Plasma chemical vapor deposition of halide glasses

Abstract

A method for producing internally coated glass tube preforms for drawing er optic conductors. The internally coated glass tubes are halogen coated, preferably coated with metal fluorides, so that an optical fiber formed will have a halogen core which conveys light having a wavelength of about 2 to 4 microns, which is in the infrared region, with low attenuation. With one aspect of the method, a carrier gas and a halogenated alkoxide are introduced into a glass tube which has an inner wall and which is surrounded by a resonator for producing a plasma from the halogenated alkoxide in the tube. With another aspect of the method, a blend of a carrier gas, an organometallic compound, and a halogen-containing gas are introduced into a glass tube which has an inner wall and which is surrounded by a resonator for producing a plasma. In both cases, the tube is moved relative to the resonator to form a plasma zone within the tube such that a halide coating is formed on the inner wall of the tube. The plasma generation and inner glass wall coating take place at a relatively low pressure and at a relatively low temperature.

Dependencies are inferred from the claim text.