Method and apparatus for producing optical fiber preform

Abstract

The invention relates to a method and an apparatus for producing optical fiber preform. The invention provides a method for producing optical fiber preform which can produce large excellent preform with low burner load through stabilization of flames of a burner. When a multi-nozzle is used for producing optical fiber preform, gas flow speed is controlled in such a way that a gas flow rate of a raw material gas ejection port is V1 and a gas flow rate of a seal gas ejection port is V2, and 1>V2 / V1>0.05. The multi-nozzle burner includes a raw material gas ejection port in a central part for ejecting a raw material gas. The multi-nozzle burner includes a seal gas ejection port on an outer side of the raw material gas ejection port for ejecting a seal gas. The multi-nozzle burner includes a combustible gas ejection port on an concentric outer side of the seal gas ejection port annularly for ejecting a combustible gas. The multi-nozzle burner includes a plurality of small diameter combustion supporting gas ejection ports surrounding the seal gas ejection port in the combustible gas ejection port for ejecting a combustion supporting gas.

Description

technical field [0001] The present invention relates to a manufacturing method and manufacturing apparatus of an optical fiber preform, which enable the manufacture of a high-quality large-scale preform with a low burner load by stabilizing a burner flame. Background technique [0002] In the VAD method, which is a well-known manufacturing method for optical fiber preforms, a starting member is mounted on a shaft that rises while rotating, and hangs down into the reaction chamber to make the glass produced by the core deposition burner and the cladding deposition burner. Particles are attached and deposited on the front end of the starting member, thereby manufacturing a porous glass base material formed by a core layer and a clad layer (clad), wherein the core deposition burner and the clad deposition burner are arranged in the reaction chamber, and Set at a predetermined angle with respect to the axial direction of the starting part. The VAD method is suitable for the enl...

AI Technical Summary

Problems solved by technology

[0006] In each burner of such a manufacturing device, a concentric multi-tube burner made of quartz glass is usually used, but in a burner with a concentric multi-tube structure, the glass raw material gas, combustible gas, and combustion-supporting gas are not sufficiently heated. Mixing, so the generation of glass particles is not sufficient

Therefore, the deposition efficiency is poor, and it is difficult to manufacture the base material at high speed

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