Research On Chaos System Based On Electro-Optical Coupling Structure

Optical fiber communication has the advantages of long transmission distance,fast transmission rate,low loss and strong anti-interference ability,and has become the main transmission method of communication network.However,with the development of optical fiber communication technology,the security problems in optical fiber communication are gradually exposed.Traditional information security entirely relies on complex encryption algorithms,but with the development of artificial intelligence,quantum computers and other technologies,the security of these algorithms is becoming more and more difficult to guarantee.The chaotic signal generated by the laser chaotic system has the characteristics of unpredictable and noise-like.Using the chaotic carrier as the carrier to hid the information can effectively ensure the security of optical fiber communication.At present,laser chaotic systems are mainly divided into all-optical and electro-optical systems,and electro-optical chaotic systems have received extensive attention because of their high modulation rate and good stability.In the electro-optic chaotic system,the main physical parameters of the system include feedback delay time and system gain.As the key parameter of the system,the feedback delay time is easy to be stolen by analyzing the statistical characteristics of chaotic carriers.And once the time delay parameters are stolen,the eavesdropper can get the system gain through parameter estimation,and further use artificial intelligence and other methods to crack the whole system.Therefore,there are serious security problems in the traditional electro-optic chaotic system.Aiming at the communication security of electro-optical chaotic systems,this paper designs and simulates two innovative electro-optical chaotic systems based on electro-optical coupling structures:(1)Aiming at the exposure of time delay parameters in electro-optical chaotic systems,this paper proposes an electro-optical coupling and mutual injection system based on classical electro-optical intensity chaotic systems.The simulation model of the system is established,and the complexity of the chaotic system,the hidden effect of delay parameters,the size of the key space and the robustness of communication are analyzed by numerical simulation.The numerical simulation results show that the chaotic signal output by the system is similar to Gaussian white noise,with a high degree of randomness;the spectrum is relatively flat,the power distribution is uniform,and the bandwidth is large;the complexity is high,and the waveform is difficult to predict and decipher.And under the physically achievable system gain,the key of the system can be hidden.At the same time,the key space of the system is large;and while the system maintains high sensitivity to key parameters,it is less sensitive to the mismatch of non-key parameters of the system,so it achieves better security and synchronization effects..(2)Aiming at the problems of time delay parameter exposure and small key space in electro-optical chaotic systems,an electro-optical chaotic system based on nonlinear processing feedback structure is proposed in this paper.Firstly,the simulation model of the system is established,and the time domain and frequency domain characteristics of the system output chaotic signal are simulated,and the complexity of the chaotic signal and the performance of key hiding are analyzed.Then,the neural network is used to control the stepwise change of the correlation between the output and the feedback signal,and the relationship between the system key hiding and the signal correlation is analyzed.The simulation results show that:in terms of chaotic optical signal performance:the signal spectrum is wide,and the effective bandwidth can reach 33GHz;the complexity of time and frequency domains is high;in terms of system security:the delay parameter of the system can be hidden under low gain;The introduction of the nonlinear module increases the key space of the system from 10~4 to 10~8;in terms of the synchronization performance of the system:the system ensures high sensitivity to the key parameters,and at the same time,the system feedback gain and other parameters that are easily affected by the environment It is not sensitive,which proves that the system has strong robustness to environmental changes.In terms of key hiding condition analysis:the step-shaped change trend of the correlation between the output signal and the feedback signal is realized through the neural network,and to a certain extent,it is proved that reducing the output feedback correlation is beneficial to the hidden delay parameter of the system.