A self-consistent eight band k.p calculation, which takes into account strain and includes Hartree, exchange, and correlation terms (determined from a local density approximation) is incorporated into a QW laser simulator (MINILASE-II). The computation is performed within the envelope function approximation for a superlattice, in which all spatially varying terms of the k.p Hamiltonian, including the exchange and correlation energies are expanded in plane waves. The k.p eigenvalue equation, and Poisson's equation are solved iteratively until self-consistency is attained. Results from the k.p calculation are exported to MINILASE-II via a density of states and an energy dependent optical matrix element factor, renormalized by a Coulomb enhancement factor to account for electron-hole attraction. Results are presented for the gain spectrum and modulation response for a Ga0.8 In0.2 As/Al0.1 Ga0.9 As quantum well laser with and without the inclusion of the Coulomb enhancement factor.