Key Laboratory of Optoelectronic Technology and Systems Chongqing University Chongqing 400044 China;
Key Lab of Broadband Optical Fiber Transmission & Communication Networks Technology Ministry of Education of China University of Electronic Science& Technology of China Chengdu 610054 China;
Key Laboratory of Optoelectronic Technology and Systems Chongqing University Chongqing 400044 China;