Abstract: An optical cable for telecommunications having an optical core and a plurality of protecting and reinforcing elements or avers placed around the optical core. The optical core has a central reinforcing element, a polymer layer, a plurality of optical fibers incorporated in the polymer layer and a thin sheath which covers the polymer layer. The optical fibers have an alternating spin about their own axes with a maximum value of at least 4 twists per meter, and a core having a mean ellipticity in the range of 0.25 to 0.55, in such a way that the effects of birefringence of the fibers caused by the cabling process are significantly reduced.

Abstract: Electrical resistant bushings and methods for making fibers such as glass fibers by passing molten glass through these bushings to form fibers wherein the bushings have novel ears for attaching to electrical terminal clamps bringing electrical current to the bushing are disclosed. The novel ears have at least one generally V shaped notch at or near the unattached end of the ear to produce an improved temperature profile on the tip plate of the bushing. One preferred bushing of the invention has ears having 5 generally V shaped notches therein.

Abstract: A method of manufacturing an optical glass element for which flatness and smoothness of the surfaces of the optical glass element can be improved while securing the similarity of the cross-sectional shape of the optical glass element to that of the mother glass, and for which continuous production involving few steps can be carried out, and an optical glass element manufactured using the method. A mother glass is prepared, which has a cross-sectional shape substantially similar to a desired cross-sectional shape of the optical glass element, and the mother glass is drawn while heating to a predetermined temperature such that the mother glass has a viscosity of 105 to 109 poise.

Abstract: The present invention provides a bushing (10) having a glass outlet portion (18) in which two nozzle holes (12) of substantially flat shape are arranged, and permitting molten glass to be drawn out of the nozzle holes (12), and the bushing is provided with a concomitant flow guide (20) for guiding a concomitant flow made with drawing of the molten glass out of the nozzle holes (12), to between the nozzle holes (12).

Abstract: A method for determining at least one parameter of a periodic spin function ?(z) with period p, to be applied to an optical fiber along its length z during a drawing process. At least one parameter is selected so that (I) where ?1 is about 0.05 and y1 is the first of the three components y1(z), y2(z), y3(z) of a periodic function y(z) of period p such that (II) where LB is an expected beat length of said optical fiber and ?(z) is the derivative of the spin function ?(z) with respect to the length z. The method is effective for substantially reducing the PMD of optical fibers drawn when applying a spin function.

Abstract: An optical fiber for use in making components of an optical communication system has cladding and core materials the constituents of which cause a component made from the fiber to have a rate of change with respect to temperature of a response to a signal which passes through zero at a temperature Tm, where the temperature Tm is at or near a selected temperature, or falls within a selected temperature range; and the value of Tm of a fiber can be controllably changed by changing the concentration of a selected constituent of the fiber, such as, for example, the concentration of boron.

Abstract: A fast (high numerical aperture) cylindrical microlens, which includes an internally reflective surface, that functions to deviate the direction of the light that enters the lens from its original propagation direction is employed in optically conditioning laser diodes, laser diode arrays and laser diode bars.

Abstract: The specification describes a technique for drawing circular core multimode optical fiber using twist during draw to increase fiber bandwidth.

Abstract: Glass fibers, particularly those prepared by flame attenuation, display excellent chemical resistance to both acids and moisture while being highly biosoluble at the same time. The glass compositions used to make the fibers consisting essentially of: 38-52 wt % SiO2, 8-17 wt % A1203, 7-17 wt % B203, 0-7 wt % RO, wherein R is Ca, Mg, in a combination thereof, 20-31 wt R120, wherein R1 is Na, K, or a combination thereof, and 0-2.5 wt % Li20, and has a Final Aged Tensile Value of at least 3000; a HTV of 1700° F. or less and a liquidus temperature at least 200° F. lower than HTV.

Abstract: An apparatus for receiving and automatically moving a moving strand of fibers from a starting position to any one of a plurality of predetermined positions in a multi-grooved separator roll is disclosed. This apparatus is particularly in processes of making continuous fiber products from molten material and replaces a manual operation that presented safety problems.

Abstract: A fiberizing apparatus for converting molten material into continuous fibers having an improved internal support structure to minimize high temperature creep and sagging of the tip plate or orifice plate is disclosed. The preferred internal support structure is welded to the sidewalls and the top surface of the tip plate and is comprised of a plurality of internal intersecting supports that form a diamond shaped structure. A method of fiberizing a molten material using the fiberizing apparatus is also disclosed.

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: Mineral fibers made of natural basalt materials are produced by preheating basalt to a temperature of between 150 and 900° C., loading the preheated basalt into a melting furnace, melting the basalt to form a glass mass, moving the melted glass mass through a stabilization zone of the melting furnace until a fiber production temperature of tmelt+(50-250° C.) is reached, further stabilizing the glass mass in a feeder at a temperature of 1250 to 1450° C. to obtain a glass mass having the composition 1 Al 2 ⁢ O 3 + SiO 2 CaO + MgO ≥ 3 ⁢   ⁢ FeO Fe 2 ⁢ O 3 ≥ 0.5 2 ⁢ Al 2 ⁢ O 3 + SiO2 2 ⁢ Fe 2 ⁢ 0 3 + FeO + CaO + MgO + K 2 ⁢ O + Na 2 ⁢ O > 0.

Abstract: A method for making preforms for use in a glass lens molding process and molding lenses is disclosed. A glass rod is formed preferably by dipping a bob into a homogeneous melt of a predetermined optical glass, maintaining the temperature of the homogeneous melt at least the melt temperature and producing a rod of glass from the homogeneous melt, allowing the rod of glass to cool and solidify, and then cutting the rod of glass into predetermined lengths. By withdrawing the bob at a predetermined pull rate the rod of glass can be produced with a predetermined diameter. Using a constant pull rate, the rod of glass will be cylindrical in shape and can be cut into a series of individual cylindrical preforms. The preforms can be inserted into a compression molding apparatus for the forming of a glass optical element therewith. The orientation of the preform is such that the cut planar surfaces of the preform are parallel to the direction of compression of the molding process.

Abstract: A process and apparatus are provided for the manufacture of a composite fibrous strand including glass fibers. Glass fibers and an additive fibrous material (e.g., thermoplastic polymeric fibers) are each introduced separately into a substantially rotationally symmetric zone that is closed circumferentially except for a longitudinal introduction locale. The glass fibers and the fibers of the additive fibrous material are subjected to a vortex to form a homogeneous composite fibrous strand. Good admixture of the fibrous components is made possible thereby facilitating the ultimate production of composite articles wherein the glass fibers are disposed as reinforcement in a highly uniform manner. Such homogeneity and uniformity provides improved mechanical properties to the end user.

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: The invention relates to a process for the manufacture of, in particular, continuous mineral fibers from rock, glass-containing technical wastes, technical glass wastes, and to an apparatus. The object of the invention is to create a process which enables the said group of starting materials to be processed from a stable melt to give, in particular, continuous fibers and thus to improve fiber quality and processability. The starting products are melted in a melting bath, transferred to a forehearth, a feeder device and then fed to a bushing device and from there taken off as thread, the melt being fed to the feeder device from a take-off area of the melt in which the melt has the parameters according to the invention of temperature, processing range, viscosity, quotient of viscosity and surface tension and energy of activation of viscous flow of the melt, and the ratio of height of the melt in the forehearth to the height of the melt in the melting bath being in a defined range.

Abstract: An active single-mode optical fiber has the core made of a rare earth doped non-oxide glass and the cladding made of an oxide glass. The glass of the core has a melting temperature lower than that of the glass of the cladding and lying within the range of the softening temperatures of the latter. In a preferred embodiment the core is made of a chalcogenide glass and the cladding is made of a lead silicate glass. To produce the fiber, a preform, obtained by introducing an element made of the non-oxide glass into the hole of a capillary tube made of the oxide glass, is brought to a temperature lying within the range of softening temperatures of the oxide glass and not lower than the melting temperature of the non-oxide glass, and is drawn. The capillary tube, during the drawing process, serves as a container for the molten glass of the core.

Abstract: A process and apparatus are described for forming glass fibers which utilizes a rotating melter for the fiber glass batch materials and stators which house the fiber forming bushings. The stators are encompassed by the rotating melter, but not physically touching it. The glass melt flows directly from the melter to the bushings in the stators and temperatures at the bushings are controlled by raising or lowering the stator with respect to the melter, the bushings being devoid of any electrical energy input as is conventionally practiced.

Abstract: Method for manufacturing cylindrical microlenses having exceptional optical properties, and the lenses manufactured according to the process. According to the present invention, a method is provided for fabricating cylindrical microlenses, the method comprising the steps of forming a glass preform by means of grinding at least one face thereof in the direction transverse to longitudinal axis of the lens, the preform having the shape of a cylindrical lens, and drawing the glass preform to reduce its cross-sectional dimensions while retaining its cross-sectional shape, thereby providing a cylindrical microlens with a high numerical aperture or other desirable characteristics. The drawing step may be facilitated by means of the application of heat to the preform. Further, the preform may be roughly formed to a shape intermediate to its finished form by casting, sintering, extruding, or other glass forming methodology.

Abstract: An apparatus is provided for producing a glass fiber package. The apparatus includes a heated bushing for supplying streams of molten glass to be drawn into continuous fibers, a rotatable member adapted to draw the streams into fibers and to wind the fibers into a package, an applicator for applying a size to the fibers, and a drying device including a heated element maintained at a temperature of between about 1000.degree. F. and 1500.degree. F. for contacting and transferring energy in the form of heat to the sized fibers to dry the fibers before they are wound into the package. The heating member is stationary while contacting the sized fibers.

Abstract: The melting tub for producing the molten mass from a mixture of raw material is associated with an additional melting unit by means of which a recycled molten mass is obtained from mineral wool waste largely corresponding to the molten mass obtained from the mixture of raw materials in quality and composition. The recycled molten mass is supplied to the molten mass in the melting tub through a suitable introduction device. The recycling exhaust gas from the additional melting unit is fed to the tub exhaust gas, and the mixture of exhaust gas is utilised for pre-heating combustion air and mixture of raw materials.

Abstract: A method for the controlled stretching of one or more optical fibers according to a desired profile and a device for its implementation. The method includes several steps. In these steps, a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating chamber is laid down, a relationship f of variation of the diameter D.sub.s of the fiber during exit from the heating chamber is chosen such that D.sub.s =f(x.sub.s) wherein x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating chamber, successive stretching operations are performed on the fiber to modify, each time, the diameter D.sub.s of the fiber during exit from the heating chamber, so as to follow the profile defined by the relationship f of variation. The method has application to the making of optic fiber devices.

Abstract: This invention is a strand of silicate glass fibers with a carbon skin or sheath around each glass fiber of the strand. The invention uses hydrocarbon pyrolysis with silicate fiber glass manufacturing to produce fibers using conventional melt-bushing technology. The formation of a carbon skin or sheath on the silicate glass fibers offers numerous advantages. For example, pyrolyzing hydrocarbons is endothermic. Heat is removed in the process and fibers are cooled faster. This helps to achieve higher throughput.

Abstract: A compact, tunable, wavelength independent, all-fiber attenuator is produced by heating a single-mode fiber to create at least one taper therein through capillarity rather than through pulling, pushing or twisting the fiber. The attenuator may be tuned to achieve the desired value of attenuation and wavelength independence by imparting a small bend to the taper. The attenuator may be a fixed value attenuator or a variable attenuator. When a fixed value attenuator is desired, the tapered and bent structure is encapsulated in an adhesive and glued onto a substrate.

Abstract: A process and apparatus are provided for coating a sizing composition onto glass fibers. The apparatus includes an applicator for applying a liquid sizing composition to the glass fibers and a treatment station for treating the sized fibers to increase the viscosity of the sizing composition, thereby improving the adherence of the sizing composition to the fibers.

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 and apparatus for producing a composite thread formed by the association or blending of continuous glass filaments and continuous filaments thermoplastic organic matter. The thermoplastic filaments are, while in the form of a sheet, blended with a cluster or sheet of glass filaments after having been heated to a temperature in excess of their transformation temperature, stretched and then cooled in their stretched state.

Abstract: In a heating furnace an optical fiber preform is heated and the optical fiber is drawn. The obtained optical fiber is cooled by a cooling gas in a cooling apparatus provided beneath the heating furnace, then a resin is coated on the outer circumference of this optical fiber by a resin coater. At this time, the blowing direction of the cooling gas blown out from the optical fiber inlet of the cooling apparatus is inclined exactly by a predetermined angle (.theta.) with respect to the axial line of the running optical fiber. As a result, even if no rise suppression gas is used, it is possible to prevent the cooling gas blown upward from the cooling apparatus from entering into the heating furnace and thereby to prevent the lowering of the quality of the optical fiber due to the adhesion of dust. Also, a cooling apparatus container enclosing the cooling apparatus is provided.