Ultra-low-loss hollow-core anti-resonant fiber

In this paper, an ultra-low-loss hollow-core anti-resonant fiber (HC-ARF) operating in the near-infrared band is proposed. The ARF is based on six nested circular tubes made of silica. Then a straight rod is added to the nested inner circular tube to reduce the transmission loss. The low-loss transmission performance of the HC-ARF is analyzed in detail using the finite element method, and the structural parameters are further optimized. The results show that the confinement loss is lower than 7.91×10^-7<i>d</i><i>B</i>/<i>m</i> in the range of 1.54-1.78 µm. Especially the confinement loss is as low as 1.31×10^-7<i>d</i><i>B</i>/<i>m</i> at 1.55 µm. In addition, the HC-ARF has good bending resistance. The bending loss can be kept below 8.02×10^-5<i>d</i><i>B</i>/<i>m</i> as the bending radius is larger than 5 cm. The performance of the designed ARF is significantly better than previously reported results, and the cladding structure of the ARF is simple and easy to process. It has great potential for commercial applications.