3D-printed high-birefringence THz hollow-core anti-resonant fiber with an elliptical core

Abstract

A high-birefringence and low-loss terahertz (THz) hollow-core anti-resonant fiber (THz HC-ARF) is designed and analyzed numerically by the finite element method (FEM). The THz HC-ARF is composed of an elliptical tube as the core for high birefringence guidance and a pair of symmetrical slabs arranged vertically as the cladding to attain low loss. Numerical analysis indicates that the birefringence reaches 10−2 in the transmission window between 0.21 and 0.35 THz. The highest birefringence is 4.61 × 10−2 at 0.21 THz with a loss of 0.15 cm-1. To verify the theoretical results, the THz HC-ARF is produced by three-dimensional (3D) printing, and the transmission characteristics are determined by THz time-domain spectroscopy (THz-TDS). High birefringence in the range of 2.17 × 10−2 to 3.72 × 10−2 and low loss in the range of 0.12 to 0.18 cm-1 are demonstrated experimentally in the 0.2 to 0.27 THz transmission window. The highest birefringence is 3.72 × 10−2 at 0.22 THz and the corresponding loss is 0.18 cm-1. The THz HC-ARF shows the highest birefringence besides relatively low loss compared to similar THz HC-ARFs reported recently.

Anti-Resonant Hollow-Core Fibers with High Birefringence and Low Loss for Terahertz Propagation

“…Additionally, 3D printing technology can also be employed to produce more precise or complex optical fibers. In 2023, Lu et al successfully fabricated a core structure similar to the proposed optical fiber using 3D printing technology, demonstrating the feasibility of manufacturing this type of AR-HCF [31].…”

“…Hong et al fabricated an AR-HCF with a birefringence of 9.1 × 10 −5 , achieving a minimum loss of 185 dB/km at 1.589 µm [30]. Xue et al utilized 3D printing technology to fabricate a high birefringence of 10 −2 but with a total loss of 0.96 dB/cm at 0.27 THz [31]. The current focus is on finding ways to achieve higher birefringence with lower loss.…”