Digital Waveguide Adiabatic Passage Part 1: Theory
  Spatial adiabatic passage represents a new way to design integrated photonic devices. In conventional adiabatic passage designs require smoothly varying waveguide separations. Here we show modelling of adiabatic passage devices where the waveguide separation is varied digitally. Despite digitisation, our designs show robustness against variations in the input wavelength and refractive index contrast of the waveguides relative to the cladding. This approach to spatial adiabatic passage opens new design strategies and hence the potential for new photonics devices. 
Jesse A. Vaitkus, M. J. Steel, Andrew D. Greentree
physics.optics quant-ph