Embodiments herein relate to a fully integrated broadband interconnect. The system comprises a first integrated circuit, a second integrated circuit, and a coupler structure to connect the first and second integrated circuits, where the coupler structure includes a base portion and a top portion that are connected by two vertical walls. The top portion has a gap that increases a strength of a transverse electric field across the gap when the coupler structure is operating in an odd higher order mode that is horizontally polarized, where the coupler structure is full of a dielectric material, and where the cross-sectional width of the coupler structure is tapered in a direction of wave propagation. The system further comprises a dielectric waveguide attached to the top portion of the coupler structure, where the dielectric waveguide supports the odd higher order mode and an even higher order mode.