Abstract: The invention relates to exemplary methods, devices, and systems for heating an elongate silica cylinder to form a core-rod for optical fibers. An exemplary heating device includes an elongate cavity, an elongate liner bounding the cavity, a heating element in a heating element space surrounding the liner, the liner separating the heating element space from the cavity, and a gas flushing device for effecting a flow of gas at least through the heating element space. An exemplary method includes providing the elongate silica cylinder such that it extends through the cavity, heating the cylinder locally beyond its softening temperature, and effecting a flow of argon and nitrogen gas during the heating.

Abstract: 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.

Abstract: The present disclosure provides a windproof cover unit for optical fiber fusion splicer. The windproof cover unit includes a windproof cover, a mounting base unit, a flexible printed circuit (FPC) unit, and a rotational axle of the windproof cover, wherein the windproof cover comprises a protruding cover surface, an inner space, and a white-light lamp unit for providing illumination for the optical fiber fusion splicer in the inner space.

Abstract: Apparatus, systems and methods for monitoring and controlling the amount of moisture introduced into the forming hood area in the manufacture of mineral fiber insulation products. Moisture from coolant liquids, binder dispersions and binder diluents are all introduced deliberately into a forming hood; ambient moisture and water from combustion are additional sources. A series of global variable control valves, one for each fluid system; as well as individual variable control valves for each fiberizing unit are provided with associated meters. Sensors monitor fibrous pack conditions and ambient conditions and provide inputs to the valve control system. A specific 3-ring liquid dispensing system is also disclosed.

Abstract: In an apparatus for conveying a glass tube strand or glass rod strand having a cross-section that is different from a circular cross-section, in particular having an oval cross-section, a plurality of support and guide members are arranged, if viewed in the direction of movement of the glass tube strand or glass rod strand, one after the other such that the moving glass tube strand or glass rod strand is directly supported thereon and guided by them. The support and guide members are disposed tilted in said direction of movement so that the moving glass tube strand or glass rod strand is directly supported on edges of the support and guide members. Thus, one-sided heat losses due to heat dissipation via the support and guide members can be significantly reduced to thereby reduce the curvature of the glass tube strand or glass rod strand.

Abstract: An optical fiber fusion splicer that heats and fusion-splices optical fibers to each other, the optical fiber fusion splicer includes: a coating clamp installation base; a coating clamp that is attached to the coating clamp installation base and has a coating clamp lid that is openable and closable; and a first power source for advancing the coating clamp installation base and opening the coating clamp lid. An operation of opening the coating clamp lid is performed using the first power source after the fusion splicing is completed.

Abstract: An optical fiber fusion splicer includes: a windshield cover having a rotating shaft and rotating around the rotating shaft so as to be openable and closable; a cable member wrapping unit coupled and fixed to the windshield cover on the same axis as the rotating shaft of the windshield cover or formed as a portion of the windshield cover, the cable member wrapping unit being rotatable in a normal direction or in a reverse direction around the rotating shaft; a first cable member winding unit that is a rotary pulley, a non-rotary pulley, or a rotary gear; and a closed-loop member including a deformable cable member wound around the cable member wrapping unit and the first cable member winding unit, the closed-loop member constituting a closed loop.

Abstract: Processes and systems for producing glass fibers having regions devoid of glass using submerged combustion melters, including feeding a vitrifiable feed material into a feed inlet of a melting zone of a melter vessel, and heating the vitrifiable material with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone. One or more of the burners is configured to impart heat and turbulence to the molten material, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products, and optionally other gas species introduced by the burners. The molten material and bubbles are drawn through a bushing fluidly connected to a forehearth to produce a glass fiber comprising a plurality of interior regions substantially devoid of glass.

Abstract: In an optical fiber drawing device of the present invention, as an operational parameters corresponding to the real drawing speed in the duration from the moment of starting the operation of the optical fiber drawing device till the moment of reaching the target drawing speed are extracted from operational parameters stored in a operational parameter storage unit and applied to the optical fiber drawing device. The operational parameters include a base preform feeding speed, a target variation of real drawing speed, a gain multiplied by the speed element related with the variation of the real drawing speed, an operation cycle, a drawing furnace temperature, a coating resin pressure to coat the optical fiber, and flow of cooling gaseous helium, etc.

Abstract: A gas supplying unit supplies a nitrogen gas into a furnace body of a graphite heating furnace in which at least a part of the furnace body is formed with a graphite. An exhausting unit exhausts a gas inside the furnace body to outside the furnace body. A dew-point temperature of the nitrogen gas supplied into the furnace body is equal to or lower than ?80° C. A pressure inside the furnace body is equal to or higher than 140 Pa with respect to an atmospheric pressure outside the furnace body.

Abstract: Apparatus, systems and methods for making a fibrous products form molten material into fibers. The fibers are sprayed with a coolant liquid to cool the fibers. A flow rate of the sprayed coolant liquid is controllable. The fibers are also sprayed with a binder dispersion. The fibers are directed toward a conveyor to form an uncured fibrous pack. A thickness of the uncured pack is measured and the flow rate of the sprayed coolant liquid is controlled based on the measured thickness of the uncured pack.

Abstract: Apparatus, systems and methods for monitoring and controlling the amount of moisture introduced into the forming hood area in the manufacture of mineral fiber insulation products. Moisture from coolant liquids, binder dispersions and binder diluents are all introduced deliberately into a forming hood; ambient moisture and water from combustion are additional sources. A series of global variable control valves, one for each fluid system; as well as individual variable control valves for each fiberizing unit are provided with associated meters. Sensors monitor fibrous pack conditions and ambient conditions and provide inputs to the valve control system. A specific 3-ring liquid dispensing system is also disclosed.

Abstract: Apparatus and methods for making an optical fiber preform at low cost avoiding the apparatus from being damaged are provided. Apparatus for making an optical fiber preform by depositing glass particles on the circumferential surface of a glass rod comprises: a chamber, a plasma torch, a glass particle supplying part, a composition modification gas supplying part, and an exhaust part. The chamber surrounds the heating portion of the glass rod heated by the plasma torch. The plasma torch heats the glass particles by a plasma flame. The glass particle supplying part introduces glass particles towards the heating portion of the glass rod in the chamber. The composition modification gas supplying part introduces composition modification gas into the chamber in order to modify the composition of the glass particles to be deposited on the heating portion of the glass rod in the chamber.

Abstract: Various embodiments of the present invention relate to glass fiber forming bushings, to methods of controlling the temperature of bushings having multiple segments, to systems of controlling the temperature of bushings having multiple segments, and to other systems and methods. In one embodiment, a method of controlling the temperature of a bushing having multiple segments comprises forming a plurality of filaments from a bushing comprising at least two segments, gathering the filaments into at least two ends, measuring the size of each of the at least two ends, comparing the measured size of the at least two ends to a desired end size, adjusting the amount of current passing through the at least two bushing segments in response to the end size comparisons.

Abstract: Apparatus, systems and methods for monitoring and controlling the amount of moisture introduced into the forming hood area in the manufacture of mineral fiber insulation products. Moisture from coolant liquids, binder dispersions and binder diluents are all introduced deliberately into a forming hood; ambient moisture and water from combustion are additional sources. A series of global variable control valves, one for each fluid system; as well as individual variable control valves for each fiberizing unit are provided with associated meters. Sensors monitor fibrous pack conditions and ambient conditions and provide inputs to the valve control system. A specific 3-ring liquid dispensing system is also disclosed.

Abstract: A method of determining conditioning pulse parameters for an optical element includes directing a pump pulse to impinge on the optical element and directing a probe pulse to impinge on the optical element. The method also includes determining a first time associated with an onset of electronic excitation leading to formation of an absorbing region of the optical element and determining a second time associated with expansion of the absorbing region of the optical element. The method further includes defining a turn-off time for a conditioning pulse between the first time and the second time. According to embodiments of the present invention, pulse shaping of the conditioning pulse enables laser conditioning of optical elements to achieve improvements in their laser induced damage threshold.

Abstract: A first generation portion divides an object to be analyzed into a plurality of finite elements to generate element division data. A first calculation portion defines and calculates a plurality of meshes dividing the object to be analyzed into units larger than the finite elements. A second generation portion assumes that a friction layer which has a thickness of “0” and a friction coefficient between a conductive material and a composite material of a predetermined value less than 1 exists at the interface between the conductive material and the composite material, and the second generation portion generates mesh data. A second calculation portion uses various solvers to calculate the physical amounts produced in the object to be analyzed on the basis of the mesh data and outputs the analysis result. In other words, the second calculation portion performs a simulation of the behavior of the object to be analyzed.

Abstract: A manufacturing apparatus for an optical waveguide structure including a clad structure having grooves in a curved surface thereof and a clad film attached to the curved surface includes a clad film shape retaining portion that has a curved surface along which the clad film is held. a position checking portion that checks the position of the clad film on the clad film shape retaining portion, and a first position adjusting portion that adjusts the position of the clad film shape retaining portion so that the clad film on the clad film shape retaining portion is disposed at a reference position while checking the position of the clad film with the position checking portion.

Abstract: Various embodiments of the present invention relate to glass fiber forming bushings, to methods of controlling the temperature of bushings having multiple segments, to systems of controlling the temperature of bushings having multiple segments, and to other systems and methods. In one embodiment, a method of controlling the temperature of a bushing having multiple segments comprises forming a plurality of filaments from a bushing comprising at least two segments, gathering the filaments into at least two ends, measuring the size of each of the at least two ends, comparing the measured size of the at least two ends to a desired end size, adjusting the amount of current passing through the at least two bushing segments in response to the end size comparisons.

Abstract: A method of optical fiber manufacture involves the writing of a grating on the fiber using a laser. A first laser beam is directed on a first locality of the fiber having a circumference. A second laser beam is then directed on a second locality circumferentially displaced from the first locality. The first laser beam may be the second laser beam. In this way, a grating is formed on the fiber. The fiber may have a core and a cladding layer. The fiber may also comprise two gratings to form an interferometer.

Abstract: An optical fiber base material manufacturing method includes: supplying oxygen, hydrogen, and silicide to a core deposition burner; depositing silicon dioxide; adjusting a drawing up speed so that a deposition tip position remains at the same position in accordance with growth of a porous base material; calculating an average of the drawing up speed at each preset time interval; calculating a difference of the calculated average from a preset value of the drawing up speed; correcting a flow rate of silicon tetrachloride when the supplied hydrogen is hydrogen produced or stored at normal temperature, and correcting a flow rate of hydrogen when the supplied hydrogen is hydrogen obtained by vaporizing liquid hydrogen, where when correcting the flow rate of hydrogen, a flow rate of hydrogen supplied to a cladding deposition burner is also corrected in a ratio of before and after the correction of the flow rate of the hydrogen.

Abstract: A non-contact method for measuring the tension applied to a drawn optical fiber includes drawing an optical fiber and displacing the optical fiber by applying a pressurized fluid to the optical fiber. The pressurized fluid may be applied to the optical fiber using a fluid bearing. The fluid bearing may include a fiber support channel. The optical fiber may be directed through the fiber support channel and is displaced relative to the fluid bearing by supplying the pressurized fluid to the fiber support channel. The displacement of the optical fiber caused by the application of the pressurized fluid to the optical fiber may then be measured. The tension applied to the optical fiber may then be determined based on the determined displacement.

Abstract: An apparatus for measuring the weight of a preform for optical fibers during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: A glass base material manufacturing apparatus for manufacturing a glass base material comprising: a plurality burners, arranged in a row at a predetermined intervals along the longitudinal direction of a starting base material of the glass base material, for forming a deposit, which is a base material of the glass base material by depositing glass soot on the starting base material while moving reciprocatory over a section of the entire length of the starting base material along the longitudinal direction of the starting base material; a plurality of flow rate regulators, at least one of which is connected to the plurality of burners, respectively, for regulating a flow rate of raw material gas of the glass soot, which is supplied to the plurality of burners; and a control unit connected to each of the plurality of flow rate regulators for controlling individually the plurality of flow rate regulators.

Abstract: There is provided an elongation method of an optical fiber base material, by which a base material rod not requiring a process for modifying a bend from base material ingot is obtained. The method for elongating base material ingot to be a base material rod having a diameter smaller than before to manufacture an optical fiber base material, includes the steps of: elongating the base material ingot while controlling a control position so that a neck-down within a horizontal surface of the base material ingot is located at a target position; measuring a bending direction and a bending amount of an elongated base material rod; and adjusting the target position based on the result. In addition, it is preferable to adjust a position of a pendant portion of base material ingot in order to control the position of the neck-down to be the target position. For example, the position of the pendant portion may be moved in an XY direction, more particularly, in a direction in which the measured bend shows convexity.

Abstract: The invention relates to a method of controlling the level of corrosivity of an aqueous solution recovered during a process for producing a blanket of mineral fibers, comprising in particular the fiberizing and the coating of said fibers with a binder comprising a polyacid typically of the acrylic type, said aqueous solution being at least partly recycled into a zone in which said resin is prepared and/or a scrubbing zone of the production plant, said method being characterized in that the pH of the solution in the recycling circuit is maintained between minimum and maximum values by injecting into said circuit an agent for modifying said pH, such as a base, the quantity injected or the flow rate of the pH-modifying agent being adjusted directly according to the quantity or the flow rate of acid binder injected during the fiberizing process. The invention also relates to the device for implementing the method.

Abstract: A recovery system recycles the washwater used to clean excess binder and debris from the production components, including a forming hoodwall constructed of non-corrosive materials, for manufacturing fiberglass insulation. A separate closed-loop recovery system is provided for the forming hoodwall in which the binder-containing washwater is screened and then recycled back to the forming hoodwall without further chemical treatment to change the pH level. A binder reclamation system is coupled to the hoodwall washwater recovery system to divert the low pH washwater when the supply of binder needs replenished at the forming hoodwall. The binder reclamation system introduces an acid solution to the cleaned washwater to lower the pH from about 2.5 to about 3.5. The other production components share a bulk washwater recovery system in which a base solution is introduced to raise the pH to approximately 8 or above to reduce corrosion in the other production components.

Abstract: Methods for substantially improving the stability of a melting furnace system including bushings and cooling apparatus for converting molten mineral material to continuous fibers is disclosed. Apparatus and methods for maintaining the molten material throughput and the electrical power load on fiberizing bushings substantially constant are disclosed. The orifice plate, with or without tips or nozzles, is subjected to a more rapid rate of heat removal after the bushing breaks out than it did while the bushing was in a desired fiberizing mode. Apparatus for blowing cooling air upward onto the orifice plate during the time the bushing is breaking out and/or hanging to provide additional cooling is disclosed along with optional additional or alternative apparatus to use for optional additional or alternative cooling is also disclosed.

Abstract: A neutralization system for controlling the pH of the washwater used to clean and maintain polyacrylic bound glass forming equipment is provided. The neutralization system introduces a base solution to a washwater solution when the pH of the washwater solution contained in a closed loop washwater recovery system and in a washwater tank holding the washwater solution is determined to be below approximately 8.0. Maintaining the pH of the washwater solution reduces the corrosion rate of the glass fiber forming equipment that is typically associated with acidic binders. In a second embodiment of the invention, a closed-loop hoodwall reclaim washwater recovery system utilized in addition to the washwater neutralization system that allows for the recovery and reuse of a polycarboxylic acid binder with a minimal amount of base solution. The closed-loop hoodwall reclaim washwater system is not connected to the closed-loop washwater neutralization system.

Abstract: The invention relates to apparatus for supporting a preform manufactured in an installation for manufacturing or building up preforms having supporting cores, said installation including at least rotation means having a horizontal axis of rotation and two mounting points between which the supporting core of the preform to be manufactured or built up is mounted, plasma-torch and material-supply means disposed radially relative to said supporting core and being mounted to move in axial translation relative to and parallel to the supporting core so as to make said preform around said supporting core, said apparatus being wherein it includes controlled support means constituting additional localized abutment points between said mounting points for said preform being manufactured or built up.

Abstract: An optical fiber drawing installation is equipped with an oscillating pulley that applies torsion to the fiber alternately in one rotation direction and then in the opposite direction. To control the torsion applied to the fiber, images are formed of the fiber and the pulley. The images are analyzed to determine the position of the fiber relative to the pulley. The torsion is calculated from the calculated position, on the assumption that the fiber rolls on the pulley.

Abstract: A gas supplying unit supplies a nitrogen gas into a furnace body of a graphite heating furnace in which at least a part of the furnace body is formed with a graphite. An exhausting unit exhausts a gas inside the furnace body to outside the furnace body. A dew-point temperature of the nitrogen gas supplied into the furnace body is equal to or lower than ?80° C. A pressure inside the furnace body is equal to or higher than 140 Pa with respect to an atmospheric pressure outside the furnace body.

Abstract: A neutralization system for controlling the pH of the washwater used to clean and maintain polyacrylic bound glass forming equipment. The neutralization system introduces a base solution to a washwater solution when the pH of the washwater solution contained in a closed loop washwater recovery system falls below about 8.5, thereby substantially reducing the corrosion rate of the components of the equipment associated with acidic polyacrylic acid binder, maleic acid cobinder or maleic anhydride cobinder and washwater solution. A closed-loop hoodwall washwater recovery system may also be introduced in addition to the neutralization system that allows for the recovery and reuse of polyacrylic acid binder and maleic acid cobinder or maleic anhydride cobinder with a minimal amount of base solution, thereby minimizing degradation of insulation properties of polyacylic acid bound glass fiber products.

Abstract: A glass base material manufacturing apparatus for manufacturing a glass base material comprising: a plurality burners, arranged in a row at a predetermined intervals along the longitudinal direction of a starting base material of the glass base material, for forming a deposit, which is a base material of the glass base material by depositing glass soot on the starting base material while moving reciprocatory over a section of the entire length of the starting base material along the longitudinal direction of the starting base material; a plurality of flow rate regulators, at least one of which is connected to the plurality of burners, respectively, for regulating a flow rate of raw material gas of the glass soot, which is supplied to the plurality of burners; and a control unit connected to each of the plurality of flow rate regulators for controlling individually the plurality of flow rate regulators.

Abstract: A neutralization system for controlling the pH of the washwater used to clean and maintain polyacrylic bound glass forming equipment. The neutralization system introduces a base solution to a washwater solution when the pH of the washwater solution contained in a closed loop washwater recovery system falls below approximately 8.0, thereby substantially reducing the corrosion rate of the components of the equipment associated with acidic polyacrylic acid binder and washwater solution. A closed-loop hoodwall washwater recovery system may also be introduced in addition to the neutralization system that allows for the recovery and reuse of polyacrylic acid binder with a minimal amount of base solution, thereby minimizing degradation of insulation properties of polyacylic acid bound glass fiber products.

Abstract: An energy-efficient inductive heater operable to heat a rotary glass fiber discharging spinner. The heater includes shielding disposed between the induction coil and the metal guard plates of the heater. The shielding may comprise any electrically insulative or dielectric material that is capable of withstanding the high operating temperatures occurring in a glass making environment.

Abstract: An apparatus for manufacturing a glass-base-material, which is a base material of an optical fiber, includes a driving unit that drives a glass rod around an axis of the glass rod; a burner for accumulating glass soot around outside surface of the glass rod, which is driven by the driving unit, to form the glass-base-material; a weight-deducting unit, on which the driving unit is mounted, for deducting a predetermined weight from a total weight of the driving unit and the glass-base-material formed by the burner; and a measuring unit provided under the weight-deducting unit for measuring the total weight, from which the predetermined weight is deducted by the weight-deducting unit.

Abstract: An apparatus for manufacturing a glass-base-material, which is a base material of an optical fiber, includes a driving unit that drives a glass rod around an axis of the glass rod; a burner for accumulating glass soot around outside surface of the glass rod, which is driven by the driving unit, to form the glass-base-material; a weight-deducting unit, on which the driving unit is mounted, for deducting a predetermined weight from a total weight of the driving unit and the glass-base-material formed by the burner; and a measuring unit provided under the weight-deducting unit for measuring the total weight, from which the predetermined weight is deducted by the weight-deducting unit.

Abstract: Methods and apparatuses estimate and control optical fiber primary coating diameter for wet-on-wet optical fiber manufacturing. The primary coating diameter for a particular length of optical fiber is calculated based upon a measurement of the weight of primary and/or secondary coating material consumed during optical fiber manufacturing. Control of the primary coating diameter is effected by a coating controller which can increase or decrease the primary coating diameter through control of glass temperature, coating viscosity and/or other parameters during wet-on-wet fiber manufacture.

Abstract: The invention concerns a device (1) for sintering of a porous mold body (2) in a gas-tight chamber (3), with the mold body (2) hanging loose from a link chain (7) so that it can be fed continuously to a heating zone (5). In the area of the upper boiler (10), the traction direction of the link chain (7) is reversed by a deviation wheel (11). The tensile force is transmitted via a traction rope (13) that can be taken up on a take-up reel (14), such take-up reel (14) being driven by a drive (16) arranged outside the chamber (3). A drive shaft (15) for the take-up reel (14) provides for easy sealing of the duct (18) towards the chamber (3), because only a rotation and not a simultaneous axial displacement is required for the hoisting movement, and moreover, because the duct (18) is arranged at a spatial distance from the heating zone (5).

Abstract: A coolant system for cooling a fiber includes a heat exchanger with an internal passage disposed between a fiber inlet and fiber outlet to cool the fiber moving through the internal passage. A plurality of chambers are disposed within the internal passage, and at least one fluid medium flows within at least a portion of the internal passage, and at least one adjustable seal is positioned within the internal passage to form a partition between two adjacent chambers. A gas analyzer communicates with at least one chamber of the internal passage to extract a fluid sample from the chamber and to measure a concentration of a gas in the extracted fluid sample. A controller communicates with the analyzer and controls at least one of the adjustable seal and the flow rate of fluid medium within the internal passage based upon the measured concentration.

Abstract: A porous preform vitrification apparatus of the present invention, provided with a means for forcibly feeding nitrogen etc. from a furnace core tube to a discharge gas pipe so as to balance a pressure between a furnace core tube accommodating a porous preform and a heating furnace body surrounding this and so as to suppress pressure fluctuation in the furnace core tube to a minimum level, controlling the gas feed rate and discharge rate to the furnace core tube and the heating furnace body, and controlling the feed rate of the nitrogen from the furnace core tube to the discharge gas pipe based on a differential pressure signal of a pressure in the furnace core tube and a pressure in the heating furnace body.

Abstract: The present invention provides systems and methods for removing or decreasing the undesirable oscillations in MFD and dispersion in an OTDR trace of an optical fiber. In addition, the present invention removes the undesirable oscillations in core ovality of a preform fabricated by a vapor deposition technique. Briefly stated, the present invention comprises increasing the rotational rate of the substrate tube during the deposition process to between 50-65 rpm, preferably approximately 60 rpm.

Abstract: A fiber drawing method according to the present invention is a drawing method of optical fiber for drawing an optical fiber 14 from one end of a fiber preform 13 by softening with heat, wherein the fiber preform 13 is set in a semi-closed space 10, 20 opening in part at a lower end in a fiber drawing furnace, the fiber preform 13 is heated by a heater 15 disposed on the lower end side of this semi-closed space 10, 20, and fiber drawing is carried out with adjusting a quantity of heat dissipation from the upper portion 20 of this semi-closed space.

Abstract: A method of fabricating an optical fiber preform is disclosed which includes a step of outside deposition of silica possibly doped with at least one dopant by injecting at least one substance in the form of silica or a precursor of silica in the vicinity of a heating area created by a heating system during at least one pass of an injector system and the heating system along a longitudinal axis of the preform during which the relative positions of the injector and heating systems ore adjusted so that silica is deposited in the heated area regardless of the position of the heating system.

Abstract: Embodiments of the invention include a method and apparatus for making optical fiber preforms and optical fiber. The method includes the steps of positioning an overclad tube around a preform core rod, heating the overclad tube along the length thereof in the presence of a pressure gradient to collapse onto the preform core to form the overclad optical fiber preform, and adjusting the radial size of a heated portion of the preform core rod and/or the overclad tube to actively match the radial dimensions of the preform core rod along the length thereof with corresponding portions of the overclad tube. The active matching reduces variations in the physical dimensions of the preform core rod and/or the overclad tube, which improves transmission and other performance characteristics of fiber drawn from the created preform, e.g., by maintaining a relatively constant D/d ratio of the preform.

Abstract: In method of making an optical fiber and an apparatus, an optical fiber coated with UV curable resin is drawn at a drawing speed of 1000 m/min or more so that the optical fiber 5 has predetermined coating diameter from 235 &mgr;m to 265 &mgr;m. A transit time from an exit of a UV curing furnace to an entrance portion of a capstan for pulling the optical fiber downstream is set to be 0.5 seconds or more.

Abstract: An apparatus for manufacturing a glass base material, which is a base material of an optical fiber, comprising: a base rod, around and along which said glass base material is formed; a burner that hydrolyzes and accumulates a gas material, which is a base material of said glass base material, around and along said base rod; a first burner-moving-unit that moves said burner in a direction parallel with a longitudinal direction of said base rod; and a second burner-moving-unit that moves said first burner-moving-unit in a same moving direction of said first burner-moving-unit.

Abstract: A neutralization system for controlling the pH of the washwater used to clean and maintain polyacrylic bound glass forming equipment. The neutralization system introduces a base solution to a washwater solution when the pH of the washwater solution contained in a closed loop washwater recovery system falls below about 8.5, thereby substantially reducing the corrosion rate of the components of the equipment associated with acidic polyacrylic acid binder, maleic acid cobinder or maleic anhydride cobinder and washwater solution. A closed-loop hoodwall washwater recovery system may also be introduced in addition to the neutralization system that allows for the recovery and reuse of polyacrylic acid binder and maleic acid cobinder or maleic anhydride cobinder with a minimal amount of base solution, thereby minimizing degradation of insulation properties of polyacylic acid bound glass fiber products.

Abstract: A neutralization system for controlling the pH of the washwater used to clean and maintain polyacrylic bound glass forming equipment. The neutralization system introduces a base solution to a washwater solution when the pH of the washwater solution contained in a closed loop washwater recovery system falls below approximately 8.0, thereby substantially reducing the corrosion rate of the components of the equipment associated with acidic polyacrylic acid binder and washwater solution. A closed-loop hoodwall washwater recovery system may also be introduced in addition to the neutralization system that allows for the recovery and reuse of polyacrylic acid binder with a minimal amount of base solution, thereby minimizing degradation of insulation properties of polyacylic acid bound glass fiber products.