TDS evolution of chaos generated in dual channel mutual-injection semiconductor lasers

In this paper, we propose a dual-channel mutual-injection (DCMI) distributed feedback semiconductor lasers (DFB) structure to generate chaos, and investigate the evolution of the time delay signature (TDS) of the generated chaos through both theoretical and experimental studies. The theoretical results show that as the injection ratio increases, the output of the DFBs transitions from a non-chaotic to a chaotic state, and TDS distributions are symmetrical with respect to frequency detuning. The experimental results show that for a small injection ratio, the output of DFBs is in a non-chaotic state, but carrier perturbations lead to chaos as the injection ratio increases. When the injection ratio is fixed, varying frequency detuning from negative to positive detuning causes TDS of the DFBs to first increase and then decrease, and the TDS distribution exhibit symmetry with respect to frequency detuning. A mapping of the TDS evolution reveals the optimal range for low-TDS in the injection ratio and frequency detuning parameter space. The theoretical and experimental results prove that this method can generate chaos with low-TDS, and it has significant potential applications in fields such as chaotic secure communication and random number generation.