Design of optical pumping scheme for quantum-dot semiconductor optical amplifiers

In this study, design of optical pumping (OP) scheme for quantum-dot semiconductor optical amplifiers (QD-SOAs) is investigated. To evaluate the static and dynamic responses of the QD-SOA under OP, a non-linear state-space model is derived in which the effects of the homogeneous and inhomogeneous broadening of the gain medium and the spectral dependence of the input signals are taken into account. Using this model, the effects of the wavelength and power of the pump signal and the homogeneous and inhomogeneous linewidths are studied in detail. Simulation results demonstrate that optimal operation of the QD-SOA under the OP scheme is realised if the detuning between the pump wavelength and the input signal wavelength is constant (around 100 nm for our investigated device). The authors found that OP scheme can be employed for non-linear signal processing applications, where the superiorities of the OP against the electrical pumping appear for small values of the homogeneous and inhomogeneous linewidths.