Highly birefringent and low loss anti-resonant hollow-core fiber with stadium-shaped nested structure

Abstract We propose a stadium-shaped nested anti-resonant hollow-core fiber (SSAF), designed to enable high birefringence and low loss in the near-infrared bands. Numerical investigation and simulation for variations in parameters of stadium-shaped nested structure are conducted, and confinement loss (CL) is reduced by parameters optimization while birefringence of 10 −4 is maintained. With optimized SSAF structure, the birefringence and CL are improved to 1.39 × 10 −4 and 26.5 dB km −1 at 1.38 µ m, 1.28 × 10 −4 and 2.64 dB km −1 at 1.55 µ m, respectively. Meanwhile, it exhibits favorable single-mode characteristics and achieves a high high-order mode extinction ratio of up to 10 3 , and the superior bending resistance characteristics are validated. Our work offers valuable guidance for designing and optimizing highly birefringent SSAF anti-resonant fiber, and the proposed SSAF has great application potential in polarization-dependent transmission and interferometric fiber gyroscope.