Efficient, narrow profile waveguide crossings based on rapid adiabatic coupling

We demonstrate an efficient s ilicon w aveguide c rossing b ased o n t he rapid adiabatic coupling (RAC) concept. Insertion loss and crosstalk are under 0.05 dB and −50 dB in simulation and under 0.3 dB and −17 dB in experiment across a 100 nm bandwidth.