Dehydroxylation annealing method and device of large-size optical fiber perform

Abstract

The invention discloses a dehydroxylation annealing method and device of a large-size optical fiber perform. The method comprises the following steps of (1) putting the optical fiber perform into an annealing furnace; (2) heating the optical fiber perform to a stress release temperature through temperature rises for three times; (3) carrying out heat preservation; and (4) cooling the optical fiber perform to a cooling temperature through cooling for four times. The optical fiber perform is heated to the stress release temperature through temperature rises for three times, the temperature rise rates of three stages are different and are gradually reduced according to the characteristics of the optical fiber perform and the thermal stability of the optical fiber perform can be ensured by the heating mode. The target of heat preservation is fully heating the inside of the perform to ensure the stress release reliability. The cooling rate of a front stage is lower than that of a later stage in a manner of gradual cooling for four times, and the heat in the perform can be slowly and uniformly sent out by the cooling mode, so that the optical fiber perform is effectively prevented from generating new thermal stress in a thermal stress release process.

Description

technical field [0001] The invention relates to the field of optical fiber manufacturing, in particular to a dehydroxylation annealing method and device for a large-size optical fiber preform. Background technique [0002] Large-size optical fiber preforms usually refer to optical fiber preforms with a diameter of more than 120mm and a length of more than 1500mm. Large-size optical fiber preforms are manufactured by external vapor deposition (OVD), and there will be a certain amount of hydroxyl groups in addition to internal stress. (OH), which will lead to excessive attenuation, fiber breakage, F change, etc. during the drawing process of the optical fiber preform. In view of the above situation, in the prior art, a single large-size optical fiber preform is suspended in a quartz tube, and the heating element wrapped around the quartz tube is directly heated to a certain temperature, and it is kept warm by preset a holding time, and then directly cooled cooling, so that th...

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Problems solved by technology

[0004] In order to solve the problems existing in the prior art, the present invention provides a dehydroxylation annealing method for a large-sized optical fiber preform, which can effectively solve the problem of new thermal stress generated after the optical fiber preform is reheated to remove thermal stress, and at the same time can make Hydroxyl content remains within a reasonable range

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