| 摘要 |
<p>The present invention relates to a method for manufacturing a preform for optical fibres by means of an internal vapour deposition process, which method comprises the following steps:
i) providing a hollow glass substrate tube,
ii) supplying dopant-containing glass-forming gases to the interior of the hollow glass substrate tube, wherein the supply flow comprises a main gas flow and one or more secondary gas flows, said main gas flow mainly comprising the glass-forming gases and said one or more secondary gas flows mainly comprising dopant(s),
iii) creating such conditions in the interior of the hollow glass substrate tube that deposition of glass layers on the interior of the hollow glass substrate tube takes place, and possibly
iv) subjecting the substrate tube thus obtained to a collapsing treatment so as to form a solid preform, wherein the secondary gas flow comprises an inlet flow and an outlet flow, wherein the secondary gas flow is subdivided into N subflows arranged parallel to each other, which subflows are supplied to the interior of the hollow glass substrate tube together with the main gas flow, wherein N ‰¥ 2.</p> |
