Time delay signature concealment of chaotic semiconductor laser subject to nonlinear feedback

Abstract

An external-cavity semiconductor laser with nonlinear optical feedback to generate broadband chaos with time delay signature (TDS) suppression is investigated. The system is composed of three semiconductor lasers, one of which is regarded as the chaos generator, while the other two play a role of a built-in nonlinear modulator in the external cavity of the generator. The results show that by properly setting the feedback strength and time delay of the first semiconductor laser in the nonlinear modulator, the TDS embedded in the intensity and phase time-series of the chaos can be effectively concealed in a wide range of frequency detuning.