Abstract: The present invention provides an apparatus for sintering a glass preform for an optical fiber, wherein the glass preform for the optical fiber is received in a muffle tube and is heated in an atmospheric gas while being suspended on a shaft and supported thereon, the apparatus comprising: a first gas seal that is provided at an upper end of the muffle tube, the shaft being inserted therethrough; a buffering chamber that is provided above the first gas seal and that covers the shaft; a second gas seal that is provided at an upper end of the buffering chamber, the shaft being inserted therethrough; and a unit that introduces the atmospheric gas exhausted from the muffle tube into the buffering chamber.

Abstract: Provided is a glass lathe that processes a glass member by heating the glass member with a burner, wherein a reflector that reflects electromagnetic waves is arranged around a portion of the glass member to be heated. The reflector preferably has a spherical surface with a portion removed therefrom, and may be formed of a mirror surface finishing agent for SUS, aluminum, or an aluminum alloy. An inner surface of the reflector is preferably covered by gold, platinum, or rhodium, and an outer surface of the reflector is preferably processed to improve thermal emittance, by applying an infrared light emitting coating thereto.

Abstract: A multi-electrode system includes a fiber holder that holds at least one optical fiber, a plurality of electrodes arranged to generate a heated field to heat the at least one optical fiber, and a vibration mechanism that causes at least one of the electrodes from the plurality of electrodes to vibrate. The electrodes can be disposed in at least a partial vacuum. The system can be used for processing many types of fibers, such processing including, as examples, stripping, splicing, annealing, tapering, and so on. Corresponding fiber processing methods are also provided.

Abstract: A method of manufacturing an optical fiber base material includes: forming a porous glass base material by depositing glass particles; providing a vessel which employs a composite tube, the composite tube including a portion formed by jacketing a first quartz glass containing aluminum equal to or less than 0.01 ppm with a second quartz glass containing aluminum equal to or more than 15 ppm; introducing dehydration reaction gas and inert gas into the vessel; heating the jacketed portion in the vessel which 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 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: Provided is a method for manufacturing an optical fiber. The method includes the steps of: heating and melting a silica-based optical fiber preform in a drawing furnace; drawing the melted preform into a linear shape from the drawing furnace, continuously cooling and solidifying the preform to form a bare optical fiber; coating the bare optical fiber with a resin to form an optical fiber; and continuously taking up the optical fiber while applying a tensile force, wherein, when a surface temperature of the cooled and solidified bare optical fiber reached down to 100° C. or lower, a surface of the bare optical fiber is reheated while applying a tensile force so as to remelt only a surface layer of the bare optical fiber, and the surface layer of the bare optical fiber is re-solidified, the bare optical fiber is coated with a resin, and the tensile force is released afterward.

Abstract: A multi-electrode system includes a fiber holder that holds at least one optical fiber, a plurality of electrodes arranged to generate a heated field to heat the at least one optical fiber, and a vibration mechanism that causes at least one of the electrodes from the plurality of electrodes to vibrate. The electrodes can be disposed in at least a partial vacuum. The system can be used for processing many types of fibers, such processing including, as examples, stripping, splicing, annealing, tapering, and so on. Corresponding fiber processing methods are also provided.

Abstract: Provided is an apparatus and method for manufacturing an optical fiber preform by supplying a high-frequency induction thermal plasma torch with at least glass raw material, dopant raw material, and oxygen, and depositing the glass particles synthesized in the plasma flame onto a surface of a glass rod that moves backward and forward relative to the plasma torch while rotating, wherein deposition of the glass particles is performed while cooling the glass rod. As a result, the concentration of fluorine doped in the cladding increase, thereby improving the relative refractive index of the preform.

Abstract: A manufacturing apparatus of a porous glass base material is provided. The manufacturing apparatus includes a burner repeatedly moving back and forthreciprocating in a direction along a longitudinal direction of an axis-rotating base member glass rod, where the burner ejects and deposits glass particles onto the base member glass rod, and an exhaust hood positioned above a porous glass soot formed by the deposition of the glass particles, where the exhaust hood repeatedly moves back and forth reciprocates in a same direction as the burner in synchronization with the burner. Here, the exhaust hood surrounds a portion of the porous glass soot corresponding to an angle ? of 100° or more with respect to an axial centera central axis of the porous glass soot. To be more specific, the angle ? may be preferably 180° or more.

Abstract: Apparatus for making glass fibers has AC induction coils for AC inductive heating of a spinner for spinning molten glass into molten glass fibers, an enclosure that at least partially surrounds the AC induction coils to protect a human worker, and electrically insulating shielding reducing AC power drain by being positioned between the AC induction coils and the enclosure to reduce inductive heating of the enclosure.

Abstract: Disclosed is a heating element having a ring shape provided in a furnace for drawing an optical fiber from a large-diameter preform so as to heat and melt a preform. The heating element according to heating element includes at least two hot zones having different heating temperatures, wherein one of the hot zones is arranged in a neck-down region of the preform to heat the preform at a temperature suitable for drawing an optical fiber. Also, the hot zone includes a first heating unit for heating a preform at a temperature suitable for draw an optical fiber from the preform; and a second heating unit for heating a surface of the preform to a relatively lower temperature than the first heating unit.

Abstract: A method of manufacturing an optical fiber base material includes: forming a porous glass base material by depositing glass particles; providing a vessel which employs a composite tube, the composite tube including a portion formed by jacketing a first quartz glass containing aluminum equal to or less than 0.01 ppm with a second quartz glass containing aluminum equal to or more than 15 ppm; introducing dehydration reaction gas and inert gas into the vessel; heating the jacketed portion in the vessel which 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 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 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 hybrid method of and apparatus for producing a structure capable of being drawn into an optical fiber. The method includes the steps of conducting vapor-phase reactants into an interior region of a glass tube, conducting aerosol form reactants into the interior of the glass tube. The tube is exposed to a heat, thereby causing a reaction among the vapor-phase and aerosol reactants. The reaction yields a product, in a solid form, within the tube. The apparatus includes a reaction tube, a vapor-phase reactant conduit, an aerosol-form conduit, and a heat source. The vapor-phase and aerosol-form reactant conduits facilitate introduction of vapor-phase and aerosol-form reactants into the reaction tube. The aerosol-form reactants are introduced proximate to a reaction zone created by the heat source. The aerosol-form reactants conduit and heat source travel the axial length of the reaction tube.

Abstract: A drawing apparatus 1 comprises a drawing furnace 11, a protecting tube 21, and a resin curing unit 31. A buffer chamber 41 is disposed between the drawing furnace 11 and the protecting tube 21, and has a length L1 in the drawing direction of the optical fiber 3. The buffer chamber 41 is constituted by a first buffer cell 42 and a second buffer cell 45. In the space within the buffer chamber 41, an He gas, which is an atmosphere gas within the drawing furnace 11, and the air, which is an atmosphere gas within the protecting tube 21, exist in a mixed state. The optical fiber 3 drawn upon heating in the drawing furnace 11 is fed to the protecting tube 21, and a predetermined part of the optical fiber 3 is annealed at a predetermined cooling rate. Thereafter, a coating die 62 coats the optical fiber 3 with a UV resin solution 63, and the resin curing unit 31 cures the UV resin 63, whereby a coated optical fiber 4 is obtained.

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: A method for forming a doped optical fiber includes drawing the optical fiber from a doped glass supply at a draw speed and a draw tension sufficient to introduce a heat aging defect in the optical fiber. The optical fiber is treated by maintaining the optical fiber within a treatment temperature range for a treatment time while preferably maintaining the optical fiber within a treatment tension range to reduce the tendency of the optical fiber to increase in attenuation over time following formation of the optical fiber. Apparatus are also provided.

Abstract: An optical fiber is formed by performing vapor phase deposition of SiO2 on the outside of a glass rod comprising a core section and a first cladding section and drawing a glass preform which formed by a second cladding section. Also, a single mode optical fiber is manufactured so that the ratio of the diameter D of the first cladding section and the diameter d of the core section is in a range of 4.0 to 4.8, and OH concentration is 0.1 ppm or less. Also, an optical fiber is manufactured so that a value of D/d>4.8, and the OH concentration is 0.1 ppm or less. It is thereby possible to maintain an initial loss in the 1380 nm wavelength range even if hydrogen diffusion occurs.

Abstract: Disclosed is an apparatus for low polarization mode dispersion. The apparatus is operative to draw an optical fiber from a prepared preform using a draw tower and includes (a) a main heating source serving to heat the preform; and, (b) a stationary auxiliary heating source disposed below the main heating source, adjacent to the optical fiber drawn from the preform, for serving to locally and periodically heating the drawn optical fiber so as to remove residual stresses from the optical fiber, thereby minimizing polarization mode dispersion.

Abstract: A method for rapidly increasing the photosensitivity of an optical fiber comprising the step of providing an optical fiber comprising a glassy material and a thermally-stable coating. The thermally-stable coating has a thermally-stable exposure band, wherein desired time/temperature exposure parameters fall within the time/temperature thermal stability exposure band for the coating. The optical fiber is exposed for the desired time/temperature exposure to a hydrogen-containing atmosphere. The desired temperature is more than 250° C. and the desired time exposure does not exceed one hour. The glassy material then may be irradiated with actinic radiation, such that the refractive index of the irradiated portion results in a normalized index change of at least 10−5.

Abstract: An optical fiber preform suspending and supporting apparatus able to prevent deformation of a pin placed in a high temperature environment and able to support a porous optical fiber preform without adversely influencing supports of the pin and without causing inclination relative to the vertical line of a main shaft, wherein a movable connector is fitted into an enlarged-diameter portion of the lower end of a main shaft, this enlarged-diameter portion is connected with the movable connector by a pin so that the movable connector is able to swing around the pin, a holding portion including a supporting portion is formed integrally at the bottom of the movable connector to hold an enlarged-diameter portion of the upper end of a starting preform, and the diameter of the pin is in the range of 20% to 50% of the outside diameter of the enlarged-diameter portion of the lower end of the main shaft, and an optical fiber processing apparatus including the same.

Abstract: There is provided a device and method for forming optical fiber anti-symmetric long period gratings by microbending. In the optical fiber grating forming device, a laser system emits a CO2 laser beam, a lens focuses the CO2 laser beam on an optical fiber in a predetermined width, an optical fiber support fixes both ends of the optical fiber and imparts tensile strain to the optical fiber, and a controller controls the intensity of the CO2 laser beam, the focusing distance of the lens, and the tensile force applied by the optical fiber support.

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: 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 for drawing a glass ingot into a rod having a given outer diameter is described. The method is characterized in that when the glass ingot is fed into a heating zone at a final tapered portion thereof, a temperature in the heating zone is decreased so that the final tapered portion is prevented from being drawn in excess owing to the heat from the heating zone.

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: An apparatus for heating an elongated glass body, which, for example, may be used as a pre-form for the drawing of glass fibers, includes a rotatable first chuck wherein the first end of the elongated glass body may be rotatably secured. In addition the apparatus includes a second rotatable chuck whereat the second end of the elongated glass body is introduced into a quartz tube and this quartz tube is clamped into the rotatable second chuck. A burner, which is adapted to slide parallel to the longitudinal axis of the elongated glass tube, heats the elongated glass body in such a manner, that a so called fire polish of the elongated glass body for the improvement of its surface quality occurs. A method for heating the elongated glass body is also disclosed.

Abstract: In a method of and an apparatus for forming composite and other fibers, individual filaments from two or more sets of continuous primary filaments of two or more heat-softenable fiberizable materials are brought together lengthwise to form pairs of continuous primary filaments. The groupings of continuous primary filaments are fed into a high energy attenuation blast where the filaments are heated, attenuated and formed into composite or other staple fibers of the heat-softenable fiberizable materials. Preferably, the individual continuous primary filaments of the groupings of continuous primary filaments are fused, adhesively bonded or otherwise joined together, prior to being introduced into the high energy attenuation blast, to prevent the individual primary filaments of the groupings of continuous primary filaments from separating in the high energy attenuation blast.

Abstract: A method for manufacturing an optical fiber (11), wherein the fiber (11) is drawn from one end of a preform (9) which is heated to above the glass softening temperature. The preform (9) is surronded by a protective gas (14) whose flow direction corresponds to the fiber drawing direction. The flow of the gas surrounding the preform (9) in the drawing area (10) is stabilized by an additional flushing gas (16).

Abstract: A thread is formed of one or a plurality of fans of continuous filaments on which a sizing composition is deposited. The moisture content on the thread is controlled by subjecting the fans of filaments to a current of air transversely to the direction of movement of the filaments between the zone in which the size is deposited and the zone in which the filaments are gathered together.

Abstract: A mass production method and apparatus of hermetic coating optical fiber where a bare fiber drawn from a preform is hermetically coated by CVD method in a reactor vessel, wherein a liquid flushes solid particles or by-products sticking to the reactor inner wall. The liquid may be supplied continuously or intermittently, to flush carbon particles generated during carbon coating process. The invention enables to produce a long hermetic coating optical fiber without choking the reactor, and improves a yield rate and productivity.