Design study of low loss single-mode hollow core photonic crystal terahertz waveguide with support bridges

We present a design study of an all-polymer low loss single-mode hollow-core photonic crystal (HCPC) terahertz (THz) waveguide with dielectric bridges used as mechanical supports. By exploiting a modal-filtering effect and Brewster phenomenon, we maximize the loss discrimination between the fundamental and other higher order modes resulting in an effectively single-mode operation, though the HCPC THz waveguide is ostensibly multi-mode. Owing to the use of support bridges, which increase the propagation loss, the non-ideal HCPC THz waveguide has higher loss than an ideal one. Nonetheless, the propagation loss of the fundamental HE₁₁ mode can still be minimized, to lower than 5 dB/m over the frequency range from 0.75 to 1.1 THz. In addition, the group velocity dispersion of the HE₁₁ mode is less than -0.5 ps/THz/cm.