An optical fiber manufacturing method includes: a drawing step of heating one end portion of an optical fiber preform to melt and deform the one end portion and drawing an optical fiber, wherein in the drawing step, drawing is performed while applying pressure to a melted-deformed portion that is melted and deformed.

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.

A preform for making a vortex optical fiber comprises a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.

A fiber draw furnace includes a heated section configured to contain and heat a glass source from which an optical fiber is drawn. A lower extended muffle having a first end and a second end. A gas screen is coupled to the second end of the lower extended muffle configured to allow a gas to flow into the lower extended muffle. A reclaim cylinder is coupled to the lower extended muffle including an outer housing defining a reclaim chamber. A plurality of reclaim ports are tangentially coupled to the outer housing and an inner housing is positioned within the outer housing.

The present invention, as disclosed and described herein, in one aspect thereof comprises a preform for making a vortex optical fiber includes a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.

It is an object of the present invention to allow a furnace core tube used for a heat treatment apparatus of a porous glass base material to be used for a long period of time.

A heat treatment apparatus includes: a furnace core tube made of silica glass; a heater provided adjacent to the furnace core tube, the heater heating a heating region; and a moving mechanism supporting a porous glass base material and relatively moving the porous glass base material with respect to the heater in the furnace core tube in a state where the heating region is heated by the heater to make the porous glass base material pass through the heating region. The heat treatment apparatus includes a thin-walled part provided in a region adjacent to a portion located in the heating region in the furnace core tube, the thin-walled part having a thickness of glass less than that of the portion located in the heating region.

A method for manufacturing an optical fibre, in which a preform is inserted into a furnace; the preform is drawn via an outlet of the furnace; and the drawn preform has a working area including a structure composed of walls, and gas streams are applied to the two opposite faces of these walls, which streams run along the walls in opposite directions, so as to subject the walls to a shear force of gas streams counter-propagating on either side of the walls. A device for manufacturing an optical fibre is also provided.

Optical fiber draw production systems, pressure devices, and methods of fabrication of optical fiber are disclosed. In one embodiment, a method of forming an optical fiber includes heating a preform to draw the optical fiber through a draw furnace, and passing the optical fiber through a pressure device while the optical fiber is still forming, wherein a pressure within the pressure device is greater than an atmospheric pressure.

The invention generally relates to optical fibers, and, more particularly, to hollow-core optical fibers and cables for use in high-speed data transmission, including transmission of telecommunications data, and methods of manufacturing such hollow-core optical fibers and cables.

A fiber draw furnace includes a heated section configured to contain and heat a glass source from which an optical fiber is drawn. A lower extended muffle having a first end and a second end. A gas screen is coupled to the second end of the lower extended muffle configured to allow a gas to flow into the lower extended muffle. A reclaim cylinder is coupled to the lower extended muffle including an outer housing defining a reclaim chamber. A plurality of reclaim ports are tangentially coupled to the outer housing and an inner housing is positioned within the outer housing.