Low-loss and bend-insensitive terahertz fiber using a rhombic-shaped core

A novel porous-core photonic crystal fiber is presented, and its guiding properties are numerically investigated by using the finite element method. It is demonstrated that by introducing a rhombic-shaped core made of circular air holes inside the conventional hexagonal cladding, it is possible to obtain very low bending loss of 3.04 x 10(-11) cm(-1) at the operating frequency of 1.0 THz. In addition to this, low effective material loss of 0.089 cm(-1) and very small confinement loss of 1.17 x 10(-3) dB/cm are achieved for optimal design parameters. Other guiding properties, including effective area, dispersion, and higher order mode characteristics are also discussed thoroughly. The design of this porous fiber is relatively simple, since it contains fewer air holes and consists of circular air holes only. Due to promising wave-guiding properties, the proposed fiber would have a great potential for terahertz imaging and flexible communication applications. (C) 2016 Optical Society of America