Minimizing Splice Loss in Hollow-Core to SMF Fusion

Hollow-core optical fibers (HCFs) offer promising parameters for next-generation optical communication systems due to their low latency, low nonlinearities, and reduced chromatic dispersion. However, fusion splicing of HCFs to standard single-mode fibers (SMFs) poses significant challenges stemming from the air-filled core structure and thermal sensitivity of the microstructured cladding. The paper deals with the most common sources of error during HCF–SMF splicing and presents a comparative evaluation of several mitigation strategies. Using a Fujikura FSM-100P fusion splicer, with custom profiles was developed, and splicing geometries were optimized via tapering, angular cleaving, and intermediate fiber techniques. Optical losses were quantified using optical time-domain reflectometry (OTDR) and insertion loss methods. The results show that combining tapering with optimized arc discharge parameters yields the lowest insertion loss of 0.97 dB, compared to over 1.7 dB for unoptimized splices. These findings provide practical insights for the reliable integration of HCFs into conventional fiber infrastructures.