Abstract:
To improve a known method for making a quartz glass tube as a semifinished product for the manufacture of optical fibers, the tube comprising an inner fluorine-doped quartz glass layer and an outer quartz glass layer, so as to achieve inexpensive manufacture and improved dimensional stability of the quartz glass tube, it is suggested according to the invention that the quartz glass of the inner layer should be produced in a first plasma deposition process with formation of an inner layer having a wall thickness of at least 1.5 mm, with a fluorine content of at least 1.5% by wt. being set in the quartz glass, and that the quartz glass of the outer layer should be produced in a second plasma deposition process and deposited directly or indirectly on the inner layer with formation of a composite tube, and that the composite tube should be elongated into the quartz glass tube.
Abstract:
A process for preparing the mandrel suitable for producing flawless optical fiber preform, wherein the mandrel can be easily removed from the soot porous body without causing any defects, such as voids, bubbles, impurities, uncollapsed portion in the centerline region of the preform thus produced, wherein said process is characterized by heating the mandrel before the start of soot deposition to form a soot porous body having core and clad.
Abstract:
Disclosed is an optical fiber having a core with an alkali metal oxide dopant in an peak amount greater than about 0.002 wt. % and less than about 0.1 wt. %. The alkali metal oxide concentration varies with a radius of the optical fiber. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained. Also disclosed are several methods of making the optical fiber including the steps of forming an alkali metal oxide-doped rod, and adding additional glass to form a draw perform. Preferably, the draw preform has a final outer dimension (d2), wherein an outer dimension (dl) of the rod is less than or equal to 0.06 times the final outer dimension (d2). In a preferred embodiment, the alkali metal oxide-doped rod is inserted into the centerline hole of a preform to form an assembly.
Abstract:
Bei einem bekannten Verfahren zur Herstellung einer Vorform für optische Fasern wird ein mit Fluor dotiertes Si0 2 -Mantelglases auf einem um seine Längsachse rotierenden Kernglaszylinder erzeugt, indem einem Plasmabrenner eine siliziumhaltige Ausgangssubstanz zugeführt wird, diese in einer dem Plasmabrenner zugeordneten Plasmaflamme zu Si0 2 -Partikeln oxidiert und die Si0 2 -Partikel unter Gegenwart von Fluor auf der Zylindermantelfläche des Kernglaszylinders schichtweise abgeschieden und zu dem Mantelglas gesintert werden. Um hiervon ausgehend ein wirtschaftliches Verfahren zur Herstellung einer Vorform bereitzustellen, aus der optische Multimodefasern (52) erhalten werden können, die sich gegenüber den nach dem Standardverfahren hergestellten Fasern (51) durch hohe Anfangstransmission im UV-Wellenlängenbereich und guter Beständigkeit gegenüber kurzweiliger UVStrahlung, insbesondere im Wellenlängenbereich zwischen 210 und 300 nm, auszeichnen, wird erfindungsgemäss vorgeschlagen, dass zur Bildung und Abscheidung der Si0 2 -Partikel auf dem Kernglaszylinder eine Plasmaflamme eingesetzt wird, die ultraviolettes Licht einer Wellenlänge von 214 nm mit einer Intensität von mindestens 0,9 µW - ermittelt anhand der Plasmaflammenintensitätsmessung - abstrahlt.
Abstract:
The method of fabricating an optical waveguide fiber from a preform having a centerline aperture which includes reducing the pressure in the centerline aperture, then increasing the pressure in the centerline aperture to a pressure in order to improve uniformity, circularity, and/or symmetry around the centerline aperture region.
Abstract:
A method of manufacturing an optical fiber preform including providing a first tubular having a silica-containing core layer as a glass tube or soot deposit depositing a doped silica soot onto the first tubular layer to form a second tubular core layer, consolidating at least the second tubular core layer (preferably both tubular layers), and etching away at least part of the first tubular core layer by exposing the layer to an etchant. Preferably less than all of the first tubular layer is etched away. According to one embodiment, the second core layer includes a rare earth element such as Er, Tm, Nd, Pm, Yb, or Sm, for example.
Abstract:
Glass soot (130) is deposited on a glass rod by a burner (140). The body is stretched (126). More depositing and stretching is effected. The final body is then drawn into a fiber.