[1] E. K. Stafford and J. Mariano, AT&T Tech. J. 74, 47 (1995).
[2] J. P. Blondel, F. Misk, and P. M. Gabla, Photon. Technol. Lett. 5, 1430 (1993).
[3] S. G. Grubb, T. Strasser, W. Y. Cheung, W. A. Reed, V. Mizrahi, T. Erdogan, P. J. Lemaire, and A. M. Vengsarkar, in Proc. Optical Amplifiers and Their Applications SaA4, 197 (1995).
[4] W. Zhang, J. D. Peng, X. M. Liu, and C. C. Fan, Chin. J. Lasers (in Chinese) 29, 729 (2002).
[5] C. R. Giles and E. Desurvire, J. Lightwave Technol. 9, 271 (1991).
[6] H. Kidorf, K. Rottwitt, and M. Nissov, IEEE Photon. Technol. Lett. 11, 530 (1999).