FURNACE FOR MANUFACTURING OPTICAL FIBER PREFORM USING MCVD

摘要

A furnace for manufacturing an optical fiber preform using modified chemical vapor deposition is provided to prevent optical loss caused by metallic impurities, thereby producing high quality optical fiber. A furnace(100) includes a case(60) equipped with an inlet(60a) and an outlet(60b), through which a quartz tube(50) passes and a heating body(70) shielding the quartz tube(50). The heating body(70) is impregnated graphite having an impurity content of 300 ppm or less. The optical fiber preform has a diameter rate of the clad layer/core layer (D/d) of 2.0 or less. By using the optical fiber preform, high quality optical fibers having an optical loss of 0.2 dB/km at a wavelength of 1550 nm are produced.