Time-delay signature elimination of chaotic laser via a self-feedback antisymmetric resonator.

A scheme for generating a chaotic output from a semiconductor laser while eliminating the time-delay signature (TDS) is proposed, leveraging the multi-path feedback provided by a self-feedback antisymmetric coupling fiber ring resonator (SACFRR). A theoretical model is developed to elucidate the feedback perturbation process in the proposed structure. The multi-path feedback can be modeled by incorporating the unit impulse response of the SACFRR into the modified Lang-Kobayashi-based model. We successfully eliminated the TDS using the SACFRR structure in our experimental demonstration. Further investigation into the impact of the coupling coefficient on the TDS revealed that the optimal value is 0.3, which results in the largest mapping area with the TDS below 0.03. The proposed structure is highly effective and simple to implement and integrate. As a result, the chaotic laser generated by this structure can serve as an efficient optical source for encrypted communications, chaotic Lidar, and random bit generation.