US Patent 8639080 Optical fiber with multi section core

An optical fiber comprising a core region embedded within a cladding. The core region of the optical fiber further comprises multiple sections, each doped with rare earth ions. The sections of the core region may be doped with different rare-earth ions or with different doping concentrations. The sections of the core region may also be made from different types of glass hosts. The optical fiber may further include multiple core regions embedded within the cladding, each core region having multiple sections doped with rare earth ions.