Frequency dynamics of semiconductor lasers with atomic absorbers: theory and experiments

In this paper we discuss the spectral behavior of monomode semiconductor laser systems whose output amplitude is constant, but whose frequency may be bistable, multistable, locked or present instabilities. The explored configurations are: (i) a laser diode (Fabry-Pérot) under orthogonal filtered optical feedback; and (ii) an extended-cavity diode laser with an intracavity strongly-saturated resonant vapor. Starting from rate equations for the carrier density and for the radiation field oscillating in the cavity of these systems we describe spectral features which are in very good quantitative agreement with experimental observations.