We report on a polymer-based porous-core photonic crystal fiber for simultaneous high-birefringent and low-loss propagation of narrowband terahertz (THz) electromagnetic waves. The high birefringence is induced by using rotated elliptical air holes inside the porous-core. The fiber is numerically analyzed with an efficient finite-element method. The simulation results exhibit an extremely high birefringence of ∼0.042 and a very low effective material loss of ∼0.07 cm−1 at an operating frequency of 1 THz. Moreover, we have found an optimal rotation angle (θ)=n30 deg (n is an odd integer). Other modal features of the fiber, such as confinement loss, power fraction, effective area, bending loss, and dispersion, also have been analyzed. We anticipate that the proposed fiber would be suitable in polarization maintaining THz wave guidance applications.
A porous-core circular photonic crystal fiber is designed for low-loss terahertz (THz) wave propagation. The circular arrangement of air holes, both in the periodic cladding and the porous core, makes it possible to guide most of the optical power through low-loss air, which is confirmed by the rigorous analysis of modal properties of the fiber while maintaining the single-mode propagation condition. The simulation results, found by using an efficient finite element method, show that a flattened dispersion of ±0.09 ps/THz/cm within 0.9 to 1.3 THz and an ultra-low material loss of 0.053 cm−1 at f=1 THz is obtained for the reported design at optimal parameters. This kind of structure can be fabricated using capillary stacking or a sol–gel technique and is expected to be useful for wideband imaging and telecom applications.
We propose a porous-core octagonal photonic crystal fiber for low-loss terahertz (THz) waveguiding. Great attention is given to the geometries of the fiber inside the core to increase the fraction of power transmitted through the air holes. At an operating frequency f=1 THz, this design exhibits a low effective material loss which is approximately 0.05 cm−1 or 0.2 dB/cm. In addition to the confinement loss, some other properties like the power fraction of the core air holes, responses of the effective material loss, and power fraction with respect to frequency have been also reported. This design is useful for efficient transmission of broadband terahertz radiation.