A LOW-VOLTAGE, HIGH-REFLECTANCE-CHANGE NORMALLY OFF REFRACTIVE GAAS AL0.2GA0.8AS MQW REFLECTION MODULATOR/

We present our optimization of a normally off refractive GaAs/AlxGa1-x As multiple-quantum-well (MQW) reflection modulator with respect to th e ON/OFF reflectance change, ON/OFF contrast ratio, and operating volt age. We use optical transfer matrices, theoretically calculated refrac tive 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/Al0.2Ga0.8As MQW reflection modul ator with a reflectance change of 42.9% and an ON/OFF contrast ratio o f 1539 for an operating voltage of only 2.44 V can be fabricated by mo lecular-beam epitaxy (MBE).