Figure 2
Michal Lipson, Cornell University

Figure 2: The experimental nonreciprocal waveguide consists of two parallel ribs, and the modes I and II are even and odd combinations of light in the two ribs, respectively. Phase-shifted microwave signals applied to a string of diodes along the waveguide create a traveling wave of modified refractive index, whose velocity is selected to match the difference in angular frequency ω and propagation constant k between the two modes.