Method and device for making prefabricated optical fibre

Abstract

The present invention relates to a production method of optical fibre prefabricated member and its equipment. It is characterized by that the upper portion of the ball reaction container whose side surface is equipped with exhaust opening and lower portion is equipped with spray gun is connected with flange tube in which an air flow regulating component is set. The seed rod is placed in the reaction container through flange tube and is directed at spray gun, and then the commutating air flow whose pressure is 0.5X10 to the power 5-2.0X10 to the power 5 Pa and temp. is 20-600 deg.C is downward introduced from upper end of flange tube, and can be passed through the air flow regulating component and flowed along the inner wall of the flange tube and reaction container, then discharged from exhaust opening so as to eliminate inordinance of air flow.

Description

【Technical field】 [0001] The invention relates to a method and device for manufacturing an optical fiber preform, belonging to the field of optical fiber manufacturing. 【Background technique】 [0002] Inorganic optical fibers have been widely used in the communication industry, among which quartz-based optical fibers have become the leading inorganic optical fibers due to their advantages such as low optical loss, wide range of applicable light waves, and adaptability to long-distance communication. Among the methods for manufacturing quartz-based optical fiber preforms, there is a vapor phase axial deposition method (VAD method). The manufacturing device used in it includes a reaction vessel with an exhaust port. A spray gun is used to vertically set seed rods in the reaction vessel. When manufacturing optical fiber preforms, place the seed rod vertically in the reaction vessel corresponding to the spray gun, pass hydrogen and oxygen into the spray gun and ignite in the re...

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Problems solved by technology

The degassing effect of this manufacturing method and device is poor, making it impossible to deposit formed SiO 2 (Silicon dioxide), GeO 2 (germanium dioxide) particles are more trapped in the reaction vessel, resulting in the following defects:

[0004] 2. As the deposition length of the optical fiber preform increases, the remaining SiO not deposited on the preform 2 、GeO 2 Particles are continuously deposited on the wall of the reaction vessel with lower temperature (especially on the upper side of the exhaust port) to form a mirror surface, which reflects heat, causing the temperature in the reaction vessel to rise gradually, which eventually leads to an unstable deposition process and fluctuations in the deposition rate

[0005] 3. Remaining SiO not deposited onto the preform 2 、GeO 2 Particles will also adhere to the preform that has been deposited and formed, which causes the inhomogeneous growth of the optical fiber preform along the axial direction, such as the core-to-core ratio everywhere along the axial direction (that is, the cylindrical outer shell with different optical refractive indices). The ratio of layer to inner layer diameter) fluctuates greatly

[0006] 4. Due to the SiO deposited on the inner wall of the reaction vessel 2 、GeO 2 The particles are peeled off and attached to the surface of the optical fiber preform being deposited to form a less dense area. When the optical fiber preform is vitrified in the subsequent process, bubbles will be generated in this area, which will cause the optical fiber preform to be pulled Fiber breakage occurs during the process of making optical fibers

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