Abstract: A burner for a vapour deposition process has a central nozzle for ejecting a glass precursor material, at least a crown of nozzles surrounding said central nozzle for ejecting a flame reactant, and a circular nozzle between said central nozzle and said crown of nozzles for ejecting an innershield gas, wherein the central nozzle has a concave shape in a cross section in the axial plane and, preferably, a symmetry about an axial plane.

Abstract: A device for contracting a hollow substrate tube made of quartz glass into an optical perform including a heat source movable relative to the longitudinal direction of the substrate tube and an insert tube positioned in the interior of the substrate tube, at one end thereof, provided with a central opening through which a gas is passed and supplied to the interior of the substrate tube.

Abstract: An apparatus for manufacturing a glass perform, includes: a dummy tube section, a reservoir portion, and a cooling portion; and a glass tube section in which particles of an alkali metal compound or an alkaline earth metal compound which have flowed into the glass tube section from the dummy tube section are heated by a second heat source which performs traverse, and oxides of the particles being deposited on an inner wall and dispersed in the glass tube section. In the cooling portion of the dummy tube section, vapor of the alkali metal compound or the alkaline earth metal compound generated by heating of a first heat source is cooled and condensed by a dry gas flowing into the dummy tube section, and thereby the particles are generated.

Abstract: Provided is a manufacturing apparatus for manufacturing a porous glass base material by depositing glass particles, which has a chamber having air inlets, and an air distribution container having air outlets from which clean air is supplied to the air inlets.

Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor comprises the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

Abstract: A dehydration-sintering furnace for dehydrating and/or sintering an optical fiber preform for use in production of an optical fiber includes a muffle for accommodating the optical fiber preform, a heater for heating the muffle, and a pressure fluctuation absorbing apparatus connected to the muffle. Since the pressure fluctuation absorbing apparatus is thermally insulated from a room temperature atmosphere or heated, vapor produced in a dehydration-sintering process is prevented from condensing (liquefying) in a pressure fluctuation absorbing apparatus, thereby preventing reduced dehydration effectiveness in the muffle and reduced quality of the optical fiber preform.

Abstract: The present invention relates to an apparatus for carrying out a PCVD deposition process, wherein one or more doped or undoped layers are coated onto the interior of a glass substrate tube, which apparatus comprises an applicator having an inner and an outer wall and a microwave guide which opens into the applicator, which applicator extends around a cylindrical axis and which is provided with a passage adjacent to the inner wall, through which the microwaves can exit, over which cylindrical axis the substrate tube can be positioned, and wherein at least one choke of annular shape having a length l and a width w is centred around the cylindrical axis within the applicator.

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: Disclosed is a method and device for manufacturing an optical preform. The method includes supplying dopant-containing glass-forming gases to the interior of a hollow glass substrate tube. Furthermore, the supply flow of dopant-containing glass-forming gases includes a main gas flow and one or more secondary gas flows. The secondary gas flows are divided into subflows, which are supplied to the interior of the hollow glass substrate tube together with the main gas flow. The method further includes effecting deposition of glass layers on the interior surface of the hollow glass substrate tube.

Abstract: A furnace for drawing an optical fiber includes a body having an upper and lower openings for supplying a preform and discharging a drawn optical fiber, a heating unit installed in the body for receiving and melting the preform, an atmosphere blocking tube installed to the lower opening for discharging the drawn optical fiber and blocking the optical fiber from the atmosphere, an upper introduction port formed at an upper portion of the body for introducing an inert gas toward the preform and partially discharged outside through a gap between the preform and the upper opening, a central and lower introduction ports formed at central and lower portions for introducing an inert gas into the body, a first flow guiding means for guiding the inert gas introduced through the central introduction port upward and then flowed down along a surface of the preform, and a second flow guiding means for guiding the inert gas introduced through the lower introduction port upward and then discharged outside through the atmosp

Abstract: A method of manufacturing an optical fiber base material includes: forming a porous glass base material by depositing glass particles; providing a synthetic quartz glass vessel at least partly made of quartz glass which contains aluminum equal to or less than 0.01 ppm; introducing dehydration reaction gas and inert gas into the vessel; heating a portion made of quartz glass which contains aluminum equal to or less than 0.01 ppm in the vessel that contains the dehydration reaction gas and the inert gas; and inserting the porous glass base material into the heated vessel to dehydrate and sinter the porous glass base material.

Abstract: A device for manufacturing a preform of glass material for optical fibres. A chemical deposition chamber, at least one burner mobile along a direction Z and adapted to deposit a chemical substance on at least an elongated element positioned along an axis Z-Z, at least one suction element mobile along the direction Z for collecting exhaust chemical substances, a collector tube associated with the at least one suction element and adapted to discharge the exhaust chemical substances outside the chemical deposition chamber through an exhaust opening formed on a wall of the chamber, and a coupling device between the collector tube and the wall at the exhaust opening, allowing sliding of the collector along the direction Z and along a direction X towards/away from the axis z-z.

Abstract: Disclosed is a low-attenuation single-mode optical fiber having a photoconductive core and a clad, which shows very low OH concentration in MFD (Mode Field Diameter) region. The optical fiber includes a core positioned at its center for photoconduction, and a dehydrated clad and a base clad which are coated on the clad in order. The dehydrated clad has a substantially identical refractive index to the base clad. A refractive index of the core is greater than those of the dehydrated clad and the base clad. The dehydrated clad has a relatively lower OH concentration than the base clad. The region composed of the core and the dehydrated clad has an MFD region at which OH concentration is less than 0.8 ppb.

Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor comprises the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

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 cap assembly for collecting cooling gas from a coolant chamber tube is disclosed. The cap assembly having connecting means and outlet means extending from its side walls being generally shaped and sized for detachable mounting on the body of the cooling gas chamber tube. The cap assembly is also employed in a hot optical fiber process which is being cooled by helium.

Abstract: Embodiments of the present invention provide a highly uniform low cost production worthy solution for manufacturing low propagation loss optical waveguides on a substrate. In one embodiment, the present invention provides a method of forming a PSG optical waveguide on an undercladding layer of a substrate that includes forming at least one silicate glass optical core on said undercladding layer using a plasma enhanced chemical vapor deposition process including a silicon source gas, an oxygen source gas, and a phosphorus source gas, wherein the oxygen source gas and silicon source gas have a ratio of oxygen atoms to silicon atoms greater than 20:1.

Abstract: A system and method in accordance with the present invention applies short bursts of a high temperature fluid to a hydrogen-loaded fiber to relocate the hydrogen within the fiber in the proximity of the fiber's core—to achieve a fiber having significantly improved photosensitivity. A stronger fiber grating is realized when the fiber is subsequently exposed to ultraviolet light.

Abstract: Disclosed is a system for drawing an optical fiber for controlling polarization mode dispersion. A furnace is provided for uniformly heating an optical fiber preform in the drawing system mounted to an optical fiber draw tower. The furnace comprises: (a) a main body; (b) a sub-body placed coaxially with the main body and having a diameter smaller than that of the main body; and (c) an upper gas feeding section over the main body, wherein the upper gas feeding section includes a first hollow rotary body having at least one slit in the inner surface thereof along the longitudinal direction of an optical fiber and at least one opening extended in the direction of the center, whereby a gas artificially/periodically creates non-contact polarization to the optical fiber by the first hollow rotary body. Effective non-contact control can be carried out about polarization mode dispersion of the optical fiber.

Abstract: An apparatus for manufacturing an optical fiber soot, which comprises a core partition having an opening portion at core burner side provided on a periphery of a core burner, in a reactor of the apparatus to be used in a conventional VAD method.

Abstract: A method and apparatus for providing a uniform coating thickness along an axial direction within an internal portion of a substrate tube is disclosed. A gas delivery unit is configured to coat the internal portion of the substrate tube. The gas delivery unit includes an insert. At least one of an inner diameter of the insert, a length of the insert, a gap between the insert and the substrate tube, and a flow of the gas mixture delivered to the substrate tube is configured to provide the uniform coating thickness along the axial direction.

Abstract: An apparatus that exposes only a selected portion of a length of optical fiber to a hydrogen atmosphere loading process. The apparatus includes a loading chamber that encloses at least the selected portion of the optical fiber and contains a hydrogen hydrogen atmosphere. At least one heating element regionally heats the hydrogen atmosphere surrounding the selected portion. The heating element may heat the hydrogen atmosphere to a temperature of at least 250° C.

Abstract: A device for manufacturing a preform of glass material for optical fibres. A chemical deposition chamber, at least one burner mobile along a direction Z and adapted to deposit a chemical substance on at least an elongated element positioned along an axis Z-Z, at least one suction element mobile along the direction Z for collecting exhaust chemical substances, a collector tube associated with the at least one suction element and adapted to discharge the exhaust chemical substances outside the chemical deposition chamber through an exhaust opening formed on a wall of the chamber, and a coupling device between the collector tube and the wall at the exhaust opening, allowing sliding of the collector along the direction Z and along a direction X towards/away from the axis z-z.

Abstract: The present invention relates to a method of making a soot particle and apparatus for making such soot particle. Preferably the method of making the soot particle is substantially free of the step of combusting a fuel and substantially free of the step of forming a plasma. Preferably, the apparatus is devoid of a heating element associated with both combustion and formation of a plasma. A preferred technique for at least one heating step for forming the soot particle is induction heating.

Abstract: A method for doping silica soot with fluorine during laydown, including providing a bait rod, and providing a burner, wherein the burner emits a reactant flame. The method also including providing at least one first gas-feed separate from the burner, wherein the gas-feed supplies a first jet of fluorine-based gases, and depositing a layer of silica soot on the bait rod by vaporizing a silica producing gas within the reactant flame of the burner. The method further including supplying the first jet of fluorine-based gases to the silica soot deposited on to the bait rod via the first gas-feed subsequent to vaporizing at least a portion of the silica producing gas within the reactant flame of the burner.

Abstract: A method for fusing an optical fiber preform comprises fusing the preform while blowing an oxidative gas against the preform to be fused from upper and lower directions of a fusing burner unit. An apparatus for carrying out the method includes a plurality of nozzles for preventing deposition of silica cloud, which are each set at an angle, &thgr;, of blowing the oxidative gas relative to the preform being drawn such 20°≦&thgr;≦60°.

Abstract: An optical apparatus includes a container filled with a gas containing hydrogen, and an optical element of silica glass which is accommodated in the container. The optical element is subjected to a heat treatment in a hydrogen atmosphere before being accommodated in the container. Within the container, the hydrogen concentration of the gas containing hydrogen is set to be less than 4% by volume, and the hydrogen having a partial pressure of in the range of 0.01 to 500 kgf/cm2 (0.98 to 49,000 kPa). By maintaining the optical element in an ambient containing hydrogen, defects in the silica glass are minimized even when high energy light such as ultraviolet light is emitted over a long period. Therefore, an increase in transmission loss and optical distortions in the silica glass are prevented.

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 preform for a low loss fiber optic cable and method and apparatus for fabricating such a preform is provided. The method includes providing AlCl3 and CVD precursors and locally doping CaCl3. Alkali and/or alkaline earth fluxing agents can be introduced. The alkali and/or alkaline earths are doped along with the aluminum into the silica glass core.

Abstract: An apparatus that exposes only a selected portion of a length of optical fiber to a hydrogen atmosphere loading process. The apparatus includes a loading chamber that encloses at least the selected portion of the optical fiber and contains a hydrogen hydrogen atmosphere. At least one heating element regionally heats the hydrogen atmosphere surrounding the selected portion. The heating element may heat the hydrogen atmosphere to a temperature of at least 250° C.

Abstract: The invention relates to the field of PCVD methods of making an optical fiber and apparatuses for use in PCVD methods. The disclosed methods and apparatuses improve the PCVD process by enhancing the efficiency of the deposition process. The use of the disclosed methods and apparatuses, individually or in combination thereof, will result in at least reducing the time necessary to deposit a predetermined amount of glass on a substrate.

Abstract: Disclosed herein is a dual-type system for producing optical fibers. According to this system, a draw tower is partitioned into a first spinning chamber and a second spinning chamber by a central partition frame. A preform feed unit, a furnace, a spinning nozzle and a diameter gauge are installed on each of the first and second spinning chambers in order to spin an optical fiber. Two coating units are installed at the lowest unit of the draw tower at positions corresponding to the first and second spinning chambers and used for coating the surfaces of the optical fibers spun and drawn through the first and second spinning chambers. Two ducts each having a filter are installed on a side of each unit of the draw tower at positions corresponding to the first and second spinning chambers for supplying fresh air to the optical fibers so as to prevent the optical fibers from absorbing foreign substances in addition to cooling the optical fibers.

Abstract: A porous optical fiber preform dehydration and sintering apparatus capable of improving the sealing performance between an upper lid and an elevating shaft and between the upper lid and a furnace tube or a furnace body, wherein an upper opening of a furnace tube for accommodating a porous optical fiber preform is shut by the upper lid, a preform holder is provided at the bottom end of an elevating shaft passing through the upper lid to be freely elevated therethrough, the porous optical fiber preform in the furnace tube is heated by a heater provided around the outer circumference of the furnace tube, the upper lid is formed by a metal, the preform holder is formed by a quartz glass or a ceramic, a corrosion-resistant layer is provided on an inner surface of the upper lid, a seal member made of rubber or resin is provided in an elevating shaft passage of the upper lid.

Abstract: A method for fusing an optical fiber preform comprises fusing the preform while blowing an oxidative gas against the preform to be fused from upper and lower directions of a fusing burner unit. An apparatus for carrying out the method includes a plurality of nozzles for preventing deposition of silica cloud, which are each set at an angle, &thgr;, of blowing the oxidative gas relative to the preform being drawn such 20°≦&thgr;≦60°.

Abstract: The present invention relates to a method and apparatus for fabricating a glass preform used in the manufacture of optical waveguides. The method utilizes a gas phase hydrolysis of a silica precursor without using a carrier gas. The flow of the reactants in the reaction chamber is confined and deposited on the target preform by careful control of the thermal profile in the system.

Abstract: Disclosed is an apparatus and method for sintering an over-jacketing tube in the zone sintering phase of an optical fiber preform fabrication process using a sol-gel process. The sintering apparatus includes: a processing tube; a gel tube assembly connected to a top rotation cap positioned at the top opening of the processing tube and being rotated at a predetermined rate, a ceramic pin extending downwardly from the center axis of the rotation cap, and a gel tube suspended from the bottom of the ceramic pin and suspended along the same axle of the processing tube; and a movable furnace initially positioned at the bottom of the processing tube and translating in a vertical direction along the processing tube for thermally treating the gel tube.

Abstract: In accordance with the invention, a preform from which fiber optics are drawn is fabricated by supplying reactants and gas vapors to the preform and by using two opposing forces to control the movement of a heat source supplying heat to the preform. The two forces function to reduce any hesitation or backlash in the movement of the heat source along predetermined portions of the preform to enable uniform layers to be formed within the preform.

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: An apparatus and a method for manufacturing an optical fiber preform by modified chemical vapor deposition (MDVD). The apparatus includes a heating device for heating a rotating substrate tube while moving in a predetermined direction, wherein the heating unit has a first heating unit located at the front with respect to the moving direction, for heating the substrate tube with a relatively low flame pressure, and a second heating unit located at the rear of the first heating means with respect to the moving direction, for heating the substrate tube with a relatively high flame pressure. The first and second heating units are selectively used for deposition and collapsing, such that the duration and temperature of collapsing can be reduced.

Abstract: An apparatus and method for sealing the top of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly constructed and arranged to removably cover the top of the draw furnace while mating with the downfeed handle. The apparatus includes an elongated sleeve having a base and a sealing mechanism positioned on the sleeve at a location remote from the base. The sleeve defines a chamber for receiving the downfeed handle, and the sealing mechanism is arranged with respect to the sleeve to mate with the downfeed handle received in the chamber. In one aspect of the invention, the apparatus further includes an inert gas purge for providing an inert atmosphere within the chamber. A method of sealing the top of an optical waveguide draw furnace is also disclosed.

Abstract: Methods, systems, and apparatus consistent with the present invention apply one or more laser beams to a glass object, such as a tube. The beams may have differing wavelengths, energy levels, and/or focal length characteristics. As the beam (single or multiple) penetrates the glass tube, it creates a channel. The beam is provided through the channel to a starting point on a region of the glass tube, usually the region below an inside diameter surface of the tube. In one embodiment, the beam is used to selectively heat a reactant gas within the tube to deposit a coating/dopant layer on the inside diameter surface. In another embodiment, the coating layer is already present and the beam selectively heats the layer causing thermal diffusion of the coating material into the glass tube at the region being heated.

Abstract: An apparatus for producing the glass soot used in the formation of optical fiber includes a burner with an internal atomizer. The atomizer includes an outer tube having a nozzle at an end thereof, and an inner tube located within the outer tube and having a closed end restricting fluid flow therethrough and defining a cylindrical sidewall having radially extending apertures spaced there along. The outer tube receives the glass-forming mixture in liquid form and the inner tube receives an atomizing gas which flows through the apertures in the sidewall of the inner tube and atomizes the glass-forming mixture as the glass-forming mixture travels through the outer tube.

Abstract: An apparatus for manufacturing optical fibers includes an external circular tube into which reactant gases are introduced from an entrance at one end thereof. An internal circular tube is inserted into the external circular tube through an exit at the other end of the external circular tube. The internal circular tube has a bore to which gas jets are supplied. Jet holes are formed to lead to the bore on the outer circumferential surface in the vicinity of the front end of the internal circular tube. The jet holes are for radially jetting the gas jets. An auxiliary jet hole is formed at the front end of the internal circular to tube to lead to the bore. The auxiliary jet hole is for jetting the gas jets frontward. A torch is installed to reciprocate along the axial direction of the external circular tube, for heating the external circular tube to induce a chemical reaction of the reactant gases to thus generate particles.

Abstract: An apparatus and process for cooling a quartz tube used in fabrication of an optical fiber preform by modified chemical vapor deposition. The apparatus has a nozzle ring supplied with a coolant. The nozzle ring has at least two vent sections that are be separatable for detaching the quartz tube from a lathe during processing, and a plurality of vents formed along the inside of the two vent sections for ejecting the coolant.

Abstract: An apparatus and method for producing dried, chopped strands from a supply of continuous fiber strands by the direct deposition of wet, chopped strands ejected from a chopping assembly into a drying chamber is disclosed. A transition chute is interposed between the chopping assembly and the drying chamber to guide the chopped strands to pass directly into the drying chamber.

Abstract: A method and apparatus for manufacturing optical fibers provided with hermetic coatings, wherein the bare fiber made from a heated preform advances through a stream of reactive gaseous medium which flows at a constant speed in the direction of advance of the fiber, which is then accelerated, and which is finally removed remote from the fiber by a stream of inert gas flowing in the opposite direction from the direction of the stream of reactive gaseous medium. Application is to manufacturing optical fibers for telecommunications.

Abstract: The invention provides a device for blocking the ingress of air on the surface of a moving member such as an optical fiber. The blocking of air is achieved by the establishment of a low pressure zone at the entry point of the fiber, the lower pressure zone being created by the injection of an inert gas in a direction opposite the direction of travel of the fiber. The invention is particularly useful in preventing the ingress of air into a UV curing apparatus for curing the ink on an optical fiber. There is also provided a method for reducing such ingress of air.

Abstract: A bubble stripping and coating apparatus for stripping entrained gas from the surface of a fiber, then coating the fiber with a coating material having a bubble stripping and coater body and a die assembly. The bubble stripping and coater body has a bubble stripping gas entrance for providing a bubble stripping argon gas to a bubble stripping gas chamber for stripping entrained gas from the fiber and having a die assembly bore. The die assembly is arranged in the die assembly bore, and has a guide die having a lower guide die opening with a diameter of less than 0.016 inches.

Abstract: Energy efficient apparatus for forming migration free glass fiber packages composed of fibers bearing substantially uniform coatings of size composition. Heated air from around the fiber forming bushing is drawn into a chamber through which the glass fibers pass to cause the water or solvent in the applied size to be evaporated. The flow of heated air through the chamber is regulated so as to obtain substantially uniform size application to the fibers.

Abstract: A method for collecting long glass fibers produces substantial lattice uniformity, eliminates the need for binder, and results in a generally rectangular wool pack which displays significant compressibility and recovery desired for commercial products. Generally spiral flow of fibers in the veil is captured on collecting conveyors and conveyed through direct forming apparatus with generally minimal disturbance of the spiral relationship between glass fibers. Further, a system is disclosed for producing wool insulation products of long glass fibers in accordance with the method. The principles and practices of the method and system may further be employed with short fibers to produce a wool pack of generally oriented short fibers.