FURNACE OF DEHYDRATING AND SINTERING OPTICAL FIBER PREFORM AND METHOD OF DEHYDRATING AND SINTERING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a furnace of dehydrating and sintering an optical fiber preform in which a gas inside a core tube can not leak out to a furnace body side and a gas at the furnace body side can not leak out to the inside of the core tube. SOLUTION: A method of dehydrating and sintering the optical fiber preform by arranging the core tube 3 in the furnace body 7, the core tube is constituted of a first core tube 3 and a second core tube 4 each coaxially arranged, and the pressure of an intermediate room 10 provided between the first core tube 3 and the second core tube 4 is set to a pressure lower than not only the pressure of the inside 8 of the first core tube but also the pressure of a space 9 of the furnace body 7, and the supply 13 of gas to the intermediate room 10 and the discharge therefrom are carried out independently.