Abstract: The invention includes inventive methods of treating a soot preform. One method includes heating a soot preform to a temperature of less than about 1000° C. and exposing the preform to a substantially halide free reducing agent. Preferred reducing agents include carbon monoxide and sulfur dioxide. Another inventive method of treating the preform includes exposing the preform, in a furnace, to a substantially non-chlorine containing atmosphere comprising carbon monoxide. The preform is heated to a temperature of at least about 1000° C. Preferably this method is incorporated into the process for making an optical fiber. An additional method of treating the preform includes doping the preform with fluorine and exposing the fluorine doped preform to a substantially chlorine free atmosphere comprising at least carbon monoxide at a temperature of at least 1100° C., thereby reacting excess oxygen present in the furnace.

Abstract: The present invention is directed to a system and method for delivering liquid reactants through a burner assembly to form soot used in the manufacture of glass, and in particular, optical waveguides. Due to the tendency of liquid reactants to react to form solids when exposed to water in the air, an evaporative liquid is first delivered through the burner assembly to the combustion zone. Once steady state liquid flow has been achieved in the system, the evaporative liquid is transitioned to the liquid reactant. The liquid reactant is delivered along the same path to the burner assembly, which discharges the liquid reactant into the combustion zone as an atomized liquid to form soot used in the manufacture of glass. Once the desired quantity of soot has been formed, the liquid reactant is transitioned back to the evaporative liquid while maintaining steady state flow. After the liquid reactant has cleared the system, flow of the evaporative liquid is terminated and the burner assembly flame turned off.

Abstract: A method for making silica includes delivering a silica precursor comprising a pseudohalogen to a conversion site and passing the silica precursor through a flame to produce silica soot.

Abstract: A method for making silica includes delivering a silica precursor comprising a perfluorinated group to a conversion site and passing the silica precursor through a conversion flame to produce silica soot.

Abstract: Disclosed are optical gain fibers which include an erbium-containing core and a cladding surrounding the core and which have ripple of less than about 25% over about a 40 nm wide window or ripple of less than about 15% over about a 32 nm wide window, or both. In one embodiment, the optical gain fibers are pumpable at 980 nm and at 1480 nm. In another embodiment, the optical gain fibers are fusion sliceable. In yet another embodiment, the core includes oxides erbium; the cladding includes silicon dioxide; and the optical gain fiber has a passive loss of less than about 0.5% of the peak absorption of the erbium absorption band in the vicinity of 1530 nm. The optical gain fibers of the present invention have a wider gain window, improved flatness across the gain window, and/or increased gain as compared to conventional optical gain fibers.

Abstract: A method and apparatus for manufacturing optical components. A burner generates soot, and a surface area collector collects the soot. The burner is disposed such that the soot collected within the surface area collector is substantially not reheated by subsequently deposited soot. Magnetic forces direct the soot to desired location(s) within the surface area collector. The surface area collector operates at relatively low temperatures sufficient to retain rather volatile substances, such as fluorine, in the soot.

Abstract: A method for making a below 200-nm wavelength optical fluoride crystal feedstock includes loading a fluoride raw material into a chamber, exposing the fluoride raw material to a flow of gaseous fluoride at a predetermined temperature, and storing the exposed fluoride raw material in a dry atmosphere.

Abstract: The invention includes inventive methods of treating a soot preform. One method includes heating a soot preform to a temperature of less than about 1000 ° C. and exposing the preform to a substantially halide free reducing agent. Preferred reducing agents include carbon monoxide and sulfur dioxide. Another inventive method of treating the preform includes exposing the preform, in a furnace, to a substantially non-chlorine containing atmosphere comprising carbon monoxide. The preform is heated to a temperature of at least about 1000° C. Preferably this method is incorporated into the process for making an optical fiber. An additional method of treating the preform includes doping the preform with fluorine and exposing the fluorine doped preform to a substantially chlorine free atmosphere comprising at least carbon monoxide at a temperature of at least 1100° C., thereby reacting excess oxygen present in the furnace.

Abstract: Disclosed are optical gain fibers which include an erbium-containing core and a cladding surrounding the core and which have ripple of less than about 25% over about a 40 nm wide window or ripple of less than about 15% over about a 32 nm wide window, or both. In one embodiment, the optical gain fibers are pumpable at 980 nm and at 1480 nm. In another embodiment, the optical gain fibers are fusion sliceable. In yet another embodiment, the core includes oxides erbium; the cladding includes silicon dioxide; and the optical gain fiber has a passive loss of less than about 0.5% of the peak absorption of the erbium absorption band in the vicinity of 1530 nm. The optical gain fibers of the present invention have a wider gain window, improved flatness across the gain window, and/or increased gain as compared to conventional optical gain fibers.

Abstract: A method for making silica includes delivering a silica precursor comprising a perfluorinated group to a conversion site and passing the silica precursor through a conversion flame to produce silica soot.

Abstract: A method for making silica includes delivering a silica precursor comprising a pseudohalogen to a conversion site and passing the silica precursor through a flame to produce silica soot.

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: 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.