Abstract: Methods, apparatus and precursors for producing substantially water-free silica soot, preforms and glass. The methods and apparatus make substantially water-free fused silica preforms or glass by removing water as a reaction product, removing water from the atmosphere, removing water from the transport process, or combinations thereof. In a first embodiment, substantially water-free soot, preforms or glass are achieved by using a hydrogen-free fuel, such as carbon monoxide, in the deposition process. In another embodiment, a soot producing burner has parameters that enable operation on a substantially hydrogen-free fuel. End burners, which minimize water production, are also described. Such water-free methods are useful in depositing fluorine-doped soot because of the low water present and the efficiency in which fluorine is incorporated. In another embodiment, glassy barrier layer methods and apparatus are described for minimizing dopant migration, especially fluorine.

Abstract: A method of manufacturing a cane suitable for forming an optical fiber, and a method of forming an optical fiber from the cane. A core composition having about 20% to 30% by weight of P2O5 is formed. An inner cladding composition is formed on an outer surface of the core composition and the core composition and the inner cladding composition are consolidated into a preform having a core and an inner cladding while substantially closing a center line hole of the preform. An outer cladding composition is formed on the preform to define a cane. The cane can then be transformed into an optical fiber.

Abstract: The disclosed invention includes an inventive drying agent. The drying agent includes at least one halide and at least one reducing agent. Preferably, the reducing agent includes a compound that will react with an oxygen by-product of the reaction of the halide and water, or the reaction of the halide and an impurity in the preform. The invention also includes a method of drying a soot preform. The method includes disposing the soot preform in a furnace. The furnace is charged with the drying agent which includes the halide and the reducing agent. Heat is then supplied to the furnace. Suitable drying agents for use in the disclosed invention include a mixture of Cl2 and CO; a mixture of Cl2, CO and CO2; and POCl3.

Abstract: An optical fiber with a non-circular cross-section is realized by creating a void having the desired cross-section in a housing and filling the void with an optical material. This structure is then collapsed to solidify it and drawn to desired dimensions. The optical material may be rods, soot or ground material.

Abstract: Methods, apparatus and precursors for producing substantially water-free silica soot, preforms and glass. The methods and apparatus make substantially water-free fused silica preforms or glass by removing water as a reaction product, removing water from the atmosphere, removing water from the transport process, or combinations thereof. In a first embodiment, substantially water-free soot, preforms or glass are achieved by using a hydrogen-free fuel, such as carbon monoxide, in the deposition process. In another embodiment, a soot producing burner has parameters that enable operation on a substantially hydrogen-free fuel. End burners, which minimize water production, are also described. Such water-free methods are useful in depositing fluorine-doped soot because of the low water present and the efficiency in which fluorine is incorporated. In another embodiment, glassy barrier layer methods and apparatus are described for minimizing dopant migration, especially fluorine.

Abstract: A method for making an optical attenuating device comprising an optical waveguide having a core doped with a transition metal and a cladding. The transition metal is deposited in the core during a core blankmaking process. The transition metal doped core is exposed to gaseous hydrogen in a furnace to significantly increase the attenuation of the device.

Abstract: A method for forming a GeO.sub.2 -doped SiO.sub.2 glass article by depositing glass particles to form a porous preform and then drying and sintering the porous preform. A precursor of SnO.sub.2 is also present in the reactant stream used to form the particles, whereby the reaction produces particles of glass that contain GeO.sub.2, SiO.sub.2 and SnO.sub.2. The presence of SnO.sub.2 in the particles reduces the reaction of GeO.sub.2 with chlorine to form GeCl.sub.4 during the drying step. The GeCl.sub.4 that would have formed would have either escaped from the porous preform or caused GeO.sub.2 to be re-deposited in an undesirable portion of the preform. The retention of GeO.sub.2 in the article is therefore enhanced.

Abstract: There is disclosed a method and apparatus for providing optically pure glass blanks, tubing, crucibles and the like for use in forming optical waveguides, lenses, prisms, filters, lamp envelopes and the like. A glass layer is formed at a high temperature on a mandrel which includes a support rod or tube upon which is disposed a layer of refractory metal wire, gauze, foil or the like. The mandrel is so constructed that stresses, which heretofore have developed in the glass layer during cooling, are avoided, and the mandrel is easily removed from the glass layer, thereby forming a hollow glass cylinder that is free from cracks, checks and the like.