Dynamics and Concealment of Time-Delay Signature in Mutually Coupled Nano-Laser Chaotic Systems

Abstract

It is well known that nano-lasers (NLs), as important optical components, have attracted widespread attention for their output characteristics. In this paper, the dynamic behavior and time-delay concealment properties of NLs mutually coupled in open-loop, semi-open-loop, and closed-loop structures have been numerically investigated. We employ bifurcation diagrams and 0–1 chaos tests in our simulations to quantitatively analyze the dynamic properties of the system and introduce the autocorrelation function to evaluate the ability of the system to conceal the time-delay signature (TDS). In the meantime, the effects of the NL parameters and the controllable variables of the system on the TDS are studied. The results indicate that, compared with an open-loop structure without feedback, the mutual coupling scheme with added feedback is beneficial for the system to output high-quality chaotic signals. Furthermore, selecting a moderate Purcell factor F and a smaller spontaneous emission coupling factor β can achieve TDS concealment over a wider parameter range of injection intensity and frequency detuning.

Time-Delay Signature Suppression and Communications of Nanolaser Based on Phase Conjugate Feedback

“…This indicates that the delay of the MNL can be well suppressed and is conducive to the subsequent study of the synchronous communication of the two SNLs. When F = 30 and β = 0.1, the ACF of MNL greatly increases with the increase in the feedback parameters because the larger the values of F and β, the greater the damping of the relaxation oscillation of NL [47]. Therefore, we can use medium F and small β to better hide the TDS of NLs in a wider parameter space.…”

Concealment of Chaos Time Delay Signature in a Ring Network With Heterogeneous Delays Based on Nano-Lasers

“…Moreover, for this RNI network, NLs cannot achieve TDS concealment at Δf12=0GHz regardless of the value of kr. It should be noted that this characteristic stands in stark contrast to the conventional system involving two mutually coupled NLs, where a "V"-like region indicating low TDS can be numerically discerned within the identical injection parameter plane[43]. Therefore, in comparison to mutually coupled NLs systems, the low TDS region of this RNI network is significantly expanded, allowing for wideranging tuning of frequency detuning.…”

“…In contrast, for the RNH network, the coupling delay is 𝜏12=𝜏, 𝜏13=p𝜏, 𝜏23=q𝜏. The theoretical model of the RNH network system is mathematically formulated using mathematical methods [41], [43], as follows.…”

Bidirectional Chaotic Synchronization Communication of Closed-Loop Mutually Coupled Nano-Lasers

“…Then, high-frequency components are eliminated through a Butterworth low-pass filter (LPF), and finally, the transmitted message can be accurately recovered. The rate equations for the proposed system are [44][45][46]: The rate equations for the proposed system are [44][45][46]:…”