Design and Study of Low Loss, High Birefringence Quasi-Symmetric Hollow-Core Anti-Resonant Fiber

Low-loss, high-birefringence, bend-resistant hollow-core anti-resonant fibers for infrared wavelengths have important applications in the fields of precision interferometric sensing, laser systems, and optical communications. In this paper, an eight-tube cladding quasi-symmetric hollow-core anti-resonant fiber is proposed, and two other anti-resonant fibers are designed based on this fiber structure. The finite element analysis method is used to numerically analyze the limiting loss, birefringence coefficient, bending resistance, and other properties of the three optical fibers after the optimized design. The results show that the limiting loss of the three optical fibers at λ = 1.55 μm is lower than 10−4 magnitude, and all of them obtain a birefringence coefficient of 10−4 magnitude; at the same time, the three optical fibers have their own characteristics and advantages, and the first optical fiber can reach a birefringence coefficient of 9.25 × 10−4 at λ = 1.52 μm.The limiting loss at λ = 1.55 μm is 3.42 × 10−5 dB/km. The minimum bending radius of the three types of anti-resonant fibers is less than 40 mm, which represents good bending characteristics, and the eight-tube cladding quasi-symmetric optical fiber has a bending loss of less than 2.10 × 10−3 dB/km when the bending radius is 28 mm. The three types of optical fibers have obtained good results in improving the mutual constraints between low limiting loss and high birefringence, with better results than the other two types. The obtained results have high development potential.