Truncated Anti-Resonant Hollow-Core Fiber for Reduced Microstructure Diameter

We present a novel design approach to reduce the overall microstructure diameter (MSD) of multi-layered anti-resonant hollow-core fiber (AR-HCF) while maintaining their exceptional optical performance. By strategically truncating the outermost layer of the large tubular element in the AR-HCF structure by a central angle of 130o, the MSD is reduced by 16% compared to its intact tube design counterpart. The fabricated truncated AR-HCF demonstrates a minimum loss of 0.28 ± 0.1 dB/km at 1290 nm and below 0.5 dB/km in the O-band from 1220-1340 nm. A similar truncated AR-HCF designed for C-band operation achieves 0.23 ± 0.1 dB/km around 1550 nm. Furthermore, the fiber exhibits low dispersion, negligible bending loss, and satisfactory higher-order mode extinction capability. This truncated AR-HCF design with reduced MSD strikes an optimal balance between exceptional optical performance and ease of integration, expanding the versatility of AR-HCFs across diverse applications like communications, sensing, and laser technologies.