Dual-core ultrawide-bandwidth and single-mode polarization beam splitter based on anti-resonant fiber.

An ultra-bandwidth and single-mode polarization beam splitter (PBS) of dual hollow-core anti-resonant fiber (DHC-ARF) with circular outer tubes and inner tubes is proposed. Four outer tubes are introduced in the horizontal direction to obtain two hollow cores. The modal coupling is realized through the gap between the two hollow cores. The inner tubes also are inserted into two the outer tubes between the two hollow cores for realizing ultrawide bandwidth in DHC-ARF. To achieve single-mode performance, the high-order modes are coupled with the cladding modes by optimizing the diameter of outer tubes and the inner tubes. The calculation results show that an 11.0 cm long DHC-ARF can be used to develop a PBS with an operating bandwidth of 410 nm, where the polarization extinction ratio is lower than −20 dB. The high-order mode extinction ratio is 625.41, and the loss of fundamental mode is below 1.018 dB/m. • Because the size of elliptical tubes is hard to fabricate, an ultra-bandwidth and single-mode PBS of DHC-ARF completely composed of circular cladding tubes and nested tubes is proposed in the structures. • The influence factors related to bandwidth, the high-order mode extinction ratio and coupling length of PBS based on DHC-ARF are systematically studied by a full-vector finite element method. • The propagation process of light in the optical fiber is also simulated by the light speed propagation method. When the light travels to a certain distance, the two polarized lights will be separated. • Numerical simulation shows an 11.0 cm long DHC-ARF can be used to develop a PBS with an operating bandwidth of 410 nm ranging from 1.35 to 1. 76 μ m , where the polarization extinction ratio reaches −39.0 dB, the high-order mode extinction ratio is 625.41. • The PBS based on DHC-ARF with circular cladding tubes and nested tubes proposed in this paper compares the performance with other existing PBS, this PBS has the widest bandwidth. [ABSTRACT FROM AUTHOR]