[2] M. Deng, J. Xu, Z. Zhang, Z. Bai, S. Liu, Y. Wang, Y. Zhang, C. Liao, W. Jin, G. Peng, Y. Wang. Opt. Express., 25, 14308(2017).
[3] X. Jiang, P. Lu, Y. Sun, H. Liao, D. Liu, J. Zhang, H. Liao. Chin. Opt. Lett., 16, 040602(2018).
[5] X. Yan, H. Fu, H. Li, H. Qiao. Chin. Opt. Lett., 14, 030603(2016).
[6] S. Guan, Q. Yu, J. Zheng. Chin. J. Lasers., 37, 1996(2010).
[7] V. Lemarquand. IEEE Trans. Magn., 35, 4503(1999).
[8] L. Wang, C. Lin, G. Chern. Meas. Sci. Technol., 12, 793(2001).
[9] Y. Rao, Y. Wang, Z. Ran, T. Zhu. J. Lightwave Technol., 21, 1320(2003).
[10] C. Sun, T. Geng, J. He, A. Zhou, W. Yang, X. Jin, X. Chen, Y. Zhou, Q. Hu, L. Yuan. IEEE Photon. Technol. Lett., 29, 2179(2017).
[11] X. Cao, Y. Liu, L. Zhang, Y. Zhao, T. Wang. Appl. Opt., 56, 5167(2017).
[12] L. Xian, P. Wang, H. Li. Opt. Express., 22, 20260(2014).
[13] T. Zhu, K. Chiang, Y. Rao, C. Shi, Y. Song, M. Liu. J. Lightwave Technol., 27, 4863(2009).
[14] Y. Wang, J. Chen, Y. Rao. Opt. Soc. Am. J. B, 22, 1167(2005).