Rod shrinking method for producing optical fiber prefabricated rod

Abstract

The invention discloses a rod shrinking method for producing an optical fiber prefabricated rod. The rod shrinking method comprises the following steps: introducing raw material gas into a through hole in a quartz base pipe from one end of the quartz base pipe, wherein a tail exhausting pipeline is connected to the other end of the quartz base pipe, and a compensating gas pipeline is further communicated to the tail exhausting pipeline; introducing gas from the compensating gas pipeline to the tail exhausting pipeline to generate positive pressure in the through hole of the quartz base pipe, heating the quartz base pipe by virtue of a blowtorch to enable the raw materials to react to deposit on the inner wall of the through hole of the quartz base pipe, and after the deposition is finished, heating the quartz base pipe by virtue of the blowtorch to enable a fused glass body to collapse inwards, so as to form the solid optical fiber prefabricated rod. According to the rod shrinking method, gas exhausted out of the tail exhausting pipeline is compensated by virtue of the compensating gas pipeline during the deposition, and positive pressure is guaranteed in the through hole of the quartz base pipe in the deposition process, so that the shrinkage force of a quartz pipe is counteracted, an uniform inner cladding layer and a uniform core layer are deposited, the situation that the prefabricated rod is shrunk to be oval is avoided, and the machining quality is improved.

Description

technical field [0001] The invention relates to the field of optical fiber technology, in particular to a shrinkage method for making an optical fiber preform. Background technique [0002] The MCVD method is a method in which high-purity useful gas with oxygen as the carrier is used in a rotating quartz substrate tube to obtain solid-phase deposition by high-temperature vapor-phase oxidation reaction. High-purity gas SiCl 4 、GeCl 4 and carrier gas O 2 Send them together into the rotating quartz substrate tube, and the high-temperature hydrogen-oxygen flame moves back and forth outside the tube, causing the material in the tube to oxidize at high temperature to form dust-like oxide SiO 2 or GeO 2 etc., and deposited on the inner wall of the tube, when the high-temperature zone of the flame passes through here again, a uniform and transparent quartz glass film layer is formed on the inner wall of the tube, and chlorine gas and unreacted materials are discharged from the t...

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Problems solved by technology

[0004] The technical problem to be solved and the technical task proposed by the present invention are to improve the prior art, provide a shrinkage method for making an optical fiber preform, and solve the shrinkage problem in the current technology when the deposited quartz substrate tube is shrunk. Unbalanced, it is easy to cause the problem that the optical fiber preform becomes elliptical

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