Borosilicate glasses for fiber optical waveguides

Of the existing optical glasses, pure fused silica is known to have the lowest optical attenuation in the red and near infrared portion of the spectrum where optical communications appears most promising. However, to approach the low attenuations afforded by pure fused silica in a waveguide structure requires that a core of fused silica be clad with a glass of slightly lower index refraction. This paper describes an investigation of the binary borosilicate glass system which has led to the realization of a promising cladding material for pure fused silica core fibers.