Processing of information with optical spikes could present an alternative path with a reduced energy consumption. It could also be well suited in the framework of novel brain-inspired computation paradigms. We investigate the spiking and pulse train dynamics in a micropillar laser with integrated saturable absorber. The optically-pumped microcavity laser is based on a specifically optimized design. The solitary laser can emit sub-nanosecond Q-switched pulses above laser threshold. Below threshold, the laser is in the so-called excitable regime, a generic all-or-none kind of response also found in biological neurons. We demonstrate several neuromimetic properties of the micropillar laser including the relative and absolute refractory periods and the temporal summation. The latter gives rise to sensitive and fast coincidence detectors of optical signals.
In the configuration with delayed optical feedback, the system is shown experimentally and theoretically to sustain controllable trains of dissipative temporal solitons controlled by adequate optical perturbations. We show that the pulse train can be started or resynchronized (retiming) with a single perturbation and that the system can store a large variety of temporal pulse patterns. We discuss the role of pump noise that may terminate a pulse train. We demonstrate a strong asymmetry in the effect of noise on the switch on and off processes, as well as a peculiar role played by noise timing. Besides its interest as a compact source of controllable pulses, this system can be arranged if needed in arrays leading to interesting prospects for artificial optical neural networks.
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