[1] [1] J. Capmany, B. Ortega and D. Pastor, Journal of Lightwave Technology 24, 201 (2006).

[2] [2] J. Yao, Journal of Lightwave Technology 27, 314 (2009).

[3] [3] Capmany J., Mora J., Gasulla I., Sanchi J., Lloret J. and Sales S., Journal of Lightwave Technology 31, 571 (2013).

[4] [4] Minasian R. A., Chan E. H. W. and Yi X., Optics Express 21, 22918 (2013).

[5] [5] Zou D., Zheng X., Li S., Zhang H. and Zhou B., Optics Communications 326, 150 (2014).

[6] [6] Ai-ling Zhang, Cong Huang and Xiao-jun Wu, Optoelectronics Letters 10, 5 (2014).

[7] [7] Xu X., Ou H. and Wong K., IEEE Photonics Technology Letters 26, 893 (2014).

[8] [8] Feng X., Lu C., Tam H. Y. and Wai P. K. A., IEEE Photonics Technology Letters 19, 1334 (2007).

[9] [9] Xue X., Zheng X., Zhang H. and Zhou B., Optics Express 20, 26929 (2012).

[10] [10] W. Li, N. H. Zhou and L. X. Huang, IEEE Photonics Journal 3, 462 (2011).

[11] [11] M. Sagues, R. Garcia Olcina, A. Loayssa, S. Sales and J. Capmany, Optics Express 16, 295 (2008).

[12] [12] W. Li, L. X. Wang and N. H. Zhu, IEEE Photonics Journal 5, 5501411 (2013).

[13] [13] W. Zhang and R. A. Minasian, IEEE Photonics Technology Letters 24, 1182 (2012).

[14] [14] C. Zhang, L.-S. Yan, W. Pan, B. Luo, X.-H. Zou, H.-Y. Jiang and B. Lu, IEEE Photonics Journal 5, 5501606 (2013).

[15] [15] E. Xu and J. Yao, IEEE Photonics Technology Letters 27, 2063 (2015).

[16] [16] Y. Wang, E. H. W. Chan, X. Wang, X. Feng and B. Guan, IEEE Photonics Journal 7, 5500311 (2015).