[4] J. Li, T. Ning, L. Pei, J. Zheng, J. Sun, Y. Li, J. Yuan. Chin. Opt. Lett., 13, 080606(2015).
[5] Y. Dong, Z. Liu, X. Wang, N. Deng, W. Xie, W. Hu. Chin. Opt. Lett., 14, 120006(2016).
[6] Y. Cheng, F. Hu, F. He, L Wu, X. He. Chin. Opt. Lett., 14, 062802(2016).
[7] J. Chou, Y. Han, B. Jalali. IEEE Photon. Technol. Lett., 15, 581(2003).
[8] C. Wang, J. P. Yao. IEEE Photon. Technol. Lett., 24, 1493(2012).
[9] W. Li, W. Wang, W. Sun, L. Wang, N. Zhu. Opt. Express, 22, 7446(2014).
[10] F. Zhang, X. Ge, B. Gao, S. Pan. Opt. Express, 23, 21867(2015).
[11] L. Wang, W. Li, H. Wang, J. Zheng, J. Liu, N. Zhu. IEEE Photon. Technol. Lett., 25, 678(2013).
[12] H. Jiang, L. Yan, J. Ye, W. Pan, B. Luo, X. Zou. Opt. Lett., 38, 1361(2013).
[13] S. Liu, D. Zhu, Z. Wei, S. Pan. Opt. Lett., 39, 3958(2014).
[14] Z. Li, W. Li, H. Chi, X. Zhang, J. Yao. IEEE Photon. Technol. Lett., 23, 712(2011).
[16] J. Xiao, Z. Zhang, X. Li, Y. Xu, L. Chen, J. Yu. IEEE Photon. J., 7, 7101206(2015).
[17] J. Xiao, X. Li, Y. Xu, Z. Zhang, L. Chen, J. Yu. Opt. Express, 23, 24029(2015).
[18] X. Li, S. Zhao, Y. Zhang, Z. Zhu, S. Pan. IEEE Photon. Technol. Lett., 28, 1980(2016).
[19] Y. Painchaud, M. Aubé, G. Brochu, M.-J. Picard. Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BTuC3(2010).