We discuss the impact of a passive dispersive reflector (PDR) on the dynamical behaviour of a single mode diode laser. It is shown that the PDR enters the single mode equations via two specific functions of the carrier density. Depending on the parameters of these functions, the resonance frequency of the laser as well as the damping of its relaxation oscillations become modified. A bifurcation analysis yields both subcritical and supercritical Hopf-bifurcations separating regions of stationary and self-pulsating operation. On this basis the conditions for achieving high self-pulsation frequencies with a large modulation depth are derived.