| 摘要 |
The invention relates to a method of drying and sintering porous optical fiber preforms, especially those consisting of a solid glass core cane surrounded by a layer of cladding soot. The porous preform is heated isothermally and dried in a chlorine atmosphere. The porous preform is again isothermally heated to increase its temperature to just below that at which it would begin to rapidly densify. The temperature of the tip of the preform is then increased to sintering temperature. After the preform tip densifies and clarifies, the hot zone traverses the preform so that sintering progresses from the initially consolidated tip to the other end of the preform. By isothermally increasing the furnace temperature to just below sintering temperatures, the entire preform is preheated and, ultimately, the time subsequently required at sintering temperatures is markedly reduced.
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