A method and corresponding apparatus for processing optical fiber include directing light from a directed light source toward an optical fiber on a fiber draw. A fiber core of the optical fiber is heated, using at least the light from the directed light source, to a fiber core temperature within a glass transformation temperature range of the fiber core. The method can be used to reduce fictive temperature of the fiber core, with Rayleigh scattering being reduced, leading to lower attenuation losses in the fiber core.

A method and corresponding apparatus for processing optical fiber include directing light from a directed light source toward an optical fiber on a fiber draw. A fiber core of the optical fiber is heated, using at least the light from the directed light source, to a fiber core temperature within a glass transformation temperature range of the fiber core. The method can be used to reduce fictive temperature of the fiber core, with Rayleigh scattering being reduced, leading to lower attenuation losses in the fiber core.

Provided is a method of processing a glass base material for optical fiber in which the glass base material for optical fiber is elongated to reduce a diameter thereof until reaching a final elongation diameter and form a completed base material. The method includes measuring an outer diameter distribution that includes an outer diameter of the glass base material for optical fiber; setting an effective region; calculating a target elongation diameter that is larger than the final elongation diameter and less than an average diameter of the effective region, and elongating the glass base material for optical fiber until reaching the target elongation diameter; and after reaching the target elongation diameter, further elongating the glass base material for optical fiber until reaching the final elongation diameter.

A method for temperature measurement includes measuring intensities of two adjacent wavelengths emitted from a heated optical fiber and calculating the thermal population distribution between associated energy levels.

Aspects of the embodiments are directed to systems and methods for forming an optical fiber in a low gravity environment, and an optical fiber formed in a low gravity environment. The system can include a preform holder configured to secure a preform; a heating element secured to a heating element stage and residing adjacent the preform holder; a heating element stage motor configured to move the heating element stage; a tension sensor; a spool; a spool tension motor coupled to the spool and configured to rotate the spool; and a control system communicably coupled to the heating element stage motor and the spool tension motor and configured to control the movement of the heating element stage based on a rotational speed of the spool. The optical fiber can include a fluoride composition, such ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN), and can be characterized by an insertion loss in a range from 13 dB/1000 km to 120 dB/1000 km.

An optical fiber manufacturing method includes: melting and drawing an optical fiber preform to form a glass fiber; cooling the glass fiber while inserting the glass fiber into a tubular slow-cooling device from an inlet end toward an outlet end thereof, and lowering an inner wall temperature of the slow-cooling device below a temperature of the glass fiber and providing a pressure gradient in which a pressure increases in a direction from the inlet end toward the outlet end inside the slow-cooling device when cooling the glass fiber, wherein the average pressure change dP/dL in a moving direction of the glass fiber inside the slow-cooling device satisfies the following Formula (1) when the tube inner diameter of the slow-cooling device is defined as D [m] and the length of an internal space of the slow-cooling device in the moving direction of the glass fiber is defined as L [m].

(πD.sup.2/4)×dP/dL≦0.03  (1)

A method of controlling the temperature of an optical fiber is provided that includes the steps of: providing an energy transfer member configured to accept or provide thermal energy, the energy transfer member defines an energy transfer surface; passing an optical fiber proximate the energy transfer member such that a gap is defined between the optical fiber and the energy transfer surface; and transferring thermal energy between the optical fiber and the energy transfer member via conduction across the gap.

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.

Method of producing glass components and preforms for use in the method. The preform includes a primary rod having a constant outside diameter and a square bottom and a sacrificial tip having a first end attached to the bottom of the primary rod, a second end opposite the first end, and a hollow interior region extending from the first end to the second end. The sacrificial tip is circular in cross section and the first end of the sacrificial tip has an outside diameter equal to the outside diameter of the primary rod. When the preform is heated in a furnace, the sacrificial tip melts and collapses into a drawing bulb which either draws the primary rod directly into the glass fiber or results in a tapered (i.e. tipped) preform for subsequent fiber draw. Material waste as well as the drip time is reduced and the cladding-to-core ratio, crucial for waveguide properties, is maintained for the whole preform compared to a square cut preform without the sacrificial tip.

Method of producing glass components and preforms for use in the method. The preform includes a primary rod having a constant outside diameter and a square bottom and a sacrificial tip having a first end attached to the bottom of the primary rod, a second end opposite the first end, and a hollow interior region extending from the first end to the second end. The sacrificial tip is circular in cross section and the first end of the sacrificial tip has an outside diameter equal to the outside diameter of the primary rod. When the preform is heated in a furnace, the sacrificial tip melts and collapses into a drawing bulb which either draws the primary rod directly into the glass fiber or results in a tapered (i.e. tipped) preform for subsequent fiber draw. Material waste as well as the drip time is reduced and the cladding-to-core ratio, crucial for waveguide properties, is maintained for the whole preform compared to a square cut preform without the sacrificial tip.