Patent ID: 6988380

Claim:
A method of manufacturing optical fiber preforms comprising the steps of: a. arranging a rod coaxially within a hollow cylindrical reactor, creating a cavity between said rod and said reactor; b. reducing pressure in said cavity to a predetermined level; c. enclosing said rod and said reactor coaxially within a hollow cylindrical furnace, and heating said rod and said reactor to a specified temperature; d. introducing a process gas mixture in said cavity, wherein said mixture is comprised of materials to be deposited; e. generating a plasma in said cavity by simultaneously exciting an E 010 electric field mode wave and an E 01 electric field type plasma surface wave in said cavity by means of a microwave system, wherein said plasma surface wave is located at an interface between said rod and said plasma; f. wherein an electric field is at a maximum intensity at a radial distance from the central axis of said cavity equal to a distance where said rod-plasma interface is located; and wherein said intensity exponentially diminishes as the radius increase to said reactor and as the radius decreases toward said axis; and g. moving said plasma along said cavity in a direction parallel to the axis of said cavity, thereby uniformly depositing said materials on said starting body.