Analog simulation of a periodically modulated laser model

We have designed an electronic circuit realization of a simple two-dimensional laser model with a periodically modulated cavity-loss parameter. The system displays a mode-locking sequence, period-doubling bifurcations, and modulation limit cycles followed by a transition to chaos. Oscillations in the unmodulated system, which exhibit only a nearly degenerate Hopf bifurcation, are weakly damped. In this paper we focus on the two principal locked modes and the bifurcation structure and make quantitative comparisons of our results with a recent theory that is due to Erneux et al. [ Phys. Rev. A35, 1165 ( 1987)]. Some dynamical behavior not considered by the theory is revealed.