The Self-correlation Performance Of Semiconductor Lasers With Optical Feedback And Optical Injection

Chaotic signals that result from chaotic dynamical systems are the families of stochastic signals.They are sensitive to initial conditions and look like "noise" in time domain.Because of the noise-like feature,chaotic signals usually occupy a wide bandwidth in frequency domain.Wideband chaotic signal is an ideal signal in radar system for its noise-like behavior and good self-correlation performance. Semiconductor lasers,introducing external disturbance-the optical feedback, optoelectronic feedback,the external optical injection,can realize chaotic output and can provide microwave chaotic emission signal for the radar.Because chaotic radar's positioning accuracy depends on the self-correlation performance of the chaotic signal, how to further improve the self-correlation performance of the chaotic carrier is the key to improve the performance of chaotic radar.In this paper,based on the rate equations describing the semiconductor lasers (SLs) with optical feedback and optical injection,the influences of the feedback strength,delay time,injected strength and frequency detuning on the self-correlation performance of the output chaotic signal have been investigated.The results show that the full-width at half-maximum(FWHM) and the peak sidelobe level(PSL) of the output self-correlation function is critically dependent on parameters related to injection and feedback.Through reasonably selecting the parameters,the self-correlation function with 0.02ns FWHM can be obtained.And if it is used as the chaotic carrier of chaotic radar,we can achieve mm-level positioning accuracy.This is prior to reported results.