Coupled metallic ring gap waveguide

Ultra-compact metal-insulator-metal plasmonic power splitter at 1550nm wavelength

“…The coupling length, L c , is the distance over which the energy of SPP modes couples completely from one waveguide to the other one, which depends on the difference between symmetric, s E , and antisymmetric, a E , propagation constants of SPPs [2,23]:…”

Backside Nanoslot Excited Sub-Wavelength Grating-Coupled Cu-Strip Plasmonic Waveguides

“…26 Besides, plasmonic waveguides with gain-assisted propagation of SPPs resulting from the integrated gain media have been also proposed due to their enhanced propagation lengths by direct optical amplification at telecommunication and other wavelengths, 17 20 27 28 and the hybrid plasmonic waveguides (usually consisting of a high-index region, a metal region, and a low-index nanoslot between them) have been proposed for relatively long lightwave propagation distance and/or nanoscale light confinement, 29-32 which can be used for submicron bending to achieve ultra-dense photonic integration circuits. 31 33 So far, many plasmonic waveguides have been proposed and investigated for various applications, e.g., the metallic nanoparticle plasmonic waveguides, 12 the plasmonic gap waveguides, 34 the plasmonic slot waveguides, 35 the plasmonic nanowire waveguides, 13 the hybrid plasmonic waveguides, 30 the photonic crystal waveguides, 36 the fibercoupled dielectric-loaded plasmonic waveguides, 37 and the grating-based plasmonic waveguides, 38 etc. However, the illumination of these SPP waveguides was not designed from the side of the substrate, limiting the potential applications for the fiber-optic plasmonic devices or elements, which require the unidirectional guiding of the SPPs excited by the illumination of the incident light transmitted through the glass substrate despite the problem of large propagation loss of the plasmonic wave.…”