Efficient Simulation Method for DFB Lasers with Large Gain Saturation Effect

In this paper, we proposed a non-linear approximation scheme to 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 approximation scheme in cases where the optical power is large enough to trigger the saturation effect. The validity of this improved scheme is demonstrated by simulation example of $\lambda/4$-shifted DFB lasers.