A wavelength demultiplexing structure based on graphene nanoribbon resonators

• A wavelength demultiplexing (WDM) structure is proposed and numerically investigated by finite-difference time-domain (FDTD) method.
• It is the first time to analyze a graphene nanoribbon bus waveguide side-coupled to several arrayed nanoribbon resonators with the function of wavelength selecting and demultiplexing.
• The transmission characteristics are influenced by the coupling distance between the resonator and drop/bus waveguides.
• Additionally, a reflection structure is introduced to improve the transmission efficiency of each channel.
• The proposed structure will have potential applications in the field of graphene-based plasmonic integrated optical devices.

A wavelength demultiplexing (WDM) structure based on graphene nanoribbon resonators is proposed and numerically investigated by the finite-difference time-domain (FDTD) method. The demultiplexing wavelength can be easily derived by adjusting the length of the resonator, which is accurately explained by the Fabry–Perot (F–P) resonant theory. Meanwhile, the transmission characteristics of the WDM structure are influenced by the coupling distance between the resonator and drop/bus waveguides, and the performance of the WDM device is analyzed at different nanoribbon width and chemical potential. In addition, in order to improve the transmission efficiency from the drop waveguide, a reflection structure is introduced at the end of the bus waveguide. The exact mechanism for the WDM structure is analyzed in detail using the temporal coupled-mode theory. The proposed structure will have potential applications in the field of ultra-compact WDM systems in highly integrated optical circuits.