| CPC G02F 1/113 (2013.01) [H03H 9/02881 (2013.01); H03H 9/14541 (2013.01); H03H 9/25 (2013.01); G02F 2201/124 (2013.01); H03H 9/02559 (2013.01); H03H 9/14502 (2013.01)] | 23 Claims | 

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               1. A tunable diffraction grating comprising: 
            a piezoelectric substrate comprising an interdigital transducer (IDT) region and a delay line region; and 
                a plurality of IDT electrodes positioned in the IDT region, 
                wherein the plurality of IDT electrodes are each individually addressable such that the signal applied to each of the plurality of IDT electrodes is phase shifted, and 
                wherein the plurality of IDT electrodes provide the phase shifted signal to induce surface acoustic waves in the piezoelectric substrate in a pattern which produces a grating in the delay line region. 
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