Influence of external optical feedback on transient processes in semiconductor lasers

An analysis is made of the influence of an external delaying feedback on transient processes in injection lasers. It is shown that, depending on the feedback delay time, the relaxational oscillations of the intensity of the laser radiation can either be quenched or built up. The most effective quenching of these oscillations occurs when the delay is equal to half the period of relaxational oscillations and the most effective buildup corresponds to a feedback delay time equal to the oscillation period. A numerical solution of the rate equations describing processes in lasers allowing for the delay are in good agreement with the experimental results.