Electro-optic variable phase diffraction grating and modulator

Claim 1

A variable electro-optic phase diffraction grating modulator comprising a thin-film optical waveguide sized to propagate an optical wave of predetermined width along a preselected direction; a layer of electro-optic material placed in proximity to the thin-film optical waveguide for interaction with the optical wave propagating therein; an array of generally parallel spaced longitudinal electrodes located to control the index of refraction of the electro-optic material which interacts with the optical wave upon the electrical excitement of the electrodes, each of said electrodes having a width dimension which is smaller than the width of the optical wave, with the spacings between electrodes being selected to control the index of refraction of individual segments of the electro-optic material in interaction with the optical wave, selected electrodes being electrically connected to each other to form sets with the electrodes in the sets being interleaved to form pairs of electrodes with adjacent electrodes of different sets; and means for electrically exciting pairs of electrodes with different electrical signals to induce correspondingly different indices of refraction in the electro-optic material segments and form a diffracted modulated optical output wave along a desired angle with a modulation component related to said electrical signals, said means further producing a plurality of phase related signals connected to respective sets of electrodes to form an apparently moving diffraction grating.