Process and apparatus for producing optical fiber preform by plasma deposition

Abstract

A method and apparatus for increasing the overcladding rate in optical fiber preform production while maintaining the integrity of the cladding glass quality. Two plasma torches are used, instead of just one, that are driven by the same power generator. The process includes the steps of supporting the preform on a lathe; providing first and second plasma torches having nozzles angled toward the preform; powering first and second plasma torches with a common generator such that the plasma torches create plasma flames directed toward a surface of the preform; introducing a quartz sand at a junction between the first plasma torch or alternatively between both torches, and to fuse the quartz sand on the surface of the preform; and moving the preform with respect to the plasma torches. The second plasma torch may be provided upstream of the first plasma torch so as to preheat the surface before the fusing of the quartz sand by the first plasma torch, or may be located downstream thereof to post-heat the quartz sand after the initial fusing by the first plasma torch.

Description

field of invention [0001] The present invention relates to a method and related apparatus for increasing the external deposition rate in preform production while maintaining perfect glass quality of the deposited layer. Background technique [0002] Due to market pressure to reduce the price of optical fiber, there is a constant need to increase the overall productivity of the manufacturing process. One of the most important steps in the process of manufacturing optical fibers is plasma processing. The process involves melting quartz sand over an initial preform with the aid of a high-temperature plasma fireball, forming a deposited layer that makes more than 90 percent of the glass preform. [0003] There are two parameters associated with this process. The first is the glass deposition rate (g / min), and the second is the quality of the deposited glass. For a particular process, these two parameters are in opposition to each other. Specifically, glass quality deteriorat...

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Problems solved by technology

Therefore the full capacity of the generator cannot be utilized, and the deposition rate and glass quality are limited

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