Vorrichtung zum Ziehen einer optischen Faser aus einer Vorform

Device is used for the fibrillation of a preformer (2) of an optical fibre in a vitreous material fitted to one end of a terminal (3) of diameter less than or equal to the diameter of the preformer. The device comprises: (a) means (10) for retaining the preformer (2) essentially vertical by the intermediary of the terminal (3), so the preformer (2) installed in the device (1) incorporates one lower free end (2B) and an upper end (2A) that is itself connected to the terminal (3); (b) means (10) for displacing the preformer (2) in an essentially vertical downwards direction (F) so its lower end (2B) penetrates and advances into a chamber (11) presenting for this purpose an opening (12) in its upper part (11A), the upper part (11A) of the chamber (11) being insulated with regard to the external environment whilst the preformer (2) is present in the opening (12); and (c) a heating system (14) to carry the chamber (11) to a temperature at least equal to the temperature for the fibrillation of the vitreous material, in a manner that allows the fibrillation of the preformer (2) progressively during its displacement in the chamber (11). The preformer (2) is fitted at the level of its junction with the terminal (3) with a sealing mechanism (5,6) that moves with it and such that the upper part (11A) of the chamber (11) remains insulated w. r. t. to the external environment whilst the terminal (3) penetrates into the chamber (11). The sealing mechanism consists of an enclosure (5) of graphite or silica and a joint (6) made up of pads of graphite and/or silica.