A kind of preparation method of optical fiber preform

Abstract

The invention discloses a production method of a prefabricated fiber rod. The prefabricated fiber rod is produced through a vapor axial deposition technology. The method comprises the following steps: depositing a core layer by using a core layer blowtorch, and depositing a wrapping layer by using a wrapping layer blowtorch. The core layer blowtorch is connected with a core layer raw gas conveying pipeline, the wrapping layer blowtorch is connected with a wrapping layer raw gas conveying pipeline, the core layer raw gas conveying pipeline is connected with an oxygen conveying pipeline in parallel, the oxygen conveying pipeline is serially connected with a glass tube, and an alkali metal raw material is placed in the glass tube; the periphery of the glass tube is provided with a heater; and when the core layer is deposited, the heater and the oxygen conveying pipeline are started, oxygen carrying the alkali metal raw material volatilizing after being heated enters the core layer raw gas conveying pipeline, and deposits through the core layer blowtorch to form the alkali-doped prefabricated fiber rod core layer. Alkali metal doping is carried out in the deposition process of the core layer, and the content distribution of the alkali metal is uniform, so the problem of non-uniform distribution of the alkali metal in the glass tube in diffusion methods is solved, and the fiber attenuation is obviously reduced.

Description

technical field [0001] The invention relates to a method for preparing an optical fiber preform, belonging to the technical field of optical fiber communication. Background technique [0002] Optical fiber communication has the characteristics of large transmission capacity, long transmission distance, and fast transmission speed, and is widely used in optical communication networks such as long-distance trunk networks, metropolitan area networks, and access networks. Reducing the optical fiber attenuation coefficient can effectively increase the transmission distance of the optical fiber communication system, greatly reduce the number and cost of relay stations, and is of great significance for optimizing the structure of the transmission system and reducing operating costs. How to reduce the optical fiber attenuation coefficient has become a hot research topic for major optical fiber manufacturers. [0003] The existing technologies for reducing the fiber attenuation coef...

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Problems solved by technology

Document US9250386B2 puts alkali metal raw materials into the inner wall of the glass tube, heats the outer wall of the glass tube, and diffuses alkali metal oxides into the glass, so that the attenuation of the optical fiber at 1550nm can reach below 0.17dB / km The alkali metal doped by this heating diffusion method forms a concentration gradient on the inner and outer walls of the glass, and the distribution is uneven

文献US20140127507A1、US9229160B2、CN102627400B、CN102603179A、CN102627398A、CN103502164A、CN104093674A、CN102617033A、CN103502164A和CN102730977A均通过连续移动的热源加热玻璃管内的碱金属原料,通过扩散在玻璃管内壁掺入碱金属,掺杂工艺复杂

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