Feedback Sensitivity of DBR-Type Laser Diodes

It is shown theoretically that the feedback sensitivity of Distributed Bragg Reflector laser diodes with low-loss Bragg section decreases with the length of the Bragg section and also can be decreased by detuning from the Bragg peak. The effect of detuning is not only due to a change in effective linewidth enhancement factor, but also due to a change of the effective cavity length. The results can be applied also to laser diodes coupled on one side to one or more ring resonators Such lasers can have very weak feedback sensitivity.