Low loss and low dispersion hybrid core photonic crystal fiber for terahertz propagation

In this paper, a hybrid- core circular cladded photonic crystal fiber is designed and analyzed for application in the terahertz frequency range. We introduce a rectangular structure in addition to a conventional hexagonal structure in the core to reduce the material absorption loss. The modal characteristics of the fiber have been investigated using full vector finite element method. Simulated results exhibit an ultra- low effective material loss of 0.035cm- 1 and ultra- flattened dispersion of 0.07 ps/ THz/ cm. Some other important fiber characteristics suitable for terahertz signal transmission including confinement loss, core power fraction, effective area and single- mode conditions of the fiber have also been investigated. In order to simplify design and facilitate fabrication, only circular shaped air holes have been employed. Due to its promising characteristics, the proposed waveguide may provide efficient transmission of broadband terahertz signals.