METHOD FOR DEPOSITING A COATING LAYER ON AN OPTICAL FIBRE WHILE IT IS BEING DRAWN AND DEVICE FOR ITS IMPLEMENTATION

摘要

A method for the deposition of a coating layer on an optical fiber while it is being drawn. The coating layer is designed to reduce the permeability of the optical fiber to water vapor and therefore to increase its lifetime. The method is characterized in that it consists in carrying out a decomposition of a gas mixture of boron halogenide and hydrogen and/or boron halogenide and ammonia gas by a microwave plasma-assisted addition of energy and in that the operation is conducted in the presence of a carrier gas in order firstly to carry the gas mixture to a reaction medium and secondly to activate the plasma.