Modeling of CMOS compatible ring resonator switch with intermediate vanadium oxide as the switching element

In this paper, silicon based dual ring resonator with hybrid plasmonic bus waveguides (Cu-SiO₂-Si-SiO₂-Cu) is investigated for achieving switching in the telecommunication C-band (λ = 1.54-1.553μm). The switch element uses vanadium oxide (VO₂) as the switching medium when inserted between the rings in order to tailor transmission from one ring to the other through heating induced phase transition. In this manner, the proposed switch element uses one vanadium oxide medium instead of refractive index tailoring of the whole ring as in the prior reported works and achieves switching response. From two-dimensional finite element analysis we have found that, the proposed switch can achieve maximum extinction ratio of 2.72 dB at λ = 1.5434μm, exclusively by tailoring VO₂ phase. Furthermore, impact of aperture width, and gap (separation between the bus waveguide and rings) are investigated to gain insight on the improvement of extinction ratio. From our numerical simulations, we find that free spectral range (FSR) and figure of merit (Q) for OFF and ON states are (173.36 nm, 92.63), and (173.58 nm, 65.39), respectively.