title: Wavelength-selective directional coupling with dielectric-loaded plasmonic waveguides.
abstract: We consider wavelength-selective splitting of radiation using directional couplers (DCs) formed by dielectric-loaded surface-plasmon-polariton waveguides (DLSPPWs). The DCs were fabricated by depositing sub-wavelength-sized polymer ridges on a gold film using large-scale UV photolithography and characterized at telecommunications wavelengths with near-field microscopy. We demonstrate a DLSPPW-based 45-microm-long DC comprising 3 microm offset S bends and 25-microm-long parallel waveguides that changes from the "through" state at 1500 nm to 3 dB splitting at 1600 nm, and show that a 50.5-microm-long DC should enable complete separation of the radiation channels at 1400 and 1620 nm. The DC performance is found to be in good agreement with full vectorial three-dimensional finite-element simulations.
authors.affiliation: Department of Physics and Nanotechnology, Aalberg University, Aalborg Øst, Denmark.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Chen
authors.forename: Tobias
authors.initials: T
authors.lastname: Holmgaard
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Bozhevolnyi
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Krasavin
authors.forename: Anatoly V
authors.initials: AV
authors.lastname: Zayats
authors.forename: Laurent
authors.initials: L
authors.lastname: Markey
authors.forename: Alain
authors.initials: A
authors.lastname: Dereux