[1] W. J. Bock and T. R. Wolinski, Opt. Lett. 15, 1434 (1990).

[2] T. A. Berkoff and A. D. Kersey, in Proceedings of 8th Optical Fiber Sensors Conference 372 (1992).

[3] K. A. Murphy and B. R. Fogg, in Proceedings of 8th Optical Fiber Sensors Conference 129 (1992).

[4] J. O. Askautrud and H. E. Engan, in Proceedings of 8th Optical Fiber Sensors Conference 101 (1992).

[5] H. C. Park, B. Y. Kim, and H. S. Park, Opt. Lett. 30, 3126 (2005).

[6] H. S. Park, K. Y. Song, S. H. Yun, and B. Y. Kim, J. Lightwave Technol. 20, 1864 (2002).

[7] K. S. Lee and J. Y. Cho, J. Opt. Soc. Am. A. 19, 1621 (2002).

[8] Y. Wu, Y. Zheng, S. Li, and J. Wang, Acta Opt. Sin. (in Chinese) 27, 1111 (2007).

[9] T. Liu, J. Cui, D. Chen, L. Xiao, and D. Sun, Chin. Opt. Lett. 6, 12 (2008).

[10] K. A. Murphy, M. S. Miller, A. M. Vengsarkar, and R. O. Claus, J. Lightwave Technol. 8, 1688 (1990).

[11] A. Safaai-Jazi and J. C. McKeeman, J. Lightwave Technol. 9, 1047 (1991).

[12] B. D. Duncan, "Modal interference techniques for strain detection in few-mode optical fibers" M. S. Thesis (Virginia Polytechnic Institute and State University, 1988).

[13] W. B. Spillman, B. R. Klin, L. B. Maurice, and P. L. Futhr, Appl. Opt. 28, 3166 (1989).

[14] H. Wang and W. Bi. Chin. Opt. Lett. 4, 631 (2006).

[15] K. Thyagarajan, S. N. Sarkar, and B. P. Pal, J. Lightwave Technol. 5, 1041 (1987).

[16] M. A. Arbore, M. J. F. Digonnet, and R. H. Pantell, Opt. Fiber Technol. 2, 400 (1996).