Method of manufacturing optical fiber preform using plasma torch

Abstract

A method of manufacturing an optical fiber preform by depositing glass fine particles onto a surface of a glass rod while the glass rod is reciprocated relative to a plasma torch, including: moving the glass rod in a first direction relative to the plasma torch while the plasma torch is applied to the glass rod and supplied at least with a dopant material and a glass material to deposit the glass fine particles onto the surface of the glass rod, in such a manner that a plasma power is set higher during a first time interval starting from a beginning of the movement of the glass rod in the first direction than during a second time interval starting from an end of the first time interval; and moving the glass rod in a second direction relative to the plasma torch, where the second direction is opposite to the first direction.

Description

technical field [0001] The invention relates to a method for manufacturing an optical fiber preform using a plasma torch such as a high-frequency induction thermal plasma torch. Background technique [0002] A plasma torch such as a high-frequency induction thermal plasma torch is a device in which a high-frequency coil is arranged around a gas channel tube, a high-frequency current is applied, and the gas inside is plasmatized and ejected from the torch. It is used as an ultra-high temperature reaction field because it can obtain an ultra-high temperature of about 10,000 degrees, and the plasma line speed is relatively slow. At the same time, it can freely choose an oxidizing or reducing gas environment. [0003] The optical fiber composed of pure silica glass core covered with fluorine-doped silica glass cladding is compared with the fiber composed of germanium-doped silica glass core / pure silica glass cladding , has the characteristics of high resistance to ultraviolet r...

AI Technical Summary

Problems solved by technology

As a result, the bottom of the glass rod with the rough surface cannot be provided as a raw material for optical fibers, resulting in a decrease in material utilization

[0015] In addition, if the power supplied to the plasma torch is increased in order to reduce roughness, the amount of fluorine doping in the straight barrel will decrease, and the relative refractive index difference will become smaller, resulting in poor optical properties.

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