Heraeus Quarzglas Gmbh & Co Kg

Heraeus Quarzglas Gmbh

Andreas Schultheis

Karsten Bräuer

Richard Schmidt

Andreas Langner

Peter Bauer

Uwe Christiansen

Gerhard Schoetz

Clemens Schmitt

Gerhard Schötz

Dagobert Knieling

Paul Bödiger

A quartz glass tube as a semi-finished product for an optical component that has an inner bore extending along a tube center axis for the acceptance of a core rod and a tube wall limited by an inner casing surface and an outer casing surface is already known; within said tube wall an inner region made of a first quartz glass and an outer region made of a second quartz glass with a different index of refraction surrounding the inner region contact one another at a contact surface which runs around the center axis. In order to provide a quartz glass on this basis that facilitates the production of optical components for special applications such as laser-activated optical components in wand or fiber form, the invention states that the contact surface has a non-round course in the radial cross-section and the inner casing surface has a circular course.

Quartz glass tube as a semi-finished product for an optical component

In plasma deposition processes for producing an optical preform according to the POD method, a cladding glass layer composed of fluorine-doped quartz glass is produced by means of a plasma torch on a cylindrical substrate body composed of quartz glass, said substrate body rotating about the longitudinal axis thereof. In this case, the plasma torch performs a reversing relative movement between two turning points (A; B) along the substrate body. In order, proceeding therefrom, to achieve a high fluorine doping in conjunction with a dopant distribution that is as uniform as possible axially, the invention proposes that a heat element has a heating effect on the region of one turning point (A; B) when the plasma torch is situated in the region of the other turning point (B; A).

Plasma deposition process for producing an optical preform with a cladding glass layer of fluorine-doped quartz glass

The invention relates to a plasma deposition process for producing an optical preform, which is characterized by a cladding glass layer having a non-round internal cross-section together with high fluorine doping and axially and radially specified dopant distribution, which in the simplest case is as uniform as possible. For this purpose, a two-stage method is proposed, wherein a substrate body having a non-round cross-section is first reshaped into a coated substrate body having a circular cross-section in that a POD filling layer made of quartz glass having the nominal fluorine concentration is deposited onto a present filling surface and rounded by grinding, and then in the second stage of the method a POD sheathing glass layer made of fluorine-doped quartz glass and having a circular-ring-shaped cross-section is deposited.

Method for producing an optical preform with a POD cladding glass layer

A method for the cleaning of SiO grain is known whereby SiO grain comprising contaminations is heated to a temperature at which the contaminations soften or form melting agglomerates with the SiO grain, thus separating the contaminations and the SiO grain. On this basis and to specify a method which achieves high grain purity at comparatively little expenditure of time, material and costs, and to provide a simple device suitable for the implementation of the method, it is proposed according to the invention that the SiO grain is fed to and heated in a gas stream which is directed towards an impingement plate, the SiO grain being accelerated in the direction of the impingement plate such that softened contaminations or melting agglomerates adhere to the impingement plate and cleaned SiO grain is removed from the impingement plate. A simple device suitable for the implementation of the method is provided with a burner into which a burner gas is introduced for a, burner gas flame, and a feeder device by means of which the SiO grain containing contaminations is fed to the burner gas or the burner gas flame, as well as an impingement plate toward which the burner gas flame is directed.

Method for cleaning SiO2 grain

A drill head carries a plurality of coaxially mounted drill crowns beginning with a first crown and followed by additional drill crowns which, upon rotation, describe concentric envelope circles of successively larger diameters. The first drill crown has cutting elements with a diamond coating with an average particle size of 200-1,000 .mu.m, and the additional drill crowns have cutting elements with a diamond coating with an average particle size of 200-300 .mu.m. The difference in diameter of succeeding drill crowns is successively small. Alignment of the drill crowns in a pilot hole is achieved by guide elements mounted behind the drill crowns and describing an inner envelope circle which is smaller than the outer envelope circle described by the largest drill crown, thereby defining a radial safety gap into which fluid is fed to form a cushion during rotation.

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Langenselbold, Germany

Andreas Schultheis