The apparatus and methods include moving an optical fiber over a fiber path that includes a marking location at which resides a marking unit that dispenses an ink-jet stream. A centering method is performed whereby the optical fiber is incrementally moved in a lateral direction through the path of the ink-stream and the mark number density of marks formed on the optical fiber is measured along with the optical fiber position. A process window is defined by the range of lateral fiber positions over which a target mark number density is formed on a consistent basis. A controller calculates an optimum fiber path position and stores it memory for future reference while also moving the fiber path to the optimum position. The initially wet ink marks are dried and the fiber coated with a transparent protective overcoat to form a coated and marked optical fiber.

The apparatus and methods include moving an optical fiber over a fiber path that includes a marking location at which resides a marking unit that dispenses an ink-jet stream. A centering method is performed whereby the optical fiber is incrementally moved in a lateral direction through the path of the ink-stream and the mark number density of marks formed on the optical fiber is measured along with the optical fiber position. A process window is defined by the range of lateral fiber positions over which a target mark number density is formed on a consistent basis. A controller calculates an optimum fiber path position and stores it memory for future reference while also moving the fiber path to the optimum position. The initially wet ink marks are dried and the fiber coated with a transparent protective overcoat to form a coated and marked optical fiber.

An apparatus for curing a coating composition disposed on a glass optical fiber. The apparatus includes a reflector, the reflector having an interior surface delineating a boundary of a cavity, the interior surface including a plurality of portions, each of the portions extending along a different curved contour. Furthermore, each of the plurality of portions is configured to reflect curing light so that the reflected curing light is concentrated to a curing zone within the cavity such that all the reflected curing light within the curing zone has an intensity of about 60% or greater relative to a maximum intensity of the reflected curing light. A fiber location for the glass optical fiber is located within the curing zone. Additionally, the plurality of portions includes at least a first portion and a second portion, the first portion having a different degree of curvature than the second portion.

An apparatus for curing a coating composition disposed on a glass optical fiber. The apparatus includes a reflector, the reflector having an interior surface delineating a boundary of a cavity, the interior surface including a plurality of portions, each of the portions extending along a different curved contour. Furthermore, each of the plurality of portions is configured to reflect curing light so that the reflected curing light is concentrated to a curing zone within the cavity such that all the reflected curing light within the curing zone has an intensity of about 60% or greater relative to a maximum intensity of the reflected curing light. A fiber location for the glass optical fiber is located within the curing zone. Additionally, the plurality of portions includes at least a first portion and a second portion, the first portion having a different degree of curvature than the second portion.

An optical fiber manufacturing method includes a process of passing a glass fiber through a fiber path before applying a resin. The glass fiber is drawn from a glass preform, the fiber path is formed through a cooling tube, and the cooling tube is housed in a casing and is cooled by a coolant. The process includes supplying a dry gas into a dry space formed between the casing and the cooling tube. The dry gas has a first dew point lower than the temperature of the cooling tube. The process includes measuring, by a dew point meter, a second dew point at one or both of an inlet and an outlet of the fiber path. The process includes controlling the temperature of the coolant in the cooling tube such that the temperature of the cooling tube is higher than the second dew point measured by the dew point meter.

A bare optical fiber manufacturing method includes applying an ultraviolet curable resin applied around an optical fiber; and irradiating the ultraviolet curable resin with ultraviolet light emitted from semiconductor ultraviolet light emitting elements, by use of an ultraviolet irradiation device having plural ultraviolet irradiation units each having plural positions where the ultraviolet light is emitted toward the ultraviolet curable resin, the plural positions being arranged on the same circle, the plural ultraviolet irradiation units being arranged in a traveling direction of the optical fiber such that the optical fiber passes centers of the circles, at least two of the plural ultraviolet irradiation units being differently arranged with respect to circumferential direction angles thereof around an axis that is the traveling direction of the optical fiber.

A bare optical fiber manufacturing method includes applying an ultraviolet curable resin applied around an optical fiber; and irradiating the ultraviolet curable resin with ultraviolet light emitted from semiconductor ultraviolet light emitting elements, by use of an ultraviolet irradiation device having plural ultraviolet irradiation units each having plural positions where the ultraviolet light is emitted toward the ultraviolet curable resin, the plural positions being arranged on the same circle, the plural ultraviolet irradiation units being arranged in a traveling direction of the optical fiber such that the optical fiber passes centers of the circles, at least two of the plural ultraviolet irradiation units being differently arranged with respect to circumferential direction angles thereof around an axis that is the traveling direction of the optical fiber.

A bare optical fiber manufacturing method includes applying an ultraviolet curable resin applied around an optical fiber; and irradiating the ultraviolet curable resin with ultraviolet light emitted from semiconductor ultraviolet light emitting elements, by use of an ultraviolet irradiation device having plural ultraviolet irradiation units each having plural positions where the ultraviolet light is emitted toward the ultraviolet curable resin, the plural positions being arranged on the same circle, the plural ultraviolet irradiation units being arranged in a traveling direction of the optical fiber such that the optical fiber passes centers of the circles, at least two of the plural ultraviolet irradiation units being differently arranged with respect to circumferential direction angles thereof around an axis that is the traveling direction of the optical fiber.

A bare optical fiber manufacturing method includes applying an ultraviolet curable resin applied around an optical fiber; and irradiating the ultraviolet curable resin with ultraviolet light emitted from semiconductor ultraviolet light emitting elements, by use of an ultraviolet irradiation device having plural ultraviolet irradiation units each having plural positions where the ultraviolet light is emitted toward the ultraviolet curable resin, the plural positions being arranged on the same circle, the plural ultraviolet irradiation units being arranged in a traveling direction of the optical fiber such that the optical fiber passes centers of the circles, at least two of the plural ultraviolet irradiation units being differently arranged with respect to circumferential direction angles thereof around an axis that is the traveling direction of the optical fiber.

A photoirradiation device includes an insertion path for inserting a wire rod; a first reflector having a circular arc shape centered on a point shifted from a center of the insertion path by a first distance, one side of the first reflector facing the insertion path being a reflective surface; a second reflector disposed adjacent open edges of the first reflector and having a circular arc shape centered on a point shifted from the center of the insertion path by a second distance that is different from the first distance, one side of the second reflector facing the insertion path being a reflective surface; and a light source that is positioned on an opposite side of the insertion path from the first reflector and that projects light toward the wire rod.