[1] [1] P. St. J. Russell, J. Lightwave Technol. 24, 4729 (2006).

[2] [2] Z. Wang, L. Zhang, J. Wang, and K. Yu, Acta Opt. Sin. (in Chinese) 29, 2909 (2009).

[3] [3] M. Hu, Y. Song, B. Liu, X. Fang, C. Zhang, H. Liu, F. Liu, C. Wang, L. Chai, Q. Xing, and Q. Wang, Chinese J. Lasers (in Chinese) 36, 1660 (2009).

[4] [4] O. Fraz ao, J. M. Baptista, and J. L. Santos, IEEE Sensors J. 7, 1453 (2007).

[5] [5] B. Dong, D.-P. Zhou, and L. Wei, J. Lightwave Technol. 28, 1011 (2010).

[6] [6] R. Jha, J. Villatoro, G. Badenes, and V. Pruneri, Opt. Lett. 34, 617 (2009).

[7] [7] W. G. Chen, S. Q. Lou, S. C. Feng, L. W. Wang, H. L. Li, T. Y. Guo, and S. S. Jian, Laser Phys. 19, 2115(2009).

[8] [8] K. Oh, S. Choi, Y. Jung, and J. W. Lee, J. Lightwave Technol. 23, 524 (2005).

[9] [9] L. V. Nguyen, D. Hwang, S. Moon, D. S. Moon, and Y. Chung, Opt. Express 16, 11369 (2008).

[10] [10] J. Villatoro, V. Finazzi, V. P. Minkovich, V. Pruneri, and G. Badenes, Appl. Phys. Lett. 91, 091109 (2007).

[11] [11] C. Martelli, J. Canning, N. Groothoff, and K. Lyytikainen, Opt. Lett. 30, 1785 (2005).

[12] [12] Y.-P. Wang, L. Xiao, D. N. Wang, and W. Jin, Opt. Lett. 31, 3414 (2006).