[1] Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China
[2] Minzu Univ China, Coll Sci, Beijing 100081, Peoples R China
[3] Edith Cowan Univ, WA Ctr Excellence MicroPhoton Syst, Electron Sci Res Inst, Joondalup, WA 6027, Australia