Fabrication of Er:YAG/Yb:YAG nanopowder-derived Er:Yb co-doped silica fibers from UV–curable composites and their application in 1550-nm fiber lasers

Abstract

Er/Yb co-doped YAG nanopowders-derived silica fibers (YNDSFs) are fabricated from UV-curable composites and achieve 1550-nm laser generation with active fiber length of 1 cm. The UV-curable nanocomposites are consisted of 40 wt% home-made Er:YAG/Yb:YAG nanopowders and 60 wt% polymer resins. The Er:YAG/Yb:YAG nanopowders are fabricated by coprecipitation method with diameters in the range of 25 - 165 nm. An Er:YAG/Yb:YAG–polymer hybrid core rod was polymerized using high power UV-lamps, and was drawn to Er/Yb co-doped fiber in silica cladding by melting-in-tube method after debound process to remove organics. The absorption coefficients of the Er/Yb co-doped fiber were measured to be 17 dB cm^-1 and 3.2 dB cm^-1 at 976 nm and 1530 nm, respectively. The background loss was 0.05 dB cm^-1 at 1200 nm. A linear fiber laser cavity was constructed with different length of Er/Yb co-doped fiber and a pair of FBGs (reflectivity: 99 % and 94 %) to quantify the laser performance. The maximum output powers were 7.5 mW and 1.5 mW with active fiber length of 6 cm and 1 cm, respectively. This scheme is expected to be an effective approach for obtaining Er:Yb co-doped fiber with high pump absorption for the generation of 1550-nm single-frequency fiber lasers.