Abstract: A switching element formed with at least a pair of intersecting channel optical waveguide paths. A polymer switching element is formed across the waveguide paths at the point of intersection. The offstate refractive index of the polymer switching element substantially matches the refractive index of the waveguide paths. Optical switching between the waveguides is achieved by changing the refractive index of the polymer switching element by applying heat to the polymer switching element. The heat can be applied by a thin-film heater formed on top of the polymer switching element at the switch intersection. The application of heat causes total internal reflection in the polymer switching element to divert light from the first or input waveguide path to the second or cross-state output waveguide path.