Efficient standing-wave model for DFB lasers by nonlinear carrier approximation

A nonlinear approximation scheme is proposed to describe the time-dependent longitudinal carrier distribution with a view toward finding the efficient solution scheme of the previously proposed standing-wave model for simulation of DFB lasers. It shows its advantage over the existing linear scheme in terms of the modal accuracy in cases where the optical power is large enough to trigger the saturation effect. The validity of this improved scheme is demonstrated through comparisons made on the static and dynamic performances of $$\lambda /4$$-phase shifted DFB lasers.