Double-slot-core terahertz photonic crystal fiber for high birefringence

In this study, we propose a terahertz photonic crystal fiber (PCF) including double rectangular air slots in the core region based on the conventional hexagonal lattice cladding. The rectangular air slots break the geometrical symmetry, which improves birefringence compared to previously reported slot core fibers. The proposed fiber consists of the reduced number of air slots to facilitate fabrication without performance deterioration. The designed PCF provides a very high birefringence of 0.93 at 1.05 THz with a low loss of 0.05 dB/cm and supports high birefringence for a wide range of frequency bands from 0.85 to 1.3 THz. We believe that this type of fiber could be applied to various efficient short-range signal transmission applications in the terahertz region.