Optical fiber eat treatment method and device

Abstract

The invention relates to optical fiber heat treatment method and device. In the method, a maintaining furnace for thrilling the optical fibers is set to perform temperature-preservation heat treatment on optical fibers which are drawn from a fiber drawing furnace and in a high temperature and uncooled state; the temperatures of the optical fibers entering and removing from the maintaining furnace are respectively controlled to be 1400 DEG C-1800 DEG C and 1145 DEG C-1170 DEG C; the optical fibers thrill through the maintaining furnace for 0.08s-0.24s; and the temperature of the chamber of the maintaining furnace is controlled between 600 DEG C and 1300 DEG C. The maintaining furnace has a heat preservation effect on the cores of the optical fibers, the stay time of the optical fibers in an annealing temperature range is prolonged, the internal stress of the optical fibers is relieved, and the Rayleigh back scatter loss is reduced. The maintaining furnace has the advantages of simple structure and reliable performance; the inner chamber of the furnace is directly communicated with ambient air, which avoids the disturbance of protective gas in a drawing channel to the optical fibers, and thus, the stability of high-speed drawing is improved; and the equipment is simplified, and the cost is saved.

Description

technical field [0001] The invention relates to a heat treatment method and device for an optical fiber, in particular to a method and a heat treatment device for a quartz glass optical fiber, which are used to further improve the performance of the optical fiber. Background technique [0002] Attenuation and sensitivity to thermal stress are key characteristics of optical fibers, especially for high-speed long-distance communication fibers. The attenuation of the working window wavelength of the optical fiber between 600nm and 1600nm mainly comes from Rayleigh scattering. When light is incident on an inhomogeneous medium, the medium produces scattered light due to the inhomogeneous refractive index. The irregular thermal movement of molecular particles in the medium destroys the fixed positional relationship between molecules, which also produces a kind of molecular scattering, that is, Rayleigh scattering. The intensity of Rayleigh scattering is greatly affected by dopan...

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Problems solved by technology

Chinese patent CN1318337 describes a method for manufacturing an optical fiber. In this method, the cooling rate is below 2000°C / s, and the temperature of the heat treatment furnace is above 800°C and below 1600°C to heat-preserve and anneal the optical fiber, but does not specifically describe the holding time and temperature setting of the holding furnace

Chinese patent CN100336753 describes a method of manufacturing an optical fiber, which includes cooling the optical fiber at a cooling rate of 830°C / sec to 4000°C / sec, the heat treatment temperature ranges from 1100°C to 1500°C, and the processing time is between 0.025 sec and 0.5 seconds, this method requires the application of a complex muffle furnace system filled with inert gas, which is costly

Chinese patent CN100453483 describes a method of manufacturing an optical fiber, which includes cooling the optical fiber at a cooling rate of 2000°C / s to 3500°C / s, and setting the heat treatment regions to different temperatures, and the first The temperature range of the zone is 1100°C to 1300°C, and the second downstream zone has a temperature in the range of 1400°C to 1600°C. The method does not specify the length of each temperature zone and the processing time of the optical fiber in each temperature zone

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