Ultra-high birefringent low loss suspended elliptical core photonic crystal fiber for terahertz applications.

This paper presents a low loss suspended core microstructured fiber with ultra-high birefringence for terahertz wave guidance. The finite element method (FEM) with a perfectly matched layer is applied to investigate different important properties including effective material loss (EML), birefringence, dispersion, confinement loss, and percentage of power flow through the core. The suspended elliptical core in the design creates asymmetry and results in an unprecedented value of birefringence. The simulated results using FEM at 1 THz show an extremely ultra-high birefringence (the highest, to the best of our knowledge) of 0.1116, a nominal EML of 0.04716cm-1, a negligible confinement loss of 2.65×10-7cm-1, a higher power fraction in the core air of 35%, and an effective modal area of 1.24×105µm. The advancement in technology makes the fabrication possible. The proposed fiber could be used satisfactorily in the terahertz regime for various polarization-preserving applications and coherent communication.

Novel porous fiber based on dual-asymmetry for low-loss polarization maintaining THz wave guidance.

In this Letter, we suggest a novel kind of porous-core photonic crystal fiber (PCF) (to the best of our knowledge) for efficient transportation of polarization maintaining (PM) terahertz (THz) waves. We introduce an asymmetry in both the porous-core and the porous-cladding of the structure to achieve an ultra-high birefringence. Besides, only circular air holes have been used to represent the structure, which makes the fiber remarkably simple. The transmission characteristics have been numerically examined based on an efficient finite element method (FEM). The numerical results confirm a high birefringence of ∼0.045 and a very low effective absorption loss of 0.08 cm(-1) for optimal design parameters at 1 THz. We have also thoroughly investigated some important modal properties such as bending loss, power fraction, dispersion, and fabrication possibilities to completely analyze the structure's usability in a multitude of THz appliances. Moreover, physical insights of the proposed fiber have also been discussed.