Abstract: Vaporizers and systems for vaporizing liquid precursor for forming glass optical fiber preforms are provided. The vaporizer includes an expansion chamber at least partially enclosed by a side wall, the expansion chamber comprising an upper end and a lower end with the side wall disposed between the upper end and the lower end. The vaporizer further includes a closed-loop liquid delivery conduit positioned in the expansion chamber proximate to the upper end of the expansion chamber, wherein the closed-loop liquid delivery conduit comprises a plurality of nozzles oriented to direct a spray of liquid precursor onto an inner surface of the side wall. Further, the vaporizer includes at least one supply conduit positioned proximate the upper end of the expansion chamber and coupled to the closed-loop liquid delivery conduit, and a vapor delivery outlet coupled to the expansion chamber and configured to direct vaporized liquid precursor from the expansion chamber.

Abstract: The present disclosure provides optical fiber preforms formed from core canes having large core-clad ratio, intermediate core-cladding assemblies, and methods for making the preforms and core cladding assemblies. The preforms are made with capped core canes. The capping material has a coefficient of thermal expansion less than the coefficient of thermal expansion of the core cane and more closely matched to or lower than the coefficient of thermal expansion of the surrounding cladding monolith in a cane-in-soot process. Presence of the cap reduces stresses that arise from differential thermal expansion of the core cane and cladding materials and leads to preforms having low defect concentration and low probability of failure during subsequent thermal processing steps.

Abstract: An optical fiber with low attenuation and methods of making same are disclosed. The optical fiber has a core, an inner cladding surround the core, and an outer cladding surrounding the inner cladding. The outer cladding is chlorine-doped such that the relative refractive index varies as a function of radius. The radially varying relative refractive index profile of the outer cladding reduces excess stress in the core and inner cladding, which helps lower fiber attenuation while also reducing macrobend and microbend loss. A process of fabricating the optical fiber includes doping an overclad soot layer of a soot preform with chlorine and then removing a portion of the chlorine dopant from an outermost region of the overclad soot layer. The soot preform with the modified chlorine dopant profile is then sintered to form a glass preform, which can then be used for drawing the optical fiber.

Abstract: Vaporizers and systems for vaporizing liquid precursor for forming glass optical fiber preforms are provided. The vaporizer includes an expansion chamber at least partially enclosed by a side wall, the expansion chamber comprising an upper end and a lower end with the side wall disposed between the upper end and the lower end. The vaporizer further includes a closed-loop liquid delivery conduit positioned in the expansion chamber proximate to the upper end of the expansion chamber, wherein the closed-loop liquid delivery conduit comprises a plurality of nozzles oriented to direct a spray of liquid precursor onto an inner surface of the side wall. Further, the vaporizer includes at least one supply conduit positioned proximate the upper end of the expansion chamber and coupled to the closed-loop liquid delivery conduit, and a vapor delivery outlet coupled to the expansion chamber and configured to direct vaporized liquid precursor from the expansion chamber.

Abstract: An optical fiber with low attenuation and methods of making same are disclosed. The optical fiber has a core, an inner cladding surround the core, and an outer cladding surrounding the inner cladding. The outer cladding is chlorine-doped such that the relative refractive index varies as a function of radius. The radially varying relative refractive index profile of the outer cladding reduces excess stress in the core and inner cladding, which helps lower fiber attenuation while also reducing macrobend and microbend loss. A process of fabricating the optical fiber includes doping an overclad soot layer of a soot preform with chlorine and then removing a portion of the chlorine dopant from an outermost region of the overclad soot layer. The soot preform with the modified chlorine dopant profile is then sintered to form a glass preform, which can then be used for drawing the optical fiber.

Abstract: An optical fiber with low attenuation and methods of making same are disclosed. The optical fiber has a core, an inner cladding surround the core, and an outer cladding surrounding the inner cladding. The outer cladding is chlorine-doped such that the relative refractive index varies as a function of radius. The radially varying relative refractive index profile of the outer cladding reduces excess stress in the core and inner cladding, which helps lower fiber attenuation while also reducing macrobend and microbend loss. A process of fabricating the optical fiber includes doping an overclad soot layer of a soot preform with chlorine and then removing a portion of the chlorine dopant from an outermost region of the overclad soot layer. The soot preform with the modified chlorine dopant profile is then sintered to form a glass preform, which can then be used for drawing the optical fiber.

Abstract: According to some embodiments a method of processing an optical fiber comprises the steps of: (i) drawing the fiber at a drawing rate of at least 30 m/sec; and (ii) cooling the drawn fiber in a gas at an average cooling rate less than 5000° C./s, such that said cooling reduces the temperature of the fiber from an entering temperature in the range between 1500° C. and 1700° C. to another temperature in the range between 1200° C. and 1400° C., the gas being at a temperature between 800° C. and 1500° C.; and the thermal conductivity ? of the gas being not greater than 1.5×10?4 cal/cm-s-K for at least one temperature within a range of 800° C. to 1500° C. at one atm (atmosphere) pressure absolute.

Abstract: An optical fiber with low attenuation and methods of making same are disclosed. The optical fiber has a core, an inner cladding surround the core, and an outer cladding surrounding the inner cladding. The outer cladding is chlorine-doped such that the relative refractive index varies as a function of radius. The radially varying relative refractive index profile of the outer cladding reduces excess stress in the core and inner cladding, which helps lower fiber attenuation while also reducing macrobend and microbend loss. A process of fabricating the optical fiber includes doping an overclad soot layer of a soot preform with chlorine and then removing a portion of the chlorine dopant from an outermost region of the overclad soot layer. The soot preform with the modified chlorine dopant profile is then sintered to form a glass preform, which can then be used for drawing the optical fiber.

Abstract: According to some embodiments a method of processing an optical fiber comprises the steps of: (i) drawing the fiber at a drawing rate of at least 30 m/sec; and (ii) cooling the drawn fiber in a gas at an average cooling rate less than 5000° C./s, such that said cooling reduces the temperature of the fiber from an entering temperature in the range between 1500° C. and 1700° C. to another temperature in the range between 1200° C. and 1400° C., the gas being at a temperature between 800° C. and 1500° C.; and the thermal conductivity ? of the gas being not greater than 1.5×10?4 cal/cm-s-K for at least one temperature within a range of 800° C. to 1500° C. at one atm (atmosphere) pressure absolute.

Abstract: The present disclosure provides optical fiber preforms formed from core canes having large core-clad ratio, intermediate core-cladding assemblies, and methods for making the preforms and core cladding assemblies. The preforms are made with capped core canes. The capping material has a coefficient of thermal expansion less than the coefficient of thermal expansion of the core cane and more closely matched to or lower than the coefficient of thermal expansion of the surrounding cladding monolith in a cane-in-soot process. Presence of the cap reduces stresses that arise from differential thermal expansion of the core cane and cladding materials and leads to preforms having low defect concentration and low probability of failure during subsequent thermal processing steps.

Abstract: An optical fiber includes a central glass core region comprising maximum refractive index delta percent ?1, a first inner annular region surrounding said core comprising refractive index delta percent ?2, a depressed annular region surrounding said inner annular region and comprising ?3 and a third annular region surrounding the depressed annular region comprising refractive index delta percent ?4; wherein the third annular region comprises chlorine an amount greater than 0.2 weight percent in a region which is within 5 microns from the depressed annular region, wherein ?1MAX>?4>?2>?3. The difference between ?4 and ?2 is greater than 0.01 and profile volume, |V3| is at least 50% ??m2.

Abstract: An optical fiber includes a central glass core region comprising maximum refractive index delta percent ?1, a first inner annular region surrounding said core comprising refractive index delta percent ?2, a depressed annular region surrounding said inner annular region and comprising ?3 and a third annular region surrounding the depressed annular region comprising refractive index delta percent ?4; wherein the third annular region comprises chlorine an amount greater than 0.2 weight percent in a region which is within 5 microns from the depressed annular region, wherein ?1MAX>?4>?2>?3. The difference between ?4 and ?2 is greater than 0.01 and profile volume, |V3| is at least 50% ??m2.

Abstract: Methods for recycling a low permeability gas such as krypton in the consolidation process of optical fiber manufacturing. The low permeability gas is sent to a purification unit or plant before being reutilized in the consolidation process. The low permeability gas can be used to produce holes or voids in a cladding region of an optical fiber preform. Upon drawing the optical preform into an optical fiber, the voids become elongated in the direction of draw.

Abstract: A system and method for cooling and coating optical fiber includes the capability to control the amount of coolant gas that is fed to and recycled through a heat exchanger for cooling the optical fiber. The capability to control the amount of fed and recycled coolant gas includes measuring at least one parameter selected from the thermal conductivity of the coolant gas, the viscosity of the coolant gas, the diameter of the primary coating on the optical fiber, and the power usage of a coating applicator for applying primary coating on the optical fiber.

Abstract: Helium recycling for optical fiber manufacturing in which consolidation process helium is recycled either directly for use in consolidation at high purity or recycled at lower purity adequate for usage in draw or other processes having a lower helium parity. Integrated processes for recycling helium from two or more helium using processes in the optical manufacturing process are also described. Substantial helium and cost savings are recognized.

Abstract: An apparatus for threading a fiber that is being continuously supplied by a supplying device for winding on a spool, includes a collecting device, adjacent to the supplying device, that collects the fiber by urging the fiber from the supplying device into the collecting device to provide a tension in the fiber between the supplying device and the collecting device, a positioning device that engages the fiber, between the supplying device and the collecting device, with an engaging portion that allows the fiber to be continuously collected in the collecting device and that moves from a position adjacent to the supplying device and the collecting device to a position adjacent to the spool to move the fiber to at least one threading position, and a threading device that automatically threads the fiber at the at least one threading position onto the spool.

Abstract: Helium recycling for optical fiber manufacturing in which consolidation process helium is recycled either directly for use in consolidation at high purity or recycled at lower purity adequate for usage in draw or other processes having a lower helium parity. Integrated processes for recycling helium from two or more helium using processes in the optical manufacturing process are also described. Substantial helium and cost savings are recognized.