Photonic crystal magneto-optical switch

We suggest and analyse theoretically a wideband switch with a very simple and compact structure. It consists of a 90° waveguide bending in a PhC with square unit cell and a circular ferrite cylinder placed in the bending. The state OFF of the switch corresponds to the nonmagnetized ferrite. The structure of the standing wave in the input waveguide with a node oriented along the output waveguide prevents excitation of the output waveguide. In the state ON, different resonant modes of the magnetized ferrite resonator provide high transmission from input port to output one, namely, both clockwise and anticlockwise dipole rotating modes, the standing dipole mode which is the sum of these two rotating modes and also travelling wave. Our numerical simulations show that in the sub-terahertz region, the switch possesses the frequency band of 8% at the levels of insertion losses lower than -2 dB and isolation better than -22 dB. This bandwidth is one order higher than that reported in the literature for switches of this type.