Low loss rotated porous core octagonal single-mode fiber for THz radiation

A novel kind of photonic crystal fiber (PCF) with a rotated hexagonal porous core and an octagonal cladding has been proposed in this paper. The fiber geometry is considered as the turning point in order to raise the fraction of power transmitted through the core air-holes and single-mode propagation of the guided wave. The rotated hexagonal lattice in the core reduces the material absorption loss to a great extent (0.05 cm
^-1
) and the octagonal structure in the periodic cladding ensures high confinement factor and a high power fraction in core air-holes at the operating frequency of 1 THz and core diameter of 360 μm. Additionally, the simple design can easily be fabricated using combination of drilling and stacking methods, by which the fiber is expected to be applied in single-mode imaging and security applications.