Abstract:
Bie einem bekannten Verfahren zur Herstellung eines optischen Bauteils aus Quarzglas wird eine koaxiale Anordnung, die einen Kernstab umfasst, der von einem eine evakuierbare Innenbohrung aufweisenden Quarzglas-Hüllrohr umgeben ist, in vertikaler Ausrichtung einer Heizzone zugeführt, darin zonenweise erweicht und unter Bildung einer Ziehzwiebel zu dem Quarzglas-Bauteil elongiert. Um hiervon ausgehen ein einfaches und kostengünstiges Verfahren anzugeben, das die Herstellung hochwertiger optischer Bauteile durch Elongieren einer koaxialen Anordnung von Kernstab und einem Hüllrohr mit hoher Wirtschaftlichkeit ermöglicht, wird erfindungsgemäss vorgeschlagen, dass ein Kernstab eingesetzt wird, der aus mindestens zwei in der Innenbohrung lose übereinander angeordneten Kernstabstücken besteht, wobei das Gewicht eines oberen Kernstabstücks in einem oberhalb der Ziehzwiebel vorgesehenen Halte- oder Stützbereich des Hüllrohres abgetragen wird.
Abstract:
Die Herstellung eines optischen Bauteils aus Quarzglas durch Elongieren einer koaxialen Anordnung eines Kernstabs und eines Hohlzylinders ist bekannt. Dabei wird die Anordnung einer Heizzone zugeführt, darin mit ihrem unteren Ende beginnend zonenweise erweicht und aus dem erweichten Bereich das Bauteil abgezogen. Zur Bildung der Verengung der Innenbohrung des Hohlzylinders, auf welcher der Kernstab aufliegt wird erfindungsgemäss ein quasi-kontinuierliches Verfahren vorgeschlagen, indem ein oberer Hohlzylinder stirnseitig mit einem unteren Hohlzylinder unter Bildung eines axialen Zylinderverbundes verschmolzen wird, in den unteren Hohlzylinder ein Kernstab eingeführt wird, und der axiale Zylinderverbund zonenweise erweicht und unter Bildung des optischen Bauteils elongiert wird, wobei sich eine zum oberen Hohlzylinder fortschreitende Ziehzwiebel ausbildet, innerhalb der die Innenbohrung unter Bildung der Verengung mindestens teilweise kollabiert, und danach der obere Hohlzylinder an einer Trennebene im Bereich der Verengung von dem abgezogenen optischen Bauteil getrennt wird, und anschliessend zur Herstellung eines optischen Bauteils zusammen mit einem Kernstab elongiert wird.
Abstract:
An optical fiber drawing method comprises the steps of heating an optical fiber preform (13) starting at one end thereof to soften the same, and drawing an optical fiber (14), wherein the optical fiber preform (13) is received in a semi-sealed space (10, 20) partly opened at the lower end thereof within a drawing furnace and is heated by a heater (15) installed on the lower end of the semi-sealed space (10, 20) while drawing is performed with the amount of heat radiation from the upper region (20) of the semi-sealed space regulated.
Abstract:
The invention is a method of making an optical fiber or cane (600) that has optical properties that vary axially. Core glass (100) and clad glass (200) are fed into a furnace to form the cane or fiber. The velocities of the feeding of the clad and core are controlled so that the total combined mass per unit time is constant. The diameter of the core (604) varies along the length of the fiber or cane in accordance with the control of the velocities. The variance in the core diameter results in the variance of the axial optical properties of the fiber or cane.
Abstract:
The method for fabricating an optical fibre comprises the steps of inserting a primary optical fibre preform (11) having a first primary axis (x1) and an outer surface (111) into an overcladding tube (12) having a secondary primary axis (x2) and an inner surface (120), so that said outer surface and inner surface define an interior space (15); holding the primary preform (11) in a centrally inserted position within the overcladding tube (12) with said first and second primary axes (x1, x2) in substantial alignment with each other; supplying overcladding grain (13) into the interior space (15) that is limited at the lower end of the overcladding tube (12) by means of a closure (125); generating a condition of reduced pressure within the interior space (15) that is limited at the upper end of the overcladding tube (12) by means of an adjoiner (3), which holds the primary optical fibre preform (11) and the overcladding tube (12) in position; and heating the unprocessed secondary preform (1), that consists of the primary preform (11), the overcladding tube (12) and the overcladding grain (13), at its lower end to a softened state and simultaneously or subsequently drawing an optical fibre therefrom.
Abstract:
The method for fabricating an optical fiber comprises the steps of inserting a primary optical fiber preform (11) having a first primary axis (x1) and an outer surface (111) into an overcladding tube (12) having a second primary axis (x2) and an inner surface (120), so that said outer surface and inner surface define an interior space (15) ; holding the primary preform (11) in a centrally inserted position within the overcladding tube (12) with said first and second primary axes (x1, x2) in substantial alignment with each other; supplying overcladding grain (13) into the interior space (15) that is limited at the lower end of the overcladding tube (12) by means of a closure (125); generating a condition of reduced pressure within the interior space (15) that is limited at the upper end of the overcladding tube (12) by means of an adjoiner (3), which holds the primary optical fiber preform (11) and the overcladding tube (12) in position; and heating the unprocessed secondary preform (1), that consists of the primary preform (11), the overcladding tube (12) and the overcladding grain (13), at its lower end to a softened state and simultaneously or subsequently drawing an optical fiber therefrom.
Abstract:
A preform, a head part for a preform and a method for manufacturing a fibre are described. Said head part being adapted to be attached to a preform of a fibre. Said head part has such a shape that a heat load directed to said preform will be distributed to the cross section of said bulk part in a predetermined manner, like evenly distributing the heat load to the cross section of the preform. When manufacturing a fibre from a preform comprising such a head part the heating of the preform is more controllable thus resulting in a fibre with a better quality.
Abstract:
A method an apparatus for continuously producing optical waveguide fiber and preforms. A continuous supply of core cane is provided to a walled deposition chamber upon which glass soot is deposited to form a soot preform. The preform is passed through an aligned drying, consolidation and draw chambers from which an optical fiber may be drawn. In one embodiment, a plurality of burners are positioned at different radial distances from a longitudinal axis of the cane in the deposition chamber. One or more environmental seal(s) are provided to prevent process gasses or contaminants from flowing into or between the chambers.