Add to ORKGIn this paper results of measurements on monolithic extended cavity ring passively mode-locked semiconductor lasers (PMMLs) are presented. We have designed PMMLs in various geometries in order to use them for theoretical model verification and subsequent development of a library of short-pulsed lasers within an active-passive integration platform. The different dynamic regimes depending on the voltage applied to the saturable absorber and current injected into the amplifier are characterized in both time and frequency domains. At the mode-locking operational conditions the output signal features an optical comb centered at 1.55 um and a 3dB bandwidth of 8.5 nm