Abstract

The maximum tolerable concentrations of transition elements calculated to give an attenuation loss of 20dB/Km in a soda-lime glass vary from 2 (Co) to 20 (Fe) to 100 (Mn or V) ng/g⁽¹⁾. In developing a program to meet these target specifications the iron level was considered to be the most difficult to attain because the iron concentration in the earth's crust is far greater than that of the other transition elements (2) (see Table I). The production of chemical components for the fibers often Involves classical preparative methods but unusually rigid contamination controls are required for all the parameters relating to ultra-purity - preparation, handling , containment and analysis ⁽³⁾

© 1975 Optical Society of America