Method of randomly irradiating an optical fiber core with a laser

摘要

A method of manufacturing an optical fiber having a core portion doped with a dopant and a surrounding optical cladding portion is disclosed. The method comprises the steps of drawing a fiber from a molten extremity of a silica preform and moving the fiber along towards a device for coating it with a protective sheath. Prior to the coating step, the moving fiber is irradiated with irregularly modulated actinic radiation, thereby causing corresponding irregular variations in the refractive index of its core portion as a function of longitudinal position. The resulting fiber demonstrates a significantly reduced polarisation mode dispersion.