Generation Of Wideband And High Complex Chaos Synchronization Based On Mutually Coupled VCSELs Subject To Chaotic Optical Injection

Chaotic secure communications is a new secure communication technology in recent years,this kind of communication system use chaotic signal as carrier,and the transmission signal is hidden in the carrier,then in the receiving end use the chaotic synchronization characteristics demodulate the transmission information.It can achieve the physical layer of information encryption,and thus has shown great development potential in the field of information security.Specially,the semiconductor lasers are easy to output chaotic signals due to external disturbances such as optical feedback,photoelectric feedback and optical injection,and become the ideal chaotic light source of chaotic synchronous communication system.Compared with conventional edging-emitting semiconductor lasers(EELs),verticalcavity surface-emitting lasers(VCSELs)possess numerous advantages such as single longitudinal-mode operation,low threshold current,circular output beam with narrow divergence,low cost and easy large-scale integration into two-dimensional arrays etc,and in appropriate condition the output includes two orthogonal linear polarization.Therefore chaotic secure communications based on VCSELs has become one of the hotspots in recent years.At present,the research based on VCSEL chaotic light source is mainly focused on increasing the bandwidth of the chaotic carrier to improve the transmission capacity of the communication system or improving the complexity of the chaotic signal to increase the security of communication and so on.However,it is comparatively less both consider the bandwidth and safety of chaotic light sources in chaotic synchronous communication system based on VCSEL.Therefore,it is of great practical value to seek a communication scheme that can simultaneously increase the effective bandwidth of the system and improve the security of the system.In this paper,a vertical cavity surface emitting laser(I-VCSEL)with light feedback is injected into the other VCSEL(D-VCSEL)to obtain broadband chaotic signals,and then use the broadband chaotic signals to drive two mutually coupled vertical cavity surface emitting lasers(MC-VCSELs)to achieve chaotic synchronization program with dual-channel,wide bandwidth,high complexity.Based on the spin-flip model(SFM),using the effective bandwidth calculation method,the permutation entropy and the cross correlation function investigate the effects of injection power from D-VCSEL and the mutual injection strength between two MC-VCSELs on the bandwidth,complexity and synchronization performance of the system numerically.By appropriately selecting the strength of the D-VCSEL injected into the MC-VCSELs and the injection power between the MC-VCSELs,each polarization component of MC-VCSELs can output wide bandwidth,high complexity chaotic signal with bandwidth of up to 30 GHz and permutation entropy greater than 0.98.After considering the synchronization performance of the system,we have identified an optimization parameter space that can realize wide bandwidth,high complexity and high quality chaos synchronization at the same time.The internal parameter mismatch of the laser has an effect on the synchronization performance of the system.Compared with the light field attenuation rate ?,the linewidth enhancement factor ? and the total carrier decay rate ?,the synchronization performance of the chaotic light injection mutual coupling VCSELs has high tolerance to spin-flip rate ?s and linear anisotropies birefringence ?_p.