Modelling and optimisation of the static saturation characteristics of quantum well semiconductor optical amplifiers

A method has been devised for optimising a multi-quantum well (MQW) semiconductor optical amplifier (SOA) operated at a constant high optical intensity. By adapting the relationship proposed by McIlroy et al. (1985) between gain and current density, the effect of gain saturation at high optical power can be calculated and minimised. Good agreement between theory and experiment has been obtained for InP-based SOA structures. For a fixed current, the optimum device length decreases as the optical input power increases.