Institution: | a Photonics Research Center, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China b Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR,, People's Republic of China c Division of Communication Engineering, School of Electrical and Electronics Engineering, Nanyang Technological University, Singapore 639798, Singapore |