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.

An optical fiber for a fiber laser includes a core to which a rare-earth element is added, a first cladding formed around the core; and a second cladding formed around the first cladding, and excitation light is guided from at least one end of the first cladding to excite the rare-earth element to output a laser oscillation light. An addition concentration of the rare-earth element to the core is different in a longitudinal direction of the optical fiber for a fiber laser, and a core diameter and a numerical aperture of the optical fiber for a fiber laser are constant in the longitudinal direction of the optical fiber for a fiber laser.

An optical fibre, for use in the field of distributed measurement of temperature or deformation by optical reflectometry in the frequency domain using the Rayleigh backscattered signal in the fibre, includes a core doped with nanoparticles for example formed from gold particles covered with zirconium oxide, and can be subjected to high temperatures during the measurement. A method for producing the optical fibre includes a step of heat treatment during which the optical fibre is subjected, for a duration of at least one hour, to a heat treatment temperature higher than a maximum temperature to which it will be subjected during a measurement.

A method of processing an optical fiber includes drawing the optical fiber from a heated glass source, reheating the optical fiber, and cooling the optical fiber under vacuum at a cooling rate less than the cooling rate of the optical fiber in air at 25° C. and 1 atm. Cooling the optical fiber under vacuum is conducted after reheating the optical fiber. Cooling the optical fiber under vacuum reduces the rate of heat transfer from the optical fiber, which may enable further relaxation of the glass and reduction in the fictive temperature of the optical fiber. A system for processing an optical fiber includes a furnace containing a fiber preform, a first positioner, a reheating device, and a treatment device downstream of the reheating device, the treatment device operable to cool the optical fiber under vacuum to reduce the rate of heat transfer from the optical fiber.

A system for processing an optical fiber includes: a draw furnace, said draw furnace containing an optical fiber preform; a bare optical fiber drawn from said optical fiber preform, said bare optical fiber extending from said draw furnace along a process pathway; and a slow cooling device operatively coupled to and downstream from said draw furnace, said slow cooling device exposing said bare optical fiber to a slow cooling device process temperature in the range from 1000° C. to 1400° C., wherein the bare optical fiber passes through the slow cooling device at least two times.

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.

A manufacturing method for an optical fiber, includes: drawing, while heating in a heating furnace, a lower end of an optical fiber preform that is to be an optical fiber having a core consisting of silica glass containing a rare earth element compound. The heating furnace has a temperature profile in which a temperature of the heating furnace increases to a maximum temperature T.sub.max and then decreases from an upstream side of the heating furnace toward a downstream side of the heating furnace. The temperature profile has a changing point at which the temperature decreases more steeply on the downstream side from a position where the maximum temperature T.sub.max is reached. At the maximum temperature, a temperature of the silica glass is higher than or equal to a glass transition temperature and the silica glass is in a single phase.

A system for processing optical fiber includes a draw furnace, a fiber conveyance pathway extending between an upstream end positioned at the draw furnace and a downstream end positioned opposite the upstream end, where optical fiber is conveyed along the fiber conveyance pathway from the upstream end to the downstream end in a fiber conveyance direction, a muffle in communication with the draw furnace and positioned downstream of the draw furnace, a second cooling device annularly surrounding the fiber conveyance pathway downstream from the draw furnace, the second cooling device including one or more second cooling device heating elements and a first cooling device positioned between the draw furnace and the second cooling device, wherein the first cooling device directs a fluid to contact the optical fiber.

Apparatuses and methods for processing an optical fiber preform are disclosed. According to one aspect, an apparatus may generally include a muffle defining an interior volume enclosed by at least one sidewall and a handle assembly for supporting the optical fiber preform in the muffle. The handle assembly may be removably coupled to the muffle and extend into the interior volume. At least one baffle may be positioned in the interior volume and define an upper portion of the interior volume and a lower portion of the interior volume. The at least one baffle may define at least one flow channel between the upper portion of the interior volume and the lower portion of the interior volume.

The present disclosure provides the installation of an apparatus for cooling a manufactured glass rod. The apparatus has at least two cooling chambers arranged along the glass strand for sectional cooling of the glass strand. A gaseous cooling medium is either blown into the cooling chamber or sucked out of the cooling chambers. The glass strand is passed through each cooling chamber, with an orifice provided at each of the pass-through points, whose opening is larger than the cross-section or diameter of the glass strand. As a result, an annular gap forms between the opening and the surface of the glass strand, so that a turbulent flow of the gaseous cooling medium is generated, which enables a high cooling rate.