本报告皆在阐述VAD光纤实现低损耗时重要的脱水透明化技术。本文首先叙述了研制伊始就作为重要的基本研究课题——玻璃透明化过程。通过对制定的简单模式进行分析,弄清了周围环境气体透过率的效果以及温度上升的影响因素。其次,围绕讨论脱水处理方法和有关装置改进的问题阐述了脱水处理技术,明确了包括技术开发经过在内的低羟基VAD光纤制造技术要点,从而获得了OH离子残留浓度为0.008ppm、最低损耗为0.25dB/km(.6μm)的低羟基光纤。 This report addresses the important dewatering and clearing techniques for VAD fibers for low loss. This article first describes the beginning of development as an important basic research topic - the process of glass transparency. Through the analysis of the simple model developed, the effects of ambient gas transmission rate and the factors of temperature rise were clarified. Secondly, the dehydration technology was elaborated on the issues of dewatering treatment and related device improvement. The key points of technology for manufacturing low-VAD optical fiber including technology development were clarified. The residual OH ion concentration was 0.008ppm and the minimum loss was 0.25 dB / km (.6 μm) low-density optical fiber.