A modified dual-core THz fiber polarization splitter with four subwavelength tubes

We propose a terahertz polarization splitter based on suspended dual-core fiber. Each core of the fiber is formed with two adherent subwavelength polymer tubes, which is helpful for a high modal birefringence. Due to the difference of coupling length between x and y polarizations, the proposed splitter can completely separate two orthogonal polarization modes at a specific splitting length. A 1.184 cm long splitter can be obtained at a center frequency of 1 THz. Meanwhile, the low insertion loss of 0.6 dB, the bandwidth of 0.05 THz and the extinction ratio better than −10 dB can be supplied. Moreover, an efficient design rule for the proposed splitter is demonstrated aiming to high extinction ratio at any desired operation frequency. The proposed terahertz polarization splitter has some potential applications in all-optical networks in THz systems.