Abstract: In a known method for producing tubes of quartz glass, a hollow cylinder (2) of quartz glass is continuously supplied to a heating zone (1) and is softened therein in regions, and a tube strand (21) is drawn off at a drawing speed from the softened region with formation of a drawing bulb (26), and the tubes to be produced are cut to length in the form of tube strand pieces by separating the tube strand (21) at a desired separation point (T, Vu, Vo) and an internal pressure differing from the external pressure applied to the outer cladding is maintained in the inner bore (4) of the hollow cylinder (2) in that the inner bore (4) of the tube strand is provided with a flow obstacle.

Abstract: In a conventional method for the production of an optical component made from quartz glass, a coaxial arrangement with a core rod, surrounded by a quartz glass envelope tube comprising an evacuable inner drilling, is introduced in the vertical direction into a heating zone, softened therein by sections and, with formation of a drawing bulb, elongated to give the quartz glass component. According to the invention, a simple and cheap method based on the above, permitting the production of high-grade optical components by elongation of a coaxial arrangement of core rod and an enveloping tube with great economy, may be achieved, whereby a core rod is used, comprising at least two separate core rods arranged one above the other in the inner drilling and the weight of an upper core rod section is taken by a mounting or support region of the enveloping tube, provided above the drawing bulb.

Abstract: A known method for producing a cylindrical body uses a precipitation assembly (5) consisting of several precipitators (4), to which a parent substance is fed via medium supply lines (9), whereby the precipitation assembly (5) completes a closed trajectory (6) according to a predetermined displacement course, said trajectory comprising at least one precipitation path (8) that runs along the longitudinal axis (2) of the support. The aim of the invention is to provide an economical, reproducible, failsafe method based on said known procedure, which enables in particular the production of soot layers (3) on a support (1) at a high precipitation rate and nevertheless a high degree of uniformity. To achieve this, the displacement course (6) comprises a first loop (7a, 8) and a second loop (7b, 8), whereby the completion of the first loop (7a, 8) causes a right-hand torsion in the medium supply lines (9) and the completion of the second loop (7b, 8) causes a left-hand torsion in said lines (9).

Abstract: In a known method for producing a hollow quartz-glass cylinder by means of the soot method , a porous soot tube with a central inner bore is produced by the deposition of SiO2 particles on the outer surface of a support that rotates about its longitudinal axis. The soot tube is then heated in a furnace and sintered. During said process, the tube is held by a retaining device, which comprises an elongated shaping element that projects into the inner bore. The soot tube collapses onto said shaping element thus forming the hollow cylinder. The aim of the invention is to develop said process to provide an economic method that can be used to obtain quartz-glass hollow cylinders with a narrower inner bore. To achieve this, during the sintering process, a pressure differential is at least temporarily generated and maintained between a lower internal pressure prevailing in the inner bore of the soot tube and a higher external pressure that exists outside the inner bore.

Abstract: A drawing method is indicated for producing an optical component of quartz glass, which aims at shortening the pulling process and minimizing the loss of material.

Abstract: According to a previously known method for producing an optical component from synthetic quartz glass, a coaxial arrangement comprising an outer jacket tube, an inner jacket tube that is provided with an internal bore, and a core rod whose bottom face rests on a thrust bearing within the internal bore, is fed into a heating zone in a vertical orientation, is softened therein zone by zone, and is elongated so as to obtain the quartz glass component. In order to create a simple and inexpensive method that is based on said method and makes it possible to reproducibly manufacture a high-quality optical component, the thrust bearing is embodied as a constriction of the internal bore of the inner jacket tube.

Abstract: An object of the present invention is to provide a polishing method for producing, in a relatively short period of time, a tubular brittle material having an inner surface of high surface precision with a maximum roughness Rmax of 0.1 ?m or smaller and a center line average roughness Ra of 0.01 ?m or smaller, and to provide a tubular brittle material with high precision using said polishing method. The polishing method according to the invention is characterized by that the inner surface of the tubular material being pre-cut into a tubular shape using a honing machine is further polished with a sheet material having diamond abrasives attached thereon. Also claimed is a tubular brittle material obtained by said polishing method.

Abstract: According to a known vertical drawing method for producing a cylindrical glass body, the cylinder longitudinal axis of the glass cylinder is adjusted by hand in relation to the longitudinal axis of a heating tube. The aim of the invention is to optimise the stability of said glass body.

Abstract: Known methods for producing a semifinished product for an optical component of synthetic quartz glass of high homogeneity require a great number of forming or shaping steps for homogenization, which is troublesome in terms of energy and time and entails the risk that impurities might be introduced.

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: An object of the present invention is to provide a polishing method for producing, in a relatively short period of time, a tubular brittle material having an inner surface of high surface precision with a maximum roughness Rmax of 0.1 ?m or smaller and a center line average roughness Ra of 0.01 ?m or smaller, and to provide a tubular brittle material with high precision using said polishing method. The polishing method according to the invention is characterized by that the inner surface of the tubular material being pre-cut into a tubular shape using a honing machine is further polished with a sheet material having diamond abrasives attached thereon. Also claimed is a tubular brittle material obtained by said polishing method.

Abstract: In a known method for the production of a blank mold for optical fibers, a fluorine-doped SiO2 enveloping glass is produced on a core glass cylinder that rotates about its longitudinal axis, wherein a silicon-containing starting substance is fed to a plasma burner, said substance is then oxidized in a plasma flame assigned to the plasma burner to obtain SiO2 particles, the SiO2 particles are deposited by layers on the enveloping surface of the cylinder of the core glass cylinder in the presence of fluorine and sintered into the enveloping glass. The invention aims at providing an economical method, which builds upon the above-mentioned method, in order to produce a blank mold from which optical multi-mode fibers (52) can be obtained.

Abstract: The invention starts from a known method for producing a glass body, comprising forming a cylindrical blank by successive deposition of a plurality of material layers on the outer surface of a substrate body which is rotating about its longitudinal axis, by using an arrangement of a plurality of depositors which are directed onto the substrate body and which are fed via supply lines with process media for material layer deposition and which are moved without a reversing movement relative to the longitudinal axis of the substrate body. Starting therefrom, to provide a method for producing a glass body of high homogeneity that can be realized in a constructionally simple way, the invention suggests that the movement of the depositor arrangement along the longitudinal axis of the substrate body should be accompanied by a displacement of the substrate body.

Abstract: Known synthetic quartz glass tubes for the production of a preform have an inner bore with a surface layer produced without using tools in the molten state and an inner zone. The aim of the invention is to provide a tube which does not release any OH groups to the surroundings. For this purpose, the surface layer (30) has a thickness of 10 ?m and an average OH content of not more than 5 ppm by weight and an average surface roughness Ra of not more than 0.1 ?m. The inner zone (34) that starts on the surface layer (30) and terminates 10 ?m before the outer wall has an average OH content of not more than 0.2 ppm by weight. A simple and inexpensive method for producing a quartz tube of the above type is to continuously draw a tube strand from a softened quartz glass mass in a vertical drawing process. A scavenging gas is circulated through the inner bore of the tube, said gas having a water content of less than 100 ppb per weight.

Abstract: On the basis of a known process for the production of a preform for an optical fiber for optical data transmission technology, the productivity of the process for the production of complex refractive index profiles is to be improved by providing a quartz glass substrate tube which exhibits different doping in radial direction, introducing a core glass made of synthetic quartz glass into the substrate tube and covering the substrate tube with a jacket tube. A substrate tube suitable therefor is also being provided which tube requires less core glass material for the production of the preform, whether during the internal deposition or for the core glass rod in the rod-in-tube technique.

Abstract: The invention relates to a method for the production of an optical component made of quartz glass by elongating a coaxial array, comprising of a hollow quartz glass cylinder that has an inner bore hole and that has been mechanically machined to the end volume and a core rod arranged inside the inner bore hole, wherein the coaxial array is fed to a heat zone with a predetermined forward feed motion and is softened zonewise therein and the optical component is drawn from the softened area, wherein an annular gap between the core rod and the hollow cylinder is collapsed. The invention aims at providing an economical method by means of which an optical component can be produced and which is characterized by a low break rate when the fibers are drawn. Depending on the outer diameter of the hollow cylinder D [in mm], the forward feed motion V [in mm/min] is maintained within a range complying with the following calculation Vmin=3000×(2/D)2 and Vmax=16000×(2/D)2.

Abstract: In a previously known method for producing a hollow cylinder made of synthetic quartz glass, a silicon-containing compound is flame-hydrolyzed and SiO2 particles are deposited layer by layer on a rotating support, resulting in the production of an elongate porous soot body (5) having a central internal bore. Said soot body is dehydrated, doped, or vitrified, a process during which the soot body is held in a vertical direction inside a treatment oven by means of a holding device (9) comprising an elongate holding body (1) which protrudes into the internal bore of the soot body and is made of a material having a higher softening temperature than quartz glass. The aim of the invention is to create a method which is based on the previously known method and by means of which the purity of the hollow cylinder is maintained during said heating process while requiring little time and material for aftertreating the internal bore.

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: A known method for producing a cylindrical body uses a precipitation assembly (5) consisting of several precipitators (4), to which a parent substance is fed via medium supply lines (9), whereby the precipitation assembly (5) completes a closed trajectory (6) according to a predetermined displacement course, said trajectory comprising at least one precipitation path (8) that runs along the longitudinal axis (2) of the support. The aim of the invention is to provide an economical, reproducible, failsafe method based on said known procedure, which enables in particular the production of soot layers (3) on a support (1) at a high precipitation rate and nevertheless a high degree of uniformity. To achieve this, the displacement course (6) comprises a first loop (7a, 8) and a second loop (7b, 8), whereby the completion of the first loop (7a, 8) causes a right-hand torsion in the medium supply lines (9) and the completion of the second loop (7b, 8) causes a left-hand torsion in said lines (9).

Abstract: A resistance furnace has a tubular heating element with a vertically-oriented longitudinal axis. The heating element has a shell surface defined by an upper side and a lower side and surrounding a furnace chamber. The heating element is connected to at least two supply terminals by which heating current is introduced at power supply points into the heating element. The supply terminals include a surrounding upper annular collar adjacent the upper side of the shell surface, and also a surrounding lower annular collar adjacent the lower side of the shell surface.