[1] T. Takahashi, T. Imai, and M. Aiki, Electron. Lett. 30, 348 (1994).
[2] F. Heismann, D. A. Fishman, and D. L. Wilson, in Proceedings of ECOC’98 WdC11, 529 (1998).
[3] H. Ooi, Y. Akiyama, and G. Ishikawa, in Proceedings of OFC/IOOC’99 WE5-1, 21 (1999).
[4] H. Y. Pua, K. Peddanarappagari, B. Y. Zhu, C. Allen, K. Demareat, and R. Q. Hui, J. Lightwave Technol. 18, 832 (1999).
[5] X. M. Liu, C. Y. Li, R. H. Li, B. J. Yang, and X. G. Zhang, Semiconductor Optoelectron. (in Chinese) 22, 386 (2001).
[6] C. D. Poole and D. Favin, J. Lightwave Technol. 12, 917 (1994).
[7] J. F. Zhang, M. Y. Yao, H. M. Zhang, Q. F. Xu, and Y. Z. Gao, Opt. Commun. 197, 385 (2001).