Abstract: The aim of the invention is to improve a known quartz glass cylinder for the production of an optical component, comprising an inner drilling, which is mechanically machined to size and provided with an etched structure by means of an etching treatment, subsequent to the mechanical machining, such that in the application thereof for production of pre-forms and optical fibres, few bubbles arise along the boundary surface between core and sleeve. Said aim is achieved, whereby the etched structure comprises striations with a maximum depth of 2.0 mm and a maximum width of 100 ?m.

Abstract: In the known method for producing an optical fiber, a coaxial arrangement comprising a core rod and an outer jacket tube is elongated, the coaxial arrangement being supplied in a vertical orientation to a heating zone and being softened therein zonewise, starting with the lower end thereof, and the optical fiber being withdraw downwards from the softened portion, whereby an annular gap existing between core rod and jacket tube is collapsed. Starting therefrom, in order to provided a method which makes it possible to produce optical fibers with a minimum curl and at low costs, the invention suggests that a quartz glass cylinder treated mechanically to its final dimension and having an outer diameter of at least 100 mm should be used as the jacket tube. An optical fiber obtained according to the method is characterized in that without the action of external forces it assumes a radius of curvature of at least 6 mm.

Abstract: Jacket tubes of synthetically produced quartz glass as a semi-finished product for producing an outer cladding glass layer of an optical fiber are generally known. The invention relates to an improvement of a jacket tube in terms of inexpensive producibility and of suitability as a semi-finished product for optical fibers having a low optical attenuation. According to the invention this object is achieved by a jacket tube in which the quartz glass has a content of metastable OH groups of less than 0.05 wt ppm and a content of anneal-stable OH groups of less than 0.05 wt ppm.

Abstract: The invention relates to a method for manufacture of a quartz glass preform for an optical fibre consisting of the following steps: preparation of a hollow cylinder made of porous quartz glass which exhibits an inner layer with a doping substance which increases the refractive index of quartz glass and an outer layer surrounding the inner layer, with a lower refractive index, and collapse of the hollow cylinder characterised by collapse of the porous hollow cylinder onto a quartz glass rod containing the doping substance.

Abstract: According to a prior art method for producing a cylindrical component comprised of silica glass, a cylinder comprised of a softened silica glass mass is drawn in a predetermined drawing direction along a drawing axis by means of a drawing device which acts upon said cylinder. The aim of the invention is to provide a method which prevents, to the greatest possible extent, warping of the drawn cylinder and other deviations from the ideal cylinder dimensions and to prevent, to the greatest possible extent, the outer surface of the drawn cylinder from being touched. To these ends, the invention provides that the drawing device comprises a plurality of guide elements which are arranged one behind the other along the drawing axis, and which can be displaced independently of one another in a drawing direction and in a direction opposite thereto.

Abstract: In the known method for producing an optical fiber, a coaxial arrangement comprising a core rod and an outer jacket tube is elongated, the coaxial arrangement being supplied in a vertical orientation to a heating zone and being softened therein zonewise, starting with the lower end thereof, and the optical fiber being withdraw downwards from the softened portion, whereby an annular gap existing between core rod and jacket tube is collapsed. Starting therefrom, in order to provided a method which makes it possible to produce optical fibers with a minimum curl and at low costs, the invention suggests that a quartz glass cylinder treated mechanically to its final dimension and having an outer diameter of at least 100 mm should be used as the jacket tube. An optical fiber obtained according to the method is characterized in that without the action of external forces it assumes a radius of curvature of at least 6 m.

Abstract: In a known method for producing an SiO2 blank, SiO2 particles are formed in a burner flame assigned to a deposition burner and are deposited under the effect of an electrical field on a deposition surface of a carrier rotating about its longitudinal axis, said at least one deposition burner being reciprocated in a predetermined sequence of movement along the developing blank between turn-around points. Starting from said method, in order to obtain blanks of a predetermined, in particular axially homogeneous, density and mass distribution, it is suggested according to the invention that the geometrical shape of the burner flame should be varied by the electrical field in dependence upon the position of the deposition burner during the sequence of movement.

Abstract: A glass composition to be softened is fed to a heating zone and is shaped continuously into a cylindrical component in a deformation zone, and the cross-sectional geometry of the component is determined. A feed device, a heating device, and a take-off device are provided, and a glass composition is supplied continuously by the feed device to the heating device, where it is softened, the component being formed from the softened glass composition by means of the take-off device under formation of a deformation zone. To produce a component with only slight deviations from the desired cross-sectional geometry and to provide a flexible apparatus suitable for this purpose, the glass composition is locally heated or cooled in at least one deformation area, which extends over only a part of the circumference of the deformation zone, as a function of a determined deviation of the cross-sectional geometry from a nominal geometry.

Abstract: In a known method for producing an SiO2 blank, SiO2 particles are formed in a burner flame of a deposition burner and are deposited under the effect of an electrical field on a substrate. Starting therefrom, in order to indicate a simple and inexpensive method by means of which blanks can be produced with a predetermined, in particular axially homogeneous, mass and density distribution, it is suggested according to the invention that the geometrical shape of the burner flame (8) is adjusted by the effect of the electrical field (9) in dependence upon the geometrical parameter of a deposition surface (12; 21) of the substrate (1) that is assigned to the burner flame (8).

Abstract: In a known procedure for the manufacture of an optical fiber by drawing from a preform with a core-clad structure or from a coaxial arrangement of several components forming a core-clad structure, a core cylinder is produced with a soot deposition method, with the core cylinder having a core glass layer of a higher refractive index, “nK”, and outer diameter, “dK”, said core glass layer being encased by a first cladding glass layer having a lower refractive index, “nM1”, and outer diameter, “dM1”, followed by applying a second cladding glass layer onto the core cylinder. The modification of this procedure according to the invention is characterized by its lower optical fiber production costs. This is achieved by providing the second cladding glass layer (4) in the form of a cladding tube manufactured in a separate step of the procedure, said cladding tube having a mean OH concentration of max. 1 wt.

Abstract: To facilitate the start of a process using a quartz glass crucible with a crucible body and an inner layer of quartz glass a quartz glass crucible is provided with an inner surface roughened at least in the starting zone region by multiple depressions disposed at a maximum distance of 5 mm from one another. Furthermore, a simple and inexpensive process for the manufacture of such a quartz glass crucible is described, by providing a crucible body with a smooth inner surface of quartz glass and subsequently roughening the inner layer in the starting zone region by multiple depressions disposed at a maximum of 5 mm from one another.

Abstract: The invention relates to a food product comprising 0.1 to 1.5 wt % of one or more anti-spattering agents comprising no native soy lecithin or native soy lecithin in an amount of from 0 to 0.05 wt % on total product, whereby the anti-spattering agent is preferably selected from the group comprising hydrolyzed lecithin, fractionated lecithin, citric acid esters or combinations thereof; optionally one or more emulsifiers in a total amount of from 0 to 0.5 wt %; optionally one or more browning agents in a total amount of from 0 to 0.07 wt %; one or more salts in an amount of from 0.5 to 3 wt %.

Abstract: Water continuous, pourable compositions comprising more than 50 to 80 wt % fat, an emulsifier having a hydrophilic/lipophilic balance value of at least 7, an antispattering composition and optionally a biopolymer in an amount of at most at most 0.3 wt % on total composition weight are suitable frying compositions.

Abstract: In a known method for producing an SiO2 blank, SiO2 particles are formed in a burner flame assigned to a deposition burner and are deposited under the effect of an electrical field on a deposition surface of a carrier rotating about its longitudinal axis, said at least one deposition burner being reciprocated in a predetermined sequence of movement along the developing blank between turn-around points. Starting from said method, in order to obtain blanks of a predetermined, in particular axially homogeneous, density and mass distribution, it is suggested according to the invention that the geometrical shape of the burner flame should be varied by the electrical field in dependence upon the position of the deposition burner during the sequence of movement.

Abstract: In a known method for producing an SiO2 blank, SiO2 particles are formed in a burner flame of a deposition burner and are deposited under the effect of an electrical field on a substrate. Starting therefrom, in order to indicate a simple and inexpensive method by means of which blanks can be produced with a predetermined, in particular axially homogeneous, mass and density distribution, it is suggested according to the invention that the geometrical shape of the burner flame (8) is adjusted by the effect of the electrical field (9) in dependence upon the geometrical parameter of a deposition surface (12; 21) of the substrate (1) that is assigned to the burner flame (8).

Abstract: Based on a known process for the manufacture of opaque quartz glass, by mixing SiO2 particles and an additive which is volatile at a melting temperature, forming a body and melting said body with an advancing melt front forming in the body, it is proposed according to the invention that in order to reduce the danger of contamination, a body (1) be formed with an inner bore (6) and be heated in such a manner that the melt front (10) advances from the inner bore (6) to the outside. The article of pure opaque quartz glass according to the invention has high resistance to temperature change, high mechanical strength and good chemical durability. It is distinguished by an opening (6) enclosed by an inner wall (9), with an inner SiO2 surface layer (15) having a layer thickness ranging from 30 mm to 500 mm and a density of at least 2.15 g/cm3.

Abstract: In a known process for the production of opaque quartz glass a blank is formed from synthetic SiO2 granulate and is heated at a vitrification temperature to form a body of opaque quartz glass. In order to provide on this basis a process for the production of pure opaque quartz glass with a homogenous pore distribution, high density, high viscosity and a low tendency to devitrify, it is proposed according to the invention that the SiO2 granulate to be used is a SiO2 granulate (21; 31) composed of at least partially porous agglomerates of SiO2 primary particles, with a specific BET surface ranging from 1.5 m2/g to 40 m2/g and an apparent density of at least 0.8 g/cm3. A SiO2 granulate (21; 31) suitable for the implementation of the process is distinguished in that it is formed from at least partially porous agglomerates of SiO2 primary particles and in that it has a specific BET surface ranging from 1.5 m2/g to 40 m2/g and an apparent density of at least 0.6 g/cm3.

Abstract: An essentially cylindrical porous blank is formed by the deposition of SiO.sub.2 particles onto the lateral cylindrical surface of a cylindrical mandrel, rotating around its longitudinal axis; this blank is provided with a holding element of quartz glass in the form of a hollow body, which surrounds a section of the mandrel and which is at least partially embedded in the area of one of the ends of the blank. The blank is then sintered. In order to securely support even heavy blanks without complicated holding devices, the holding element is fused into the area of at least one of the ends of the blank during the deposition process by the maintenance of a high temperature.

Abstract: In an optical component having a cylindrical core of quartz glass and a coaxial jacket of quartz glass containing a dopant which decreases the index of refraction, the jacket glass contains a viscosity-increasing stiffening agent to reduce tensile strength on the core at drawing temperature of 1000.degree. to 2500.degree. C. or a relaxation agent for lowering the viscosity of the quartz glass in a concentration which is lower than that present in the core glass.

Abstract: The invention relates to lenses, prisms or other optical members which are subjected to high-power ultraviolet light having a wavelength of about 360 nm or less, or ionizing radiation, particularly optical members for use in laser exposure apparatus for lithography, and to blanks for such optical members. The homogeneity of the refractive index distribution and the resistance to optical deterioration when the optical members are exposed for a long period of time to short wavelength ultraviolet light from a laser beam are improved. The optical members are made of high-purity synthetic silica glass material containing at least about 50 wt. ppm of OH groups, and are doped with hydrogen.