A study of microstructured fibre design for terahertz applications

In this paper, two types of microstructured fibre are designed and compared for use as a terahertz (THz) waveguide. For the first type, the photonic crystal fibre (PCF), made from HDPE or PTFE, is designed to obtain a ultra-wideband single mode propagation in the range of 0.19 THz to 3.28 THz. The propagation loss of the PCFs is characterized using the finite element method, and the predicted propagation loss is revealed to be strongly affected by the material loss, being as high as 217 dB/m at 1 THz. For the second type, a hollow core Bragg fibre is designed as a low loss single HE₁₁ mode THz waveguide, and the HE₁₁ mode is demonstrated to have a predicted loss of only 1.8-2.5 dB/m in the range of 0.8 THz to 1.2 THz, while the TM₀₁ mode has loss much higher than 40 dB/m. The designed Bragg fibre can work effectively as a single mode THz waveguide with low loss.