Two step etching process for an optical fiber preform
First Claim
1. A process for preparing an optical fiber preform comprising the steps of:
- a) etching an optical fiber preform a first time to remove a portion of an oxide material deposited on the preform by using a gas comprising a first etchant gas containing fluorine at a sufficient temperature and gas concentration to create a fluorine contamination layer in the remaining oxide material; and
b) etching the preform a second time using a gas comprising a second etchant gas containing fluorine at a sufficient temperature and gas concentration to remove the fluorine contamination layer without any substantial further fluorine contamination of the remaining deposited oxide material.
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Abstract
This invention relates to a method of preparing an optical fiber preform with the preform having a uniform refractive index profile for the deposited oxide material that ultimately forms the optical fiber core. One embodiment of the invention relates to a process for preparing an optical fiber preform comprising the steps of etching a substrate a first time to remove a portion of a deposited oxide material from the preform by using a gas comprising an etchant gas containing fluorine at a sufficient temperature and gas concentration to create a fluorine contamination layer in the remaining deposited oxide material; and etching the preform a second time using a gas comprising an etchant gas containing fluorine at a sufficient temperature and gas concentration to remove the fluorine contamination layer without any substantial further fluorine contamination of the remaining deposited oxide material. Further embodiments relate to similar processes.
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Citations
17 Claims
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1. A process for preparing an optical fiber preform comprising the steps of:
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a) etching an optical fiber preform a first time to remove a portion of an oxide material deposited on the preform by using a gas comprising a first etchant gas containing fluorine at a sufficient temperature and gas concentration to create a fluorine contamination layer in the remaining oxide material; and
b) etching the preform a second time using a gas comprising a second etchant gas containing fluorine at a sufficient temperature and gas concentration to remove the fluorine contamination layer without any substantial further fluorine contamination of the remaining deposited oxide material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A process for preparing an optical fiber preform comprising the steps of:
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a) partially collapsing a glass tube, with an inner and outer surface comprising at least one oxide material deposited on the inside of the tube, the oxide material comprising a dopant, under conditions which results in the depletion of some of the dopant out of the deposited oxide material for a distance from the inside surface;
b) etching the glass tube a first time to remove part or all of the dopant depleted layer from the deposited oxide material using a gas comprising a first etchant gas containing fluorine at a sufficient temperature and gas concentration to create a fluorine contamination layer in the remaining deposited oxide material; and
c) etching the partially collapsed glass tube a second time using a gas comprising a second etchant gas at a sufficient temperature and gas concentration to remove any remaining dopant depleted layer and at least a portion of the fluorine contamination layer. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification