Research On Information Encryption And Coherent Reception Based On Wideband Chaotic Signals

Nowadays,the world is gradually moving towards an information age.Developed communication technology and the internet link everything together.In the future,the world will be a main body of the organic combination of the network society,network economy,and network information.However,with enjoying the convenience,personal information may sometimes be exposed.Thus,communication security has become one of the most important focuses in all walks of life.With the continuous deepening of research on semiconductor lasers,the size,power consumption,and reliability of lasers have been greatly improved.Semiconductor lasers exhibit rich dynamic characteristics when subjected to external disturbances.Optical chaos is often used as a carrier to encrypt messages due to its performance of noise-like,wideband,and complexity.In this case,optical chaos communication systems based on semiconductor lasers have become a good solution to improve communication security.However,in traditional optical feedback chaos communication schemes,optical chaotic signals often have significant time delay characteristics(TDS),which is a great threat to the security of information.In addition,the rate of optical chaos communication is often limited within the effective bandwidth of chaotic carriers,so many schemes are unable to meet the communication capacity requirements of currently deployed high-speed optical fiber communication systems.This article focuses on the important applications and international cutting-edge hotspots of chaos outputs of semiconductor lasers in the field of secure communication,focusing on the above issues.By systematically analyzing the time delay,bandwidth,and synchronization characteristics of optical chaos systems,and comprehensively exploring the influence of relevant parameters,the aim is to optimize the chaos carrier and improve the above application performance,which has important theoretical significance and practical value.The main research content and innovation points are as follows:1.A dual channel chaotic optical communication scheme based on intensity modulation optical injection semiconductor laser system was proposed,and the bandwidth and synchronization characteristics of chaotic signals in the intensity modulation optical injection system were analyzed,revealing the impact of fiber transmission on communication.In this scheme,the influence of injection and modulation parameters on the chaotic region was systematically studied,and the generation of dual parallel wideband chaotic signals was achieved,which were used as carriers to encrypt two quadrature amplitude modulation(QAM)signals.The secure transmission of 16-QAM and 64-QAM signals with symbol rates of 20 GBaud in 120 km and 20 km single-mode fiber(SMF)was successfully achieved.Finally,the study of parameter mismatch also proves that this scheme has satisfactory robustness characteristics.2.A coherent optical chaos communication based on semiconductor lasers subject to intensity modulation optical injection was established,revealing the principle of wideband optical chaotic signal generation through theoretical and experimental methods.The transmission performance of coherent communication systems has been explored through experiments.A wideband signal generation scheme based on intensity modulation optical injection was numerically studied,and the results showed that under appropriate modulation parameters and cascade injection parameters,the system can generate two wideband chaos synchronization signals.The autocorrelation characteristics of chaotic signals in the system were analyzed,proving that there is no obvious TDS in the signal.Using the obtained wideband synchronous chaotic signal,a quadrature phase shift keying(QPSK)signal was encrypted and decrypted,ultimately achieving coherent optical communication with a transmission distance of 80 km and a symbol rate of 12.5 GBaud.In addition,the evaluation of the recovery information error rate under different masking coefficients,received optical power,and modulation depth further indicates that this experimental scheme has excellent characteristics of high sensitivity,high security,and high tolerance for device differences.