The Lang–Kobayashi system of delay differential equations describes the behavior of the complex
electric field
and inversion
inside an external cavity semiconductor laser. This system has a family of special
periodic solutions known as external cavity modes (ECMs). It is well known that
these ECM solutions appear through saddle-node bifurcations, then lose stability
through a Hopf bifurcation before new ECM solutions are born through a secondary
saddle-node bifurcation. Employing analytical and numerical techniques, we show
that for certain short external cavity lasers the loss of stability happens only after the
secondary saddle-node bifurcations, which means that stable ECM solutions
can coexist in these systems. We also investigate the basins of these ECM
attractors.