A method for the stabilization of the emission frequency of a ring laser operating in the two- and three-mode regimes

A method was developed for stabilizing the emission frequency of a ring laser operating in the two- and three-mode emission regimes with frequency splitting between the opposite waves. In this method, the mode positions were symmetric relative to the center of the gain profile in the two- or three-mode-locked regimes and then the signal representing the interference between the opposite waves had its minimum value. The depth of the minimum was optimized by suitable selection of the difference between the lengths of the interferometer arms. An experimental check of this method was made in the two- and three-mode regimes. This check demonstrated the feasibility of the method and its considerable advantages compared with the stabilization based on the power maximum.