Terahertz photonic crystal fiber polarization rotator

Polarization control of terahertz (THz) waves is highly required due to their immense practical applications. Most of the THz polarization rotators in the literature depend on the transmission or reflection from metamaterials or all-dielectric metasurfaces. There is also a lack of THz polarization handling waveguides due to the material absorption in this frequency regime. In this paper, a THz photonic crystal fiber (PCF) polarization rotator (PR) is introduced and analyzed for the first time to the best of our knowledge. The suggested PCF-PR has an asymmetric porous core to decrease the material losses and increase the hybrid ness of the two polarized modes. Therefore, high polarization conversion ratio of 80.7% is achieved with a good crosstalk of -18.9 dB at a frequency of 1 THz along a device length of 7.9 mm. Further, the operating frequency has a tolerance of f =1 +/- 0.1 THz where the crosstalk is still better than -15 dB. (C) 2020 Optical Society of America