[1] Hong Kong Polytech Univ, Photon Res Ctr, Dept Elect & Informat Engn, Hong Kong, Peoples R China
[2] Univ New South Wales, Sch Elect Engn, Photon & Opt Commun, Sydney, NSW 2052, Australia
[3] Beijing Inst Technol, Sch Opt & Photon, Beijing 100081, Peoples R China