Ultra-high birefringent and dispersion-flattened low loss single-mode terahertz wave guiding

This study proposes a dielectric terahertz (THz) porous core fibre with ultra-high birefringence and near zero dispersion-flattened properties. The finite element method is used to design and analyse properties of the proposed THz fibre. The proposed porous core crystal fibre has a triangular lattice with microstructured circular air holes in the outer cladding and elliptical air holes in the core. The design exhibits a high birefringence of 7 x 10(-2) and a low effective material loss of 0.1 cm(-1) at the operating frequency of f = 1 THz. It also shows nearly zero flattened dispersion with an absolute dispersion variation of +/- 0.05 ps/THz/cm in the frequency range of 1.3 to 2.2 THz. Power fraction and confinement loss are also reported in this study. The proposed THz porous fibre is deemed suitable for polarisation-maintaining THz wave guidance.