Compact and low crosstalk waveguide crossing using impedance matched metamaterial

A waveguide crossing mechanism based on metamaterial is proposed and numerically investigated using finite difference in time domain method. The waveguide cross is filled with impedance matched metamaterial, which has a large absolute value of refractive index, and effectively suppresses the diffraction of the guiding mode in the crossing region. The waveguide cross is ultra compact, and valid for a wide range of crossing angle with negligible crosstalk and insertion loss. The compactness and high efficiency make this crossing mechanism valuable in micro and nano photonics.