Abstract:
The present invention is generally directed to a photonic bad gap fiber and/or fiber preform with a central structured region comprising a first non-silica based glass and a jacket comprising a second non-silica based glass surrounding the central structured region, where the Littleton softening temperature of the second glass is at least one but no more than ten degrees Celsius lower than the Littleton softening temperature of the first glass, or where the base ten logarithm of the glass viscosity in poise of the second glass is at least 0.01 but no more than 2 lower than the base ten logarithm of the glass viscosity in poise of the first glass at a fiber draw temperature. Also disclosed is a method of making a photonic bad gap fiber and/or fiber preform.
Abstract:
A photonic band gap fiber and method of making thereof is provided. The fiber is made of a non-silica-based glass and has a longitudinal central opening, a microstructured region having a plurality of longitudinal surrounding openings, and a jacket. The air fill fraction of the microstructured region is at least about 40%. The fiber may be made by drawing a preform into a fiber, while applying gas pressure to the microstructured region. The air fill fraction of the microstructured region is changed during the drawing.
Abstract:
Methods of forming glass articles sensitive to aggressive heat treatment are disclosed. Glass preforms have sections of glass fusion bonded to the preforms, and the preforms are subsequently drawn into glass articles.
Abstract:
A starting material for producing optical fibers contains metal halides. The refractive index of the optical fiber formed from the starting material is predeterminable by adjusting a partial pressure ratio of a halogen-containing gas mixture. The starting material is produced by mixing halogenated gases into a gas mixture with the desired partial pressure ratio, causing a chemical reaction at a first temperature of the gas mixture with at least metal to form a reaction product, the first temperature being higher than the melting temperature of the reaction product and cooling the reaction product to a second temperature that is below the melting temperature.
Abstract:
A method of making silver halide fibers involves reducing turbulence and friction during extrusion by moving an extrusion die in a direction opposite from flowing fiber and against a stationary preform arrangement. In another embodiment, the preform is doped with AgI or is a metal compound of the formula MY wherein M is selected from Li, Na, K, Rb, Cs; or MY.sub.2 wherein M is selected from Mg, Ca, Sr, Pb, Ba, Cd or Hg, and Y is selected from Cl, Br, or I. The resulting fiber has a more even core/clad interface with decrease in grain size to fiber surface and texture elongated along the fiber axis. This structure together with strengthening and stabilizing dopants, added to fiber material, gives decreased and stabilized optical losses and a higher elasticity of fibers.
Abstract:
The present invention is directed to silver halide fibers. In one embodiment, the fiber has been doped with AgI or a metal compound of the formula MY wherein M is selected from Li, Na, K, Rb, Cr, Mg, Ca, St, Ba, Cd or Hg, and Y is selected from Cl, Br, or I. The fiber has large, elongated grain core structure and decreased infrared transmission losses and a more even/cladding interface in cladded embodiments.
Abstract:
Disclosed is a method and apparatus for drawing an elongated glass article such as a fiber optic device. The article is drawn upwardly from a source through the surface of a quantity of molten metal having a vertical temperature gradient. The source can be an elongated solid glass preform that is vertically positioned within the molten metal such that the temperature of that portion of the molten metal adjacent the upper end region is sufficiently high to heat that region to drawing temperature. The upper end region is pulled to form a tapered root, continued pulling resulting in the formation of an elongated article from the small diameter root end. The relative position of the root is maintained with respect to the surface of the molten metal during the drawing operation. Alternatively, the glass can be drawn from an orifice located within the molten metal.The apparatus includes container means for supporting the molten metal, and external or internal means for heating and/or cooling portions of the molten metal. The container can also be provided with baffle means for dividing the container into a plurality of chambers.
Abstract:
A low loss cladded halide fiber for transmission of infrared energy is provided, and a process for making the same by growing a single crystal ingot from a powder of a core halide, extruding or machining the ingot to provide a cylindrical billet core, assembling the billet core, preferably wrapped in a polymer film, within a sleeve member of a second halide of lower refractive index than the core, prepared in the same fashion as the core, and coaxially core drilled to accept the billet core. The assembled composite billet is covered with a polymer film, heated, and extruded to form a polymer coated fiber having a diameter in the range of 75 to 2,000 microns. The extruded fiber may be rapidly cooled as it leaves the extrusion die to minimize grain size and scattering loss and may be contained in a coaxial outer strength member.
Abstract:
Apparatus and method for forming ultrapure glass rods (13) or fibers (28) from a polycrystalline rod (11) in which the method comprises the steps of heating a selected short section of the rod in the first furnace (21) to form a molten zone of the rod, heating a second selected short section of the rod in a second furnace (19) which initially is separated from the first furnace by a very short gap to form a second molten zone of the rod which initially is contiguous with and part of the first molten zone of the rod to form a single molten zone 14, and then gradually moving the first and second furnaces apart to first form a rod (13) and then, ultimately, a fiber (28), of ultrapure glass in the increasingly widening gap forming therebetween.
Abstract:
A process is disclosed for producing an infrared light transmitting optical fiber by drawing a rod of single crystal or polycrystalline metal halide into a fiber through a die; also disclosed is a process for producing an infrared light transmitting optical fiber of step-index type by forming around a single crystal or polycrystalline fiber core, an intimate cladding crystal layer having a lower refractive index than the core by working in the temperature range that does not cause recrystallization of the core or cladding during working.