Mode switching in a thin-film waveguide with boundary modulation of the refractive index

A demonstration is given of the feasibility of the amplitude modulation of light traveling along a passive waveguide which adjoins a liquid crystal. Light modulation appears because of phase mismatch of the waveguide modes. Deflection of light by transfer of energy from one mode to another occurs because of the dependence of the refractive index of the bounding medium (liquid crystal) on the voltage applied to it.