Process for making glass with a preselected refraction index profile having the form of a gradient index profile and a process for making a glass preform for drawing optical fibres for use in the communications industry

摘要

It is described with a predetermined radial refractive index profile, a method for the manufacture of glass rods, in which on the glass rod one or more glass layers from the gas phase under thermal initiation of the reaction are deposited and the composition of the glass layers is selected in detail so that the refractive index course in the layers in total corresponding to the predetermined radial refractive index profile. A problem with such a method is that undesirable refractive index variations that are superimposed on the predetermined refractive index profile, occur. Such undesirable refractive index variations are to be eliminated. This is achieved in that the glass layers are doped with fluorine. Fluorine has a damping effect on an undesirable refractive index variations.