Crescent-Shaped Anti-Resonant Hollow Core Fiber

Antiresonant hollow-core fibers (AR-HCFs) have emerged as a groundbreaking fiber technology. However, an inherent tradeoff exists between birefringence, loss, and bandwidth in AR-HCF. Here we propose a crescent-shaped core AR-HCF that achieves significant birefringence through asymmetric shaping, without compromising loss or bandwidth characteristics. Simulation results show, at birefringence of 10 ⁻⁵ level, a confinement loss below 0.1 dB/km over 600 nm bandwidth can be achieved. Alternatively, at 10 ⁻⁴ level birefringence, a confinement loss below 1 dB/km over 300 nm bandwidth is viable. The crescent-shaped AR-HCF intrinsically offers the coveted combination of ultralow loss, wide bandwidth, and high birefringence that has eluded previous approaches. It holds the promise of enabling polarization maintaining light transmission across long fiber length and wide bandwidths, paving the way for versatile applications in nonlinear optics, interferometric sensing, and coherent communications that hope to capitalize on the advantages offered by hollow core guidance.