| We propose and numerically investigate a multiplexing metal grating coupler based on metal/insulator/metal (MIM) structure. The coupler consists of gold grating/silicon/gold layers, which combines with MIM waveguide, concurrently achieving path multiplexing and wavelength multiplexing through TMn modes coupling. In visible light band, TM waves are coupled to the upper surface of gold plate, and the coupling efficiency reaches maximum of 31.67% at wavelength of 736 nm. In near infrared and mid infrared bands, TM waves are coupled into MIM waveguide, and the coupling effi-ciency reaches maximum of 53.57% at wavelength of 2550 nm. There can be four modes of TM0, TM1, TM2 and TM3 simultaneously in MIM waveguide, which are excited at different wavelengths. The preparation process of the structure designed in this article is simple, with dimensions at the micrometer level, easy to be integrated, and can be applied to be integrated optical circuits. |
