[1] J. C. Knight, T. A. Birks, P. St. J. Russell, and D. M. Atkin, Opt. Lett. 21, 1547 (1996).
[2] P. St. J. Russell, J. Lightwave Technol. 24, 4729 (2006).
[3] T. A. Birks, J. C. Knight, and P. Russell, Opt. Lett. 22, 961 (1997).
[4] R. F. Cregan, B. J. Mangan, J. C. Knight, T. A. Birks, P. St. J. Russell, P. J. Roberts, and D. C. Allan, Science 285, 1537 (1999).
[5] J. Dai and B. Yang, Opt. Commun. Technol. (in Chinese) (1) 61 (2008).
[6] T. Gong, F. Yan, L. Wang, Y. Li, P. Liu, and S. Jian, Chinese J. Lasers (in Chinese) 35, 559 (2008).
[7] Q. Wang, B. Yang, L. Zhang, H. Zhang, and L. He, Chin. Opt. Lett. 5, 538 (2007).
[8] T. Sun, G. Kai, Z. Wang, S. Yuan, and X. Dong, Chin. Opt. Lett. 6, 93 (2008).
[9] H. Fang, S. Lou, T. Guo, and S. Jian, Acta Opt. Sin. (in Chinese) 27, 202 (2007).
[10] K. Li, Y. Wang, W. Zhao, G. Chen, Q. Peng, D. Cui, and Z. Xu, Chin. Opt. Lett. 5, 347 (2007).
[11] B. Liu, M. Hu, Y. Song, L. Chai, and Q. Wang, Chinese J. Lasers (in Chinese) 35, 479 (2008).
[12] Z. Wang, T. Taru, T. A. Birks, J. C. Knight, Y. Liu, and J. Du, Opt. Express 15, 4795 (2007).