Low-loss polarization-maintaining hollow-core anti-resonant terahertz fiber

摘要

Polarization-maintaining terahertz (THz) fibers have been considered as fundamental elements in polarization sensitive THz systems. Based on the anti-resonant waveguiding mechanism, we propose a low-loss polarization-maintaining hollow-core THz fiber with four half-elliptical cladding membranes. Numerical simulations indicate that birefringence of the fundamental mode group could be introduced by modifying the thickness of a pair of membranes while sacrificing available low-loss bandwidth. We observe that the core size, the dimension and shape of cladding membranes, have significant impacts on modal properties. For the half-circular membranes based fiber with optimized parameters, the attenuation coefficients of fundamental modes are below 10 dB m(-1), the birefringence is above 10(-4) and the group velocity dispersion values are lower than 60 ps THz(-1) m(-1) within the frequency bandwidths of 0.46-0.6 THz and 0.74-1.1 THz. At 0.9 THz, the lowest attenuation coefficient is 0.5 dB m(-1) with birefringence of 1.52 x 10(-4) Moreover, this THz fiber is insensitive to neither x- nor y-direction bend with a bend radius no less than 2 cm.