[1] V. P. Gapontsev, N. S. Platonov, O. Shkurihin, and I. Zaitsev, in Proceedings of Conference on Lasers and Electro-Optics CThPDB9 (2003).

[2] J. P. Koplow, D. A. V. Kliner, and L. Goldberg, Opt. Lett. 25, 442 (2000).

[3] J. Limpert, F. Roser, T. Schreiber, and A. Tunnermann, IEEE J. Sel. Top. Quantum Electron. 12, 233 (2006).

[4] Q. Lou, J. Zhou, J. Zhu, D. Xue, L. Kong, J. Li, S. Li, J. Dong, Y. Wei, Z. Wu, Z. Ye, L. Ling, and Z. Wang, Chin. J. Lasers (in Chinese) 32, 20 (2005).

[5] D. Xue, Q. Lou, J. Zhou, L. Kong, J. Li, and S. Li, Chin. Opt. Lett. 13, 345 (2005).

[6] J. Zhou, Q. Lou, J. Zhu, B. He, J. Dong, Y. Wei, F. Zhang, J. Li, S. Li, H. Zhao, and Z. Wang, Acta Opt. Sin. (in Chinese) 26, 1119 (2006).

[7] L. Kong, Q. Lou, J. Zhou, D. Xue, and Z. Wang, Opt. Eng. 45, 010502Q (2006).

[8] A. Galvanauskas, Optics and Photonics News 15, (7) 42 (2004).

[9] H. L. Offerhaus, N. G. Broderick, D. J. Richardson, R. Sammut, J. Caplen, and L. Dong, Opt. Lett. 23, 1683 (1998).

[10] J. M. Sousa and O. G. Okhotnikov, Appl. Phys. Lett. 74, 1528 (1999).

[11] J. A. Alvarez-Chavez, A. B. Grudinin, J. Nilsson, P. W. Turner, and W. A. Clarkson, in Proceedings of Conference on Lasers and Electro-Optics 247 (1999).

[12] O. G. Okhotnikov and J. M. Sousa, Electron. Lett. 35, 1011 (1999).

[13] D. Marcuse, J. Opt. Soc. Am. 66, 216 (1976).

[14] D. Marcuse, J. Opt. Soc. Am. 66, 311 (1976).

[15] T. F. Johnston, Jr., Appl. Opt. 37, 4840 (1998).

[16] H. Wu, Optics and Precision Engineering (in Chinese) 8, 128 (2000).