Self-pulsing in Fabry-Perot lasers: An analytic scenario

Abstract

We analyze multimode instabilities in the Fabry-Perot laser. It is well known that in the case of a ring cavity the multimode instability can arise only when the pump parameter is several times above threshold. We focus on the parametric conditions that allow for the adiabatic elimination of the atomic polarization only. Under such conditions no multimode instability is possible in the ring configuration. By investigating the stability of the stationary solutions in a fully analytical manner, we demonstrate that, on the contrary, in the Fabry-Perot case a multimode instability can arise very close to threshold and is governed by a remarkably simple formula. Numerical solutions of the dynamical equations confirm this scenario and describe the self-pulsations generated by this instability.