Design of 0.26 THz Low-Loss Single-Mode 3D-Printed Anti-Resonant Fibers

With the goal of obtaining low-loss and single-mode transmission of terahertz waveguide, in this paper, we investigate the waveguide performance of different 3D-printed HC-ARFs with elliptical cladding tubes at 0.26 THz, including the fiber's confinement loss (CL) of fundamental mode (FM) and higher-order modes (HOMs), and the higher-order mode extinction ratio (HOMER), through extensive simulations and numerical analyses. By optimizing the structural parameters, we respectively propose the optimal fiber designs under different structures. Among them, a six-tube elliptical cladding HC-ARF with a loss of 0.35 dB/m and a HOMER up to 7.7 at 0.26 THz, is to the best of our knowledge the most ideal microstructured fiber reported so far operated around this frequency, which provides an efficient and high-performance fiber designed for 3D printing for terahertz spectroscopy, communication, and other applications.