Enhanced Dual-Task Reservoir Computing in Semiconductor Ring Laser with FBG Feedback

A semiconductor ring laser (SRL) with optical feedback from fiber Bragg gratings (FBGs) is proposed and numerically investigated to enhance the performance of time-delay reservoir computing (TDRC) in dual-task simultaneous processing. Different from an SRL with conventional optical feedback (COF), the FBG optical feedback (FBGOF) has a new degree of freedom, i.e., FBG bandwidth, which can further optimize the effective parameter range for TDRC operations. A chaotic time series prediction task is adopted to verify the improvement of proposed scheme. In single-task processing, numerical results reveal that the effective range of feedback rate for TDRC operation can be expanded by reducing the FBG bandwidth to be smaller than twice of transient response frequency. Quantitatively, the effective range can be expanded by more than two times when the FBG bandwidth is about 1.64 GHz. Moreover, such improvement is successfully maintained even in dual-task simultaneous processing. Furthermore, converting from single-task processing to dual-task simultaneous processing, the narrowband FBGOF suppresses the accuracy degradation by about 50% in reference to the COF.