Light waveguide and an optical fiber isolator

The invention pertains to an optical waveguide and a fiberoptic isolator containing the waveguide. The invention describes an optical waveguide and a fiberoptic isolator wherein the optical waveguide rotating the plane of polarization of coupled light consists of a fiber core () exhibiting the Faraday effect, a fiber cladding () and a coating () concentrically surrounding the YIG-doped fiber core () and generating a permanent magnetic field. The outer coating () is manufactured from a material that is magnetizable or has magnetic properties, and the outer coating () is subdivided into two half-shells whose magnetic orientations are mutually opposed.