Highly birefringent photonic crystal fiber with D-shaped air holes for terahertz (THz) application

Abstract A new type of high birefringence terahertz (THz) band photonic crystal fiber (PCF) is proposed. D-shaped air holes are introduced into the core of the PCF and the cladding near the core. Some important parameters of this waveguide were researched in the range of 0.6–1.2 THz. The simulation results show that the proposed fiber has a high birefringence of 0.0425 at 0.7 THz. In addition, the confinement loss and the effective mode area are respectively 6.63 × 10 −7 dB/m and 0.77 × 10 5 μm 2 , when the operating frequency is 1 THz and the high birefringence of 0.04 is maintained. At the same time, very low bending loss and near zero flat positive dispersion are obtained. And has single-mode operating characteristics in the entire research frequency range. The PCF structure will provide new solutions for the application of THz waves and the design of THz waveguides.