Terahertz photonic crystal fiber polarization rotator

Abstract

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 hybridness of the two polarized modes. Therefore, high polarization conversion ratio of 80.7% is achieved with a good crosstalk of − 18.9 d B 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 T H z where the crosstalk is still better than − 15 d B .

Asymmetric dual-core liquid crystal channel-based tunable mode converter

“…The crosstalk (CT) can be obtained from Eq. ( 6 ) as reported in 48 : where P undesired is the power fraction remains in the launching core exactly after a distance of L D while P desired is the power fraction coupled from the launching core to the BK7 core at L D . Using Eq.…”

Ultra-Short Polarization Rotator Based on Flat-Shaped Photonic Crystal Fiber Filled with Liquid Crystal

“…The passive scheme controls the mode evolution by changing the geometry of the waveguide [ 5 , 6 , 7 , 8 ], but this method has the issues of unidirectional conversion and large volume. The active scheme uses mode coupling [ 9 , 10 , 11 , 12 , 13 , 14 ]. The main design idea is to change the birefringence of the waveguide so that the input light can excite two mutually orthogonal polarization modes on the transmission section.…”