Four-wave mixing in quantum dot SOAs: Theory of carrier heating

Abstract

Carrier heating (CH) theory in a four-wave mixing quantum dot structure has been investigated. The impact of wetting layer (WL) carrier density, CH time constant, effective intraband relaxation time have been examined. The derived heat capacity for QD structure have (T-1) dependence. It is shown here that both WL carrier density and QD excited state (ES) occupation controls the overall nonlinear contributions. Then inclusion of WL and ES in the CH induces a new equilibrium reached at a faster recovery time. The proposed model yields results in a line with experiments at high carrier density reflecting the efficiency of our model. Keywords: Quantum dot, Carrier heating, Four-wave mixing, Excited state