Adiabatic evolution of light in parallel curved optical waveguide array is investigated theoretically. This problem is shown to bear a close connection with the process of coherent population transfer in a “bow-tie” model in quantum physics. Under certain conditions on the geometry of the waveguides and the optical properties of the system complete light transfer between the outer waveguides is achieved. Special attention is paid to the case of three waveguides, which is analyzed using the solutions of the well-known bow-tie model. The analytic solution is used to design recipes for creating arbitrary superpositions of light intensity between the waveguides, with possible applications in achromatic optical multiple-beam splitters. For more than three waveguides complete light transfer between the outer waveguides and beam splitting is demonstrated numerically.

• Received 21 February 2013

DOI:https://doi.org/10.1103/PhysRevA.88.013808