Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

Abstract: A fused-biconical-taper bend-insensitive single mode optical fiber includes a core and a cladding. The core is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a diameter Dcore thereof is 7-10 ?m, and a relative refractive index difference ?1 thereof is 0.20% to 0.40%. A range of ?Ge is 0.30% to 0.60%, and a range of ?F is ?0.05% to ?0.15%. The cladding includes three layers. A first layer is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a relative refractive index difference ?31 thereof is ?0.02% to ?0.10%, and a diameter D31 thereof is 15-30 ?m. A second layer is a fluorine-doped silicon-dioxide quartz glass layer, a relative refractive index difference ?32 thereof is ?0.01% to ?0.05%, and a diameter D32 thereof is 30-50 ?m. A third layer is a pure silicon-dioxide quartz glass layer, and a diameter D33 thereof is 124-126 ?m.

Abstract: A manufacturing method that enables stably making a high-quality optical fiber is provided. The manufacturing method of the present invention comprises: a softened portion falling step in which an optical fiber preform is heated in a heating furnace and a dropping part of softened portion of the preform thus heat-softened is allowed to drop; and a drawing step for drawing the preform such that the softened glass is drawn into a fiber by applying a tension with a take-up means after the softened portion falling step, whereas the preform is rotated about its axis at the softened portion falling step.

Abstract: Optical fibers are provided for modal discrimination which include a central core and a cladding disposed about the central core. The central core has a non-circular and non-elliptical cross-section, and it is rotated about a central axis of the optical fiber along the length of the optical fiber at a selected pitch resulting in the capability of a fundamental mode beam output for large core sizes. An optical system includes a seed optical source configured to provide a seed beam and an optical amplifier configured to receive and amplify the seed beam. The optical amplifier also includes an active optical fiber having a large mode area non-circular and non-elliptical core rotated about a central axis of said active optical fiber to provide modal discrimination and fundamental mode output.

Abstract: The disclosure is directed to an all glass method that frustrates the internal reflection on the outside diameter of an optical fiber's glass cladding thus allowing the light to be directed to a light absorbing material/ medium and allowing the desired light in the core of the fiber to be preserved with no loss. The frustration is achieved by having at least one glass frustrater in glass-to-glass contact with the outermost cladding layer of the optical fiber. The glass frustrater is made of a glass that has a glass transition point lower that both the core and cladding glasses of the fiber. Chalcogenide and phosphate glasses are among the glasses suitable for this application.

Abstract: A twin fiber laser arrangement is configured with active and passive fibers supporting respective signal and pump lights and a reflective coating surrounding the fibers along a section of the arrangement. The passive fiber has regions covered by respective protective layer and coating-free regions alternating with the layer covered regions, wherein the reflective coating is configured to overlap the protective layer which shields the end of the reflective coating from high power pump light.

Abstract: An optical fiber includes a bare optical fiber portion, to which elastic torsion is applied, and a coating layer, which coats the bare optical fiber portion, is formed of curable resin, and causes elastic repulsion against resilience occurring in the bare optical fiber portion so that the elastic torsion applied to the bare optical fiber portion is held.

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: A multi-core optical fiber according to the present invention includes plural single-core optical fibers, and comprises an intermediate portion in which a side surface of each single-core optical fiber is covered with a resin layer, and a terminal portion in which the each single-core optical fiber is exposed from the resin layer. In the terminal portion of the multi-core optical fiber, the single-core optical fibers are separated from each other.

Abstract: An optical fiber having excellent strength that can be manufactured at low cost, as well as a method for making such optical fiber, is provided. An optical fiber 1 is a silica-based optical fiber comprising a core 11, an optical cladding 12 surrounding the core & 11, and a jacketing region 13 surrounding the optical cladding 12 and having a uniform composition throughout from the internal circumference to the outer circumference. A compressive strained layer having a residual compressive stress is provided at the outermost circumference of the jacketing region 13.

Abstract: Apparatus for applying traction to an elongate cylindrical element produced by fusion of an end portion of a preform of glass material, in which a traction device is capable of being connected to a portion of the elongate cylindrical element to provide traction of the elongate cylindrical element along an axis. A device for the rotation of the elongate cylindrical element applies a twist to the elongate cylindrical element about the axis simultaneously with the traction.

Abstract: Light diffusing optical fibers and methods for producing light diffusing optical fibers are disclosed. In one embodiment, a light diffusing optical fiber includes a core portion formed from silica glass and comprising a plurality of helical void randomly distributed in the core portion of the optical fiber and wrapped around the long axis of the optical fiber. A pitch of the helical voids may vary along the axial length of the light diffusing optical fiber in order to achieve the desired illumination along the length of the optical fiber. A cladding may surround the core portion. Light guided by the core portion is scattered by the helical voids radially outward, through the cladding, such that the light diffusing optical fiber emits light with a predetermined intensity over an axial length of the light diffusing optical fiber, the light diffusing optical fiber having a scattering induced attenuation loss greater than about 0.2 dB/m at a wavelength of 550 nm.

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 single-mode fiber with certain parameters into the core of another fiber with different parameters; in particular single-mode guided light of a shorter wavelength is coupled into the core of a fiber which is a single-mode fiber at a longer wavelength but acts as multimode fiber for the shorter wavelength. Fabrication involves use of a model to determine a length of a pre-taper.

Abstract: The shape of the exterior surface of a portion of an optical fiber that is to be attached to, or embedded in, an external structure or material is modified to improve the adhesion characteristics of that portion of the fiber. Improving the adhesion characteristics of that portion of the fiber allows a very strong bond to be formed between it and the structure or material to which it is attached or in which it is embedded. Strengthening this bond helps prevent relative movement from occurring between the fiber and the exterior material or structure to which it is attached or in which it is embedded.

Abstract: Provided is a method of manufacturing an optical fiber base material by an inside mounting method, including: a step of rotating and heating a glass tube fixed at two positions and supplying a gas into a through-hole of the glass tube, wherein in the step, the glass tube is warped so that an axis between respective fixed portions of the glass tube has a shape in which a catenary curve is reversed in the vertical direction.

Abstract: A method for producing an optical fiber is provided. The method includes the steps of drawing an optical fiber from a heated glass source in a furnace and introducing index perturbations to the optical fiber via a plurality of perturbation sources arranged at a plurality of different azimuthal locations. The index perturbations are introduced synchronously at different locations along the axial length of the fiber by the plurality of perturbation sources in a generally helical pattern on the outside surface of the fiber in one embodiment. According to another embodiment, the index perturbations are introduced by the plurality of perturbation sources at different frequencies.

Abstract: A multimode optical fiber is drawn form an optical fiber preform, and during said drawing step, a series of perturbations are imparted to the fiber along the length of the optical fiber, said perturbations exhibiting a non-constant amplitude or repeat period.

Abstract: Method for manufacturing optical fibers, comprising cutting mirror-symmetrical grooves (2, 3) on a preform rod (1) which is inserted into a tube (4) of optical material; fusing the perform rod and the tube in a nonworking area; pulling the fused perform rod and tube into a perform which has longitudinal channels defined by the grooves (2, 3) and the tube (4); cutting the perform (5) into segments; etching the longitudinal channels; sealing segment end(s), assembling segments with a capillary tube and tubular process holder; joining the segment and capillary tube on a side opposite to the tubular process holder; drawing the perform segment into an optical fiber, and applying a protective strengthening coating on the drawn optical fiber. As a result, an optical fiber is produced, which has birefringent properties influenced by dimensions of the mirror-symmetrical grooves and the etching step.

Abstract: In a process for producing a low polarization mode dispersion optical fiber, which comprises the steps of drawing a glass preform into an optical fiber and of spinning, during drawing, the optical fiber about an optical fiber axis, the spinning is imparted according to a bidirectional and substantially trapezoidal spin function, which includes zones (P) of substantially constant amplitude (plateau) and zones of transition (T) where inversion of the spin direction takes place, wherein the extension (p) of the zones of substantially constant amplitude is greater than the extension (t) of the zones of transition, and the number of inversions of the direction of spin in a length of fiber of 20 m is at most two.

Abstract: A method for producing a single-mode fiber for submarine cables including washing and flame polishing of a preform, fiber drawing, coating with a first coating layer and curing therein using an UV-curing device, coating with a second coating layer and curing therein using the UV-curing device, fiber selection with a 2% screening strain, and testing the properties of the fiber. The fiber has a high strength and long coiling length exceeding 100 km and the method is easy to practice with low production cost and parameters involved therein are highly controllable.

Abstract: A method of elongating a glass base material to obtain a glass rod having a smaller diameter, using a glass base material elongating apparatus including a feeder at least for the glass base material, a heating furnace, and an elongating mechanism of the glass base material below the heating furnace, is such that a horizontal plane position measuring unit of the glass base material is provided inside or near the heating furnace, the feeder has a glass base material horizontal plane position adjusting unit, and the elongating mechanism has three or more sets of elongating rollers capable of switching between grasping and releasing for keeping the position of the glass rod in the horizontal plane to be constant, and the glass base material is elongated with the position thereof in the horizontal plane kept as targeted by controlling the glass base material horizontal plane position adjusting unit.

Abstract: Simple and small-sized equipment which continuously afford alternate twists to an optical fiber and a method using the apparatus are provided. The equipment includes: a guide roller for causing the fiber to roll; a roller supporting member for holding the roller in a manner allowing the roller to freely turn about an axial center X; and a driving unit to cause the roller to oscillate by making the supporting member to turn about an axial center Y that is inclined relative to the axial center X. The method includes: arranging a guide roller to intersect the fiber, the roller being held by a roller supporting member to freely turn about an axial center X; oscillating the roller by driving the supporting member to revolve about the axial center Y which is inclined relative to the axis center X; and causing the fiber to roll to afford alternate twists to the fiber.

Abstract: A method for performing a multi-stage dilation of optical fibres is described, the method comprising performing successive dilation steps such that the adiabatic condition is maintained throughout the fibre. There is also described various optical devices employing such multi-stage dilated optical fibres, as well as methods of manufacture of the optical devices.

Abstract: Armored fiber optic assemblies are disclosed that include a dielectric armor along with methods for manufacturing the same. The dielectric armor has an armor profile, thereby resembling conventional metal armored cable to the craft. The dielectric armor provides additional crush and impact resistance and the like for the optical fibers and/or fiber optic assembly therein. The dielectric armor is advantageous to the craft since it provides the desired mechanical performance without requiring the time and expense of grounding like conventional metal armored cables. Additionally, the armored fiber optic assemblies can have any suitable flame and/or smoke rating for meeting the requirements of the intended space.

Abstract: A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.

Abstract: A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.

Abstract: A composite waveguide includes a central core configured to transmit a plurality of modes and at least one side core helically wound about the central core and configured to be selectively coupled to at least a portion of the plurality of modes in the central core.

Abstract: A coating is applied on an optical fiber drawn from a melted tip of an optical-fiber preform. A glass spin is applied to a coated optical fiber by gripping the coated optical fiber with at least a pair of spinning applying rollers arranged in different levels with parallel rotation axes, rotating the spinning applying rollers so that the coated optical fiber is guided in a predetermined direction, and alternately shifting the spinning applying rollers in opposite directions along the rotation axes. The glass spin is applied to the coated optical fiber in a state in which each of the rotation axes is tilted at a predetermined angle from a plane perpendicular to the first direction.

Abstract: A coating is applied on an optical fiber drawn from a melted tip of an optical-fiber preform. A glass spin is applied to a coated optical fiber by gripping the coated optical fiber with at least a pair of spinning applying rollers arranged in different levels with parallel rotation axes, rotating the spinning applying rollers so that the coated optical fiber is guided in a predetermined direction, and alternately shifting the spinning applying rollers in opposite directions along the rotation axes. The glass spin is applied to the coated optical fiber in a state in which each of the rotation axes is tilted at a predetermined angle from a plane perpendicular to the first direction.

Abstract: A terminal for mounting to a fiber distribution cable includes a housing having a base and a cover. The cover is connectedly engaged with the base. The terminal further includes a plurality of adapters disposed on the cover. A fiber routing tray having a top panel and a bottom panel is disposed in an interior cavity. The fiber routing tray includes a storage space defined between the top and bottom panels for storing a length of optical fiber. A method for installing a terminal includes providing a terminal having a housing defining an interior cavity. A cable is pulled from the interior cavity of the housing. The cable is spliced to a fiber distribution cable with a splice. The cable is inserted back into the interior cavity. A spliced end of the cable, a spliced end of the fiber distribution cable and the splice are inserted in a retention device.

Abstract: A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.

Abstract: A method of forming a nanowire is disclosed. In one embodiment, a primary preform is formed comprising at least one central region and a support structure. The primary preform is then drawn to a cane, which is then inserted into an outer portion, to form a secondary preform. The secondary preform is then drawn until the at least one central portion is a nanowire. The method can produce nanowires of far greater length than existing methods, and can reduce the likelihood of damaging the nanowire when handling.

Abstract: A method for producing an optical fiber having low polarization mode dispersion, by the steps of a) providing an optical fiber perform of glass material; b) heating the glass material of an end portion of the optical fiber perform; c) drawing the heated glass material at a drawing speed V to form an optical fiber, the drawn glass material having a viscous zone; and d) applying to the optical fiber a substantially sinusoidal spin, which is transmitted to the viscous zone, the spin function frequency ?, the viscous zone length L and the drawing speed V being such that both a torsion and at least a 50% detorsion are applied to the viscous zone.

Abstract: The present invention is generally directed to a device comprising multiple specialty glass optical fibers that combines several different mid-infrared optical signals from multiple optical fibers into one signal in a single optical fiber. In addition, the present invention provides for a method of making the device.

Abstract: A method and apparatus for impulsively spinning optical fiber while the optical fiber is being drawn is disclosed herein.

Abstract: An optical fiber twisting apparatus that prevents line distortion in an optical fiber undergoing a drawing process and provides a consistent coating on a bare optical fiber. This optical fiber twisting apparatus includes a twist roller apparatus that having a twist roller that, by imparting a twist to an optical fiber, imparts a twist to a molten portion of an optical fiber preform positioned on an upstream side of the optical fiber, and a support portion that supports the twist roller. The accuracy of the outer circumference of the twist roller when the twist roller is forming a part of the twist roller apparatus is 15 ?m or less.

Abstract: Simple and small-sized equipment which continuously afford alternate twists to an optical fiber and a method using the apparatus are provided. The equipment includes: a guide roller for causing the fiber to roll; a roller supporting member for holding the roller in a manner allowing the roller to freely turn about an axial center X; and a driving unit to cause the roller to oscillate by making the supporting member to turn about an axial center Y that is inclined relative to the axial center X. The method includes: arranging a guide roller to intersect the fiber, the roller being held by a roller supporting member to freely turn about an axial center X; oscillating the roller by driving the supporting member to revolve about the axial center Y which is inclined relative to the axis center X; and causing the fiber to roll to afford alternate twists to the fiber.

Abstract: A glass composition for glass fiber comprises, by mass percentage in terms of oxide, 60 to 75% SiO2, 0 to 10% Al2O3, 0 to 20% B2O3, 5 to 15% Li2O+Na2O+K2O, 0 to 10% MgO+CaO+SrO+BaO+ZnO, 0 to 10% TiO2 and 0 to 10% Zr02. A glass fiber consists of the above glass composition for glass fiber. A process for producing a glass fiber comprises the steps of melting the above glass composition in a heat-resistant vessel and continuously drawing out the molten glass through a heat-resistant nozzle so as to form a glass fiber; coating the surface thereof with a chemical; and continuously reeling the coated glass fiber. A composite material is obtained by compositing the glass fiber with an organic resin.

Abstract: An optical fiber preform, and method for fabricating, having a first core, a second core spaced from the first core and first and second regions, the first region having an outer perimeter having a first substantially straight length and the second region having an outer perimeter having a second substantially straight length facing the first straight length. One of the regions can comprise the first core and the other comprises the second core. The preform can be drawn with rotation to provide a fiber wherein a first core of the fiber is multimode at a selected wavelength of operation and a second core of the fiber is spaced from and winds around the first core and has a selected longitudinal pitch. The second core of the fiber can couple to a higher order mode of the first core and increase the attenuation thereof relative to the fundamental mode of the first core.

Abstract: An optical fiber twisting apparatus that prevents line distortion in an optical fiber undergoing a drawing process and provides a consistent coating on a bare optical fiber. This optical fiber twisting apparatus includes a twist roller apparatus that having a twist roller that, by imparting a twist to an optical fiber, imparts a twist to a molten portion of an optical fiber preform positioned on an upstream side of the optical fiber, and a support portion that supports the twist roller. The accuracy of the outer circumference of the twist roller when the twist roller is forming a part of the twist roller apparatus is 15 ?m or less.

Abstract: A method and apparatus for manufacturing an optical fiber includes the steps and/or means of: drawing a fiber from a heated preform by applying a pulling force to the fiber; spinning the fiber while it is drawn, wherein the step of spinning the fiber includes the sub-steps of winding the fiber on a spin roller by a winding arc, such that a friction force is generated between the fiber and the spin roller resulting from the winding arc and from the pulling force; axially displacing the spin roller such that the fiber is caused to roll over the spin roller surface by the friction force.

Abstract: An expeditious method for introducing geometric perturbations into lightguide during fabrication offers a perturbation stream of amplitude and periodicity—constant or varying—to satisfy a variety of needs.

Abstract: The strain-managed optical waveguide assemblies of the present invention utilize a large-mode-area (LMA) optical fiber that is annealed in a first bending such that the fiber in that configuration has substantially no axial strain. A fiber support member is then used to support the annealed LMA optical fiber in a second bending configuration that forms within the LMA optical fiber an axial strain profile that reduces stimulated Brillouin scattering (SBS) as compared to the first bending configuration, and that also preferably causes the LMA optical fiber to operate in a single mode. The LMA optical fiber may have a double-clad configuration and include a doped core that serves as a gain medium. The strain-managed optical waveguide assembly can then be used to constitute a fiber amplifier that mitigates the SBS penalty associated with high-power fiber-based optical systems.

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: Method of making a microstructured optical fiber. Silica glass based soot is deposited on a substrate to form at least a portion of an optical fiber preform by traversing a soot deposition burner with respect to said substrate at a burner traverse rate greater than 3 cm/sec, thereby depositing a layer of soot having a thickness less than 20 microns for each of a plurality of burner passes. At least a portion of the soot preform is then consolidated inside a furnace to remove greater than 50 percent of the air trapped in said soot preform, said consolidating taking place in a gaseous atmosphere containing krypton, nitrogen, or mixtures thereof under conditions which are effective to trap a portion of said gaseous atmosphere in said preform during said consolidation step, thereby forming a consolidated preform which when viewed in cross section will exhibit at least 50 voids therein.

Abstract: The method uses capillary holes in a glass preform for precise positioning of the optical fibers in the manufacture of a coupler. The glass preform is preferably cylindrical and longitudinal capillary holes are made in it in a desired pattern. Optical fibers are inserted in the holes and the glass preform is heated and stretched in its middle section so that the fibers, from which coating has been removed, contact and are fused with the glass preform in this tapered section. Then the tapered section is cleaved to form a coupling end which is spliced with another fiber to form the coupler.

Abstract: A method and a system based on the method imparts to an optical fiber a predetermined rotation about its axis, wherein the fiber is rotated by way of a frictional force acting on the fiber while it is advanced in a predetermined direction. The rotation actually imparted to the optical fiber is measured on-line while the fiber is advancing in the direction and the frictional force is controlled responsively to the measured rotation so as to obtain the predetermined rotation. Spinning devices acting on the optical fiber by way of an externally controllable frictional force and particularly suitable to be used with the method are disclosed.

Abstract: An anti-PMD system comprises a pulley which oscillates in rotation and applies a torsion torque alternately in the clockwise direction and in the counterclockwise direction to an optical fiber during drawing of the optical fiber to reduce its PMD. A portion of a peripheral external surface of the pulley intended to be in contact with the optical fiber during drawing is convex.

Abstract: A method for drawing an optical fiber having reduced polarization mode dispersion (PMD) draws an optical fiber from an optical fiber preform whose core ovality is at max about 3%, coats the optical fiber with acrylic polymer and twists the coated optical fiber with a pair of spinning wheels. The twisting of the fiber is achieved by four discrete spin rates that repeat in a periodic fashion after the drawing of certain lengths of the optical fiber. At least one of the spin rates varies in a trapezoidal manner along the respective one of drawn lengths of the optical fiber.