Silicon wire waveguide crossing with negligible loss and crosstalk

Current paper introduces efficient silicon wire waveguide crossing by means of vertical coupling of tapered Si wire with upper SU-8 polymer wide strip waveguide through a silica buffer. Numerical 3D simulations by FDTD proves that optimal structure of 70 μm length provided 98% efficiency for through pass and 99.9% efficiency for cross pass as well as negligible back reflection (−50 dB) and cross talk (−70 dB). Proposed waveguide crossing on thin silicon-on-insulator CMOS compatible structures could find multiple applications in photonics.