[1] M. Aikawa and H. Ogawa, IEEE Trans. Microwave Theor. Tech. 37, 406 (1989).
[2] J. Capmany and D. Novak, Nature Photon. 1, 319 (2007).
[3] J. Yao, J. Lightwave Technol. 27, 314 (2009).
[4] J. Dai, K. Xu, X. Sun, J. Niu, Q. Lv, J. Wu, X. Hong, W. Li, and J. Lin, IEEE Photon. Technol. Lett. 22, 1162 (2010).
[5] J. Li, S. Fu, K. Xu, J. Q. Zhou, P. Shum, J. Wu, and J. Lin, Opt. Lett. 34, 743 (2009).
[6] M. V. Drummond, P. Monteiro, and R. N. Nogueira, Opt. Express 17, 5433 (2009).
[7] J. Zhou, S. Fu, S. Aditya, P. P. Shum, and C. Lin, IEEE Photon. Technol. Lett. 21, 1069 (2009).
[8] H. Chi, X. Zou, and J. Yao, IEEE Photon. Technol. Lett. 20, 1249 (2008).
[9] X. Zou, H. Chi, and J. Yao, IEEE Trans. Microwave Theor. Tech. 57, 505 (2009).
[10] J. Zhou, S. Fu, P. P. Shum, S. Aditya, L. Xia, J. Li, X. Sun, and K. Xu, Opt. Express 17, 7217 (2009).
[11] J. Zhou, S. Aditya, P. P. Shum, and J. Yao, IEEE Photon. Technol. Lett. 22, 682 (2010).
[12] X. Zou, W. Pan, B. Luo, and L. Yan, IEEE Photon. Technol. Lett. 22, 1090 (2010).
[13] J.-J. Dong, X.-L. Zhang, and D.-X. Huang, Chin. Phys. B 17, 4226 (2008).
[14] J. Dong, X. Zhang, J. Xu, D. Huang, S. Fu, and P. Shum, Opt. Lett. 32, 1223 (2007).
[15] J.-J. Dong, X.-L. Zhang, and D.-X. Huang, Chin. Phys. Lett. 24, 3450 (2007).
[16] F. Coppinger, S. Yegnanarayanan, P. D. Trinh, and B. Jalali, Electron. Lett. 33, 973 (1997).
[17] J. Mora, A. Martinez, M. D. Manzanedo, J. Capmany, B. Ortega, and D. Pastor, Electron. Lett. 41, 921 (2005).
[18] Y. Xiaoke, F. Wei, N. J. Hong, and L. Chao, IEEE Photon. Technol. Lett. 13, 857 (2001).
[19] N. You and R. A. Minasian, J. Lightwave Technol. 24, 2558 (2006).
[20] E. Xu, X. Zhang, L. Zhou, Y. Zhang, Y. Yu, X. Li, and D. Huang, Opt. Lett. 35, 1242 (2010).
[21] N. Sarkhosh, H. Emami, L. Bui, and A. Mitchell, in Proceedings of 2008 IEEE MTT-S International Microwave Symposium Digest 599 (2008).