Method for activating an inner surface of a substrate tube for the manufacturing of an optical-fiber preform
US9831068B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 2016 |
| Grant date | Nov 28, 2017 |
| Priority date | — |
| Expiry date | Jul 1, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/334
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method activates the inner surface of a substrate tube via plasma etching with a fluorine-containing etching gas. An exemplary method includes the steps of (i) supplying a supply flow of gas to the interior of a substrate tube, wherein the supply flow includes a main gas flow and a fluorine-containing etching gas flow, (ii) inducing a plasma via electromagnetic radiation to create a plasma zone within the substrate tube's interior, and (iii) longitudinally reciprocating the plasma zone over the length of the substrate tube between a reversal point near the supply side and a reversal point near the discharge side of the substrate tube. The flow of the fluorine-containing etching gas is typically provided when the plasma zone is near the supply side reversal point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.