Highly Birefringent Single-Mode Suspended-Core Fiber in Terahertz Regime

In this study, we report a highly birefringent terahertz (THz) fiber that contains rectangular air slots in the suspended core. The proposed fiber can provide a high birefringence of the order of 10 ^-2 over a wide frequency region in single-mode operation. An ultrahigh birefringence of 0.078, low effective material loss of 0.39 dB/cm, and low confinement loss of 1.25 × 10 ^-5 dB/cm are obtained simultaneously at 0.95 THz. Moreover, numerical results indicate that a low dispersion with small variation can be achieved, and the power profile envelope has a Gaussian shape, which is important for coupling with common THz sources. The calculated coupling efficiency is as high as ~95% for y-polarization mode. It is anticipated that the proposed suspended-core fiber would be useful in THz polarization maintaining wave guidance and bacteria detection applications.