Abstract: A fused silica glass having a refractive index homogeneity of less or equal to about 5 ppm over an aperture area of at least about 50 cm2. The fused silica glass is also substantially free of halogens and has an adsorption edge of less than about 160 nm. The glass is dried by exposing a silica soot blank to carbon monoxide before consolidation, reducing the combined concentration of hydroxyl (i.e., OH, where H is protium (11H) and deuteroxyl (OD), where D is deuterium (12H)) of less than about 20 ppm by weight in one embodiment, less than about 5 ppm by weight in another embodiment, and less than about 1 ppm by weight in a third embodiment.

Abstract: A fused silica article having a combined concentration of hydroxyl (OH) and deuteroxyl (OD) concentration of less than 10 parts per million (ppm) and, in one embodiment, less than 1 ppm. The fused silica article is formed by drying a soot blank in a halogen-free atmosphere comprising carbon monoxide. The dried soot blank may optionally be doped to reach target levels of OH and OD concentrations and improve homogeneity within the fused silica article. The dried soot blank is then oxidized and, sintered to form the article. A method of reducing the combined concentration of OH and OD to less than 10 ppm is also described.

Abstract: A fused silica glass and a fused silica article having a combined concentration of at least one of OH and OD of up to about 50 ppm. The fused silica glass is formed by drying a fused silica soot blank or preform in an inert atmosphere containing a drying agent, followed by removal of residual drying agent from the dried soot blank by heating the dried soot blank in an atmosphere comprising an inert gas and of oxygen.

Abstract: According to some embodiments an optical waveguide fiber comprises (i) a Ge free core having an effective area of 100 ?m2to 150 ?m2, at 1550 nm wavelength, said core comprising: a) a central core region extending radially outwardly from a centerline to a radius r1, and having a relative refractive index percent profile ?1(r) in % measured relative to pure silica, wherein ?0.1%??1(r)?0.12%, wherein the central core region has a maximum relative refractive index percent, ?1MAX; (b) a first annular core region surrounding and directly adjacent to the central core region, having an ? value 1.5???10, and extending to an outer radius r2, wherein 6 ?m?r2?10 ?m, and having a relative refractive index percent profile, ?2(r) in % measured relative to pure silica, a minimum relative refractive index ?2MIN, a maximum relative refractive index ?2MAX and the relative refractive index measured at a radius r=2 ?m, wherein 0.45??2?0; ?0.25??2MIN??0.

Abstract: A fused silica glass having a refractive index homogeneity of less or equal to about 5 ppm over an aperture area of at least about 50 cm2. The fused silica glass is also substantially free of halogens and has an adsorption edge of less than about 160 nm. The glass is dried by exposing a silica soot blank to carbon monoxide before consolidation, reducing the combined concentration of hydroxyl (i.e., OH, where H is protium (11H) and deuteroxyl (OD), where D is deuterium (12H)) of less than about 20 ppm by weight in one embodiment, less than about 5 ppm by weight in another embodiment, and less than about 1 ppm by weight in a third embodiment.

Abstract: Disclosed is an optical fiber having a silica-based core comprising an alkali metal oxide selected from the group consisting of K2O, Na2O, LiO2, Rb2O, Cs2O and mixtures thereof in an average concentration in said core between about 50 and 500 ppm by weight, said core further comprising chlorine and fluorine, wherein the average concentration of fluorine in said core is greater than the average concentration of alkali metal oxide in said core and the average concentration of chlorine in said core is greater than the average concentration of alkali metal oxide in said core; and a silica-based cladding surrounding and directly adjacent the core. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained.

Abstract: A fused silica article having a combined concentration of hydroxyl (OH) and deuteroxyl (OD) concentration of less than 10 parts per million (ppm) and, in one embodiment, less than 1 ppm. The fused silica article is formed by drying a soot blank in a halogen-free atmosphere comprising carbon monoxide. The dried soot blank may optionally be doped to reach target levels of OH and OD concentrations and improve homogeneity within the fused silica article. The dried soot blank is then oxidized and, sintered to form the article. A method of reducing the combined concentration of OH and OD to less than 10 ppm is also described.

Abstract: A fused silica glass and a fused silica article having a combined concentration of at least one of OH and OD of up to about 50 ppm. The fused silica glass is formed by drying a fused silica soot blank or preform in an inert atmosphere containing a drying agent, followed by removal of residual drying agent from the dried soot blank by heating the dried soot blank in an atmosphere comprising an inert gas and of oxygen.

Abstract: Disclosed is an optical fiber having a silica-based core comprising an alkali metal oxide selected from the group consisting of K2O, Na2O, LiO2, Rb2O, Cs2O and mixtures thereof in an average concentration in said core between about 50 and 500 ppm by weight, said core further comprising chlorine and fluorine, wherein the average concentration of fluorine in said core is greater than the average concentration of alkali metal oxide in said core and the average concentration of chlorine in said core is greater than the average concentration of alkali metal oxide in said core; and a silica-based cladding surrounding and directly adjacent the core. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained.

Abstract: The invention relates to fiber optics and can be employed in fiber radiation collimators, optical waveguide couplers, spectral filters, optical isolators, long-period gratings, dispersion compensators, cascade mode field diameter conversion fibers on simulated Raman effect, physical value sensors, radiation suppression units for predetermined wavelengths, and for smoothing the gain spectrum in erbium fiber amplifiers. The invention facilitates fabrication of optical waveguides and apparatuses based on them. To produce preforms for optical waveguides (1) by a plasma chemical vapor deposition method, molecular gaseous agents, fed to a substrate tube (24), are mixed so that less than five atoms of oxygen fall on every atom of silicon and more than one atom of nitrogen falls on every 1000 atoms of oxygen. The refractive index is locally changed by heating a length of an optical waveguide (1). This causes a local thermal diffusion of elements contained in a core (3) into a cladding (2), or vice versa.