Direct Generation of Chaotic Microwave Pulse Based on Optoelectronic Oscillator

A novel approach for chaotic microwave pulse (CMP) direct generation based on optoelectronic oscillator (OEO) is proposed and demonstrated. In the present method, an external square wave pulse sequence is injected into the OEO cavity to periodically modulate the feedback gain which results in the CMP direct generation. Compared with the externally modulated CMP generation technique, the present scheme has a simpler and more compact structure. Numerical simulations and experimental results show that the OEO will output CMP if the loop feedback gain is high enough, while the duration and period of the CMP can be flexibly regulated by the external square wave pulse sequence. Due to the presence of bandpass filters in the OEO loop, the generated CMP has a chaotic envelope and contains high-frequency carrier information inside. Furthermore, the precise dynamics of the pulse build-up and cut-off processes are observed by time-frequency analysis, which has consistent results in numerical simulations and experiments. Correlation analysis and phase space reconstruction also eventually confirm the chaotic characteristics of the experimentally obtained envelope of the CMP. The proposed scenario can find applications in high-speed pulsed chaotic radar and chaotic wireless communication systems.