Chaotic characteristics enhancement by introducing optical feedback into a sole intensity modulation optical injection system

Abstract

Wideband chaotic signals generated in an intensity modulation (IM) optical injection system were successfully implemented and provided new insight into overcoming the implementation bottleneck that semiconductor lasers under continuous-wave (CW) optical injection can generate chaos only in very narrow regions above the Hopf bifurcation. Despite its success, the dimensionality of chaos is relatively low due to the absence of delay loops in an optical injection system, which may only support low-dimensional optical chaos-based applications. Therefore, we introduce optical feedback into the sole IM optical injection system to enhance the chaotic dimension and demonstrate chaotic characteristics enhancement both experimentally and numerically. In detail, the influences of some key parameters, such as injection parameters, modulation parameters, and the feedback parameter, on the chaotic performance are systematically researched. The results show that the chaotic regions, bandwidth, and correlation dimension (CD) can be augmented through introducing optical feedback. Additionally, when the weak optical feedback is introduced, better chaotic quality with the time delay signature (TDS) value at a low level can be expected in an extensive range of the injection ratio and modulation depth.

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

“…Currently, time series with specific time-delay can be extracted using standard statistical measurement analysis techniques, which mainly include autocorrelation function (ACF) [14], permutation entropy (PE) [15], and delay mutual information (DMI) [16]. In recent years, how to suppress TDS has become a popular topic of research, for which many published papers have proposed various schemes [17][18][19][20][21][22][23][24][25][26][27]. For example, introducing multiple feedback loops into the system, exploring complex feedback schemes, and adding multiple injection paths have all been considered.…”