Tapered core fibers are produced using tapered core rods that can be etched or ground so that a fiber cladding has a constant diameter. The tapered core can be an actively doped core, or a passive core. One or more sleeving tubes can be collapsed onto a tapered core rod and exterior portions of the collapsed sleeving tubes can be ground to provide a constant cladding diameter in a fiber drawn from the preform.

Described are systems and techniques for characterizing optical fibers. Disclosed systems and techniques employ optical metrology, functional metrology, or both to characterize microstructured optical fibers and determine fiber characteristics, errors, and quality control metrics. The characteristics, errors, and quality control metrics are useful for improving the manufacturing of optical fibers.

A system for drawing optical fiber in microgravity including a sealed housing to prevent infiltration of at least humidity and filled with a dry environment, a preform holder located within the sealed housing to hold preform material, a furnace located within the sealed housing to receive the preform material from the preform holder and to heat the preform material from which the optical fiber is pulled, a feed system to move the preform material from the preform holder to the furnace, a drawing mechanism located within the sealed housing to pull the optical fiber from the preform material within the furnace, a diameter monitor located within the sealed housing to measure a diameter of the optical fiber and a fiber collection mechanism located within the sealed housing to gather and store the optical fiber.

A technique for fabricating a hollow core optical fiber with a controllable core region (in terms of diameter) is based upon regulating conditions (gas flow, volume, and/or temperature) within the hollow core region during the fiber draw process. The introduction of a gas, or any change in volume or temperature of the hollow core region, allows for the diameter of the hollow core region to self-regulate as a multistructured core rod (MCR) is drawn down into the final hollow core optical fiber structure. This self-regulation provides a core region having a diameter that selected and then stabilized for the duration of the draw process. The inventive process is also useful in controlling the diameter of any selected hollow region of an MCR including, but not limited to, shunts and corner capillaries disposed around the core region.

A method for manufacturing an optical fiber includes: gripping a preform by a gripper that includes an aligner; forming a bare fiber by melting the preform in a melting furnace; cooling the bare fiber by blowing gas in a cooler; applying a resin and coating an outer circumference of the bare fiber; curing the resin; acquiring input information that changes a flow rate of the gas blown to the bare fiber in the cooler; and adjusting based on the input information an entry position of the bare fiber into the cooler by controlling the aligner and moving the preform.

A light diffusing optical fiber includes a core, a cladding surrounding the core, an outer surface, and a plurality of scattering structures positioned within the core, the cladding, or both the core and the cladding. The plurality of scattering structures are configured to scatter guided light towards the outer surface, such that light including a wavelength of from about 450 nm to about 650 nm diffusing through the outer surface along a diffusion length of the light diffusing optical fiber includes a spectral attenuation percent relative range of about 15% or less.

An optical fiber manufacturing method includes: drawing an optical fiber preform to form a bare optical fiber; cooling the bare optical fiber by a non-contact direction changer; adjusting a temperature of the bare optical fiber in a temperature adjusting unit disposed downstream of the non-contact direction changer and upstream of a coating unit; disposing, in the coating unit, an uncured coating layer that comprises a resin precursor on an outer periphery of the bare optical fiber; and curing the uncured coating layer in a curing unit.

A method for manufacturing an optical fiber includes: heating an optical fiber preform to draw glass fiber; measuring an outer diameter of the glass fiber to obtain a function of time; transforming the function of time into a function of frequency; identifying a first peak caused by a first drawing condition and a second peak caused by a second drawing condition in the function of frequency; and adjusting the second drawing condition so as to satisfy fn<fm−wm/2 or fn>fm+wm/2, where fm is a frequency of the first peak, wm is a full width at half maximum of the first peak, and fn is a frequency of the second peak.

A method of processing an optical fiber includes drawing the optical fiber from an optical fiber preform within a draw furnace, the optical fiber extending from the draw furnace along a process pathway, the optical fiber comprising at least one halogen-doped core; and drawing the optical fiber through at least one slow cooling device positioned downstream from the draw furnace at a draw speed. The at least one slow cooling device exposes the optical fiber to a slow cooling device process temperature greater than or equal to 800° C. and less than or equal to 1600° C. The draw speed is such that the optical fiber has a residence time of at least 0.1 s in the at least one slow cooling device. An optical fiber made by such a process is also disclosed.

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.