The Basic Building Block of ${\lambda }$ -Router With Multimode-Interference Waveguide Crossings on Silicon-on-Insulator Technology

Optical properties of the λ-router basic building block are simulated using a matrix method. Experiments are performed for the -router basic building block with multimode-interference (MMI) crossings, which shows large free spectral range (~35 nm) and more than 24 dB on/off contrast of the drop resonance. Theoretical and experimental results reveal that the λ-router basic building block with MMI crossings can suppress the crosstalk (defined as the difference between the drop efficiency and the throughput attenuation at resonance), offer relatively symmetric resonance, and increase the on/off contrast of the drop resonance, compared with a λ-router building block using conventional crossings.