Electro‐optic modulator based on vanadium dioxide epsilon‐near‐zero nanorods embedded in silicon slot waveguide

Abstract

Abstract We present an electro‐optic modulator exploiting a metamaterial made of an array of vanadium dioxide nanorods operating in epsilon‐near‐zero regime as the active switching material in a silicon waveguide. The modulator takes advantage of the insulator‐to‐metal transition of vanadium dioxide along with near‐zero effective permittivity to achieve a modulation depth of 19.7 dB µm–1 in a footprint of 1.6 µm × 1 µm over a broad range of wavelengths. Using simulations, we demonstrate how the effective permittivity of the metamaterial can be tuned to a near‐zero value by varying the nanorod geometry to increase the modulation depth. The paper further investigates a novel hexagonal array design using the metamaterial nanorods to obtain a lower insertion loss and high modulation depth. The results provide insight into the design of ultra‐compact epsilon‐near‐zero modulators with high operation frequencies and low insertion losses.

Keywords

• electro‐optics
• epsilon‐near‐zero
• modulators
• phase change materials
• plasmonics
• silicon photonics