Showing papers on "Hard-clad silica optical fiber published in 1977"

Pulse delay measurements in the zero material dispersion wavelength region for optical fibers.

Abstract: Subnanosecond pulses in the 1120-1550-nm region are generated by multiple-order stimulated Raman scattering in a small core single-mode silica fiber pumped by a Q-switched and mode-locked Nd:YAG laser at 1064 nm. These near ir pulses are injected into various km long test fibers, and relative time delay changes between different wavelengths are used to determine dispersion in a region where fiber material dispersion is small. Zero material dispersion has been observed in germanium and boron-doped single-mode and multimode est fibers.

Short-Fiber-Reinforced Elastomer Composites

Abstract: The reinforcement of elastomers with short fibers results in composites with a wide variety of properties. The performance and properties are a function of fiber type, fiber content, fiber...

Process for low attenuation methacrylate optical fiber

Abstract: Low attenuation, all-plastic optical fiber is made by using starting materials which are rigorously purified to remove light-absorbing impurities and solid particles of dirt, polymerizing the core monomer under pressure with a heating schedule which leads to at least 98% conversion to polymer as a cylindrical preform, and ram extruding the core of the optical fiber while melting only the forward end of the preform of core polymer so as to preclude contamination of the core by dirt or formation of bubbles by polymer degradation. Optical fibers so made exhibit light attenuations as low as 300 dB/km or lower.

A new LED structure with a self-aligned sphere lens for efficient coupling to optical fibers

Abstract: A practical new structure of the high radiance GaAs-GaAlAs LED with a self-aligned sphere lens has been developed for efficient coupling to low-less optical fibers as a light source for fiber optic communications. In this new configuration, the sphere lens is automatically settled into the center of the light-emitting surface by an etched hole containing clear epoxy resin. When applied to a low-loss optical fiber ( NA = 0.14 , core diameter: 80 µm), a coupling efficiency in excess of 9 percent has been reproducibly achieved for an LED structure with an emitting-area diameter of 35 µm and with a lens having a diameter of 100 µm and a refractive index of 2.0. Using an LED with a light-emitting-layer carrier concentration of 3 × 1018/cm3, an optical power of 150 to 200 µW coupled into the fiber and a cut-off frequency (optical power down to ½) of about 90 MHz have been reproducibly obtained.

Optical fiber splicing with a low-power CO(2) laser.

Abstract: Low loss splicing of silica fibers by means of a 5-W CO2 laser has been demonstrated. Step-index fibers with a core diameter of 56 μm and an outer diameter of 154 μm were fused together. The chopped laser beam, effectively 2.3 W and about 1.0 mm in beam-spot diameter, was moved across the fiber ends at a speed of 10 μm/sec. Ninety percent of twenty-one splices had losses less than 0.12 dB with a minimum loss of 0.02 dB. Good reproducibility of the low loss splice was achieved by contacting the fibers tightly before fusing them together.

Process for producing novel polymeric fibers and fiber masses

Abstract: We have prepared a new class of polymeric fibers and masses which are produced by precipitation from solutions of the polymer. The fibers and fiber masses have novel and useful characteristics. A fiber mass of this invention is a coherent, three-dimensional network of interconnected crystalline polymeric fibers and fiber bundles randomly arrayed in all directions. The fibers are smaller in diameter than can be consistently produced by conventional fiber drawing and spinning techniques. The novel fiber masses are produced from solutions of fiber-forming linear organic polymers having regularly repeated chain structures. The polymers are precipitated from these solutions by simultaneously cooling and agitating the polymer solution at vibrations in the sonic frequency range. The fiber masses may then be removed from the solvent or, in the case of a polymerizable solvent, a composite may be formed.

Apparatus for producing optical fiber

Abstract: Apparatus for producing an optical fiber including apparatus for heating an optical fiber preform, apparatus for drawing out the optical fiber from the optical fiber preform whose fore end part has been made molten by the heating and for taking up the drawn out fiber, apparatus for causing a gas to flow along the outer peripheral surface of the molten part of the optical fiber preform, and apparatus for controlling both the flow rate of the gas and the drawing-out speed of the optical fiber according to a fluctuation in the diameter of the optical fiber. The controlling apparatus includes (i) a fiber diameter detector and a fiber diameter measuring device which detect and measure the diameter of the optical fiber drawn out, (ii) a fiber diameter controlling circuit which receives an output of the fiber diameter measuring device and a reference value for specifying a fiber diameter and which compares them so as to deliver an output for controlling the fiber diameter, (iii) a gas flow rate controller which is driven by the output for controlling the fiber diameter, and (iv) a take-up speed controller which is driven by the output for controlling the fiber diameter. With this apparatus, the optical fiber of uniform diameter can be easily produced.

OH-ion distribution profiles in rod preforms of high-silica optical waveguide

Abstract: To investigate the OH-contamination mechanism in high-silica optical waveguide, we have measured optically OH-ion distribution profiles in rod preforms prepared by the c.v.d. technique. The contamination due to OH diffusion from the supporting silica tube was clarified in relation to the deposited barrier-glass-layer thickness.

Filter for a light wave in a light guiding fiber

Abstract: A filter comprising multiple cylindrical layers of alternately high- and low-refractive materials and surrounded by a light-absorbent material with an outer diffusing surface is deposited by evaporation about a short axial length of a glass fiber to polarize or spectrum-filter light passing through said fiber. The indices of refraction of the filter layers are higher than the effective guide indices of the modes of the fiber core.

Glass fiber dispersions for making uniform glass fiber mats by the wet-laid process

Abstract: In accordance with the present invention, there is provided herein improved glass fiber dispersions for making uniform glass fiber mats by the wet-laid process. The well dispersed glass fiber compositions of this invention usually are prepared by mixing chopped glass fiber bundles in water with a small amount of an amine oxide surfactant to disperse the bundles into individual fibers. As a feature of the invention, the dispersions may be formed at relatively high glass fiber consistencies. The resultant dispersions then are used to make very high quality glass fiber mats at high rates of production.

Optical fiber branching inserter

Abstract: PURPOSE:To make possible branching of light from one optical fiber to a plurality of optical fibers by connectin one optical fiber and a fiber bundle containin containing a plurality of ootical fibers by way of an optical fiber whose outside diameter gradually changes.

Method of making solid preforms and optical fibers drawn therefrom

Abstract: An optical glass fiber is formed of an inner layer of germania doped glass within the bore of the outer cladding tube of silica. The tube with the higher index of refraction inner layer is rotated while being heated to collapse the bore to form an optical fiber preform. The preform is then drawn into fiber in a separate operation. A first silica layer can be deposited within the tube bore before the germania doped layer. The deposition of germania takes place under hydrogen free conditions. Appropriate heat treatment of the tube avoids excessive evaporation of germania and provides a graded transition of the refractive index in the boundary between core and cladding.

Large-core, broadband optical fiber

Abstract: A broadband optical fiber with larger core diameter than that of a conventional single-mode fiber is proposed. By appropriately choosing normalized frequency υ = 4,6 and core profile parameter α = 4.5, a core diameter as large as 16.3 μm with relative index difference Δ = 0.3% at the 1.25-μm wavelength is attainable. Fabrication tolerances, bandwidth, and bending loss of the fiber are discussed.

Optical fiber with graded index core and pure silica cladding

Abstract: An optical fiber having three dopants in the core of the fiber and a pure silicon dioxide cladding is disclosed. Phosphorus pentoxide and germanium dioxide are radially graded in the core of an optical fiber to obtain minimum modal dispersion over a broad range of wavelengths. A uniform concentration of boron oxide is present throughout the core of the fiber in order to permit a pure silicon dioxide cladding without encountering any step discontinuity in the index of refraction at the core-cladding interface.

Low attenuation, high strength optical fiber with silica filament core

Abstract: Low attenuation, high strength optical fiber is made by drawing a silica filament core at a temperature from 2040° C. to 2140° C. and melt coating onto it cladding polymer having an index of refraction lower than that of the silica core by extrusion at a draw-down ratio from 1.2 to 2.0.

Observation of surface flaws in fused silica optical fibers

Abstract: Surface flaws existing in optical fibers are directly observed using an optical microscope and SEM. Among scattering centers observed by launching a He‐Ne laser beam into a fiber, those still remaining after careful cleaning of the fiber surface are found to be most probably the flaws. Several cracks and voidlike defects observed by SEM correspond to the scattering centers. Tensile tests have been accomplished for fiber specimens containing the centers. It is found that fractures occur just at the centers in high probability and that fracture strength for the specimens is one‐third to two‐thirds of the strength for a specimen without an observable scattering center.

Optical element for incorporation into optical transmission means

Abstract: An optical element for incorporation into optical transmission means and comprising an optical fiber provided with a coating with a substantially circular cross section applied essentially coaxially closely around the fiber, to which coating is imparted such an adhesion to the optical fiber that a contraction tendency in the coating brought about in connection with the application of the coating affects the fiber with such an axial compressive force in its whole length that the force causes a real shortening of the fiber and a corresponding increase of the elongation at break of the fiber. The fiber can be provided with an intermediate protective layer, and an intermediate adhesive layer can be used. Optical transmission means comprising one or more optical elements in a sheath are described.

Optical fiber drawing apparatus

Abstract: PURPOSE:To prevent an optical fiber from being damaged by abruptly cooling the fiber in a manner to blow gases to the fiber.

Excess loss caused by a lossy outer layer in multimode optical fibers.

Abstract: Theoretical and experimental investigations are made on an excess loss arising due to a lossy outer layer attached around a cladding in multimode step-index fibers. Equations for evaluating the excess loss are derived using the electromagnetic theory for LP modes. Experiments are made on fibers with a pure fused silica jacket around a cladding, focusing on the wavelength dependence of the excess loss. It is found that the loss increases as the wavelength becomes long and that the measured values are in good agreement with the calculated ones.

Efficient white laser illuminators for plastic optical fibers

Abstract: Multiwavelength lasers are used to compensate for color distortion in transmission of light through plastic optical fibers. Efficient methods to eliminate the speckle effect and to generate multicolor laser light are described.

Optical transmission glass fiber and production therfor

Abstract: PURPOSE: To improve the optical transmission, strength and anti-weather property of an optical transmission glass fiber by forming the glass fiber with a coating layer composed of four sub-layers. COPYRIGHT: (C)1978,JPO&Japio