A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO.sub.2 granulate particles from synthetically produced SiO.sub.2, (b) thermally densifying the SiO.sub.2 granulate particles to form partly densified SiO.sub.2 granulate particles, (c) forming a dispersion from the partly densified SiO.sub.2 granulate particles, (d) comminuting the partly densified SiO.sub.2 granulate particles to form a slip containing comminuted SiO.sub.2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO.sub.2 green body with a green density rG, and (f) sintering the SiO.sub.2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO.sub.2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m.sup.2/g, and during step (d), comminuted SiO.sub.2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m.sup.2/g.

A large sized opaque quartz glass ingot having an excellent heat ray shielding property, an outstanding light blocking property, high mechanical strength and small roughness of a baked finished smooth surface. The shape of bubbles inside the quartz glass are almost complete spheres and the average particle size of the bubbles is 1 ?m or less, such that the strength of the opaque quartz glass ingot is increased as the stress concentration at the edges of the bubbles is eliminated and an increase of surface roughness caused by baking is alleviated.

An optical fiber with low fictive temperature along with a system and method for making the optical fiber are provided. The system includes a reheating stage that heats the fiber along the process pathway to a temperature sufficient to lower the fictive temperature of the fiber by relaxing the glass structure and/or driving the glass toward a more nearly equilibrium state. The fiber is drawn from a preform, conveyed along a process pathway, cooled and subsequently reheated to increase the time of exposure of the fiber to temperatures conducive to lowering the fictive temperature of the fiber. The process pathway may include multiple reheating stages as well as one or more fiber-turning devices.

A method for manufacturing a glass ingot includes preparing a supply system including a gasifier that gasifies a raw material compound and a burner that combusts the gasified raw material compound; adding an oxygen-containing gas to the raw material compound at a plurality of addition places including an upstream addition place located in the gasifier or on an upstream side of the gasifier and a downstream addition place located on a downstream side of the gasifier in which locations of the raw material compound in a flow direction are different in the supply system so as to form a raw material mixture; and adding the oxygen-containing gas at the upstream addition place so that a concentration of oxygen or a concentration of the raw material compound in the raw material mixture is not in a combustible range of the raw material mixture.

The invention concerns a Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and comprises a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region comprises a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF comprises hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further comprises a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50? C., preferably 50? C.<Th<250? C.

An optical fiber with low fictive temperature along with a system and method for making the optical fiber are provided. The system includes a reheating stage that heats the fiber along the process pathway to a temperature sufficient to lower the fictive temperature of the fiber by relaxing the glass structure and/or driving the glass toward a more nearly equilibrium state. The fiber is drawn from a preform, conveyed along a process pathway, cooled and subsequently reheated to increase the time of exposure of the fiber to temperatures conducive to lowering the fictive temperature of the fiber. The process pathway may include multiple reheating stages as well as one or more fiber-turning devices.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) Providing a silicon dioxide granulate obtainable from a silicon dioxide powder, wherein the silicon dioxide granulate has a larger particle size than the silicon dioxide powder, ii.) Making a glass melt out of silicon dioxide granulate and iii.) Making a quartz glass body out of at least part of the glass melt, wherein the melting crucible has at least one inlet and at least one outlet, wherein at least part of the glass melt is removed via the melting crucible outlet. The invention further relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

The invention relates to a continuous sol-gel method for producing quartz glass, comprising the following steps: (a) continuously metering a silicon alkoxide into a first reactor (R1) and carrying out an at least partial hydrolysis process by adding an aqueous mineral acid, thereby obtaining a first product flow (A); (b) continuously producing an aqueous silicic acid dispersion by continuously mixing water and silicic acid in a second reactor, thereby obtaining a second product flow (B); (c) continuously mixing the product flows (A) and (B) in a third reactor (R3) in order to produce a pre-sol, thereby obtaining a third product flow (C); (d) continuously adding an aqueous base to the product flow (C), thereby obtaining a sol; (e) continuously filling the exiting sol into moulds, thereby obtaining an aquagel; (f) drying the aquagel, thereby obtaining xerogels; and (g) sintering the xerogels, thereby obtaining quartz glass, with the proviso that at least one of the steps (a) to (e) additionally includes a degassing process of at least one feed material used in the step.

A manufacturing method of a large-outer-diameter quartz crucible for a Czochralski (CZ) single crystal is provided. The manufacturing method is a vacuum arc method, and specifically includes: releasing a high-temperature arc with an electrode bundle composed of 2N+1 electrodes to fuse a crucible blank, and performing rapid cooling to form an initial quartz crucible product, where N is an integer greater than or equal to 2; the 2N+1 electrodes include one central main electrode and 2N auxiliary electrodes; the 2N auxiliary electrodes are equidistantly distributed on a circumference with the central main electrode as a center; the central main electrode is aligned at an axis of the crucible mold; the 2N auxiliary electrodes are connected to two phases of an industrial three-phase power, and the two phases are alternately arranged on the auxiliary electrodes; the central main electrode is connected to a remaining phase of the industrial three-phase power.

A manufacturing method of a large-outer-diameter quartz crucible for a Czochralski (CZ) single crystal is provided. The manufacturing method is a vacuum arc method, and specifically includes: releasing a high-temperature arc with an electrode bundle composed of 2N+1 electrodes to fuse a crucible blank, and performing rapid cooling to form an initial quartz crucible product, where N is an integer greater than or equal to 2; the 2N+1 electrodes include one central main electrode and 2N auxiliary electrodes; the 2N auxiliary electrodes are equidistantly distributed on a circumference with the central main electrode as a center; the central main electrode is aligned at an axis of the crucible mold; the 2N auxiliary electrodes are connected to two phases of an industrial three-phase power, and the two phases are alternately arranged on the auxiliary electrodes; the central main electrode is connected to a remaining phase of the industrial three-phase power.