A novel analytical model for spin-polarization in quantum dot VCSEL has been derived. The derived
model includes the effect of spin relaxation of electron and hole in all discret energy states. The model
also takes into account the gain dispersion of the quantum dots,the birefringence,the linewidth enhancement factor and the doping concentration in the active layer. We find that spinrelaxation of
electrons has stronge reffecton the polarization characteristics of quantum dot VCSEL than spin relaxation of holes(especially in p-type doped spin injected quantum dot VCSEL).The derived model is
accurate and exhibits negligible computational time compared with numerical models. In addition,the
derived model is suitable for device design and optimization.