Fabrication of yttrium aluminosilicate fibers with high Yb³⁺ doping from Yb:YAG ceramic nanopowders and its application in single-frequency fiber lasers

A yttrium aluminosilicate fiber with a Yb doping concentration of 4.53 wt.% was fabricated by powder-in-tube method, in which the preform core was Yb:YAG ceramic nanopowders synthesized by co-precipitation method. Compared with the method of using YAG crystal rod as fiber core, the fiber composition design can be more flexible and a series of crystal rod processing technology can be circumvented. The absorption coefficient of the Yb-doped YAS fibers was measured 28.4 dB/cm at 976 nm. A single-frequency fiber laser was constructed with the YAS fiber length of 1cm. To our knowledge, this is the first time that rare earth (RE) doped YAS fiber prepared by powder-in-tube method was used in fiber laser.