Abstract: A resistive heating element is used to fabricate a long-period grating mode converter. The resistive heating element creates a localized heating zone for creating an asymmetric perturbation at a periodic series of axial locations along the length of a segment of optical fiber that supports the propagation of both a symmetric mode and an asymmetric mode. In a further technique, a grating is written with an index contrast value that is higher than a selected optimum value. The heating element is then used to anneal the fiber segment so as to reduce the contrast value of the grating to the selected optimum value.

Abstract: An optical transmission medium bend working device that reduces bending loss of an optical transmission medium includes: an arc-discharge electrode that partially and sequentially heats a bend working area of a tape core wire in an up-down direction, the tape core wire extending in the up-down direction with a distal end thereof being located on a lower side, the bend working area being located above the distal end; a core wire holding unit that holds a portion of the tape core wire located above the bend working area; and a bending arm that applies force to the tape core wire in a state where the bend working area is heated to bend the tape core wire at the bend working area.

Abstract: A method and apparatus are described, which permit a simple, rapid manufacture of an end of an optical fiber bundle. According to the method a metallic sleeve is placed on an end section of the bundle, the end section with the sleeve on it is positioned in a shaping tool without pressing the sleeve and then pressure is exerted on the sleeve exclusively in a radial direction by press jaws of the shaping tool. In the optical fiber bundle made by the method the outer optical fibers (4?) of the optical fiber bundle (1) are embedded at least partially in the sleeve material. The apparatus for making the end of the bundle (1) with the sleeve (10) has a shaping tool (20) including at least two radially movable press jaws (22a-22f) that substantially surround the sleeve (10).

Abstract: A multi-functional method and apparatus are disclosed for producing a low hydroxyl ion-containing core rod from a tube suitable for the production of low-water optical fibers. The method and apparatus combine the use of process steps of (1) hermetically sealing a tubular quartz handle of a tubular porous core preform to a tube used to feed the porous preform into a sintering furnace, (2) dehydration and sintering, and (3) elongation of the sintered preform under vacuum, all without exposing the preform's central aperture surface to ambient atmosphere.

Abstract: A method and apparatus for consolidating an optical fiber preform, wherein the optical fiber preform is located in a furnace comprising a muffle tube, said muffle tube comprising an inner section and an outer section surrounding the inner section. The inner and outer sections are comprised of different materials, and the preform is exposed to a pressure less than 0.8 atm while simultaneously exposing said preform to a temperature of at least 1000 C.

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: In a furnace for heating an optical fiber preform to be inserted from an insertion opening, the furnace includes an annular sealing body for sealing a clearance gap between the optical fiber preform and the insertion opening. The annular sealing body is formed from stacked annular disks respectively having an insertion hole in its center area. The annular disk has slits formed from a inner edge of the annular disk toward its periphery side and flexible portions that are defined by the slits and bend by an interference with the optical fiber preform to be inserted into the insertion hole. When the optical fiber preform is inserted into the insertion hole of the annular sealing body, the flexible portions bend.

Abstract: A method and apparatus are described, which permit a simple, rapid manufacture of an end of an optical fiber bundle. According to the method a metallic sleeve is placed on an end section of the bundle, the end section with the sleeve on it is positioned in a shaping tool without pressing the sleeve and then pressure is exerted on the sleeve exclusively in a radial direction by press jaws of the shaping tool. In the optical fiber bundle made by the method the outer optical fibers (4?) of the optical fiber bundle (1) are embedded at least partially in the sleeve material. The apparatus for making the end of the bundle (1) with the sleeve (10) has a shaping tool (20) including at least two radially movable press jaws (22a-22f) that substantially surround the sleeve (10).

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: Disclosed are an optical fiber preform manufacturing apparatus and method in which processes for shrinking and closing a deposited tube are conducted using a device suitable for those processes, which device is other than the device used in a deposition process for forming the deposited tube on the inner surface of a preform tube, thereby reducing the processing time while reducing the amount of OH penetrated from the preform tube into a vitreous component of the deposited tube, thereby achieving a reduction in OH loss.

Abstract: The present invention discloses a generic method for producing void and gas occlusion free materials, as well as apparatuses for batch and continuous production of same. This generic method can be utilized in the production of a wide variety of polymeric compounds and composites and specifically encompasses the two ends of the polymeric composite spectrum, that is, polymer concretes on the one hand, and fiber-reinforced polymer composites on the other. The composite materials of the present invention are characterized by visual count as being void and gas occlusion free to the level of 1 micron at 1250.times. magnification. Concomitantly, the invention produces useful polymer concrete materials which exhibit substantially improved integrity for easy machining at high speeds, and high dielectric and mechanical strength, as compared with composite materials produced by conventional methods.

Abstract: The present invention discloses a generic method for producing void and gas occlusion free materials, as well as apparatuses for batch and continuous production of same. This generic method can be utilized in the production of a wide variety of polymeric compounds and composites and specifically encompasses the two ends of the polymeric composite spectrum, that is, polymer concretes on the one hand, and fiber-reinforced polymer composites on the other. The composite materials of the present invention are characterized by visual count as being void and gas occlusion free to the level of 1 micron at 1250.times. magnification. Concomitantly, the invention produces useful polymer concrete materials which exhibit substantially improved integrity for easy machining at high speeds, and high dielectric and mechanical strength, as compared with composite materials produced by conventional methods.

Abstract: A flame attenuation apparatus for forming flame attenuated fibers, preferably glass fibers, includes means for providing continuous filaments; burner means for providing a high temperature, high energy stream of combustion gases; means for feeding the continuous filaments into the high temperature, high energy stream of combustion gases; and an elongated rod filament guide with a plurality of grooves therein for receiving, guiding and supporting the continuous filaments, as the continuous filaments are fed into the high temperature, high energy stream of combustion gases. The elongated rod is preferably made from graphite with a boron-nitride coating and, preferably, has at least two flat surfaces and at least two curved surfaces with the grooves therein.

Abstract: An annealing mold and fiber retaining device includes a fiber holding plate having fiber channels and an annealing insert. Retainers are provided for attachment to the plate to retain fibers in the channels. After annealing, the annealing insert is replaced by a packaging insert. The fiber holding plate is mounted between a support plate and a cover plate. The mounted plates include a coextensive current conductor port and the plates are mounted in a housing which includes vibration mounts for isolating the plates from vibration within the housing.

Abstract: A holder for annealing a fiber optic coil uses a silica ring on a silica substrate, or silica tubular coil, either of which may be directly incorporated into a coil subassembly for a Faraday-effect current sensor. The ring may be formed in a silica plate by sandblasting or grinding, or formed separately and adhered to the plate. In the tubular holder embodiment, silica tubes and sleeves are used to protect fusion splices between the ends of the fiber coil and polarizing fibers. Use of silica for most of the subassembly components matches the coefficients of thermal expansion of the subassembly to that of the fiber coil, and also allows the coil to be annealed at extremely high temperatures. Annealing yields fiber coils of lowered birefringence, particularly when used with spun fibers. Ferrules are used to adjust the angular orientation of the fibers with respect to their planes of polarization.

Abstract: A method and apparatus for the treatment of fiber pieces, with which the fiber pieces (24) in a gas/solid mix are fed through a transport line (11) into a heating device (14). Inside the heating device (14) the exposed ends of the fiber pieces (24) are rounded off and/or thickened. Subsequent to the treatment in the heating device the treated fibers (25) flow into a feed line and from there into a separating device (18), in which the gas/solid mix is separated. The fiber bits produced according to the invented method improve the mechanical quality and characteristics of fiber composite materials considerably. By utilizing the described device the invented method can be carried out most economically. (FIG.

Abstract: Apparatus for fabricating fused optical fibre devices comprises a furnace provided with an electric heating element (5). A heat-distributing insert (7) is provided within the heating element (5), the heating element and the insert being sized and shaped to define a heating chamber for an optical fibre arrangement. The apparatus includes means for passing electric current through the heating element (5), and means (8) for supplying and maintaining an inert atmosphere within the heating chamber.