Abstract
One-way edge states realized in magneto-optical photonic crystals (MOPCs) is generally believed to be robust to scattering from disorders and even strong perturbations. In this work, we experimentally and theoretically study the influence of obstacles on the transport of forward and backward edge states in two-dimensional MOPCs under a dc magnetic field. We find that the passage of electromagnetic wave around the obstacles mainly takes advantage of the formation of new edge states at the new interfaces formed between the obstacle and bulk MOPC. The forward edge states can be blocked when the new edge state channel is cut off or the coupling with the original edge states to the new edge states is strongly reduced.