<p>The present invention provides a variabel optical modulator for optical communication systems using a tunable dynamic grating. The variable optical modulator comprises a gel or membrane layer attached adjacent to a prism communicating light to/from said optical communication system, a substrate having a plurality of indevidually adressable electrodes and drive means for providing regulated excitation voltage to each of said plurality of electrodes providing a wave pattern on a surface of said gel or membrane superimposed on an initial state of said gel or membrane layer.</p>
