[1] [1] K. O. Hill and G. Meltz, J. Lightwave Technol. 15, 1263 (1997).

[2] [2] Y. J. Rao, Optics and Lasers in Engineering 31, 297 (1999).

[3] [3] J. Sun, C. C. Chan, and X. Y. Dong, J. Optoelectronics and Advanced Materials 8, 1250 (2006).

[4] [4] D. Huang, W. Liu, C. Wu, and C. C. Yang, Photon. Technol. Lett. 12, 176 (2000).

[5] [5] C. K. Kirkendall and A. Dandridge, J. Phys. D: Appl. Phys. 37, R197 (2004).

[6] [6] Z. Meng, X. Zhang, F. Dong, Z. Li, and Y. Hu, J. Opt. A: Pure Appl. Opt. 7, S352 (2005).

[7] [7] T. Jiang, B. Hao, and Y. Jiang, J. Guangxi Normal. Univ. (in Chinese) 23, 99 (2005).

[8] [8] C. Okawara and K. Saijyou, Acoust. Sci. & Tech. 29, 232 (2008).

[9] [9] Y. Yu and H. Zhao, IEEE, Photon. Technol. Lett. 17, 166 (2005).

[10] [10] X. Shu, D. Huang, G. Deng, W. Shi, and S. Jiang, Acta Phys. Sin. (in Chinese) 49, 1731 (2000).

[11] [11] Z. Meng, Z. Hu, Y. Hu, S. Xiong, and C. Cao, Proc. SPIE 6552, 65521C (2007).

[12] [12] X. Zhang, Z. Meng, Z. Hu, H. Yang, Z. Song, and Y. Hu, Proc. SPIE 7278, 72781N (2008).