[1] South China Univ Technol, Sch Phys & Optoelect, Guangzhou 510641, Peoples R China
[2] South China Univ Technol, Inst Opt Commun Mat, State Key Lab Luminescent Mat & Devices, Guangdong Engn Technol Res Dev Ctr Special Opt Fib, Guangzhou 510641, Peoples R China
[3] South China Univ Technol, Guangdong Prov Key Lab Fiber Laser Mat & Appl Tech, Guangzhou 510641, Peoples R China
[4] Guangdong Univ Technol, Sch Phys & Optoelect Engn, Guangzhou 510006, Peoples R China