Optimization of photonic crystals for terahertz waveguiding

Abstract

As technology advances, there is a demand for devices that are increasingly more wirelessly interconnected. This has led to the development of the sixth generation (6G) communications standard. The 6G standard is expected to support the transmission of close to terabit per second data rates. This is enabled by developing terahertz (THz) communications, which have large bandwidth that can support the high data rates. However, THz communications suffer from a few drawbacks, one of which is that THz waves have short propagation distances, and their devices suffer from high loss. Hence, there is a need to develop compact and efficient waveguides for THz waves. Photonic crystals are structures that are periodic in their refractive index, which have been extensively studied in recent years due to their potential applications in optical communications. Photonic crystals have been used to create THz waveguides that can effectively channel the flow of light. In this report, we investigate the design and simulation of these waveguides based on photonic crystals with hexagonal symmetry. We use the plane wave expansion method to simulate the band structure of the crystal to determine the photonic bandgap. By identifying ideal crystal structures for waveguiding, we then construct waveguides with both bearded and zigzag symmetry. It is then shown that the triangular structure is ideal for forming waveguides for the transverse electric mode, but more work needs to be done to identify photonic crystals that are ideal waveguides in the transverse magnetic mode.