Terahertz Band Communications With Topological Valley Photonic Crystal Waveguide

The sixth generation (6 G) communication standard is expected to include support for very-high data rates (over 100 Gbit/s) and device electronics will require processors with on-chip communications able to support such high bandwidths. Although the terahertz band possesses ample bandwidth, conventional THz waveguides suffer from high bending losses and are sensitive to process defects. The recent revelation of the topological valley photonic crystal (VPC), which exhibits near zero-loss bends, zero back-scattering and zero junction-area, holds much promise for future high speed inter-device communications. Low dispersion in the photonic bandgap region as the number of bends increase is demonstrated through simulation and experiment of the transmission and group delay characteristics. Through comprehensive communications experiments we demonstrate online results below the forward error correction level including an 108-Gbit/s bit rate using multi-level modulation for a 10 mm straight VPC waveguide and a 62.5-Gbit/s bit-rate for a ten sharp bended structure.