Ultralow-loss fusion splicing between negative curvature hollow-core fibers and conventional SMFs with a reverse-tapering method

Negative curvature hollow-core fibers (NC-HCFs) can boost the excellent performance of HCFs in terms propagation loss, nonlinearity, and latency, while retaining large core delicate cladding structures, which makes them distinctly different from conventional fibers. Construction low-loss all-fiber NC-HCF architecture with single-mode (SMFs) is important for various applications. Here we demonstrate an efficient reliable fusion splicing method to achieve connection between a SMF. By controlling mode-field profile SMF two-step reverse-tapering method, realize record-low insertion loss 0.88 dB SMF/NC-HCF/SMF chain at 1310 nm. Our simple, effective, reliable, compared those methods that rely on intermediate bridging elements, such as graded-index fibers, greatly facilitate integration NC-HCFs promote more advanced applications