[1] Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Minist Educ, POB 72, Beijing 100876, Peoples R China
[2] Shanxi Univ Technol SNUT, Sch Phys & Telecommun Engn, Hanzhong 723001, Shaanxi, Peoples R China
[3] Beijing Computat Sci Res Ctr, Beijing 100084, Peoples R China
[4] Chinese Acad Sci, Shanghai Inst Microsyst & Informat Technol, State Key Lab Funct Mat Informat, Shanghai 200050, Peoples R China
[5] Chalmers Univ Technol, Dept Microtechnol & Nanosci, Photon Lab, S-41296 Gothenburg, Sweden