Designing passive transmission asymmetry for active photonics

Transmission asymmetry is a characteristic manifestation of non-reciprocal systems incorporating an active bias mechanism e.g. via a non-linear material or an external magnetic field. However, certain design routes to non-reciprocal transmission asymmetry enhancement, such as self-biasing nonlinear routes, can further benefit from having the underlying passive linear reciprocal system exhibiting also an asymmetric transmission. Reciprocal systems can exhibit transmission asymmetry when more than one output channels for light are available. We discuss here an all-dielectric system where additional output channels are provided via higher-order Bragg diffracted beams. We analyze how the structural characteristics of the unit cell building blocks impact the strength of the transmission asymmetry achieved.