Electro-optic modulators along fiber optic lines commonly use LiNbO3 or GaAs waveguides that are expensive and often limit bandwidth to 10 GHz. Using a hybrid covalent/ionic self-assembly process, researchers at Virginia Polytechnic Institute in Blacksburg have constructed organic thin-film structures that may offer a cheaper and higher-bandwidth alternative.Molecular monolayers composed of monomeric chromophores attach covalently to preceding films and ionically to the next. The alternating connections give stability to the polar order of the films, which has been problematic in previous electro-optic organic films. The researchers said their layering method provides electro-optic responses like those of currently used inorganic materials.