Hollow and filled fiber bragg gratings in nano-bore optical fibers

Zhang Yong-Xin¹, Liang Sheng^{1, ‡}, Yu Qian-Qing^{2, 3}, Lian Zheng-Gang², Dong Zi-Nian¹, Wang Xuan¹, Lin Yu-Qin¹, Zou Yu-Qi¹, Xing Kun¹, Liang Liu-Yan¹, Zhao Xiao-Ting⁴, Tu Li-Jing⁴

Variation of effective index of fundamental mode (n_eff) with bore diameter (D_bore).