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Micropillar lasers with integrated saturable absorber (LSA) have been demonstrated to show important neuromimetic properties such as ultrafast excitable behavior, temporal summation, relative & absolute refractory periods and spike latency. In this work we study a LSA with self delayed connection which can show regenerative spiking. Such delayed self connections called as autpases are found in living nervous systems in regions essential for memory. The characteristic response of a single LSA is a 200 ps wide pulse emitted in response to an optical perturbation above the excitable threshold. In the presence of an external feedback, a single above threshold perturbation will trigger a train of pulses. Additional perturbations are capable of retiming an existing pulse train and adding or removing a pulse train, thus enabling all optical control of spikes.
If the system is perturbed under correct conditions several times during the external cavity roundtrip time τ, we can create several coexisting pulse trains in the cavity which are essentially the input perturbation repeating with the time period τ. This can be seen as an optical buffer for spikes. However, in the long term these seemingly independent pulses interact and converge towards a stable solution. This final stable solution is based on the input sequence, thus this long term behavior can be seem as an associative memory. Numerical simulations of the Yamada model with delayed feedback and noise are presented and found to be in good agreement with the experimental observations. All the observed dynamics of spike interaction and convergence can be explained solely based with the internal dynamics of carriers.
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