Patent ID: 8561431

Claim:
A method of manufacturing an optical fiber base material, comprising the steps of: depositing glass particles to form a base material; dehydrating and transparently vitrifying the base material to form a core member; drawing the core member; and forming a cladding material on the drawn material at a predetermined core to cladding ratio, wherein the dehydrating step comprises suspending the base material in a quartz furnace tube having a heating region in a first atmosphere at a first temperature and moving the base material through the heating region in an upward motion, wherein the transparently vitrifying step comprises passing the dehydrated base material through the heating region in a second atmosphere at a second temperature in an upward motion, wherein the base material moves during the dehydrating step and the transparently vitrifying step in the same direction as a gas flowing direction in the quartz furnace tube, the second temperature is in the range between 1300 and 1600 degrees Celsius while the first temperature is in the range between 900 and 1200 degrees Celsius, and the first atmosphere comprises chlorine of 10% by volume and an inert gas of 90% by volume, while the second atmosphere comprises an inert gas of 100% by volume.