The Design of Polarization-Maintaining and Polarization-Filtering Hollow Core with Nested Anti-Resonance Nodeless Fiber for THz Guidance

A polarization-maintaining and polarization-filtering hollow core fiber with nested anti-resonant nodeless tubes for the THz regime is proposed. The model is designed by the finite element method to operate at 1.0 THz using TOPAS copolymer as the fiber material. The proposed structure consists of four outer tubes with one inner tube each in the orthogonal arrangement. The fiber was optimized to obtain the lowest loss by varying the tube thickness. The simulation results show that the thickness of 0.09 mm was suitable for a low loss of 0.2 dB m(-1) operating at 1.0 THz. The fiber property of high birefringence @ 1.5 x 10(-4) was made by introducing unequal radial distances between the outer and inner tubes of the orthogonal arrangement. In addition, at a particular difference of the radial distance, it was found that the proposed fiber can act as a polarization filter indicating by having a high crosstalk.