Method of building up an optical fiber preform by plasma deposition, and an optical fiber obtained from the preform built up by the method
AssigneeAlcatel Fibres Optiques
InventorsAlain Drouart, Benoit Gouez, Bernard Jouvenel, Yves Lumineau, Max Matau, Pierre Ripoche
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Abstract
A method of using a plasma to build up an optical fiber preform consists in injecting hydroxyl ions in a controlled manner into the build-up silica that is deposited on the preform. The invention is applicable to the manufacture of optical fibers, in particular monomode fibers.
Claims18
A method of building up an optical fiber preform by using plasma deposition, the method comprising the steps of:
- depositing build-up silica on the primary preform to be built up by means of a plasma torch;
- and
- injecting hydroxyl ions in a controlled manner into said build-up silica so as to obtain an average hydroxyl ion concentration lying in the range of from 50 ppm to 100 ppm in the build-up silica deposited on said primary preform.
A method of building up an optical fiber preform by using plasma deposition, the method comprising the steps of:
- depositing build-up silica on the primary preform to be built up by means of a plasma torch;
- injecting hydroxyl ions in a controlled manner into said build-up silica so as to obtain an average hydroxyl ion concentration lying in the range of from 50 ppm to 100 ppm in the build-up silica deposited on said primary preform, said step of injecting further comprising injecting said hydroxyl ions into said build-up silica substantially at the flame of the plasma torch as said primary preform is being built up;
- and
- using silica grains for constituting the build-up silica.
An optical fiber made from a primary preform built up with silica by depositing build-up silica on the primary preform to be built up by means of a plasma torch, and injecting hydroxyl ions in a controlled manner into said build-up silica, the fiber comprising an optical core, optical cladding, and at least one outer silica covering, with the outer silica covering being the result of said primary preform being built up, wherein said outer silica covering has an average hydroxyl ion concentration lying in the range of from 50 ppm to 150 ppm.
An optical fiber made from a primary preform built up with silica, the fiber comprising an optical core, optical cladding, and at least one outer silica covering, with the outer silica covering being the result of said primary preform being built up, wherein said outer silica covering has an average hydroxyl ion concentration lying in the range of from 50 ppm to 150 ppm, wherein said outer silica covering has a hydroxyl ion concentration that varies progressively, the outer silica covering comprising an innermost first layer having a hydroxyl ion concentration that is less than 50 ppm, and a second layer covering said first layer having a thickness that is greater than the thickness of said first layer, and having a hydroxyl ion concentration lying in the range of from 50 ppm to 250 ppm.
Dependencies are inferred from the claim text.