Other

Fibercore Limited

Mikhail Ivanovich Gouskov

Dau Wu

Mohammad Afzal Aslami

Mohd Aslami

John Edward Mattison

Evgueni Borisovich Danilov

Evguenie B Danilov

Evguenic Borisovich Danilov

A plurality of glass deposition targets are rotated simultaneously and a first plasma torch, having a coil diameter larger than the sum of the target diameters, deposits glass simultaneously on the plurality. After the diameter of the targets reaches a threshold a second plasma torch is used. The diameter of the second plasma torch can provide for simultaneous deposition. In a further embodiment, after the target diameter reaches a second threshold a third plasma torch is used. In a further embodiment the spacing between the axes of rotation of the targets is widened as the target diameter increases. In a still further embodiment a single plasma torch includes movable concentric tubes within its coil to selectively operate as any of a plurality of different diameter plasma torches.

Multiple torch&mdash;multiple target method and apparatus for plasma outside chemical vapor deposition

A method for producing an optical fiber preform starting with a first-generation target typically comprising pure silica. A plasma torch deposits an annular region of doped silica to form an intermediate structure. The intermediate structure is drawn down to a second-generation target and another annular region of doped silica is deposited. The process is repeated a plurality of times until an Nth generation target is formed. The deposition optionally employs repeated cycles of depositing a plurality of layers of silica at a high traversal rate without sintering, followed by periodic sintering. In a further embodiment, stabilizer bars extending out from the plasma coils improve distribution of the deposition material. Another embodiment injects the source gas into a particular region of the plasma for control of soot deposition.

Method of making an optical fiber preform via multiple plasma depositing and sintering steps

An apparatus and method for producing a tubular member, which is suitable for use as a starter tube or an optical fiber preform, on a rotating cylindrical target mounted on a lathe. The tubular member is made by means of plasma outside vapor deposition. In this process, a source gas comprising SiCl,and, optionally, a fluorine-laden chemical, is introduced into an air plasma. Both the air and the source gas are dry gases and have low hydroxyl content. The air plasma is created by a high-frequency induction plasma torch which travels along the length of the target on a carriage. The torch is provided with a short U-shaped gutter on either side of its rim directly beneath the target and the growing tubular member. This gutter helps channel reaction products of the source gas and the plasma so as to enhance deposition on the growing tubular member. The torch is further provided with an induction coil having a plurality of windings, the uppermost winding being maintained a predetermined distance from the surface of the tubular member as the latter is built up.

Method of making a tubular member for optical fiber production using plasma outside vapor deposition

Growing community of inventors

St.-Petersburg, Russia

Mikhail Ivanovich Gouskov