Wavelength-Polarization Multiplexer for Routing and Detection of Surface Plasmon Polaritons Based on Plasmonic Gratings

High-bandwidth and high-speed plasmonic interconnection is a long-term goal in constructing next-generation optoelectronic integrated circuits (OEICs). Here, we report a strategy to achieve plasmonic interconnection with higher bandwidth by simultaneously utilizing wavelength and polarization multiplexing technologies. The proposed multiplexer consists of four orthogonal detection channels operating under different wavelengths and polarization conditions. On the basis of plasmonic gratings, the excitation, propagation, and detection of surface plasmon polaritons are realized in each detection channel. A proof-of-concept multiplexing functionality is experimentally demonstrated through the measured wavelength- and polarization-dependent photocurrent of the four channels. Additionally, finite-difference time-domain calculations corroborate the experimental results. The proposed multiplexer is a promising building block for highly integrated OEICs and can guide the potential development direction of high-speed plasmonic interconnection with high bandwidth.