Bursting in an optically injected two-mode laser: The cusp-pitchfork bifurcation

Bursting is a striking feature found in a wide range of physical and biological systems. It is characterized by periods of quiescence that are interspersed with periods of activity. We present an experimental and theoretical study of an interesting bursting mechanism in a two-mode semiconductor laser with single-mode optical injection. By tuning the strength and frequency of the injected light we find a transition from purely single-mode intensity oscillations to bursting in the intensity of the uninjected mode. We show that this bursting is organized by an interaction between a cusp and a pitchfork bifurcation of limit cycles. The underlying bursting mechanism is not specific to laser systems and was recently predicted theoretically on the basis of a simple two-dimensional dynamical system [1]. Here we experimentally confirm this new bursting mechanism.