Abstract: A method for manufacturing a base material of optical fibres having a desired ratio of core to clad, including forming a porous base material upon depositing glass particles, producing a core member upon dehydrating and vitrifying the porous base material, adding a clad member onto the core member, is characterized in that the method includes, a step of dehydrating the porous base material in an atmosphere of gas including helium and chlorine within an electric furnace; a step of vitrifying the porous base material in an atmosphere of inert gas including helium; and a step of providing a purging step of heating the porous base material in an atmosphere of inert gas mainly including helium between the dehydrating step and the vitrifying step.

Abstract: A method for manufacturing a preform, which is a base material of an optical fiber, comprising: forming porous-glass-base-material by accumulating glass particles; dehydrating the porous-glass-base-material by heating the porous-glass-base-material in an atmosphere of gas that contains chlorine; heating the porous-glass-base-material dehydrated by the dehydrating with a first heating temperature in an atmosphere of a first inert gas; and vitrifying the porous-glass-base-material by heating the porous-glass-base-material with a second heating temperature in an atmosphere of second inert gas.

Abstract: An apparatus for fabricating a soot preform for an optical fiber. The soot preform is fabricated by depositing glass particles on a starting rod capable of being rotated and pulled up. The apparatus comprises elements as follows. A reaction chamber is used for depositing the glass particles on the starting rod. An upper room is located above the reaction chamber for receiving the soot preform formed in the upper portion of the reaction chamber. At least one core burner is installed in the reaction chamber. A gas-supplying inlet is located in the top part of the sidewall of the reaction chamber closest to burner(s), and a gas-exhausting outlet is located in the top part of another sidewall opposite to the gas-supplying inlet. In addition, at least one cladding burner is installed in the reaction chamber.

Abstract: A method for manufacturing a base material for an optical fiber, includes steps of: holding a bar material by a support member; and adjusting to reduce a difference between an axis of the bar material and a rotational axis of the support member. Furthermore, an optical fiber base material grasping apparatus for holding a bar material having an axis, includes: a support member having a center axis, the support member being rotatable around the center axis; and an adjusting mechanism for reducing a difference between the axis of the bar material and the central axis of the support member.