Demultiplexing characteristic of MIM waveguide based on multiple-ring shaped resonators

A multiple-ring shaped Metal-Insulator-Metal (MIM) plasmonic waveguide with multi-output ports was proposed. From visible lightto nearinfrared wavelengths, the transmission characteristics of the structure were investigated by finite-difference time-domain method. The structure exhibits typical wavelength demultiplexing function, which is due to that the electromagnetic wave energy of different wavelengths can be trapped in different insulator rings and coupled into the corresponding output ports. The resonance theory is employed to analyze the trapping phenomenon. The resonant wavelength of the ring has near linear relationship with the radius and has red shift with increase the value of the filled refractive index. The transmittance of resonant wavelength in the output ports are heavily influenced by the coupled thickness. The proposed multiple-ring shaped MIM waveguide may be useful for plasmonic designs. © 2016, Chinese Optical Society. All right reserved.