Elliptical hollow-core optical fibers for polarization-maintaining few-mode guidance

•PM-FM elliptical hollow-core optical fibers with simple triple-layer structure.•Parameters of air hole and ring core can be adjusted for PM performance.•10 effectively separated polarization modes with Δneff > 1.93 × 10−4at 1550 nm.•Expandable number of guided PM modes with modified structural parameters.•Those fibers could be promising candidates toward high-capacity SDM systems.