A method for producing a preform for optical fibers, in particular of a preform with a large diameter

摘要

The process is intended to be implemented in an installation with means allowing the translation and rotation of a preform (1 ′), held between two points by means of end pieces (6a, 6b). The heating means of a preform by plasma torch, are associated with a material supply means, in order to allow manufacture by layers. The preform / torch relative displacements, with or without addition of material, lead, or to a deposit of a new layer on the preform, or a glaze on the last layer déposée.ledit process which is interposed a one-ended reduction of the length of the layer, from one of the intermediate layers, during the deposition of a succession of layers in which the lengths of the layers are progressively reduced so that the preform is smaller at the ends. The one-ended reduction leads to a limitation of the thickness to a particular section (10 ') at the level of the deposited layer before the reduction.