Designing optical negative curvature hollow-core fibers with rotated elliptical cladding elements

We propose a unique design of negative curvature optical fibers utilizing rotational elliptical cladding structures. The silica-based fibers were numerically characterized using a finite element method-based electromagnetic solver. Different topologies consisting of rotational cladding elements with different tube thicknesses and core diameters were studied. The investigation focused on confinement losses, birefringence, and higher-order mode extinction based on varying tube sizes and rotational angles. Results showed up to 20% improvement in confinement losses for rotated structures, with minimum losses of 4.47*10-4 dB/m at 1.5 μm wavelength. The designed fibers possess polarization-dependent characteristics, and higher-order mode extinction analysis showed dominant single-mode transmission.