Method for preparing doped optical fiber outer cladding layer

Abstract

The invention discloses a method for preparing a doped optical fiber outer cladding layer, and the method comprises the following steps: 1) a deposition tube and a head tube are butted by fusion, and impurities are removed; 2) one end of a core rod is provided with a groove along the length direction of the core rod, the end, which is provided with the groove, of the core rod stretches into a negative pressure suction connection pipe, and the negative pressure suction connection pipe is heated for fusion fixing with the core rod; 3) one end, which is not provided with the groove, of the core rod stretches into the deposition tube toward the direction of the head tube, and the opening of the deposition tube is heated for sealed connection of the negative pressure suction connection pipe and the deposition tube; 4) the pressure of the deposition tube is pumped to a negative pressure, a blast burner moves from the head tube to the direction of the negative pressure suction connection pipe for heating to fuse the deposition tube and the core rod together. Through arrangement of the groove on one end of the core rod, when air is pumped, the groove plays a key role, air between the deposition tube and the core rod enters the negative pressure suction connection pipe through the groove, and a negative pressure system is formed in the deposition tube, so that the deposition tube and the core rod can be reliably fused.

Description

technical field [0001] The invention relates to the field of optical fiber prefabricated rod manufacturing, in particular to a method for preparing a doped optical fiber outer cladding. Background technique [0002] In order to reduce the core-to-clad ratio of the optical fiber preform and increase the drawing length of the preform, generally after the core rod of the optical fiber preform is manufactured, a layer of outer casing will be added to the outer layer of the core rod by MCVD equipment as the preform. Outer cladding. [0003] In the process of using MCVD equipment to increase the outer cladding of the optical fiber preform, in order to achieve no bubbles and impurities on the joint surface of the deposition tube and the core rod, we need to ensure that the deposition tube and the core rod have a certain degree of cleanliness, and the preform is heated and melted in the MCVD equipment During the process, there must be a certain negative pressure inside the depositi...

AI Technical Summary

Problems solved by technology

[0005] In the existing scheme of making the cladding of the doped optical fiber preform, the through hole on the tapered slope is used to combine the tube wall of the head tube with the deposition tube so that the inside and outside of it communicate with each other for vacuuming, but the hole on the tapered slope There will be many problems in the hole, because the stress at the opening position is particularly large. One of the serious problems is that the tapered slope is easy to crack, which seriously affects the subsequent process.

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