A glass cane is manufactured by filling a glass tube with a combination of glass structures forming a cross-sectional pattern within the glass tube, to form a preform. The preform is attached to a draw assembly, such as a draw tower. The draw assembly is operated to draw the preform to a reduced-diameter glass cane by passing the preform through a furnace of the draw assembly while pulling the preform or the reduced-diameter glass cane and rotating the preform or the reduced-diameter glass cane.

An apparatus for tensioning and threading an optical fiber includes a first roller, a second roller, a belt that wraps around the first and second rollers, and a third roller. The belt may be in direct physical contact with the first and second rollers. The third roller may be movable between an engaged and a disengaged configuration relative to the belt. Alternatively, the first roller, second roller, and belt may be movable between the engaged and the disengaged configuration relative to the third roller. Actuation from the disengaged to the engaged configuration captures an optical fiber between the third roller and the belt.

Methods of manufacturing multi-mode optical fiber, and multi-mode optical fiber produced thereby, are disclosed. According to embodiments, a method for forming an optical fiber may include heating a multi-mode optical fiber preform and applying a draw tension to a root of the multi-mode optical fiber preform on a long axis of the multi-mode optical fiber preform thereby drawing a multi-mode optical fiber from the root of the multi-mode optical fiber preform. The draw tension may be modulated while the multi-mode optical fiber is drawn from the root of the multi-mode optical fiber preform. Modulating the draw tension introduces stress perturbations in the multi-mode optical fiber and corresponding refractive index perturbations in a core of the multi-mode optical fiber.

A system for controlling an ambient microgravity environment of a system for drawing optical fiber including a filter arranged to cleanse an environment from contaminants, a molecular sieve arranged in a series of at least one of meshes and baffles to dehumidify the environment, at least one of a pump and a fan to draw an environmental gas through the filter, through the molecular sieve and back in to an ambient environment and a housing in which the filter, molecular sieve and at least one of pump and fan reside.

An optical fiber draw system and method of coating an optical fiber. The system includes a furnace for heating an optical fiber preform, a draw assembly for drawing the optical fiber at a draw speed greater than 50 meters per second, a first coating applicator for applying a first coating onto the fiber, and a first curing assembly comprising a first plurality of light sources comprising light-emitting diodes for partially curing the first coating. The optical fiber draw system also includes a second coating applicator for applying a second coating onto the fiber on top of the first coating, and a second curing system comprising a second plurality of light sources for curing the second coating, wherein the first coating is further cured in the range of 15-50 percent after leaving the first curing assembly.

A preform material including a starter tip to facilitate an initial fiber draw from the preform within a furnace, wherein the tip comprises a vacuum-sealed tip to receive a plastic grip which attached to an end of a preform.

A method of manufacturing an optical fiber of the invention includes: preparing one or more direction changers; drawing the bare optical fiber from an optical fiber preform; providing a coated layer on a periphery of the bare optical fiber; obtaining an optical fiber by curing the coated layer; changing the direction of the bare optical fiber at the position between the bare-optical-fiber formation position and the coated-layer provision position; detecting the position of the bare optical fiber in at least one of the direction changers; and adjusting the introduction flow rate of the fluid into the direction changer based on positional information obtained by the detection.

A method is disclosed of making a coated optical fiber. The method may involve drawing a preform through a furnace to create a fiber having a desired diameter and cross sectional shape. The fiber is then drawn through a slurry, wherein the slurry includes elements including at least one of metallic elements, alloy elements or dielectric elements, and the slurry wets an outer surface of the fiber. As the fiber is drawn through the slurry, it is then drawn through a forming die to impart a wet coating having a desired thickness on an outer surface of the fiber. The wet fiber is then drawn through an oven or ovens configured to heat the wet coating sufficiently to produce a consolidated surface coating on the fiber as the fiber exits the oven or ovens.

An optical fiber drawing furnace heating element includes a heat generator including: a tubular resistance heating element in which at least a part of an optical fiber preform is disposed in a through-hole; a first portion extending, from a first end portion, over a predetermined section along a longitudinal direction; and a second portion disposed closer to a second end portion than the first portion. The second portion has a wall thickness on a side of the first end portion being equal to or larger than a wall thickness of the first portion. The wall thickness of the second portion increases toward a side of the second end portion from the side of the first end portion.

An optical fiber manufacturing method includes: coating an outer periphery of a bare optical fiber with a resin before curing by a coating device; and curing the resin with a coating curing device. The following equations are satisfied: tsin >T1 tan and =tan.sup.1 (d/L), where T1 is a tension in the upstream of the coating device, t is the shear force applied to the bare optical fiber by the resin, d is the design maximum value of a deviation amount of an entry position of the bare optical fiber into the resin in the coating device with respect to the center axis of the die hole of the coating device, and L is the contact length between the resin and the bare optical fiber in the coating device along the center axis.