Single Mode Porous Core Photonic Crystal Fiber for THz Wave Propagation with Extremely Low Losses

A porous core terahertz (THz) waveguide consists of sectored cladding and square core photonic crystal fiber (PCF) is designed with low losses and flattened dispersion. The mode test and others wave guiding properties are evaluated by using finite element method (FEM) and a perfectly matched layer (PML) as a boundary condition. To investigate the numerical values and electric field distribution, comsol multiphysics software v.5.3a is used. The mode test result of proposed PCF structure shows single mode characteristics besides it renders extremely low effective material loss of 0.0257 cm⁻¹ and confinement loss of 0.0001 cm⁻¹at 1 THz operating frequency. Additionally, a very flat dispersion is achieved from this proposed PCF structure. The effective area and core power fraction are also verified for efficient THz wave guidance. Simple sectored cladding and square core structure are feasible to fabricate using existing extrusion and 3D printing fabrication techniques.