Abstract: The present invention provides doped titania-doped silica glass articles having low thermal expansions and low variations in thermal expansion. According to one embodiment of the invention, a titania-doped silica glass article has a titania content of between about 5 wt % and about 9 wt %; a coefficient of thermal expansion of between about ?30 ppb/° C. and about +30 ppb/° C. at a temperature between 15° C. and 30° C.; and a variation in coefficient of thermal expansion of less than about 5 ppb/° C. at a temperature between 15° C. and 30° C.

Abstract: Disclosed are high purity synthetic silica glass material having a high OH concentration homogeneity in a plane perpendicular to the optical axis, and process of making the same. The glass has high refractive index homogeneity. The glass can have high internal transmission of at least 99.65%/cm at 193 nm. The process does not require a post-sintering homogenization step. The controlling factors for high compositional homogeneity, thus high refractive index homogeneity, include high initial local soot density uniformity in the soot preform and slow sintering, notably isothermal treatment during consolidation.

Abstract: A method of manufacturing a glassy optical preform is disclosed that includes providing a preform having a silica soot layer and then sintering the soot layer into a glassy layer, and water is selectively added to the preform by exposing the soot layer to a gaseous water-containing atmosphere during the sintering step. The preform is controllably doped with water.

Abstract: The present invention provides doped titania-doped silica glass articles having low thermal expansions and low variations in thermal expansion. According to one embodiment of the invention, a titania-doped silica glass article has a titania content of between about 5 wt % and about 9 wt %; a coefficient of thermal expansion of between about ?30 ppb/° C. and about +30 ppb/° C. at a temperature between 15° C. and 30° C.; and a variation in coefficient of thermal expansion of less than about 5 ppb/° C. at a temperature between 15° C. and 30° C.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: A method and apparatus for producing an optical fiber preform including a metal remover, which operates by adsorption, that removes gaseous transition metal impurities present in a process gas to be provided to a furnace for drying, doping or consolidation. The apparatus and method may reduce attenuation of the resultant optical fiber drawn from the preform.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: An optical waveguide fiber or body having a doped outer region which can be utilized in an optical coupler, a preform which can serve as the precursor for the fiber, an optical coupler, and methods of making same. Water, for example in the form of H2O and/or D2O, may be added to the cladding of the optical waveguide fiber or body.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: A method and apparatus for producing an optical fiber preform including a metal remover, which operates by adsorption, that removes gaseous transition metal impurities present in a process gas to be provided to a furnace for drying, doping or consolidation. The apparatus and method may reduce attenuation of the resultant optical fiber drawn from the preform.

Abstract: A method of forming an optical fiber preform that includes providing a consolidated glass preform, depositing a layer of silica soot onto the consolidated glass preform to form a composite preform having a consolidated glass portion and a silica soot portion, and exposing the composite preform to an atmosphere containing a concentration of a deuterium compound for a time and at a temperature sufficient to cause the deuterium compound to penetrate the consolidated glass portion without pervading the entire glass portion. Preferably, the deuterium compound penetrates the glass portion to a desired depth.

Abstract: A method for manufacturing optical fiber preform and fiber. According to the method, a core cane segment is formed with a refractive index delta preferably between 0.2% and 3% that is most preferably formed by an OVD method. A sleeve is formed including at least one down-doped moat preferably having a refractive index delta between −0.1% and −1.2% and at least one up-doped ring preferably having a refractive index delta between 0.1% and 1.2%. The sleeve is formed by introducing glass precursor and dopant compounds into a cavity of a preferably silica glass tube (e.g., one of an MCVD and PCVD method). The core cane segment is inserted into the sleeve and the sleeve is collapsed onto the core cane segment to form a core-sleeve assembly. The core-sleeve assembly is again drawn into a cane and additional cladding is preferably formed thereon. Optical fiber may be drawn from the preform in a conventional draw apparatus.

Abstract: A furnace assembly for heating an optical waveguide preform includes a furnace. The furnace includes a muffle and a heating device. The muffle defines a furnace passage. The furnace passage has a length extending from a first end to a second end. The heating device is operative to heat the furnace passage. A process gas supply provides a process gas to the furnace passage. A handle is disposed in the furnace passage and is adapted to hold the waveguide preform. A flow shield is positioned between the first and second ends and extends across the furnace passage between the handle and the muffle. The flow shield is arranged and configured to restrict flow of the process gas from the first end to the second end of the furnace passage.

Abstract: A method for manufacturing optical fiber preform and fiber. According to the method, a core cane segment is formed with a refractive index delta preferably between 0.2% and 3% that is most preferably formed by an OVD method. A sleeve is formed including at least one down-doped moat preferably having a refractive index delta between −0.1% and −1.2% and at least one up-doped ring preferably having a refractive index delta between 0.1% and 1.2%. The sleeve is formed by introducing glass precursor and dopant compounds into a cavity of a preferably silica glass tube (e.g., one of an MCVD and PCVD method). The core cane segment is inserted into the sleeve and the sleeve is collapsed onto the core cane segment to form a core-sleeve assembly. The core-sleeve assembly is again drawn into a cane and additional cladding is preferably formed thereon. Optical fiber may be drawn from the preform in a conventional draw apparatus.

Abstract: A cylindrical glass body having a low water content centerline region and method of manufacturing such a cylindrical glass body for use in the manufacture of optical waveguide fiber is disclosed. The centerline region of the cylindrical glass body has a water content sufficiently low such that an optical waveguide fiber made from the cylindrical glass body of the present invention exhibits an optical attenuation of less than about 0.35 dB/km, and preferably less than about 0.31 dB/km at a measured wavelength of 1380 nm. A low water content plug used in the manufacture of such a cylindrical glass body, an optical waveguide fiber having a low water peak, and an optical fiber communication system incorporating such an optical waveguide fiber is also disclosed.

Abstract: Optical waveguide fiber having low water peak as well as optical waveguide fiber preforms and methods of making optical waveguide fiber preforms from which low water peak and/or low hydrogen aged attenuation optical waveguide fibers are formed, including optical waveguide fiber and preforms made via OVD. The fibers may be hydrogen resistant, i.e. exhibit low hydrogen aged attenuation. A low water peak, hydrogen resistant optical waveguide fiber is disclosed which exhibits an optical attenuation at a wavelength of about 1383 nm which is less than or equal to an optical attenuation exhibited at a wavelength of about 1310 nm.

Abstract: An optical waveguide fiber or body having a doped outer region which can be utilized in an optical coupler, a preform which can serve as the precursor for the fiber, an optical coupler, and methods of making same. Water, for example in the form of H2O and/or D2O, may be added to the cladding of the optical waveguide fiber or body.

Abstract: A glass optical fiber includes multiple cores fused into a single fiber. The new optical fiber is coherent, in the sense that the cores maintain their relative position with respect to each other within the fiber throughout the length of the fiber. That is, a core having specific radial and angular positions at one end of the fiber will have the same radial and angular positions throughout the fiber, including at the fibers opposite end. In one aspect of the invention the fiber presents a circular cross section, in another it presents an elliptical cross section of greater eccentricity to ease the task of orienting the cores within the fiber for connection to signal sources, other fibers, integrated optic devices, receivers and other optical components. An orienting core may suitably be included in the fiber to further assist in orienting the fiber end. In manufacturing the new optical fiber, a silica tube is stuffed with core canes.

Abstract: The invention relates to a method of drying and sintering porous optical fiber preforms, especially those consisting of a solid glass core cane surrounded by a layer of cladding soot. After it is dried in a dehydrating atmosphere, the porous preform is heated to a presinter temperature just below that at which it would begin to rapidly densify. The various temperature holds and ramp rates are such that the preform is consolidated in a relatively short time without becoming cloudy or exhibiting other defects that would adversely affect the optical fiber drawn from the consolidated draw blank.