Air-clad chirally-coupled-core Yb-fiber femtosecond oscillator with >10W average power Hung-Wen Chen, Guoqing Chang, Cheng Zhu, Xiuquan Ma, Almantas Galvanauskas and Franz X. Kärtner EPJ Web of Conferences, 41 (2013) 10006 Published online: 13 March 2013 DOI: 10.1051/epjconf/20134110006