1. Beijing Jiaotong University, Key Laboratory of All Optical Network and Advanced Telecommunication of EMC, Institute of Lightwave Technology, Beijing, China
2. Osaka Institute of Technology, Department of Electronics, Information and Communication Engineering, Omiya, Asahi-ku, Osaka, Japan
3. Nara Institute of Science and Technology, Graduate School of Information Science, Takayama, Ikoma Nara, Japan
4. Beijing Union University, School of Information, Beijing, China