Optical waveguide switch based on a negative-index metamaterial load

An optical switch concept is presented which involves moving a negative-index metamaterial (NIM) load, possibly with loss, close to one waveguide in a two-waveguide directional coupler. The NIM load limits the number of optical modes in the switch, creating a system where the single waveguide mode propagation constant is far from other mode propagation constants. The wide spacing in propagation constants, not possible with positive-index media (PIM) loads, permits a small switch size. Three-dimensional (3D) finite-difference time-domain (FDTD) simulations confirm results from a simple one-dimensional (1D) model. Importantly, realistic NIM losses do not impede switch operation.