Optimization algorithm and fabrication technique of a monolithic image plane modulator

The Piezo-Electric Elasto-Optic (PEEO) effect was studied previously by G.Sirat, N.Ben-Yosef and Y.Fisher. The main problem is the technological one i e. the manufacture of the modulation array. The requirements of the array are a large number of piezoelectric elastooptic crystals vibrating at different resonant frequencies. The monolithic approach was introduced previously by using a configuration of three well separated electrodes. The present work will describe a fabrication technique of a Monolithic Image Plane modulator. Crystal thickness and pixel definition were optimized for maximum pixel density and minimum crosstalk. The optimization algorithm solves the acoustical wave equation with the boundary conditions for a three electrode configuration. Iterating with the length, thickness and density of the electrodes, a well defined standing wave beneath the central electrode is achieved.In order to assess the appropriate density and conversion values, the wave envelope may be graphically displayed.The common electrode deposition technique is replaced by a structural etching method. Previously a metalized electrode was used as the mass load. It is replaced by etching a quasi electrode on the crystal substrate, thus obtaining a modulated surface. The uni-dimensional monolithic frequency multiplexer is defined on a single intrinsic GaAs crystal. The experimental results agree with the numerical predictions.A maximum signal to noise ratio of 2.6 and a minimum band width of 49 Hz has been achieved.