1. School of Aerospace Science and Technology
2. Xidian University
3. Xi'an 710126
4. P. R. China
5. College of Electronic and Information Engineering
6. Southwest University
7. Chongqing 400715
8. State Key Laboratory on Integrated Optoelectronics
9. College of Electronic Science and Engineering
10. Jilin University
11. Changchun 130012