A surface-plasmon-polariton wavelength splitter based on a metal–insulator–metal waveguide

• A SPPs wavelength splitter based on metal–insulator–metal waveguide is proposed.
• The band gap is identified in the waveguide by the transfer matrix method.
• The FDTD method is employed to simulate the propagation in the wavelength splitter.

A surface-plasmon-polariton (SPP) wavelength splitter based on a metal–insulator–metal waveguide with multiple teeth is proposed. Using the transfer-matrix method, a plasmonic band gap is identified in the multiple-toothed structure, and the splitting wavelength of the SPP splitter can be easily adapted by adjusting the widths of the teeth and the gaps. The proposed wavelength splitter is further verified through finite-difference time-domain (FDTD) simulations, in which SPPs with incident wavelengths of 756 nm and 892 nm are successfully split and guided in opposite directions in the waveguide, with extinction ratios of 30 dB and 29 dB, respectively.