An optical switch, comprising an optical resonator, a first input optical waveguide optically coupled to the optical resonator for guiding a first optical signal to the optical resonator; a second input optical waveguide optically coupled to the optical resonator for guiding a second optical signal to the optical resonator; and an output optical waveguide optically coupled to the optical resonator for guiding a third optical signal from the optical resonator, wherein the optical resonator has a first region and at least one separate second region made of different materials, at least one of which is non-linear to cause different resonance frequencies of the optical resonator for different intensities of light.