1. The Chinese University of Hong Kong,Dept. of Electronic Engineering,Hong Kong
2. The Hong Kong Polytechnic University,Photonics Research Institute,Dept. of Electrical and Electronic Engineering,Hong Kong
3. The Hong Kong University of Science and Technology (Guangzhou),Microelectronics Thrust,China
4. National Yang Ming Chiao Tung University,Dept. of Photonics,Hsinchu,Taiwan,30010