Single photonic reservoir dual-task simultaneous computing based on a semiconductor ring laser with filtered optical...

A single photonic reservoir based on a semiconductor ring laser with filtered optical feedback (FOF) is proposed to achieve simultaneous reservoir computing (RC) through multiplexing of the two directional modes and enhance the robustness of RC operations by using a Fabry-Perot filter. Numerical investigations of laser dynamics reveal that the FOF successfully provides RC-preferred dynamically stable, steady state for both directional modes simultaneously. Moreover, the FOF can expand the parameter ranges of the RC-preferred state when the filter bandwidth is smaller than twice the transient response frequency of the laser. Furthermore, such expansion can be enhanced by optimizing the detuning frequency between the filter and the free-running laser. In addition to the advantages in laser dynamics, the positive effects of FOF on RC operations are further verified by benchmark tasks of complex time series prediction and pattern classification. The results show that the robustness of RC operations against parameter fluctuations is significantly enhanced not only in single-task computing independent of task types but also in dual-task simultaneous computing without significant degradation of performances independent of task combinations.