Showing papers on "Hard-clad silica optical fiber published in 1978"

Self-phase-modulation in silica optical fibers

Abstract: We report measurements of frequency broadening due to self-phase-modulation (SPM) in optical fibers. The use of single-mode silica-core fibers and mode-locked argon-laser pulses leads to the simplest and cleanest measurements yet made of SPM. The qualitative features of the frequency spectrum are in good agreement with theoretical expectations. The experiment provides an independent measurement of ${n}_{2}$, the self-focusing coefficient. The results also point to some simple and useful techniques based on fibers for the measurement and analysis of mode-locked laser pulses.

Narrow-band Bragg reflectors in optical fibers.

Abstract: The formation and characterization of narrow-band-waveguide reflection filters in Ge-doped silica optical fibers is described. The filters can have complex response profiles and are tunable in frequency by mechanical strain.

A universal fiber-optic (UFO) measurement system based on a near-IR fiber Raman laser

Abstract: A universal fiber-optic measurement system, which is useful for measuring loss and dispersion in the 1.06-1.6 \mu m wavelength region, is described. The source is a silica fiber Raman laser pumped by a mode-locked and Q -switched Nd:YAG laser at 1.06 μm. Subnanosecond multiple-Stokes pulses in the 1.1-1.6 \mu m wavelength region are generated in a low-loss single-mode silica fiber. The use of this near-infrared fiber Raman laser for characterizing various transmission properties of single and multimode test fibers is demonstrated. Loss spectra, intramodal dispersion, and intermodal dispersion data are obtained in the wavelength region of minimum loss and minimum material dispersion for silica fibers.

ZnCl2 glass: A potential ultralow‐loss optical fiber material

Abstract: Zinc chloride glass is a potentially useful medium for ultralow‐loss (∼1 dB/103 km) optical fibers for wavelengths in the 3.5–4‐μm region. In this region, intrinsic absorption, scatter, and material dispersion are all expected to be small, and the common fully oxidized transition metal impurities and H2O should exhibit extremely weak absorption as well.

Single polarization optical fibers: Exposed cladding technique

Abstract: A simple method is described for fabricating fibers with large strain birefringence starting with standard MCVD preforms. The method is illustrated using borosilicate fibers. The birefringence and polarization properties are measured in a long fiber and the birefringence is also measured using a fiber slice and polarizing microscope.

Fiber optic temperature sensor using liquid component fiber

Abstract: This invention provides apparatus for remote temperature sensing by means of fiber optics in which the sensor is optical and passive, with no electrical power required at the sensor. The temperature-sensing section of the fiber optic makes use of a transparent liquid as core or cladding and in which the transparent liquid has a temperature-dependent index of refraction.

Optical coupler for connecting a light source to an optical transmission line

Abstract: An optical coupler for optically coupling an LED to an optical fiber includes a transparent spherical shell surrounding a transparent spherical core. The index of refraction of the core is greater than of the spherical shell. A surface is formed on the opposite side of the coupler for coupling the optical fiber to the optical coupler, and a cylinder is used to mount the optical coupler at a predetermined distance from the LED in an orientation maximizing the amount of light entering the optical fiber.

Light-conducting fibers

Abstract: A clad light-conducting fiber comprising a core, a cladding of lower refractive index than the core, fused to the core, and a plurality of spots of inhomogeneity such as bubbles wholly within the core, spaced along the length of the light-conducting fiber. These light-conducting, bubble-containing fibers are used in a decorative structure comprising a light source and a suitably mounted group of light-conducting, bubble-containing fibers wherein the light is transmitted into and thereafter through the group of fibers, showing decorative points of light along the length of the fibers as well as at their ends.

Fusion splices for optical fibers by discharge heating

Abstract: A new type of electric discharge fusion splicing apparatus for optical fibers offering several advantages is developed and evaluated. An average splicing loss of 0.10 dB is obtained for step-index multimode silica fibers with a 60-μm core diameter. Tolerances in discharge energy, fiber misalignment, compression force and stroke length during fusion, and end face conditions are discussed experimentally. No accurate fiber axis adjustment is necessary in this apparatus. Mechanical strength of the splice is also excellent.

Polymeric fiber masses, fibers therefrom, and processes for producing the same

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.

Effect of temperature on optical fiber transmission

Abstract: Results are presented concerning the effects of temperature on the transmission properties of various optical fibers including a silicone plastic clad, an acrylic plastic clad, and CVD step-index fibers both with and without polyurethane jackets Results are presented for the normalized transmitted power vs temperature, the index of refraction vs temperature, and induced attenuation coefficients vs temperature The data show that the intrinsic transmission of a CVD fiber is independent of temperature over the -110 to +150 C range Plastic clad fused silica fibers are subject to transmission losses at lower temperatures due to changes in the optical index of the cladding polymer Acrylic-clad and plastic-clad silica fibers also show transmission losses at lower temperatures, but to lesser extents

Transmission characteristics of graded-index optical fibers with a lossy outer layer

Abstract: Changes in transmission characteristics caused by an outer layer have been investigated for graded-index fibers. Equations have been derived using the WKB method for calculating baseband frequency response and excess loss in a general type of the graded-index fiber. Numerical examples have been given for a square-law fiber, mainly with cladding thickness and index difference between outer layer and cladding as parameters. Measurement of the excess loss has been carried out for fibers with various cladding thickness and outer layer-cladding index differences. The measured loss is in agreement with the theoretical value.

Method of manufacturing graded index optical fibers

Abstract: A process is disclosed for making an optical fiber having a graded index glass core enveloped by a cladding material. The ingredients from which the peripheral part of the core glass is to be formed are placed in a closed tube of the cladding material which is more refractory than the core glass. The ingredients are melted to form a glassy liquid which is fined within the tube and then coated (for example, by rotational casting) on the inner surface of the tube. Additional ingredients, from which the inner part of the core glass is to be formed, are then placed in the coated tube, melted and similarly coated on the inner surface of the tube. In this way successive core glass layers, each having a different index of refraction, may be formed within the tube of cladding material. The temperature is then elevated further and the tube and glassy liquid drawn into a fiber.

Process for the production of glass fiber light conductors

Abstract: A process for producing a glass fiber light conductor which has increased tensile strength characterized by forming a protective layer at an elevated temperature either on a preform of the fiber and cladding or on the cladding of a drawn fiber with the material of the protective layer having a coefficient of thermal expansion, which is lower than the adjoining glass material of the fiber so that on cooling from the elevated temperature, the layer is subjected to compressive stresses to increase the tensile strength of the fiber.

Method of splicing optical fibers by CO2 -laser

Abstract: A method of permanently joining or splicing optical fibers containing a fused silica or fused quartz fiber as a main component and having a high softening temperature by using a CO 2 -laser with TEM oo mode in such a manner that laser power of about 1 watt may be applied to the optical fiber per unit area thereof. Two or more optical fibers are joined together through fusion with the end portions being positioned in opposition to one another, resulting in a joint having a low joint loss and an increased tensile strength.

Low-loss single-mode fibers with different B(2)O(3)-SiO(2) compositions.

Abstract: Design considerations, fabrication, and transmission characteristics of single-mode optical fibers made with different borosilicate compositions are discussed. Fibers with core sizes as large as 15 microm and refractive-index differences below 0.1% were made with the modified chemical vapor deposition (MCVD) process. Minimum losses achieved with fibers up to 1-km lengths were 1.3-1.4 dB/km in the 1.02-1.1-microm range. Microbending losses were avoided by jacketing the fibers with silicone resin. Single-mode operation is maintained in moderately overmoded fibers (V ~ 3.0) because of leakage loss through a finite cladding thickness and because of bends in the fiber axis.

Method of producing optical fiber

Abstract: A method of producing an optical fiber comprising (i) the step of depositing a glass film of desired refractive index onto the inner wall surface of a quartz tube by the CVD (chemical vapor deposition) process, (ii) the step of heating the quartz tube to a high temperature while the gas of a compound which forms an oxide, enhancing the refractive index of the glass film, in an oxidizing atmosphere at the high temperature is kept flowing into the quartz tube along with an oxidizing gas, (iii) the step of heating and collapsing the quartz tube into a solid rod or the so-called preform, and (iv) the step of heating and drawing the optical fiber preform into the optical fiber. In the optical fiber produced by this method of manufacture, the lowering of the refractive index of the central part of the optical fiber is sharply reduced. At the step (iii), one end of the quartz tube is sealed and a gas is introduced into the tube from the other end so as to slightly raise the internal pressure of the tube, whereby a more favorable result is obtained.

End-butt optical fiber coupler

Abstract: An optical waveguide coupler having intersecting deep and shallow grooves in a planar solid substrate, in which the deep groove accommodates an alignment fiber for fine vertical alignment of an optical fiber with another optical fiber or with an optical component such as a switch, modulator, multiplexer or source of light. The shallow groove accommodates the optical fiber. The alignment fiber may be tapered or have any configuration such that its manipulation causes the alignment fiber to contact the underside of the optical fiber for raising or lowering the optical fiber. There may be a plurality of shallow and deep grooves for coupling more than one optical fiber.

Limited mode optical fiber

Abstract: A single mode optical fiber having a central core region of uniform composition and thickness and core end regions each having a core with a graded composition and increasing thickness towards the ends of the fiber. The fiber maintains a constant normalized frequency with a minimum bending loss. Methods are also provided for forming the fibers from a fiber optic preform.

Method of reducing absorption losses in fused quartz and fused silica optical fibers

Abstract: A method of reducing the absorption losses in an optical fiber by irradiating the optical fiber with ultraviolet light at a reduced pressure and elevated temperature.

Photo multiple distributor

Abstract: PURPOSE: To distribute the light in a single optical fiber into each optical fiber and to increase the degree of light bonding, by increasing the light bonding between optical fibers bundled without inserting optical parts such as mixer rods between input and output optical fibers CONSTITUTION: A plurality of optical fibers 12 are heated, twisted, and boundled into a thin strand to form a light bonding part 13 Photo input 14 propagated through one optical fiber is bonded with each optical fiber at the light bonding part 13 and distributed to be propagated as photo outputs 15 to 18 Thus, by bundling into a small diameter while heating and twisting an optical fiber bundle, the bundling of optical fibers becomes excellent and each core may be adjacent to each other Also, by applying twists, the light intensity distribution becomes wider In addition, since the flexibility is increased by bundling into a small diameter, even if a long light bonding part 13 is formed, it can be wound around a cylinder 27 so that the size can be reduced Thus, a long light bonding degree may be obtained, and the light bonding degree between optical fibers may be enhanced COPYRIGHT: (C)1980,JPO&Japio

Method of producing a coupling element for an optical transmission fiber

Abstract: Method of producing a coupling element for coupling a laser radiation source to a monomode optical transmission fiber. The end of the fiber is monotonically flattened at a temperature at which the fiber's core has a viscosity of between 107 to 108.5 poises. The fiber has a cladding glass chosen to have a viscosity of between 1010 -1011 poises at the flattening temperature. This causes the core glass to emerge in the form of a semi-ellipsoidal lens, when the fiber is flattened.

Optical fiber and method for producing the same

Abstract: A method for producing an optical fiber comprises (i) the step of depositing a barrier layer on the inner wall surface of a glass tube by the CVD (chemical vapor deposition) process, said barrier layer being capable of preventing the diffusion of impurities and being made of high-silica glass which has a refractive index that is substantially equal to that of the glass tube and which contains at least one substance for lowering the refractive index of silica and at least one substance for raising the refractive index of silica, (ii) the step of depositing a glass film of desired refractive index on the barrier layer by the CVD process, (iii) the step of heating and collapsing the resultant glass tube into a composite rod or the so-called optical fiber preform, and (iv) the step of heating and drawing said optical fiber preform into the optical fiber, whereby the optical fiber which has the impurity diffusion-preventing layer between the core and the outside glass layer can be easily produced.

Two-dimensional silicon grooves for altitudinal alignment in fiber end-butt coupling.

Abstract: We report a practical approach to the fine altitudinal alignment between single-mode optical fibers and channel waveguides, or between optical fibers with slightly different radii, wherein the preferentially etched silicon-fiber-alignment approach has been modified to have two-dimensional silicon grooves of different depths. The altitudinal alignment is achieved by pulling a tapered alignment fiber through the deep groove. This tapered alignment fiber is in contact with the signal fiber and raises or lowers it, depending on the diameter of the tapered fiber at the point of contact.

Optical fiber device and production thereof

Abstract: PURPOSE:To improve the optical coupling efficiency by making an optical fiber having a smaller core diameter so taper as to have a larger numerical aperture and by giving a special condition to the taper angle when the optical fiber is coupled to an optical fiber having a larger core diameter.

OH-Ion Distribution in Preforms of High-Silica Optical Fiber

Abstract: The OH-ion distribution in preforms of high-silica optical fibers was investigated and related to the OH-contamination mechanism in the preform fabrication processes of the C.V.D method. The OH-ion distribution profiles were measured optically at 2.73 µm with a high spatial resolution of about 90 µm. It was confirmed from the OH-ion distribution profiles that one of the OH-contamination processes is the thermal diffusion of OH-ions from the supporting silica tube into the deposited glass layers during deposition. No significant difference was observed in the OH-ion diffusivity between nondoped silica glass and B2O3-doped silica glass. The OH-contamination in the center of the preform was attributed to the dissolution of the water vapor due to an accidental leak from the outlet of the deposited tube during the collapsing procedure. Based on this result, the OH-ion solubility in silica glass at a high temperature of 1900°C is estimated to be about 1.4×1020 OH/cm3atm.1/2

Production of optical fiber cables

Abstract: A room temperature vulcanizable silicone rubber having a high coefficient of thermal expansion is provided at the interface between an optical fiber and a surrounding fiber reinforced resin shell in a cable construction. The surrounding rubber because of high coefficient thermal expansion shrinks more than the optical fiber or the resin shell during the manufacture operation. This relieves radial compressive loads on the optical fiber and prevents the distortion of the optical fiber by the surrounding fiber reinforced shell in manufacture and use. As a consequence, light transmission qualities are not impaired.

Measurement technique of OH-ion distribution profile in rod preform of silica-based optical fiber waveguides.

Abstract: To study the OH-ion contamination mechanism in silica-based optical fiber waveguides, a method for measuring the OH-ion distribution profile in fiber-rod preforms has been developed Using a low-OH-content optical fiber as a light probe of the measuring set, high spatial resolution of several tens of micrometers was obtained Using this technique, the OH-ion distribution profiles in nondoped silica-rod preforms were measured optically at 273 microm The OH-ion distribution profile observed closely agreed with the calculated diffusion profile, from which the diffusion coefficient of OH-ion in silica glass was estimated to be ~70 x 10(-9) cm(2) sec(-1) at 1600 degrees C

Optical fibers for communication transmission having high stability to nuclear radiation

Abstract: An optical fiber comprising a light-conducting core and a borosilicate glass optical insulation cladding thereon is stabilized against the effects of nuclear radiation by incorporating in the core and the cladding an amount of Sb2 O3 effective to harden the fiber against nuclear radiation. Amounts of 0.002-6 wt. % Sb2 O3 are generally useful.