Abstract: A method for manufacturing a preform for a multicore fiber, including stacking (S1) a plurality of core rods and a plurality of silica-based filler rods in a tube; collapsing (S2) the tube around the stack of core rods and silica-based filler rods, forming a collapsed stack; depositing (S3) a layer of silica around the collapsed stack; removing (S4) at least part of the deposited layer of silica. The preferential process for depositing a layer of silica around the collapsed stack and removing at least part of the deposited layer of silica is Advanced Plasma and Vapor Deposition.

Abstract: A system for fabricating an optical fiber preform including glazing the outside surface of the preform using inductive heating, the system including a plasma torch for localized heating of the preform during the glazing, and an injector for injecting into the plasma in the area of the outside face of the preform on which the plasma impinges a gas which is substantially free of silica particles to reduce the power of the plasma during the glazing operation.

Abstract: A method of fabricating an optical fiber preform includes an operation of glazing the outside surface of the preform using inductive heating, of the plasma torch type, for localized heating of the preform. A flow of gas between the plasma and the preform in the area of the outside face of the preform on which the plasma impinges reduces the power of the plasma in this outside surface area.

Abstract: A method of fabricating an optical fiber preform includes an operation of glazing the outside surface of the preform using inductive heating, of the plasma torch type, for localized heating of the preform. A flow of gas between the plasma and the preform in the area of the outside face of the preform on which the plasma impinges reduces the power of the plasma in this outside surface area.

Abstract: The invention relates to a method of performing surface treatment on a preform manufactured in an installation for manufacturing or building up preforms having supporting cores, the installation including at least rotation means having a horizontal axis of rotation and two mounting points between which the supporting core of the preform to be manufactured or built up is mounted, plasma-torch and material-supply means disposed radially relative to the supporting core and mounted to move in axial translation relative to and parallel to the supporting core so as to make the preform around the supporting core, the preform being manufactured or built up by effecting successive passes with the plasma torch while material is being supplied.

Abstract: A device for producing spherical silica grains includes a cylinder having its axis inclined to the horizontal and an inside wall made from a material that is significantly softer than silica. The cylinder has an entry chute for non-spherical silica grains and an exit chute for spherical cylinder grains. A rotary member is rotated at high speed by a drive shaft having its axis coincident with the axis of the cylinder. The rotary member includes at least one paddle vertically aligned with the entry chute so that silica grains entering via the entry chute are thrown by the paddle against the inside wall of the cylinder and follow a path most of which is against the wall before leaving via the exit chute.

Abstract: A method for producing spherical silica grains using a cylinder having its axis inclined to the horizontal and having an inside wall made from a material that is significantly softer than silica. The cylinder has an entry chute for non-spherical silica grains and an exit chute for spherical cylinder grains. According to the method, a rotary member is rotated at high speed by a drive shaft having its axis coincident with the axis of the cylinder. The rotary member includes at least one paddle vertically aligned with the entry chute so that silica grains entering via the entry chute are thrown by the paddle against the inside wall of the cylinder and follow a path most of which is against the wall before leaving via the exit chute. As a result, the silica graining have a spherical shape.