Controlling quasiperiodicity in a CO2 laser with delayed feedback

In this paper we present an experimental scheme for controlling the chaotic regime, reached through quasiperiodicity, of a CO2 laser with delayed electro-optic feedback. This method, bused on a selective filter rejecting one of the two characteristic frequencies of the quasiperiodic motion, allows stabilization of the limit cycle present at the beginning of the bifurcation sequence. By coupling the CO2 laser model with the differential equations of the filter, we obtain numerical results in good agreement with the experimental observation.