title: Directional coupling in channel plasmon-polariton waveguides.
abstract: We investigate directional couplers (DCs) formed by channel plasmon-polariton (CPP) waveguides (CPPWs). DCs comprising 5-µm-offset S-bends and 40-µm-long parallel CPPWs with different separations (0.08, 0.25, 0.5 and 2 µm) between V-groove channels are fabricated by using a focused ion-beam (FIB) technique in a 2-μm-thick gold film and characterized at telecom wavelengths (1425-1630 nm) with near-field optical microscopy. Experimental results reveal strong coupling, resulting in approximately equal power splitting between DC-CPPWs, for small CPPW separations (0.08 and 0.25 µm). The coupling gradually deteriorates with the increase of separation between V-grooves and practically vanishes for the separation of 2 µm. The DC-CPPW characteristics observed are found in good agreement with finite-element method (implemented in COMSOL) simulations.
authors.affiliation: Institute of Technology and Innovation, University of Southern Denmark, Niels Bohrs Allé 1, DK-5230 Odense M, Denmark. zenin@iti.sdu.dk
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Zenin
authors.forename: Valentyn S
authors.initials: VS
authors.lastname: Volkov
authors.forename: Zhanghua
authors.initials: Z
authors.lastname: Han
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Bozhevolnyi
authors.forename: Eloïse
authors.initials: E
authors.lastname: Devaux
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Ebbesen
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*