Active compensators for ferroelectric-optical circuits

Abstract

Disturb pulse and fatigue effects have prevented or limited the use of ferroelectric materials as matrix addressed arrays of light valves suitable for optical memories, page composers, displays and printers. These problems can be optically balanced out by building an array of compensators out of a second piece of ferroelectric and applying to the compensator array the same disturb and polarization reversal history that the light valve array receives. Experimental data obtained on a lanthanum doped lead zirconate titanate ferroelectric ceramic shows the effectiveness of the active compensator technique in balancing out the disturb pulse effect. The optical balancing technique is not limited to ferroelectrics, but can also be applied to other optically active materials which do not have an absolute switching threshold and/or decay. The balancing technique can also be used to overcome the problems of elastic switching, which would normally cause light to escape momentarily from a half selected valve.