[1] Knight J C, Birks T A, Russell P St J, et al. Optics Letter, 1996, 21(19): 1547.
[2] Birks T A, Knight J C. Russell P S. Optics Letter, 1997, 22 (13): 961.
[3] Jonathan C K. Nature, 2003, 424(14): 847.
[4] Hu J, Menyuk C, Shaw L B. Optics Communications, 2013, 293: 116.