Electro-optic modulator based on Vanadium dioxide epsilon-near-zero vertical nanowire triple-cavity in Silicon Waveguide

Abstract

We present an electro-optic modulator exploiting an array of Vanadium dioxide nanorods operating in the epsilon near regime as the active switching material integrated in a silicon waveguide. The modulator takes advantage of the insulator-to-metal transition of Vanadium dioxide to achieve a robust modulation depth of 19.7 dB/micron with a broad wavelength of operation. Using simulations, we demonstrate how the effective permittivity of the metamaterial can be tuned to a near-zero value by varying the nanorod geometry. The paper also proposes a novel hexagonal array design which achieves low insertion losses while retaining a strong modulation depth. The results provide insight into the design of ultra-compact modulators with high operation frequencies and low insertion losses.