DIELECTRIC-LOADED PLASMONIC WAVEGUIDE COMPONENTS

Abstract

This chapter concerns modeling, design, and characterization of dielectric-loaded plasmonic waveguide components at telecommunication wavelengths, aimed at establishing a new technology platform for integratable nanophotonic components by combining photonics and electronics on the same chip. The dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) consist of dielectric ridges with rectangular nano-meter-sized cross-sections, deposited on smooth metal films. The SPPs are strongly confined to the ridges due to the large index contrast between the dielectric ridge region and the surrounding air. Theoretical studies of the DLSPPW structure show that single mode propagation with sub-wavelength confinement and low propagation loss can be achieved by proper design of the waveguide dimensions, which is confirmed by near-field optical imaging of fabricated DLSPPWs, performed with a scanning near-field optical microscope. The performance basic waveguide components along with several different passive wavelength selective components is demonstrated. The coupling between two parallel DLSPPWs is investigated by characterizing directional couplers, where the two waveguides are brought into close proximity of one another by means of S-bends. Periodic modulation of the transmission is achieved by realizing waveguide-ring resonators and wavelength filtering is obtained by realizing Bragg gratings. In addition an approach for designing components capable of physically separating two signals of different wavelengths is introduced.