A method for packing quartz glass cloth includes the step of packing quartz glass cloth that is at least 99.5 wt % comprised of SiO.sub.2 with packaging film to form a package, wherein the package has a volumetric absolute humidity therein of 10.0 g/m.sup.3 or less.

Preform for an optical waveguide containing a core with a non-circular geometry and at least one cladding layer, in which the dopand concentration of the cladding layer is increased compared to the dopand concentration of a preform with circular core geometry and identical NA. A method for the production of a preform for an optical fiber is provided. An optical waveguide with a nominal dopand concentration of c(eff)Fc(nom) in at least one cladding layer is also provided.

A crucible structure is adapted for manufacturing a silicon crystal structure. The crucible structure includes a crucible body and a release coating layer. A material of the crucible body includes silicon dioxide. The release coating layer directly covers the crucible body, and a material of the release coating layer includes barium silicate. The barium silicate is a continuous film to contact the silicon crystal structure, and a thickness of the release coating layer is between 35 m and 350 m.

A method for depositing SiO2 soot particles on a deposition surface using at least two mutually spaced and adjacent build-up burners, and a corresponding device for carrying out the method.

An optical sensor that includes a photonic crystal fiber (PCF) and an optical coupler. The PCF includes a hollow core with a first diameter (Dc), an inner cladding section, and an outer layer surrounding the inner cladding section. The inner cladding section includes a cladding material and a plurality of spaced apart circular-shaped channels disposed in the cladding material surrounding the hollow core. The cladding material includes at least one of glass, ceramic, and glass-ceramic. Each spaced apart circular-shaped channel has substantially the same size and an average diameter (d). A first end of the PCF is in optical communication with a light source and a second end of the PCF is in optical communication with the optical coupler.

An optical fiber includes a core and a cladding surrounding an outer periphery of the core and has a refractive index profile in which a relative refractive index difference with respect to a distance r from a center of the core is represented by (r), where a value of A represented by
A=.sub.0.sup.0.22MFD.sup.1.31((r).sub.ref(r))dr+.sub.0.22MFD.sub.1.31.sup.0.44MFD.sup.1.31((r).sub.ref(r))dr(Formula 1)
is 0.3%.Math.m or less, where a unit of r is m, a unit of a relative refractive index difference (r) is %, .sub.ref(r)=0.064r+0.494, and MFD.sub.1.31 is a mode field diameter at a wavelength of 1.31 m.

A system and method for making an edge section of a thin, high purity fused silica glass sheet. The method includes a step of directing a laser to melt through the glass sheet with localized heating of a narrow portion of the glass sheet to form an edge section of the glass sheet, and continuing the edge section to form a closed loop defining a perimeter of the glass sheet. The method further includes rapidly cooling the glass sheet through the glass transition temperature as the melted glass of the edge section contracts and/or solidifies to form an unrefined-bullnose shape extending between first and second major surfaces of the glass sheet.

A method for packing quartz glass cloth includes the step of packing quartz glass cloth that is at least 99.5 wt % comprised of SiO.sub.2 with packaging film to form a package, wherein the package has a volumetric absolute humidity therein of 10.0 g/m.sup.3 or less.

A method for producing synthetic quartz glass by fusion of SiO.sub.2 granulate involves synthesizing amorphous SiO.sub.2 primary particles, granulating the amorphous SiO.sub.2 primary particles to form an open-pore SiO.sub.2 granulate, sintering the open-pore SiO.sub.2 granulate by heating in a sintering atmosphere at a sintering temperature and for a sintering period to form a densified SiO.sub.2 granulate, and melting the densified SiO.sub.2 granulate at a melting temperature to form the synthetic quartz glass. To provide an inexpensive production of low-bubble transparent components of quartz glass despite the use of still open-pore SiO.sub.2 granulate, the sintering atmosphere, sintering temperature and sintering duration are adjusted such that the densified SiO.sub.2 granulate still comprises open pores but manifests a material-specific infrared transmission T.sub.1700 at a wavelength of 1700 nm. This transmission is in the range of 50-95% of the infrared transmission T.sub.1700 of quartz glass granules of the same material.

The synthetic amorphous silica powder of the present invention is characterized in that it comprises a synthetic amorphous silica powder obtained by applying a spheroidizing treatment to a silica powder, and by subsequently cleaning and drying it so that the synthetic amorphous silica powder has an average particle diameter D.sub.50 of 10 to 2,000 m; wherein the synthetic amorphous silica powder has: a quotient of 1.00 to 1.35 obtained by dividing a BET specific surface area of the powder by a theoretical specific surface area calculated from the average particle diameter D.sub.50; a real density of 2.10 to 2.20 g/cm.sup.3; an intra-particulate porosity of 0 to 0.05; a circularity of 0.75 to 1.00; and an unmolten ratio of 0.00 to 0.25. This synthetic amorphous silica powder is less in amount of gas components adsorbed to surfaces of particles of the powder and in amount of gas components within the particles, so that a synthetic silica glass product manufactured by using the powder is remarkably decreased in amount of generation or degree of expansion of gas bubbles even upon usage of the product in a high temperature and reduced pressure environment.