Ultralow-Loss and Polarization-Maintained Fusion Splicing for Asymmetric Antiresonant Hollow-Core Fibers

We develop an approach to tailoring the mode of a solid-core polarization-maintaining fiber, with both the reverse tapering process and the thermally expanded core technique, enlarging the mode area and reshaping the mode shape to construct a matched interface with an asymmetric antiresonant hollow-core fiber. An ultralow fusion splicing loss of 0.41 dB and a maintained polarization extinction ratio of 28 dB were demonstrated, with no additional intermediate component.