Ultra-Broadband Mode Converter and Multiplexer Using a Sub-Wavelength Metamaterial

Our mode-division multiplexer leverages the potential of sub-wavelength engineered metamaterial to achieve simulated insertion loss of 0.84 dB and −20 dB crosstalk within a 300-nm-bandwidth. First experimental validation distinctly shows multiplexed $TF_{0}$ and $TE_{1}$ modes in the output multimode waveguide.