Abstract: A method of manufacturing active optical fibers comprising preparing a preform and then drawing a fiber from the preform, wherein the method consists in using a preform having a doped peripheral outer zone, said zone being intended to constitute the outer cladding of the optical fiber, the doping of the peripheral zone giving it a refractive index greater than that of the optical cladding, and giving it a difference in softening temperature relative to that of the core of the optical fiber which is less than the difference that would exist if the outer zone were not doped.

Abstract: Low attenuation, low dispersion of optical waveguides are provided by a process initiating with axial deposition of a high velocity-core soot stream impinging on a target at a high angle of incidence relative to the axis of rotation of the target. A core cylinder is built up axially by relative movement between the soot stream and target during deposition, the movement being non-constant in order to maintain a substantially constant diameter with a constant deposition rate. A cladding layer is then built up by deposition of soot radially on the core. Subsequent drying and sintering provides a vitreous preform which may be drawn directly into optical waveguides. Alternatively, the sintered product may be drawn down to smaller rods, which then are covered with further deposited soot cladding to a desired final thickness, and after further drying and sintering may be drawn to optical waveguides.

Abstract: The present invention relates to a method for the fusion splicing of carbon coated optical fibers and to a method for providing reinforced performance of the spliced points. Concretely, carbon coated optical fibers are fusion spliced in an atmosphere containing less than 0.5 vol % of oxygen without the removal of the carbon coating. In order to minimize the amount of damage to the carbon coating resulting from the fusion, the decline in the failure probability of the optical fiber is controlled by means of applying moisture to the spliced part or by means of the adhesion of the oxidized carbon gases to the optical fiber. On the other hand, the carbon coating layer which was removed by oxidation at the time of the fusion splicing is recoated by means of a CVD reaction using a laser as a heat source. By means of this, the decline in the fatigue characteristics of the spliced part can be controlled.

Abstract: A method of making a preform for an optical fiber, in which method a plurality of layers of fluoride glass are deposited inside a support tube (10); said layers (14) are deposited by laser ablation in a controlled atmosphere using a target (12) having the composition of said glass, which target is moved back-and-forth parallel to the axis of said tube, the temperature of the enclosure (1) in which said ablation is performed being not greater than the vitreous transition temperature Tg of said glass.

Abstract: Incidence of breakage in optical fiber drawn from sol-gel produced preforms is reduced by treatment of the still-porous glass by use of a chlorine-containing, oxygen-free gas mixture. Improved satisfaction of proof-rest requirements to at least 100 kpsi is assured by size reduction of unassimilated discrete particles in the fiber.

Abstract: Disclosed is a method and apparatus for providing reactant vapors to a utilization site. The apparatus includes a vaporization chamber enclosed by top and bottom walls, side walls and first and second end walls. The first end wall is elevated with respect to the second end wall. The reactant is supplied in liquid form to a flow distributor that delivers the liquid to that portion of the bottom wall near the first end wall. The angle with which the bottom wall is inclined with respect to horizontal is sufficient to cause the liquid to flow down the bottom wall at a rate sufficient to form a film, the thickness of which is smaller than that thickness which would support a bubble during heating of the film. The surface is heated to a temperature greater than the boiling point of the liquid, thereby converting the liquid reactant to a vapor that is delivered to the vapor utilization site.

Abstract: In a method for making optical fiber preforms, the time taken for sintering and annealing the clad or jacket layer is significantly reduced by only partially sintering the jacket soot boule in an atmosphere of helium. For example, instead of using one hundred forty-three minutes to sinter completely the soot boule, the boule is only partially sintered by heating in a helium atmosphere for fifty-nine minutes. At this stage of course, the soot boule is still partially porous and is generally opaque. The completion of the sintering and the annealing is then done in a single step in an atmosphere of nitrogen. Surprisingly, we have found that this process does not entrap nitrogen in the soot jacket layer to any noticeable or harmful extent, and the total time for sintering and annealing is significantly reduced.

Abstract: Apparatus for the formation of mineral wool fibres comprising a set of rotors (1) mounted on a front face (2) of a housing (3) wherein a rotor (5, 6, 7) has associated with it an air supply slot (8, 9, 10) for discharging an air blast close to the periphery of the rotor with an axial component for carrying off the mineral wool fibres and wherein the air slot has direction means (25) to direct the air at an angle to the axial direction that varies along the length of the slot.

Abstract: A method for producing a silica glass optical fiber, which comprises coating carbon on the optical fiber with the use of the remaining heat of not less than 800.degree. C. possessed by the optical fiber just after heat wire drawing, for thermal decomposition of a carbon coat-forming gas comprised of one or more members selected from the group of halogenated hydrocarbons, hydrocarbons, and halogen molecules, which has 5 to 15 hydrogen atoms per 10 halogen atoms, and a reaction apparatus for coating carbon, wherein the area of the outer end of an exhaust region is greater than the transverse sectional area of a coating region, and the outer end is outwardly opened.

Abstract: The process and apparatus of the present invention enable the production of glass fiber product from scrap glass fibers. The process includes: feeding the scrap glass fibers having an average length up to around 12 inches to a glass melting tank having a pool of molten fiberizable glass, melting the scrap glass fibers without the presence of non-vitrified glass forming materials in an oxidizing environment, conditioning the melt to a formable viscosity, and forming the glass fiber from the conditioned melt where for a given glass fiber product there is a near constant pull of the melted glass from the melter. The rate of feeding of the scrap glass to the melter is sufficient to maintain the pool of melted glass with a level within the range of .+-.0.35 inch (9 mm.) over a period of eight hours. The scrap glass fibers have a similar fiberizable inorganic composition to that of the desired glass fiber product and generally include fibers with organic-containing sizes and/or coatings.

Abstract: The initial stages in the manufacture of a glass-like mineral fiber suitable for a multiplicity of industrial uses are essentially conventional; a charge of raw minerals (igneous rock, basalt, slag from a blast furnace or other metal working furnace, phosphate slag, etc.) is melted, then spun and collected to produce a fibrous mineral "blanket". The "blanket" is chopped up, separated, and screened, producing a prilled material constituting a multiplicity of mineral fiber pellets of given average size. These pellets are subjected to brief, rapid acceleration, as by contact with a high-speed toothed rotary wheel, to accelerate and stress the pellets into an industrially usable material constituting a multiplicity of shredded, flake-like mineral fiber elements, at least one such element for each pellet.

Abstract: There is provided an apparatus for the production of a hermetically coated optical fiber in which a glass preform for an optical fiber is melt drawn in a melt drawing furnace to produce a bare optical fiber which is passed to a reactor where a feed gas is supplied and the bare optical fiber is coated with a thin carbon coating made from the feed gas by the Chemical Vapor Deposition method characterized in that the reactor comprises an upper portion to which the feed gas is supplied, a middle portion in which the CVD method is substantially carried out and a lower portion from which an exhausted gas is withdrawn, and a cross sectional area of the middle portion perpendicular to a longitudinal direction of the optical fiber is larger than that of the upper portion.

Abstract: An apparatus for manufacturing a hermetically coated optical fiber having a single reaction chamber into which a fare fiber and raw gas are to be introduced for applying a hermetic coating to the bare fiber while the bare fiber passes through the reaction chamber is characterized by that the reaction chamber has a plurality of inlet tubes to introduce the raw gas, and the plurality of inlet tubes open to the reaction chamber at different positions from each other in a direction of movement of the bare fiber passing through said reaction chamber.

Abstract: A reactor for applying a carbon coating to an optical waveguide fiber wherein the buildup of reaction by-products within the reactor is reduced by providing internal and external fiber exit ports with the diameter of the internal fiber exit port being greater than the diameter of the external fiber exit port, and gas shielding at the external fiber exit port.

Abstract: A method and apparatus are disclosed which place a glass blank on a lower mold arranged in an opposed relation to an upper mold, heat these molds and glass blank by an infrared lamp unit or high-frequency coil arranged around the molds and press-mold an optical glass element. In the method and apparatus, the infrared lamp unit or high-frequency coil is supported by a supporting mechanism such that it is movable along a direction in which the mold is moved. In cases where a relative position of the infrared lamp unit or high-frequency coil to the mold varies depending upon the shape and size of such molds or the shape and size of optical glass elements obtained, the infrared lamp or high-frequency coil is adjustably moved relative to the mold by a movable mechanism using a motor or air cylinder as an operation source. By using temperature sensors attached to both the molds, the temperatures of the upper and lower molds are controlled to a corresponding desired level.

Abstract: An oxygen-fuel firing system for a furnace comprising separate, spread apart nozzles for introducing gaseous streams of oxygen and fuel into the furnace at spaced apart locations. The gaseous streams merge within the furnace away from the furnace walls and crown. Thus, the main combustion within the furnace takes place in the central portion of the furnace where a broad flame cloud is created. The broad flame cloud provides a more uniform temperature profile within the furnace for a more efficient processing of materials being melted in the furnace.

Abstract: An apparatus for fabricating an optical fiber coupler having a well-controlled quality and an improved packaged strength is provided. The apparatus includes a holding device holding thereon a quartz tube sleeving therein an optical fiber strand having a spliced portion to be fused, two pulling stages oppositely pulling the fiber strand, a heating device having two torch blowpipes for heating through the quartz tube the spliced portion, a first driving mechanism for oppositely translating the pulling stages, a second driving mechanism for reciprocatingly translating the blowpipes along the quartz tube, and a programmable controller coupled to and for controlling the heating device, the first and the second driving mechanisms. A method for fabricating the optical fiber coupler is also disclosed.

Abstract: Optical fiber drawn from preforms including sol-gel-derived glass is found to contain small refractory particles of the order of a micron in size. These particles initiate fiber breaks with the result that fiber may not meet proof-test tensile strength requirements. An effective separation method relies upon density and/or size difference from suspended sol particles for separation in the ungelled sol. A preferred separation procedure is centrifugation.

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.

Abstract: A method of forming a fibrous composite that includes forming first and second layered groups of fibers extending in side-by-side relation; and passing gas such as air through the groups of fibers to effect controlled reduction in overall thickness of the two groups of fibers. The two groups of fibers are typically bonded together, and a think flexible, porous support layer may support the first layer which consists of glass fibers of smaller diameter than the glass fibers in the second layer.