1. National Engineering Laboratory of Next Generation Internet Access Networks, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
2. Transmission &Access Research Department, Huawei Technologies, Shenzhen, China
3. State Key Laboratory of Optical Fiber and Cable Manufacture Technology, Yangtze Optical Fibre and Cable Joint Stock Limited Company and Optics Valley Laboratory, Hubei, China