High-Speed Glass Fiber Drawing from Heated and Softened Silica Preform in an Optical Fiber Draw Furnace

摘要

Modern manufacturing of optical fibers starts with the glass fiber drawing process from the highly purified silica preform in a draw furnace. A preform of rod shape is continuously fed into the furnace, and very thin glass fiber is pulled from the heated and softened preform by applying a proper amount of draw tension, while the neck-down region of preform experiences a drastic diameter change. In this article, heating of preform in neck-down region and glass fiber drawing from the softened preform is numerically simulated by using the iterative computational scheme between the one-dimensional model for preform neck-down profile and the two-dimensional flow and heat transfer computations on the helium/argon working gas and preform inside the inner furnace geometry of preform feeding, preform heating, and glass fiber cooling tubes. The computational results for the typical glass fiber drawing conditions yield the expected preform neck-down profile and the draw tension on the glass fiber. The effects of the heating conditions of the furnace heating element such as heating temperature and heating width on the glass fiber drawing process are also studied and discussed in order to investigate the working conditions of a high speed optical fiber drawing system.