Abstract

A method for generating wideband chaos with time-delay signature suppression in semiconductor lasers by asymmetrical mutual injection is proposed and demonstrated experimentally. Through the beating frequency effect between the two semiconductor lasers subjected to asymmetrical mutual injection, a chaotic signal with the standard bandwidth of 33.5 GHz, the spectrum flatness of 8.5 dB and the time delay signature value of 0.059 is generated. The influences of the coupling strength and the frequency detuning on the output characteristics of chaotic laser and synchronization coefficient of the two semiconductor lasers are analyzed. Furthermore, the relationships between the synchronization coefficient and the output characteristics of the two lasers are also discussed, respectively. The results show that in the case of asymmetrical mutual injection, the region of the high synchronization coefficient is larger when the output characteristics of the two lasers are different than those of the two lasers are identical.