[1] A. R. Chraplyvy, A. H. Gnauck, R. W. Tkach, J. L. Zyskind, J. W. Sulhoff, A. J. Lucero, Y. Sun, R. M. Jopson, F. Forghieri, R. M. Derosier, C. Wolf, and A. R. McCormick, IEEE Photon. Technol. Lett. 8, 1264(1996).

[2] P. Boffi, M. Ferrario, L. Marazzi, P. Martelli, P. Parolari, A. Righetti, R. Siano, and M. Martinelli, IEEE Photon. Technol. Lett. 20, 1118 (2008).

[3] P. S. Cho, G. Harston, C. J. Kerr, A. S. Greenblatt, A. Kaplan, Y. Achiam, G. Levy-Yurista, M. Margalit, Y. Gross, and J. B. Khurgin, IEEE Photon. Technol. Lett. 16, 656 (2004).

[4] X. S. Yao, L.-S. Yan, B. Zhang, A. E. Willner, and J. Jiang, Opt. Express 15, 7407 (2007).

[5] M. I. Hayee, M. C. Cardakli, A. B. Sahin, and A. E. Willner, IEEE Photon. Technol. Lett. 13, 881 (2001).

[6] R. No'e, S. Hinz, D. Sandel, and F. W¨ust, J. Lightwave Technol. 19, 1469 (2001).

[7] X. Liu and S. Chandrasekhar, in Proceedings of OFCINFOEC 2008 OTuG4 (2008).

[8] T. Pfau, C. Wordehoff, R. Peveling, S. K. Ibrahim, S. Hoffmann, O. Adamczyk, S. Bhandare, M. Porrmann, and R. No'e, in Proceedings of OFCINFOEC 2008 OtuM3 (2008).

[9] M. T. Core, J. Lightwave Technol. 24, 305 (2006).

[10] B. Milivojevic, A. F. Abas, A. Hidayat, S. Bhandare, D. Sandel, R. No'e, M. Guy, and M. Lapointe, IEEE Photon. Technol. Lett. 17, 495 (2005).

[11] Z. Wang and C. Xie, Opt. Express 17, 3183 (2009).

[12] M. Karlsson and H. Sunnerud, J. Lightwave Technol. 24, 4127 (2006).

[13] R. Khosravani, Y. Xie, L.-S. Yan, Y. Song, A. Willner, and C. Menyuk, in Proceedings of OFC 2001 WAA (2001).

[14] D. van den Borne, N. E. Hecker-Denschlag, G. D. Khoe, and H. de Waardt, J. Lightwave Technol. 23, 4004(2005).

[15] L. E. Nelson and H. Kogelnik, Opt. Express 7, 350(2000).

[16] W. Xu, G. Duan, G. Fang, L. Xi, and X. Zhang, Acta Opt. Sin. (in Chinese) 28, 226 (2008).

[17] X. Zhang, Chinese J. Lasers (in Chinese) 36, 526 (2009).