Dual-core antiresonant fiber-based polarization beam splitter with high-index-material coating

Abstract A novel way of achieving polarization beam splitting in antiresonant (AR) fibers has been developed and investigated to fulfill the growing demand for integrated photonic devices. The proposed device comprises identical circular tubes with a simple cladding arrangement. The device is supported by an additional coating of high-index material in two tubes, which leads to excellent splitting performance. We reveal that, owing to the special phenomenon of the high-refractive-index material coating, various complex structures such as multinested tubes, double-layered elliptical tubes, adjacent nested tubes, etc. can be simplified and transformed into circular AR-tube-based structures. Hence, the proposed splitter has a modest size and can function effectively over a broad spectrum of wavelengths, exceeding an extinction ratio of 20 dB. This splitter is specifically designed to work effectively at a wavelength of 1.55 µ m. In addition, we examine the effects of including or omitting silicon-coated layers, as well as the results of varying the positions and numbers of silicon tube layers. Our findings show that two silicon-coated layers in the second cladding achieve the best performance. Ultimately, this work reveals a feasible strategy for developing significant splitting performance using a relatively simple cladding configuration on AR fibers, thus making it a promising candidate for optical device integration in communication networks.