A novel 2-to-4 electro-optical decoder using graphene stacks in photonic crystal resonant cavities
摘要
In this study, a new 2-to-4 electro-optical decoder is introduced, featuring several waveguides alongside adjacent one-dimensional photonic crystals. Each photonic crystal structure, comprising 27 air holes in a silicon slab, functions as a resonant cavity. When incident light enters the cavity, resonance phenomena occur, corresponding to an interference pattern. To manipulate these interferences and achieve desired outcomes, a graphene-Al2O3 stack is positioned within the central hole. Altering the graphene chemical potential changes the stack’s effective parallel component and the effective refractive index. According to the Bragg principle, these changes impact the interference pattern within the resonant cavity. The cavities, located 50 nm from the waveguide, operate as an electro-optical switch, with their switching behavior controlled by the graphene chemical potential. Six pairs of cavities are used to guide two input lights toward four output ports via two Y-shaped splitters. The area of the designed decoder and the contrast ratio are 380 µm2 and 15.05 dB, respectively. The proposed decoder exhibits a high contrast ratio of 15.05 dB and enables electro-optical tunability via graphene chemical-potential control, demonstrating its potential for implementation in reconfigurable photonic integrated circuits. The strong optical confinement and distinct discrimination margins between logic states 0 and 1 validate the device’s potential for optical applications.