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

• Published in: Nano select 2023-05, Vol.4 (5), p.346-352
• Main Authors: Tanyi, Gregory, Lim, Christina, Unnithan, Ranjith R.
• Format: Article
• Language: English
• Subjects: electro‐optics; epsilon‐near‐zero; modulators; phase change materials; plasmonics; silicon photonics
• ISSN: 2688-4011; 2688-4011
• DOI: 10.1002/nano.202200258

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. A metamaterial modulator consisting of vanadium dioxide nanorods operating in the epsilon‐near‐zero regime has been demonstrated and studied with a high modulation depth and broad wavelength of operation. The modulator achieves a modulation depth of 19.7 dB µm–1 and a hexagonal array design is investigated for low insertion loss applications. The results provide insights into the design of compact epsilon‐near‐zero modulators with high operation frequencies.