Theoretical study of dilute nitride 1.3 µm quantum well semiconductor lasers for short pulse generation: Effect of incorporation of N compositional fluctuations

The influence of compositional fluctuations of N in GaInNAs Quantum Well (QW) lasers has been studied using a rate equation model. These fluctuations can be treated as Quantum-Dot (QD)-like fluctuations at the Conduction Band Edge (CBE). The gain model includes the QW material gain derived using a Band Anti-Crossing (BAC) model and includes QD fluctuations in the conduction band. For low N, (N ~ 1%), the QD-like fluctuations act as defect-related non-radiative centres. However as N is increased (N > 2%), the density of QD-like fluctuations increase and can support lasing. The dynamics of the electrons and photons in both the QW and the QD-like fluctuations is explored. Lasing can occur at either or both of the QW and QD states with the carrier densities being strongly coupled. In addition, short pulse generation from the QW is observed due to interaction with the carriers within the QDs demonstrating the potential of dilute nitride QW for short pulse generation at optical communications wavelengths.