| 摘要 |
PURPOSE:To provide a glass preform for a low-loss optical fiber with the glass defects reduced. CONSTITUTION:The raw gas is flame-hydrolyzed and deposited on a rotating starting member to form a deposit 2 of fine glass particles, the deposit 2 is dehydrated, then sintered and vitrified to obtain a transparent glass body, and a glass preform for an optical fiber with the core contg. Ge is produced. In this case, the bulk density of the deposit 2 is controlled to 0.35-0.1g/cm<2> before dehydration. Otherwise, the bulk density is attained when the deposit is formed, or the deposit 2 having an ordinary bulk density is contracted by heating before dehydration to increase its bulk density to the desired value. A low-loss optical fiber with the glass defects decreased is obtained by inhibiting the reduction reaction of GeO2. |
