Numerical analysis of an optoelectronic integrated device composed of coupled periodic MQW phototransistor and strained-QW laser diode

A rigorous numerical analysis for dynamic response of a voltage-tunable optoelectronic integrated device is presented. The device is composed of a coupled periodic multi quantum wells heterojunction phototransistor (CP-MQW HPT) integrated over a strained quantum well laser diode. The model is based on small signal analysis of device rate equations, for which we require to calculate laser diode gain and HPT electro-absorption coefficient. The Hamiltonian of quantum well laser diode structure is numerically solved by transfer matrix method taking in to account the strain effect and band mixing between heavy hole and light hole. The results are used to obtain laser diode gain. In order to calculate the electroabsorption coefficient, the exciton equation is solved numerically in momentum space using combination of the Transfer matrix method and Gaussian quadrature method. The valence band mixing is also considered here. The quantum confined Stark effect in the absorption spectra results in changes in the optical gain of the device which provides voltage tunability for the device. Based on the model, we show that the device has two operation modes: amplification for small optical feedback coefficient and switching for higher values.