| With the rapid development of the information society,5G and high-speed optical communication networks are rapidly popularized.While high-speed and large-capacity communication networks bring convenience to human life,network information security issues are becoming more and more important.Network security is a national strategy,and information encryption is one of the core technologies of network security.At present,it is difficult to guarantee the security of encryption methods based on mathematical algorithms.Although quantum key distribution has an absolute security guarantee from the physical layer,the compatibility of the key distribution rate and the transmission key of the existing scheme limits the use of quantum key distribution.Chaos laser synchronization can realize classical physical layer key distribution.Chaos key distribution has huge potential advantages in terms of distribution speed and security,and is compatible with current optical fiber communication.It is a promising high-speed key distribution technology.The current chaos key distribution scheme is mainly based on closed-loop synchronization and external random modulation.The synchronization recovery time of tens of nanoseconds brought by the system restricts the key distribution rate.Therefore,it is of great significance to propose a high-speed and secure chaos key scheme.This thesis focuses on the construction of a chaos key distribution system for a distributed Bragg reflector laser driven by noise light,and the following two main tasks are carried out:(1)In experiments and numerical simulations,the dynamic characteristics of chaos generated by the distributed Bragg reflector laser driven by noise light were observed,and the influence of injection strength and frequency detuning on the chaos were further analyzed.The results show that the distributed Bragg reflector laser has a larger frequency detuning range that produces chaos than ordinary semiconductor lasers.And when the frequency detuning is greater than 25 GHz,the generated chaotic signal energy is concentrated in the low frequency part,and the frequency spectrum is flat.At the same time,it is found that when noise light is injected into the main mode,high-dimensional chaos with a correlation dimension of 6 can be generated and the correlation dimension of the chaos fluctuates greatly;when the noise light is in the side mode,the correlation dimension of the chaos is about 2 and the fluctuation is small.(2)The theoretical model of the chaos key distribution system of the noise optically driven distributed Bragg reflector laser was built on the numerical simulation,and the influence of the noise optical main mode injection and side mode injection on the synchronization coefficients,and the modulation parameters on the synchronization recovery time and on/off modulation contrast.The key distribution rate of the system is analyzed.The results show that when noise light is injected into the side mode,both users can obtain a higher synchronization coefficient,and the correlation coefficient between drive and response is lower.Distributed Bragg reflector lasers have a shorter synchronization recovery time(?5.5ns)than chaotic lasers with external feedback.In the end,a key distribution with a bit error rate of 3.8×10-3 and a rate of 285.6 Mbit/s was realized on a 192-kilometer optical fiber link with dispersion compensation. |
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