High-speed polarization modulation in a hybrid ridge-plasmonic waveguide

Abstract

We propose a novel hybrid ridge-plasmonic waveguide Faraday rotator for high-speed polarization manipulation in nanoplasmonic circuitry. Our design, based on bismuth-substituted yttrium iron garnet (Bi:YIG), provides a unique geometrical mechanism of phase matching both the plasmonic TM and photonic TE waveguide modes, and hence facilitates effective mode conversion via the Faraday effect. This structure yields 99.4% mode conversion within 830 μm, which is easily attainable within the long (>1mm) propagation lengths of the two supported modes. Furthermore, our simulations show that the application of magnetic field transients can alter the magnetization of the Bi:YIG to actively switch the polarization state, or produce a polarization oscillator at frequencies up to 10GHz. This structure is envisioned to play a fundamental role in future integrated nanoplasmonic networks.