A low-voltage, high-reflectance-change normally off refractive GaAs/Al/sub 0.2/Ga/sub 0.8/As MQW reflection modulator

We present our optimization of a normally off refractive GaAs/Al/sub x/Ga/sub 1-x/As multiple-quantum-well (MQW) reflection modulator with respect to the on/off reflectance change, on/off contrast ratio, and operating voltage. We use optical transfer matrices, theoretically calculated refractive indices, and absorption coefficients to simulate the operation of a normal-incident Fabry-Perot MQW modulator. Our calculations suggest that a normally off refractive GaAs/Al/sub 0.2/Ga/sub 0.8/As MQW reflection modulator with a reflectance change of 42.9% and an on/off contrast ratio of 1539 for an operating voltage of only 2.44 V can be fabricated by molecular-beam epitaxy (MBE).<
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