METHOD OF PLASMA DEPOSITING A GLASS, A GLASS OR SILICA OPTICAL FIBRE PREFORM PRODUCED BY THIS METHOD, AND METHOD OF MAKING A SILICA OPTICAL FIBRE FROM THIS PREFORM

摘要

A vitreous material, for example silica, is deposited on the inner surface of a tube (11) from the decomposition of a volatile silicon compound in a hot intense inductive plasma material by the application of radio frequency power from a generator (17) via a coupling coil (15) and a matching coil (16). The use of such an inductive plasma feed with gas at a pressure within the range of 0,1 to 50 Torr, provides fusion of the deposited silica on the inner surface of the tube, the outer surface of the tube (11) being water cooled. The process may be employed in the production of preform tubes for step or graded index optical fibre manufacture.