Modified relaxation oscillation parameters in optically injected semiconductor lasers

One of the most significant features in the optically injected laser system is the modification of the damping of the relaxation oscillations. We derive an analytic expression for the nonlinear modification to this important laser parameter and calculate various quantities of interest using the result. In particular, this leads to a novel method to experimentally determine the free-running damping. The variation of the effective damping with detuning also explains the marked detuning dependence of the form of excitable pulsations in optically injected semiconductor lasers.