One aspect relates to a process for the preparation of a quartz glass body, including provision of a silicon dioxide granulate, making a glass melt from the silicon dioxide granulate and making a quartz glass body from at least part of the glass melt. The provision includes making a silicon dioxide powder with at least two particles prepared from a silicon-chlorine compound, bringing the silicon dioxide powder into contact with ammonia to obtain a treated silicon dioxide powder, and granulating the treated silicon dioxide powder to obtain a silicon dioxide granulate. The chlorine content of the silicon dioxide powder is greater than the chlorine content of the silicon dioxide granulate. One aspect relates further to a quartz glass body which is obtainable by this process. One aspect also relates to a process for the preparation of a silicon dioxide granulate.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate I prepared from a pyrogenically produced silicon dioxide powder, treating the silicon dioxide granulate I with a reactant at a temperature in a range from 1000 to 1300 C., and making a glass melt out of the silicon dioxide granulate. A quartz glass body is made out of at least a part of the glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a light guide, an illuminant, and a formed body, each of which is obtainable by further processing of the quartz glass body. One aspect additionally relates to a process for the preparation of a silicon dioxide granulate II.

A coupled-core multi-core fiber in which an inter-core distance is stabilized is manufactured. A method of manufacturing a coupled-core multi-core fiber includes forming a second cladding base material by depositing glass particulates on an outer periphery of a first cladding base material and sintering the glass particulates. The first cladding base material has a hydroxyl group concentration that is less than or equal to 10 ppb; obtaining a ground rod by grinding an outer periphery of the second cladding base material; and forming holes in the first cladding base material in the ground rod, inserting a core base material into each of the holes, and obtaining an assembly.

A method of forming a doped silica-titania glass is provided. The method includes blending batch materials comprising silica, titania, and at least one dopant. The method also includes heating the batch materials to form a glass melt. The method further includes consolidating the glass melt to form a glass article, and annealing the glass article.

A glass composite for use in Extreme Ultra-Violet Lithography (EUVL) is provided. The glass composite includes a first silica-titania glass section. The glass composite further includes a second doped silica-titania glass section mechanically bonded to a surface of the first silica-titania glass section, wherein the second doped silica-titania glass section has a thickness of greater than about 1.0 inch.

A doped silica-titania (DST) glass article that includes a glass article having a glass composition comprising a silica-titania base glass containing titania at 7 to 14 wt. % and a balance of silica, and a dopant selected from the group consisting of (a) F at 0.7 to 1.5 wt. %, (b) B.sub.2O.sub.3 at 1.5 to 5 wt. %, (c) OH at 1000 to 3000 ppm, and (d) B.sub.2O.sub.3 at 0.5 to 2.5 wt. % and OH at 100 to 1400 ppm. The glass article has an expansivity slope of less than about 1.3 ppb/K.sup.2 at 20? C. For DST glass articles doped with F or B.sub.2O.sub.3, the OH level can be held to less than 10 ppm, or less than 100 ppm, respectively. In many aspects, the DST glass articles are substantially free of titania in crystalline form.

There is provided a method for producing a low-loss alkali metal-doped silica core optical fiber having excellent hydrogen resistance. The method for producing the optical fiber according to the present invention includes a drawing step of drawing an optical fiber preform in a drawing furnace to produce a silica glass-based optical fiber including a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region and a heating step of heating the optical fiber in a heating furnace through which the optical fiber drawn from the drawing furnace passes.

A high silica glass composition comprising about 92 to about 99.9999 wt. % SiO.sub.2 and from about 0.0001 to about 8 wt. % of at least one dopant selected from Al.sub.2O.sub.3, CeO.sub.2, TiO.sub.2, La.sub.2O.sub.3, Y.sub.2O.sub.3, Nd.sub.2O.sub.3, other rare earth oxides, and mixtures of two or more thereof. The glass composition has a working point temperature ranging from 600 to 2,000 C. These compositions exhibit stability similar to pure fused quartz, but have a moderate working temperature to enable cost effective fabrication of pharmaceutical packages. The glass is particularly useful as a packaging material for pharmaceutical applications, such as, for example pre-filled syringes, ampoules and vials.

An optical component made of synthetic quartz glass includes a glass structure substantially free of oxygen defect sites and having a hydrogen content of 0.110.sup.16 to 1.010.sup.18 molecules/cm.sup.3, an SiH group content of less than 210.sup.17 molecules/cm.sup.3, a hydroxyl group content of 0.1 to 100 wt. ppm, and an Active temperature of less than 1070 C. The optical component undergoes a laser-induced change in the refractive index in response to irradiation by a radiation with a wavelength of 193 nm using 510.sup.9 pulses with a pulse width of 125 ns and a respective energy density of 500 J/cm.sup.2 at a pulse repetition frequency of 2000 Hz. The change totals a first measured value M.sub.193 nm when measured using the applied wavelength of 193 nm and a second measured value M.sub.633 nm when measured using a measured wavelength of 633 nm. The ratio M.sub.193 nm/M.sub.633 nm is less than 1.7.

Provided is a method for producing a multi-core optical fiber that includes a plurality of cores made of pure silica glass and exhibits a minor transmission loss. The method for producing a multi-core optical fiber according to the present invention is a method for producing a multi-core optical fiber including a plurality of cores made of pure silica glass substantially free of Ge and a cladding surrounding the plurality of cores and made of a fluorine-containing silica glass. The multi-core optical fiber is produced by drawing an optical fiber preform at a drawing tension T satisfying the relationship 0.06 g/m.sup.2<T/S<0.4 g/m.sup.2, wherein S is a total cross-sectional area of the plurality of cores.