19-core MCF transmission system using EDFA with shared core pumping coupled via free-space optics - Sakaguchi, Jun; Klaus, Werner; Puttnam, Benjamin J.; Delgado Mendinueta, Jose Manuel; Awaji, Yoshinari; Wada, Naoya; Tsuchida, Yukihiro; Maeda, Koichi; Tadakuma, Masateru; Imamura, Katsunori; Sugizaki, Ryuichi; Kobayashi, Tetsuya; et al. (OPTICS EXPRESS, 2014)