[1] [1] H. Ogawa, D. Polifko, and S. Banba, IEEE Trans. Microw. Theory Tech. 40, 2285 (1992).

[2] [2] L. Noel, D. Wake, D. G. Moodie, D. D. Marcenar, L. D. Westbrook, and D. Nesset, IEEE Trans. Microw. Theory Tech. 45, 1416 (1997).

[3] [3] T. Kuri, K. Kitayama, A. Stohr, and Y. Ogawa, J. Lightwave Technol. 17, 799 (1999).

[4] [4] J. Yu, Z. Jia, L. Yi, Y. Su, G. Chang, and T. Wang, IEEE Photon. Technol. Lett. 18, 265 (2006).

[5] [5] L. Chen, S. C. Wen, Y. Li, J. He, H. Wen, Y. Shao, Z. Dong, and Y. Pi, J. Lightwave Technol. 25, 3381 (2007).

[6] [6] Z. Jia, J. Yu, D. Boivin, M. Haris, and G. Chang, IEEE Photon. Technol. Lett. 19, 653 (2007).

[7] [7] Q. Chang, H. Fu, and Y. Su, IEEE Photon. Technol. Lett. 20, 181 (2008).

[8] [8] X. Yu, T. B. Gibbon, and I. T. Monroy, IEEE Photon. Technol. Lett. 20, 2180 (2008).

[9] [9] T. Jian, D. Huang, X. Zhang, Q. Zhang, and J. Wang, Acta Opt. Sin. (in Chinese) 28, 36 (2008).

[10] [10] Z. Jia, J. Yu, Y. Hsueh, A. Chowdhury, H. Chien, J. A. Buck, and G. Chang, IEEE Photon. Technol. Lett. 20, 1470 (2008).

[11] [11] C. Lin, S. Dai, J. Chen, P. Shih, P. Peng, and S. Chi, IEEE Photon. Technol. Lett. 20, 1106 (2008).

[12] [12] H. Ryu, Y. Seo, and W. Choi, IEEE Photon. Technol. Lett. 16, 1942 (2004).

[13] [13] H. Sung, E. K. Lau, and M. C. Wu, IEEE Photon. Technol. Lett. 19, 1005 (2007).

[14] [14] C. Wang, Q. Chang, and Y. Su, Chin. Opt. Lett. 7, 339(2009).

[15] [15] L. Hu, L. Chen, J. Yu, and S. Wen, Acta Opt. Sin. (in Chinese) 28, 238 (2008).

[16] [16] C. Hong, C. Zhang, M. Li, L. Zhu, L. Li, W. Hu, A. Xu, and Z. Chen, IEEE Photon. Technol. Lett. 22, 462(2010).

[17] [17] X. Zhao and C. J. Chang-Hasnain, IEEE Photon. Technol. Lett. 20, 395 (2008).