Methods and apparatus for producing fibers from igneous rock, including basalt include heating igneous rock by electrical conductive coils to achieve an homogenous melt and forming homogenous fibers from the melt.

To restrict deterioration of non-circularity in a constricted portion of an optical fiber preform, provided is an optical fiber preform manufacturing method including introducing inert gas along a surface of the optical fiber preform, causing the inert gas to circulate around the optical fiber preform with an axis of the optical fiber preform in a longitudinal direction as a center, and heating the optical fiber preform in an inert gas environment. In this manufacturing method, the inert gas may be introduced in a direction parallel to a tangent line of the optical fiber preform in a plane orthogonal to the axis.

Methods and apparatus for producing fibers from igneous rock, including basalt include heating igneous rock by electrical conductive coils to achieve an homogenous melt and forming homogenous fibers from the melt.

A wire-drawing optical fiber base material manufacturing method of heating an optical fiber base material by a heater and forming a drawing shape portion at an end portion. The manufacturing method includes: forming, by a flow-regulating member disposed adjacent to the heater, a gas flow such that formation, along a surface of the optical fiber base material, of a flow of a gas containing a Si compound generated from the optical fiber base material heated by the heater is inhibited; and forming, while maintaining the gas flow, the drawing shape portion by pulling part of the optical fiber base material softened by being heated by the heater.

A wire-drawing optical fiber base material manufacturing method of heating an optical fiber base material by a heater and forming a drawing shape portion at an end portion. The manufacturing method includes: forming, by a flow-regulating member disposed adjacent to the heater, a gas flow such that formation, along a surface of the optical fiber base material, of a flow of a gas containing a Si compound generated from the optical fiber base material heated by the heater is inhibited; and forming, while maintaining the gas flow, the drawing shape portion by pulling part of the optical fiber base material softened by being heated by the heater.

Methods and apparatus for producing fibers from igneous rock, including basalt include heating igneous rock by electrical conductive coils to achieve an homogenous melt and forming homogenous fibers from the melt.

Methods and apparatus for producing fibers from igneous rock, including basalt include heating igneous rock by electrical conductive coils to achieve an homogenous melt and forming homogenous fibers from the melt.

The present invention relates to a method (200, 400, 500, 600) for drawing a bare optical fiber (118) from a cylindrical glass preform (102) in a furnace chamber (104) by hanging the cylindrical glass preform (102) near a first end (104a) of the furnace chamber (104), injecting first and second inert gasses inside the furnace chamber (104) in a predefined ratio of 0.3 to 5, and melting the cylindrical glass preform (102) while maintaining a positive pressure in the furnace chamber (104) to form the bare optical fiber (118) such that a Bare Fiber Diameter (BFD) variation of the bare optical fiber (118) is less than 0.1 micrometers (?m) from a mean diameter of the bare optical fiber (118).

A wire-drawing optical fiber base material manufacturing method of heating an optical fiber base material by a heater and forming a drawing shape portion at an end portion. The manufacturing method includes: forming, by a flow-regulating member disposed adjacent to the heater, a gas flow such that formation, along a surface of the optical fiber base material, of a flow of a gas containing a Si compound generated from the optical fiber base material heated by the heater is inhibited; and forming, while maintaining the gas flow, the drawing shape portion by pulling part of the optical fiber base material softened by being heated by the heater.

A wire-drawing optical fiber base material manufacturing method of heating an optical fiber base material by a heater and forming a drawing shape portion at an end portion. The manufacturing method includes: forming, by a flow-regulating member disposed adjacent to the heater, a gas flow such that formation, along a surface of the optical fiber base material, of a flow of a gas containing a Si compound generated from the optical fiber base material heated by the heater is inhibited; and forming, while maintaining the gas flow, the drawing shape portion by pulling part of the optical fiber base material softened by being heated by the heater.