1. Institute
of Optoelectronic Sciences, National Taiwan Ocean University, No.
2, Beining Road, Jhongjheng District, Keelung 20224, Taiwan
2. Department
of Electrical and Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27606, United States
3. Department
of Applied Materials and Optoelectronics Engineering, National Chi Nan University, Daxue Road, Puli Township, Nantou 54561, Taiwan