Efficient laser action in composite fibers with Yb,Er co-doped phosphate core and silica cladding

Fabrication and laser tests of a composite optical fiber with phosphate glass core in a silica cladding are described. The fiber was made by drawing a high-purity silica tube filled with Yb, Er co-doped phosphate glass. 1.54 μm laser action was demonstrated both with core and cladding pumping by ytterbium fiber laser and by laser diode respectively.