Neuronal oscillatory patterns in coupled lasers with optical feedback

We investigate the intensity time series in a pair of mutually coupled laser oscillators, which display some essential patterns observed in the neuronal oscillations in the brain of mammals. An asymmetry is implemented by a mismatch among the laser pump parameters, while the coupling scheme is induced by fast saturable absorbers, which interact with a beam that coherently combines the electric fields of both lasers. The laser oscillator with the smaller pump level exhibits mixed-mode oscillations (MMOs), a class of large amplitude oscillations (LAOs), while the other one displays small amplitude oscillations (SAOs). An additional relevant neuronal oscillatory pattern is the frequency of oscillations, which is higher for the SAOs compared to that of the MMOs. Depending on the coupling parameters, these two robust patterns can emerge as a result of a boundary crisis or an interior crisis. In both cases the dynamics display robust hyperchaotic behavior with two positive Lyapunov exponents of similar order of magnitude in the intensity time series. Nevertheless, in these time series the correlation dimension remains essentially unchanged. These two robust patterns, which are also found in many systems displaying chimera states, persist in the coupled lasers as the phase mismatch changes in the beam combining fields.