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.

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 at least one laser beam is applied to a working zone of the drawn preform, each laser beam being power-modulated according to a modulation frequency. A device for manufacturing an optical fibre is also provided.

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 at least one laser beam is applied to a working zone of the drawn preform, each laser beam being power-modulated according to a modulation frequency. A device for manufacturing an optical fibre is also provided.

An optical fiber drawing method where a glass base material passes through an opening provided in a drawing furnace from the material side and drawing is performed by suspending and descending the material into the drawing furnace while being sealed by a sealing mechanism provided in the vicinity of the opening, in which a first portion of the sealing mechanism seals a gap between an outer peripheral surface of the material and an inner surface of the opening when drawing starts and a tapered portion of the material starts passing through the first portion, and a second portion is disposed above the first portion before sealing by the first portion becomes ineffective, and then conduction between inside and outside of the drawing furnace is carried out to prevent fluctuation of pressure inside the furnace immediately after disposing the second portion and the conduction is interrupted when the material further descends.

An optical fiber drawing method where a glass base material passes through an opening provided in a drawing furnace from the material side and drawing is performed by suspending and descending the material into the drawing furnace while being sealed by a sealing mechanism provided in the vicinity of the opening, in which a first portion of the sealing mechanism seals a gap between an outer peripheral surface of the material and an inner surface of the opening when drawing starts and a tapered portion of the material starts passing through the first portion, and a second portion is disposed above the first portion before sealing by the first portion becomes ineffective, and then conduction between inside and outside of the drawing furnace is carried out to prevent fluctuation of pressure inside the furnace immediately after disposing the second portion and the conduction is interrupted when the material further descends.

Provided is a method of fabricating an optical fiber glass base material, the method including a first step for dehydrating an optical fiber porous base material while causing a gas that includes at least a halogen or argon to distribute within a quartz core tube that accommodates the optical fiber porous base material; a second step for, after the first step, at least partially ventilating within the quartz core tube by causing a gas having helium as a main component to distribute within the quartz core tube; and a third step for, after the second step, transparently vitrifying the optical fiber porous base material while causing the gas having helium as a main component to distribute within the quartz core tube.

Provided is a method of fabricating an optical fiber glass base material, the method including a first step for dehydrating an optical fiber porous base material while causing a gas that includes at least a halogen or argon to distribute within a quartz core tube that accommodates the optical fiber porous base material; a second step for, after the first step, at least partially ventilating within the quartz core tube by causing a gas having helium as a main component to distribute within the quartz core tube; and a third step for, after the second step, transparently vitrifying the optical fiber porous base material while causing the gas having helium as a main component to distribute within the quartz core tube.

The present invention relates to a flexible sealing assembly (100) for an optical fiber draw furnace (500) comprising a first plurality of curved ring sections (110) arranged in a circular arrangement and a plurality of tension loaders (114) exerting continuous radially inward force on at least one curved ring section. Each curved ring section of the first plurality of curved ring sections (110) is separated from each other and defined by the same radius of curvature. Further, the first plurality of curved ring sections (110) is radially movable such that the first plurality of curved ring sections (110) creates a seal between a glass preform (504) and a vertical hollow body (506) in the optical fiber draw furnace (500). The diameter of the glass preform (504) varies.

This seal structure of a wire drawing furnace for an optical fiber is for sealing a gap between an upper end opening of the wire drawing furnace for an optical fiber and a glass base material for an optical fiber inserted from the upper end opening into a furnace core tube. This seal structure has: a plurality of blade members circumferentially arranged in contact with a circumferential side surface of the glass base material for an optical fiber; a guide member, provided around the plurality of blade members, for allowing the plurality of blade members to slide linearly toward the circumferential side surface of the glass base material for an optical fiber; and a pushing/pulling action mechanism that causes the blade members to move in the radial direction of the glass base material for an optical fiber. The center of gravity of the plurality of blade members is located behind the tip surface of the guide member.

This seal structure of a wire drawing furnace for an optical fiber is for sealing a gap between an upper end opening of the wire drawing furnace for an optical fiber and a glass base material for an optical fiber inserted from the upper end opening into a furnace core tube. This seal structure has: a plurality of blade members circumferentially arranged in contact with a circumferential side surface of the glass base material for an optical fiber; a guide member, provided around the plurality of blade members, for allowing the plurality of blade members to slide linearly toward the circumferential side surface of the glass base material for an optical fiber; and a pushing/pulling action mechanism that causes the blade members to move in the radial direction of the glass base material for an optical fiber. The center of gravity of the plurality of blade members is located behind the tip surface of the guide member.