1. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
2. State-Key Laboratory of Analog and Mixed-Signal VLSI/IME and FST-ECE, University of Macau, Macau, China
3. School of Electrical and Electronic Engineering, Nanyang Technological University, Jurong West, Singapore
4. Wuhan National Laboratory of Optoelectronics and the School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China