A method for elongating a glass preform for an optical fiber is provided for producing a glass rod having a smaller diameter by elongating the glass preform having a large diameter, the method including: when the glass preform having a tapered transparent glass portion at one end of a straight body of the glass preform and a tapered portion including an opaque glass portion at another end is elongated, prior to the elongating, cutting a part of the tapered portion including the opaque glass portion, wherein a cut surface of the part is a lower end of the glass preform; and welding the cut surface of the tapered portion to a pulling dummy connected to a pulling mechanism in a elongating apparatus, wherein the cut surface is circular and has an outer diameter ranging from 135 mm to 160 mm.

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 system for precoating a preform for drawing optical fiber including a diameter sensor to determine a diameter of pulled optical fiber, a cooling system to cool the optical fiber once it is pulled from a furnace, a coating system to apply a coating to the optical fiber once it has cooled and an ultra-violet lamp to cure the coating.

A system for precoating a preform for drawing optical fiber including a diameter sensor to determine a diameter of pulled optical fiber, a cooling system to cool the optical fiber once it is pulled from a furnace, a coating system to apply a coating to the optical fiber once it has cooled and an ultra-violet lamp to cure the coating.

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.

A system for precoating a preform for drawing optical fiber including a diameter sensor to determine a diameter of pulled optical fiber, a cooling system to cool the optical fiber once it is pulled from a furnace, a coating system to apply a coating to the optical fiber once it has cooled and an ultra-violet lamp to cure the coating.

A muffle for an optical fiber draw furnace. The muffle including an inner surface and an outer surface, the inner surface forming an inner cavity. A protective coating is disposed on the inner surface, the protective coating having a melting point of about 1850° C. or greater. Furthermore, an absolute difference between a coefficient of thermal expansion of the protective coating and a coefficient of thermal expansion of a material of the muffle is 2.0 ppm/° C. or less over a temperature range from 25° C. to 1000° C.

A muffle for an optical fiber draw furnace. The muffle including an inner surface and an outer surface, the inner surface forming an inner cavity. A protective coating is disposed on the inner surface, the protective coating having a melting point of about 1850° C. or greater. Furthermore, an absolute difference between a coefficient of thermal expansion of the protective coating and a coefficient of thermal expansion of a material of the muffle is 2.0 ppm/° C. or less over a temperature range from 25° C. to 1000° C.

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: t×sin θ>T1× tan θ and θ=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.

A method of manufacturing an optical fiber, the method including drawing a bare optical fiber from an optical fiber preform along a draw pathway. The method further includes during the drawing step, moving a first fluid bearing from a first position to a second position, the first position being removed from the draw pathway and the second position being disposed in the draw pathway such that the movement of the first fluid bearing to the second position causes at least a first portion of the draw pathway to change direction.