A signal transfer link includes a first plasmonic coupler, and a second plasmonic coupler spaced apart from the first plasmonic coupler to form a gap. An insulator layer is formed over end portions of the first and second plasmonic couplers and in and over the gap. A plasmonic conductive layer is formed over the gap on the insulator layer to excite plasmons to provide signal transmission between the first and second plasmonic couplers.