Patent ID: 6263706
Filing Date: 2001-07-24
Classification: C03B,C03C

Abstract:
A method of making a fluorine-doped optical fiber preform comprising of steps of:chemically reacting at least some of the constituents of a moving stream of gas mixture comprising at least one glass-forming precursor compound and an oxidizing medium, the reaction resulting in the formation of a glassy silica-based reaction product,forming a body by depositing at least a part of the reaction products on a substrate, anddoping the body with fluorine by contacting a surface of the body with a fluorine containing gas for a time and at a temperature which is sufficiently to result in a fluorine content at or near said surface which is lower than the fluorine content internal to said body and which is lower than the fluorine content at or near said surface when doped at said temperature but for a shorter time.