Patent ID: 6372305
Filing Date: 2002-04-16
Classification: C03B,C23C,H01J,Y02P

Abstract:
A method of manufacturing an optical fiber by using an apparatus comprising an elongated microwave guide coupled to a resonant cavity substantially cylindrically symmetric about a cylindrical axis, the resonant cavity having a length, L, parallel to the cylindrical axis, an inner wall, and an outer cylindrical wall, the inner cylindrical wall comprising a slit having a width, W, and extending in a fall circle around the cylindrical axis, and the guide having a longitudinal axis which is substantially perpendicular to the cylindrical axis and which does not intercept the slit, the elongated microwave guide configured to deliver microwave radiation energy to the resonant cavity, the width, W, of the slit and the length, L, of the resonant cavity both measured in a direction parallel to the cylindrical axis to satisfy the relationship: W&lE;L/10, the method comprising:locating a substrate tube along the cylindrical axis and within the inner wall of the resonant cavity, the substrate tube having an inner surface and a length, the substrate tube and resonant cavity being substantially coaxial, and the resonant cavity being caused to move back and forth along the length of the substrate tube; using Plasma Chemical Vapor Deposition to deposit layers of doped silica on the inside surface of the substrate tube; thermally collapsing the substrate tube so as to form a preform rod; causing an extremity of the preform rod to become molten; and drawing an optical fiber from the preform rod.