An ultra-low power 2×2 photonic switch based on VO2/Si technology is proposed. The switch structure consists of an add-drop ring resonator with a footprint below 50 µm2. The waveguide structure is based on a fully etched silicon waveguide with a VO2 film on top of it. Electro-optical switching is achieved by means of the metal-insulator-transition (MIT) that can be induced in VO2.
This MIT provides an ultra-large change of the refractive index at 1550 nm optical wavelengths that yields to ultra-low power operation. Waveguide structures have been fabricated by a combination of molecular beam epitaxy (MBE) growth, ex-situ annealing, e-beam lithography and lift-off. Experimental results have also been carried out to evaluate propagation losses as well as the electro-optical performance.