Double-end low-loss coupling of anti-resonant hollow-core fibers with solid-core single-mode fibers by tapering technique

摘要

We report here the low-loss double-end coupling of an anti-resonant hollow-core fiber (AR-HCF) with a solid-core single-mode fiber by the fiber tapering technique for the first time. The double-end coupling model is established by the beam propagation method, and the various influences, such as those of insertion depth, tapered waist offset, tapered waist bending, etc, on the coupling efficiency are simulated in detail. Results show that the coupling efficiency can be optimized by choosing proper waist diameters of the tapered solid-core fibers at both ends; meanwhile, the output taped fiber must be inserted into the proper depth. The calculated maximum coupling efficiency is 70.8% for AR-HCF of the core diameter 46 mu m at the 1.5 mu m band, and the measured value is similar to 52.3%, which is hoped to be further increased by improving the performance of the tapered fibers and the coupling system. This work opens new opportunities for all-fiber structured gas lasers, which is very significant for its future applications.