Erbium and Al2O3 nanocrystals-doped silica optical fibers

Fibre lasers and inherently rare-earth-doped optical fibers nowadays pass through a new period of their progress aiming at high efficiency of systems and their high power. In this paper, we deal with the preparation of silica fibers doped with erbium and Al2O3 nanocrystals and the characterization of their optical properties. The fibers were prepared by the extended Modified Chemical Vapor Deposition (MCVD) method from starting chlorides or oxide nanopowders. Conventional as well as modified approaches led to a nanocrystalline mullite phase formation in the fiber cores in which erbium is dissolved. The proposed modified approach based on starting nanopowders led to improved geometry of preforms and fibers and consequently to the improvement of their background attenuation. Such nanocrystal -doped fibers can be used for ASE sources. Further improvement of fiber optical properties can be expected.