[1] T. Komine and M. Nakagawa, in Proceedings of IEEE Transac-tions on 50 Consumer Electronics 100 (2004).

[2] J. Grubor, S. C. J. Lee, K. D. Langer, T. Koonen, and J. W. Walewski, in Proceedings of European Conference on Optical Communication 2007 (2007).

[3] M. Z. Afgani, H. Haas, H. Elgala, and D. Knipp, in Proceedings of 2nd International Conference on Testbeds and Research Infra-structures for the Development of Networks and Communities, 2006 6 (2006).

[4] R. Li, Y. Wang, C. Tang, Y. Wang, H. Shang, and N. Chi, Chin. Opt. Lett. 11, 080605 (2013).

[5] J. Vucic, C. Kottke, S. Nerreter, K. D. Langer, and J. W. Walewski, J. Lightw. Technol. 28, 3512 (2010).

[6] H. Dong, H. Zhang, K. Lang, B. Yu, and M. Yao, Chin. Opt. Lett. 12, 052301 (2014).

[7] D. Tsonev, S. Sinanovic, and H. Haas, J. Lightw. Technol. 31, 3064 (2013).

[8] N. Chi, Y. Wang, Y. Wang, X. Huang, and X. Lu, Chin. Opt. Lett. 12, 010605 (2014).

[9] A. Khalid, G. Cossu, R. Corsini, P. Choudhury, and E. Ciaramella, IEEE Photon. J. 4, 1465 (2012).

[10] J. Armstrong, J. Lightw. Technol. 27, 189 (2009).

[11] R. A. Shafik, S. Rahman, and R. Islam, in Proceedings of In-ternational Conference on Electrical and Computer Engineering, 2006 408 (2006).

[12] "LED modules for general lighting–Performance requirements" GB/T 24823-2009.

[13] "Lighting of indoor work places" GB/T 26189-2010.