Three-port circulators with low symmetry based on photonic crystals and magneto-optical resonators

Abstract

Three-port circulators based on magneto-optical resonators in 2D photonic crystals with low symmetry are investigated. We consider different geometries of the circulators in photonic crystals with triangular and square unit cells. All of the three-ports possess only one specific element of symmetry named antiplane of symmetry. The theoretical part of our paper concerns scattering matrix analysis for different regimes of circulation. In particular, we define the scattering matrices of ideal circulator and a special type of conditions which allow one to transform the non-reciprocal three-port in ideal circulator. One case of non-ideal circulators is considered as well. We also discuss some peculiarities of a special regime of the circulators when they are used as isolators. Finally, one example of the circulator simulations with calculated frequency responses in photonic crystals based on triangular unit cells is presented.