[1] [1] X. Wan and H. F. Taylor, Opt. Lett. 27, 1388 (2002).

[2] [2] J. Zhang, G. D. Peng, L. Yuan, and W. Sun, Opt. Lett. 32, 1833 (2007).

[3] [3] Q. Wang and Q. Yu, Chin. Opt. Lett. 8, 266 (2010).

[4] [4] M. Yang, Y. Sun, X. Li, and D. Jiang, Chin. Opt. Lett. 8(S), 189 (2010).

[5] [5] T. Hu, Y. Zhao, X. Li, J. Chen, and Z. L¨u, Chin. Opt. Lett. 8, 392 (2010).

[6] [6] Y. Jiang and W. Ding, Photon. Sensor. 1, 62 (2011).

[7] [7] Q. Yu and X. Zhou, Photon. Sensor. 1, 72 (2011).

[8] [8] Z. L. Ran, Y. J. Rao, H. Y. Deng, and X. Liao, Opt. Lett. 32, 3071 (2007).

[9] [9] T. Wei, Y. Han, H. Tsai, and H. Xiao, Opt. Lett. 33, 536 (2008).

[10] [10] Y. Gong, Y. Rao, Y. Guo, Z. Ran, and Y. Wu, IEEE Photon. Technol. Lett. 21, 1725 (2009).

[11] [11] Y. Gong, T. Zhao, Y. Rao, Y. Wu, and Y. Guo, Opt. Express 18, 15844 (2010).

[12] [12] Y. Zhu and A. Wang, IEEE Photon. Technol. Lett. 17, 447 (2005).

[13] [13] D. W. Kim, F. Shen, X. Chen, and A. Wang, Opt. Lett., 30, 3000 (2005).

[14] [14] D. Donlagic and E. Cibula, Opt. Lett. 30, 2071 (2005).

[15] [15] E. Cibula and D. Donlagic, Opt. Express 15, 8719 (2007).

[16] [16] M. Ohtsu, J. Lightw. Technol. 13, 1200 (1995).

[17] [17] C. J. Tuck, R. Hagure, and C. Doyle, Meas. Sci. Technol. 17, 2206 (2006).

[18] [18] Y. Rao, B. Xu, Z. Ran, and Y. Gong, Chin. Phys. Lett. 27, 024208 (2010).

[19] [19] Z. L. Ran, Y. J. Rao, W. J. Liu, X. Liao, and K. S. Chiang, Opt. Express 16, 2252 (2008).

[20] [20] T. Wei, Y. Han, Y. Li, H. Tsai, and H. Xiao, Opt. Express 16, 5764 (2008).