Back to results
US 4,659,354 AGranted
Method of producing silica optical fibres with reduced volume and surface defects
AssigneeCselt Centro Studie Laboratori Telecomunicazioni S.p.A.
InventorGiacomo Roba
Life of this patent
Estimating the term…
Abstract
The method allows surface defect reduction in silica optical-fibers by enriching the external layer by silica bonded carbon atoms within the silica lattice: SiC.SiO.sub.2. Carbon is obtained from chemical reaction directly during the drawing step. Volume defects are reduced by rapidly cooling the fiber structure heated up to vitreous transition temperature.
Claims1
A method of producing an optical fiber with reduced volume and surface defects which comprises the steps of:
- (a) heating a silica preform to a glass drawing temperature and drawing an optical fiber therefrom at a transition zone between the fiber and the preform;
- (b) chemically activating said transition zone concurrently with the drawing of the fiber and depositing carbon in a nascent state thereon whereby carbon diffuses into said fiber and reacts therewith in accordance with the relation:
- Si.[SiO.sub.2 ]+C=SiC.[SiO.sub.2 ]
- and the square brackets mean a prevailing silica pressure in the preform;
- (c) immediately thereafter heating the drawn fiber to a temperature at least equal to but not substantially greater than the vitreous transition temperature;
- and
- (d) thereafter rapidly cooling said fiber.
4 more elements
Dependencies are inferred from the claim text.