  We design sub-wavelength high-performing non-reciprocal optical devices using
recently discovered magnetic Weyl semimetals. These passive bulk topological
materials exhibit anomalous Hall effect which results in magnetooptical effects
that are orders of magnitude higher than those in conventional materials,
without the need of any external magnetic bias. We design two optical isolators
of both Faraday and Voigt geometries. These isolators have dimensions that are
reduced by three orders of magnitude compared to conventional magneto-optical
configurations. Our results indicate that the magnetic Weyl semimetals may open
up new avenues in photonics for the design of various nonreciprocal components.
