Mingfeng Xu

Chaotic optical cryptographic communication using a three-semiconductor-laser scheme

In this paper, a secure optical chaos-based communication scheme is proposed. A semiconductor laser (SL) subjected to polarization-rotated optical feedback serves as the drive laser (DL), and two identical or near-identical SLs act as the transmitter laser (TL) and receiver laser (RL). The TL and the RL receive identical polarization-rotated optical injection from the DL. Two channels are used, and the TM mode of the DL, after being rotated by 90°, serves as the perturbation quantity. The communication performance is numerically studied. More importantly, the high fidelity and high degree of privacy of the proposed scheme are verified in detail, and the failure of two potential attacker scenarios is demonstrated, even if the attacker can get access to both channels simultaneously.

Analysis of nonlinear dynamics and detecting messages embedded in chaotic carriers using sample entropy algorithm

Sample entropy is introduced as a versatile measure for analyzing chaos dynamics and chaos communications. This measure can be directly applied to distinguish different dynamic behaviors for their superior advantages, such as fast computation (available for short data), extreme simplicity, robustness, and even more efficiency in the presence of a certain amount of noise. For the unidirectional coupling master–slave configuration of semiconductor lasers, it is shown that sample entropy analysis can be an effective tool to reveal the chaos synchronization quality. More particularly, when employed to discriminate the encryption performance of a chaos modulation scheme, the sample entropy algorithm seems to be a powerful and complementary tool for detecting and quantifying the presence of a message within a chaotic carrier.

Experimental Evidence of Time-Delay Concealment in a DFB Laser With Dual-Chaotic Optical Injections

The experimental evidence and characterization of time-delay concealment in a semiconductor laser (SL) with dual-chaotic optical injections (DCOIs) are reported. Autocorrelation function and permutation entropy are employed to extract the time-delay signature (TDS). Our experimental results show that both TDSs associated with the dynamics of master lasers or only one of the two TDSs can be concealed in the SL with DCOI, depending on the choices of the injection ratio and frequency detuning of the two injection lights. The experiments are in good agreement with the simulations. Furthermore, the possibility to use the chaotic signal with no obvious TDS generated by the SL with DCOI for high-speed random number generation is experimentally demonstrated.