Novel single-polarized single-mode low-loss hollow-core anti-resonant fiber

Abstract A novel hollow-core anti-resonant fiber (HC-ARF) design is proposed, featuring a cladding structure composed of five nested tubes and five anti-resonant nested rings. The nested tubes are engineered with two distinct wall thickness configurations (resonant and anti-resonant) to tailor the optical properties. This unique structure endows the fiber with comprehensive superior performance, including single-polarization operation, low modal loss, a high polarization extinction ratio (PER), a high higher-order mode extinction ratio (HOMER), and a broad operating bandwidth. Numerical simulations demonstrate that the proposed design effectively reduces the loss of the x-polarized fundamental mode (x-pol FM) while significantly enhancing the PER. Compared with previous studies, this scheme simultaneously improves both PER and HOMER, while remarkably reducing the bending loss in the -x direction. At the wavelength of 1.55 μm, the x-pol FM loss, PER, and HOMER reach 0.012 dB km −1 , 2,413,562.253, and 688, respectively. Furthermore, the fiber maintains an x-pol FM loss below 1 dB km −1 and a PER exceeding 100 within a bandwidth of 31 nm. For a bending radius of 6 cm, the total bending loss in the -x direction is as low as 0.11 dB km −1 , with a corresponding PER of 126. Considering practical fabrication processes, a tolerance analysis of the cladding strut angle was conducted. The results indicate that the fiber achieves optimal performance when the offset angle is 0°, providing valuable theoretical guidance for the fabrication optimization of similar fibers.