ABSTRACT
We introduce compact tunable spatial mode converters between the even and odd modes of graphene parallel plate (GPP) waveguides. The converters are reciprocal and are based on spatial modulation of graphene's conductivity. We show that the wavelength of operation of the mode converters can be tuned in the mid-infrared wavelength range by adjusting the chemical potential of a strip on one of the graphene layers of the GPP waveguides. We also introduce optical diodes for GPP waveguides based on a spatial mode converter and a coupler, which consists of a single layer of graphene placed in the middle between the two plates of two GPP waveguides. We find that for both the spatial mode converter and the optical diode the device functionality is preserved in the presence of loss.
ABSTRACT
We introduce highly compact resonant-cavity-enhanced magneto-optical switches for metal-dielectric-metal (MDM) plasmonic waveguides. The field profile of the fundamental mode of a MDM waveguide in which the metal is subject to an externally applied static magnetic field is asymmetric. The static magnetic field induced asymmetry, which enhances or reduces the coupling between the waveguide and a side-coupled resonator, and the relatively large induced wave vector modulation are used to design a Fabry-Perot cavity magneto-optical switch, consisting of a MDM waveguide side-coupled to two MDM stub resonators. The on and off states correspond to either the presence or the absence of the externally applied static magnetic field.