Patent ID: 7068899
Filing Date: 2006-06-27
Classification: C03B

Abstract:
1. A method of manufacturing an optical fibre, which method comprises the following steps: i) providing a hollow substrate tube, ii) passing doped or undoped reactive, glass-forming gases through the interior of the hollow substrate tube, iii) depositing glass layers onto the interior of the hollow substrate tube, wherein a non-isothermal plasma is reciprocated between two reversal points along the substrate tube, wherein the velocity of movement of the plasma decreases to zero from each deceleration point to each reversal point, iv) collapsing the substrate tube thus obtained so as to form a solid preform, and v) drawing an optical fibre from said solid preform, wherein the velocity at which the plasma is moved along the hollow substrate tube is changed in a first end region adjacent to a reversal point during step iii), both as a function of time in the deposition process and as a function of position in the first end region, which change marks the starting point of the first end region, wherein the end point of the first end region coincides with the reversal point and wherein the starting point is located further away from the reversal point than the deceleration point, said first end region having a length that suffices to reduce the taper in the perform, and a velocity profile at which the plasma is moved along the hollow substrate tube is changed for each succeeding glass layer.