Multiple time scale analysis of lasers

In many areas of engineering and science the mathematical formulation leads to nonlinear problems that are difficult to solve even numerically. Many of the numerical difficulties come from the stiffness of the equations due to the presence of small or large parameters multiplying time derivatives. Very often, the solution exhibits different time scales because of these parameters. It is therefore important to identify them and possibly simplify our equations by applying asymptotic techniques appropriate for multiple scale problems. In this paper, we review a certain number of multiple time scale problems which have appeared for a variety of lasers.