1State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
2National Research Center for Optoelectronic Engineering, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100871, China
3Ultrafast Laser Laboratory, Key Laboratory of Opto-electronic Information Technical Science of Ministry of Education, School of Precision Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China
4Huakuai Photonic Technologies Inc., Zhongshan 528400, China