PRODUCING OPTICAL FIBRES FOR TELECOMMUNICATION

摘要

When producing a glass fiber, having a graded refractive index profile, by means of the double crucible method, the initial materials being core and cladding glass compositions having mutually different alkali ions, a profile is usually obtained which greatly deviates from the desired parabolic form. The invention furnishes the possibility of approximating this parabolic form very closely. This is attained by a partial substitution of the core alkali ion by the cladding alkali ion.