Design and Analysis of a Low-Loss Suspended Core Terahertz Fiber and Its Application to Polarization Splitter

We propose the design of a low-loss suspended core terahertz fiber with rectangular-shaped dielectric strips in the fiber cross section. The finite element method is used to analyze the characteristics of the suspended core terahertz fiber. Terahertz wave in a frequency range from 0.74 ~ 0.95 THz is efficiently confined in the suspended core region with a total loss lower than 0.086 dB/cm ( ~ 0.02 cm-1). Meanwhile, any contact on the surface of this fiber will not disturb the field and induce additional losses. A 3.36-cm-long terahertz polarization splitter derived from this fiber with a transmission loss less than 0.89 dB, is also numerically demonstrated. A bandwidth of 0.032 THz at the center frequency of 1 THz with an extinction ratio better than -20 dB is obtained.