1. Institute of Photonics and Communications, National Kaohsiung University of Applied Sciences,
Kaohsiung 80778, Taiwan
2. Institute
of Electronic Engineering, Cheng Shiu University, Kaohsiung 83347, Taiwan
3. Institute of Optoelectronic Science, National Taiwan Ocean University, Keelung 20224, Taiwan
4. Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 30031,
Taiwan