Applications of Tunable Nanoscale Midinfrared Graphene Based Slot Cavity in Nanophotonic Integrated Circuits

A graphene-based slot cavity is proposed and investigated numerically by using two-dimensional finite-difference time-domain method. The structure can be used as a tunable midinfrared multichannel bandpass filter, mode separator, multi/demultiplexer, and logic gates. Passbands of the designed filters can be tuned by varying the length and/or the chemical potential of the graphene slot cavity. The filter can be promoted to a mode separator by using another graphene output waveguide in the middle of the slot cavity filter. The even and odd order resonance modes can be separated and transmitted to the outputs. The proposed mode separator can also be used to design a wavelength multi/demultiplexer with minimum number of the slot cavities. We also proposed and simulated an ultracompact nanoscale logic gates of xor, or, and not with graphene slot cavity resonators, especially in the midinfrared wavelengths with an extinction ratio of 19.85 dB, which can be utilized for design of the nanoscale photonic integrated circuits (PICs). The gates behaviors are based on the suppression or enhancement of the resonance modes in the slot cavity due to the place of the input and output waveguide ports. These components are efficient and can be utilized in the design of midinfrared nanoscale devices and PICs.