Heraeus Quarzglas Gmbh

Heraeus Quarzglas Gmbh & Co Kg

Furukawa Electric North America, Inc.

Heraeus Tenevo Gmbh

Hartwig Schaper

Norbert Treber

Waltraud Werdecker

Klaus Ruppert

Wolfgang Englisch

Helmut Leber

Rolf Gerhardt

Udo Peper

Donald Jablonowski

Klaus Reimann

Gerhart Vilsmeier

Oliver Humbach

Hans-Georg Fritsche

Uwe Haken

J&uuml;rgen R&ouml;per

Frank Neubauer

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. Regarding the process it is proposed according to the invention that a substrate tube be used which was obtained by vitrification of a porous tube-shaped SiOblank, the substrate tube being provided with a core glass layer which is produced in that to the first radial portion of the SiOblank there is added before the vitrification a first dopant which increases the refractive index of quartz glass. The substrate tube according to the invention has in the radial direction regions of different doping whereby it incorporates a core glass layer which has a refractive index of at least 1.459.

Method of making a jacketed preform for optical fibers using OVD

In a known process for the manufacture of an elongated porous SiO,preform, SiO,particles are deposited on the mantle surface of a cylindrical carrier rotating about its longitudinal axis. The SiO,particles are formed by means of a plurality of deposition burners which are arranged, at a distance from one another, in at least one burner row extending parallel to the longitudinal axis of the carrier. The burners are moved in a repeated cycle back and forth along the forming preform and between turnaround points where the direction of their motion is reversed. Measures are taken in the process to prevent or reduce overheating of the preform in the turnaround point regions. These measures can lead to variations in the rate of deposition. In order to prevent this it is proposed according to the invention that the measures comprise localized removal of heat from the turnaround points (,), or a localized heat shielding of the regions (,) around the turnaround points (,), and that these measures be kept time-constant within a motion cycle. As far as concerns an apparatus suitable for implementation for the manufacture of a porous SiO,preform, with a cylindrical carrier rotatable about its longitudinal axis, with a plurality of deposition burners arranged in at least one burner row extending parallel to the carrier's longitudinal axis, connected with one another and at a distance from one another and with a jogging device which moves the deposition burners along the carrier and between turnaround points where the direction of the motion is reversed and by means of which burners SiO,particles are deposited on the carrier, forming the preform, it is proposed that heat sinks (,) be provided in the regions (,) around the turnaround points (,).

Process and apparatus for manufacturing a porous SiO2 preform

Method of producing quartz glass bodies

To produce a free-flowing granulate which has a high bulk density and a defined particle size distribution, which generates little dust, is easy to handle, and is suitable as a starting material for quartz glass products, the mixing operation includes a first mixing phase, in which the materials to be mixed are subjected to a slow mixing action to form a coarse-grained mass, and a second mixing phase, in which the coarse-grained mass is converted to a fine-grained mass by a more intensive mixing action which grinds and compacts the grains. The content of silica powder in the materials to be mixed is adjusted at least during the second mixing phase to a value of at least 75 wt. %.

Process for manufacture of silica granules

Starting from a process for producing a rod-like preform, in particular for optical fibers, in which a tubular blank whose refractive index changes, viewed in the radial direction is fed to a heating zone, is softened there, and in the softened state is shaped to give the preform, a method is described for producing preforms which are hyperpure and low in defects, in which the blank used is one whose refractive index decreases, viewed in the radial direction, from the outside inwards, starting from at least one interface which is at a sufficient distance from the outer surface of the blank, of which that part which has been softened in the heating zone is introverted apart from an outer skin, and by which the preform is formed in the longitudinal axis of the tubular blank, counter to the direction in which the latter is fed to the heating zone, and in which the remaining outer skin is drawn off as a rod in the feed direction of the blank.

Method of partially introverting a multiple layer tube to form an

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Aschaffenburg, Germany

Hartwig Schaper