PRODUCTION OF OPTICAL FIBER PREFORM AND SINTERING FURNACE

摘要

PURPOSE: To provide a process for producing an optical fiber preform constituted to continuously execute sintering and subsequent cooling within the same muffle in a process for producing the optical fiber preform. CONSTITUTION: The part 2b upper than the heating means installing section of the muffle 2 installed with the heating means 3 on its outer periphery is so formed as to be made properly dividable by a shutter mechanism 4. Sintering is executed by opening this shutter mechanism 4 and inserting the perforated optical fiber preform from above at the time of sintering. The optical fiber preform 13 is pulled up to the upper part 2b of the muffle 2 and the shutter mechanism 4 is closed at the time of cooling the optical fiber preform 13 vitrified to transparent glass after the sintering. A cooling gas is then supplied from the outside into the upper part 2b of the muffle 2 to cool the optical fiber preform 13 in the muffle 2.