1Information Photonics Research Center, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350117, China
2Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
3College of Photonic and Electronic Engineering, Key Laboratory of Opto-Electronic Science and for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Provincial Engineering Technology Research Center of Photoelectric Sensing Application, Fujian Normal University, Fuzhou 350117, China