Effect of residual doping on optimum structure of multiquantum-well optical modulators

Using a variational method we have calculated the effect of residual doping on the optimum structure of multiquantum-well (MQW) optical modulators which utilise the quantum confined Stark effect. Residual doping gives a nonuniform electric field and a degraded modulation depth. For example, for a structure consisting of 100 Å GaAs wells and 100 Å Ga0.7A10.3As barriers, we calculate the optimum number of wells to be 20 for a doping of 5 × 1015 cm¿3.