Theoretical analysis of VO2 filled double rectangular cavity-based coupled resonators for plasmonic active switch/modulator and band pass filter applications

Abstract

In this paper, we have designed an electrically tunable nano-plasmonic waveguide-based band pass filter which works on the phenomena of phase transition of Vanadium dioxide. The device operates on telecommunication wavelength and can work as a modulator and a switch with a modulation depth of 26.40 dB. It has shown its promising applications in the area of filtering by providing a high-quality factor of 156. Whereas, the modulation depth and quality factor of the device can be increased and decreased by changing various device parameters. A large tunability of 280 nm in the resonant wavelength is achieved by changing the applied voltage on the device between 0 V and 2.7 V in switch-on and switch-off states. Figure of merit of 12 is also attained by the device. Our device consists of a main waveguide which is coupled to two uneven length rectangular cavities filled with Vanadium dioxide. Active material present as the dielectric of rectangular cavities transforms its state from insulator to metallic and vice versa according to the applied voltage. However, single band transmission is obtained for the device and this can be tuned by changing different geometrical parameters of the device. The device can find its applications in nano plasmonic on-chip applications due to its small size, good modulation depth, and large quality factor with moderate loss.