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Asymmetric double quantum wells (ADQWs) are optimized to exhibit maximum optical modulation sensitivity by varying the barrier width, barrier position, and well width. Anticrossing of the two lowest excitons in ADQWs significantly enhances the modulation sensitivity. Consideration of exciton mixing is crucial to obtain accurate estimates of the effects. For a given linewidth of the excitonic peaks, we find optimum structural parameters that exhibit maximum modulation sensitivity. Values of dα/dE of ∼ 6.51 × 104 kV-1 at 4.2 K and of ∼ 1.25 × 10³ kV-1 at 298 K are predicted in GaAs-based ADQWs. The result provides new design guidelines in fabricating high-sensitivity QW electroabsorption modulators. [ABSTRACT FROM AUTHOR]