The effect of optical feedback on the relaxation oscillation in semiconductor lasers

The influence of weak optical feedback on the relaxation oscillation in semiconductor lasers is studied both theoretically and experimentally. In the approximation used the frequency branches of the relaxation oscillation are described by multiples of the fundamental frequency of the external cavity. However, especially for the low multiples, the deviation from this behavior is quite pronounced. The authors discuss the dependence of the frequency and the damping rate on the length of the external cavity in detail. Furthermore, they find that the damping rates that correspond to the various frequency branches are quite different. The accessibility of the various frequency branches is determined by the damping rates that belong to them