Abstract: A plasma buildup method for building up an optical fiber perform. The method includes the steps of: providing a plasma torch having an outlet nozzle adjacent to a primary perform, wherein an interaction zone is defined between the outlet nozzle and the primary preform; feeding the plasma torch with a plasma-generating gas in the presence of a silica-based material so as to deposit a buildup material on the primary preform; and introducing a reducing element into the interaction zone, the reducing element reacting to induce reduction of the nitrogen oxides produced by interaction between nitrogen and oxygen in the presence of the plasma generated by the torch.

Abstract: Apparatus (1) is dedicated to plasma buildup of an optical fiber preform (2). The apparatus comprises firstly a plasma torch (3) fed with plasma-generating gas by primary feed means (5) and arranged in such a manner as to enable a buildup material to be deposited on a primary preform (2) for building up in the presence of a silica-based material, and secondly secondary feed means (9) arranged to introduce at least one reducing element upstream from the primary preform (2), the reducing element reacting to induce reduction of the nitrogen oxides produced by the interaction between nitrogen and oxygen of the air contained in the enclosure in which buildup takes place in the presence of the plasma generated by the plasma torch (3).

Abstract: The invention relates to a method of treating germanium-containing gaseous waste coming from a unit for manufacturing an optical fiber preform, the method comprising the following steps:a liquid effluent is formed from the gaseous waste; andthe germanium is precipitated in the liquid effluent. According to the invention, the precipitation is performed by adding magnesium MgO to the liquid effluent.

Abstract: A machine for manufacturing disks on a very long rod, said machine including two conveyor-driven chains of moulding units that press against one another and receive said rod therebetween in an area provided with at least one orifice for injecting a plastics substance into a cavity formed between a pair of mating units, one from each chain, the units then parting to release a disk-shaped part moulded onto said very long rod. At least one of the sets of moulding units has a so-called "hermaphrodite" unit (1) with leading tabs 8 and trailing tabs (10) for fixing to its adjacent units in the chain. The tabs are such that they allow the "hermaphrodite" unit to be inserted between a female unit and a male unit or between two other hermaphrodite units. Applications to manufacturing insulator disks on the central conductor of a coaxial cable.