METHOD FOR MANUFACTURING A PRIMARY FORM FOR OPTICAL FIBERS, PRIMARY FORM, FINAL FORM, OPTICAL FIBERS.

摘要

The present invention relates to a method for manufacturing a primary preform for an optical fibre, using a plasma chemical internal vapour deposition process, wherein doped or undoped glass-forming precursors are supplied to the interior of a hollow glass substrate tube, a reaction zone in the form of a plasma is moved back and forth along the length of the aforesaid hollow glass substrate tube between a point of reversal near the supply side and a point of reversal near the discharge side of the hollow substrate tube, wherein the substrate tube is positioned in a furnace and wherein such conditions are created in the aforesaid reaction zone that one or more glass layer packages made up of at least two separate glass layers are deposited on the interior of the aforesaid substrate tube. The present invention further relates to a method for manufacturing a final preform, to optical fibres as well as to primary preforms, final preforms and optical fibres obtained therewith.