Light-propagation management in coupled waveguide arrays: Quantitative experimental and theoretical assessment from band structures to functional patterns

Abstract

We assess the band structure of arrays of coupled optical waveguides both by ab initio calculations and by experiments, with an excellent quantitative agreement without any adjustable physical parameter. The band structures we obtain can deviate strongly from the expectations of the standard coupled mode theory approximation, but we describe them efficiently by a few parameters within an extended coupled mode theory. We also demonstrate that this description is in turn a firm and simple basis for accurate beam management in functional patterns of coupled waveguides, in full accordance with their design.