Coherent tunneling by adiabatic process in a four-waveguide optical coupler

•We numerically simulate Schrödinger-like paraxial wave equation of a four-waveguide optical coupler.•The coherent tunneling passage in a four-waveguide optical coupler is analyzed by using the dressed state theory.•We discussed the adiabatic condition and the adiabatic conversion efficiency in this waveguides system.

We numerically simulate Schrödinger-like paraxial wave equation of a four-waveguide system. The coherent tunneling by adiabatic passage in a four-waveguide optical coupler is analyzed by borrowing the dressed state theory of coherent atom system. We discuss the optical coupling mechanism and coupling efficiency of light energy in both intuitive and counterintuitive tunneling schemes and analyze the threshold condition from adiabatic to non-adiabatic regimes in intuitive scheme. The results show that this coupler can be used as power splitter under certain conditions.