Cavity solitons in driven VCSELs above threshold

This paper studies cavity solitons (CSs) in semiconductor microresonators adopting a phenomenological model recently proposed by Agrawal. It describes a semiconductor laser with a macroscopic polarisation, similar to a simple two level model (5 variables), but containing all the information concerning the physics of semiconductors. By performing the linear stability analysis, the authors found some regimes where the Hopf instability, typical of lasers above threshold, affects only the lower intensity branch of the homogeneous steady state, while the higher intensity branch is affected by a Turing instability. Preliminary numerical results obtained by direct integration of the dynamical equations show that stable localised structures, such as CSs, are possible in this regime, sitting on an unstable background. Therefore CSs result to be robust structure and possible candidates for optical information treatment also in VCSELS somewhat above threshold.