1. Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, Tainan City, Taiwan
2. Department of Electronic Science, Xiamen University, Xiamen, China
3. Xiamen San'an Optoelectronic Company Ltd., Xiamen, China
4. Department of Microelectronics Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan