Magnetoplasmonic Faraday Rotators: Enabling Gigahertz Active Polarization Control for Integrated Plasmonics

Abstract

We present the design and theoretical characterization of a magnetoplasmonic Faraday rotator for active polarization control in integrated plasmonics. By incorporating bismuth-substituted yttrium iron garnet (Bi:YIG) into a unique hybrid ridge–plasmonic waveguide structure, we effectively overcome the phase-matching limitations between photonic TE and plasmonic TM modes, and hence attain efficient Faraday rotation within a plasmonic device. The device provides 99.4% polarization conversion within a length of 830 μm, while the two modes exhibit propagation lengths in excess of 1 mm. This versatile optical building block can be operated with either a TE or TM input, making it ideal for polarization switching and polarization division multiplexing. Additionally, a buried Ag transmission line under the waveguide facilitates high-speed active polarization modulation by generating transient magnetic fields and modulating the Bi:YIG magnetization. We show that with these transient fields and an external static b...