[1] Z. Jiang, C. Huang, D. Leaird, and A. M. Weiner, Nat. Photon. 1, 463 (2007).

[2] F. Tian, X. Zhang, J. Li, and L. Xi, J. Lightwave Technol. 29, 1085 (2011).

[3] C. Chen, C. Zhang, D. Liu, K. Qiu, and S. Liu, Opt. Lett. 37, 3954 (2012).

[4] J. Yu, Z. Dong, and N. Chi, IEEE Photon. Technol. Lett. 23, 1061 (2011).

[5] A. Clarke, D. Williams, M. Roelens, and B. Eggleton, IEEE Photon. Technol. Lett. 28, 97 (2010).

[6] P. J. Delfyett, I. Ozdur, N. Hoghooghi, M. Akbulut, J. Davila-Rodriguez, and S. Bhooplapur, IEEE J. Sel. Top. Quantum Electron. 18, 258 (2012).

[7] J. Li, X. Li, X. Zhang, F. Tian, and L. Xi, Opt. Express 18, 17597 (2010).

[8] J. Zhang, J. Yu, N. Chi, Z. Dong, X. Li, Y. Shao, and L. Tao, Opt. Lett. 37, 4714 (2012).

[9] X. Li, J. Yu, Z. Dong, J. Zhang, Y. Shao, and N. Chi, Opt. Express 20, 21833 (2012).

[10] J. Li and Z. Li, Opt. Lett. 38, 359 (2013).

[11] J. Zhang, J. Yu, N. Chi, Y. Shao, L. Tao, J. Zhu, and Y. Wang, J. Lightwave Technol. 30, 3938 (2012).

[12] J. Zhang, J. Yu, N. Chi, Y. Shao, L. Tao, Y. Wang, and X. Li, IEEE Photon. Technol. Lett. 24, 1405 (2012).

[13] J. Yu, Z. Dong, J. Zhang, X. Xiao, H. C. Chien, and N. Chi, J. Lighwave Technol. 30, 458 (2012).

[14] Y. Dou, H. Zhang, and M. Yao, Opt. Lett. 36, 2749 (2011).

[15] S. Zou, Y. Wang, Y. Shao, J. Zhang, J. Yu, and N. Chi, Chin. Opt. Lett. 10, 070605 (2012).

[16] J. Zhang, J. Yu, L. Tao, Y. Fang, Y. Wang, Y. Shao, and N. Chi, J. Lightwave Technol. 30, 3911 (2012).

[17] J. Zhang, J. Yu, N. Chi, Z. Dong, X. Li, Y. Shao, J. Yu, and L. Tao, Opt. Lett. 38, 552 (2013).

[18] H. Hu, J. Yu, L. Zhang, A. Zhang, Y. Li, Y. Jiang, and E. Yang, Opt. Express 15, 8931 (2007).

[19] J. Yu, Z. Jia, M. Huang, M. Haris, P. Ji, T. Wang, and G. Chang, J. Lightwave Technol. 27, 253 (2009).

[20] D. Mahgerefteh, Y. Matsui, X. Zheng, and K. McCallion, IEEE J. Sel. Top. Quantum. Electron. 16, 1126 (2010).

[21] C. Tang, R. Li, Y. Shao, N. Chi, J. Yu, Z. Dong, and G. Chang, Chin. Opt. Lett. 11, 020608 (2013).