materials in multicomponent glasses are avoidable in this method, since concentrations of dopants are very small. [ABSTRACT FROM AUTHOR]