Optically injected lasers: The transition from class B to class A lasers

We investigate changes in several features of the stability diagram of an optically injected single mode laser as the ratio of the photon lifetime to the carrier lifetime is progressively increased from very low values to very high values. In particular we consider the creation of a region of phase-locked bistability, changes in the nature of codimension-2 bifurcation points, and the presence or otherwise of chaos in the system. We show that many of the features associated with high values of the aforementioned ratio also emerge for very low pump currents regardless of the ratio of the lifetimes.