Near-field vertical coupling between terahertz photonic crystal waveguides

We demonstrate near-field coupling between terahertz photonic crystal waveguides in the out-of-plane dimension, with no direct physical contact, by making use of coupledline techniques. Efficient transfer (i.e. ~ 80%) of terahertz power from one waveguide to another is experimentally achieved. Thereafter, multi-Gbps data is successfully transmitted via this near-field link. This study can be considered a step towards practical connectors between terahertz photonic crystal waveguide circuits.