【作者】 李桂兰；

【导师】 江宁；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2018， 硕士

【摘要】 半导体激光器(SL)支持在物理层上对信息加密解密操作,在一定条件下容易实现高维混沌输出,广泛应用于混沌保密光通信、高速随机数、混沌密钥分发等领域。随着研究的不断深入,人们发现混沌激光光源会暴露安全性缺陷,如采用时延分析技术可获取SL的外腔长结构信息,这会增加攻击方利用时延信息试图重组激光混沌系统的可能性,因此SL的应用也会受到制约。对SL进行加密操作或者引入非线性因素可以有效确保激光器系统输出混沌的安全性。本论文基于外腔反馈半导体激光器,在反馈外腔引入相位调制器,对相位调制器中加载数字随机信号或者模拟信号,这不仅可以作为相位加密方案实现加密操作,并且在反馈部分引入非线性因素来优化混沌输出。基于随机相位调制反馈激光器提出分别采用相位调制双反馈的结构以及级联相位调制的结构,重点研究相位调制参数对时延标签(TDS)及相位调制速率隐藏效果。结果表明随机相位调制双反馈激光器在高速的相位调制速率下能成功隐藏TDS,但是在频谱上无法消除相位调制速率的信息;而级联随机相位调制激光器控制高速相位调制速率为15Gbit/s~28Gbit/s,低速相位调制速率低于8Gbit/s时,不仅能成功隐藏TDS,并且在频谱上能消除低速相位调制速率的信息。基于正弦信号相位调制反馈激光器,重点研究相位调制速率对混沌带宽增强的效果,带宽增强最高可达30.9GHz。研究这三种结构相位调制激光器的通信系统的通信性能,并分析非法攻击方式:注入-锁定法、直接线性滤波(DLF)法,密钥丢失、延时信息缺失以及相位调制器参数失配对系统安全性的影响。在适当的信息传输速率下,不仅能保证信息的合法解调性能,并且能成功抵御几种非法攻击,从而保证系统的安全性。相位共轭反馈(PCF)激光器的反馈镜采用相位共轭镜(PCM),为激光器引入了非线性因素,相比于常规光反馈(COF)激光器的混沌输出复杂度更高,而有关PCF激光器同步研究屈指可数。本论文基于PCF激光器,提出了闭环结构的同步条件:分别在接收端的反馈项或者注入项引入合适的相移,零频率失谐时分别为1.13π、0.44π(1.44π)。两种闭环结构同步方式的同步性能相差不大,并且比COF激光器更容易实现同步。由于PCF激光器比COF激光器混沌输出的有效带宽高约20%,PCF激光器两种同步结构的通信系统的通信性能比COF激光器通信系统的通信性能更优。更多还原

【Abstract】 Semiconductor laser(SL)supports the encryption and decryption of information on physical layer,it is easy to realize high dimensional chaotic output under certain conditions,and it’s widely used in chaotic secure optical communication,high speed random number,chaotic key distribution and other fields.With the deepening of the research,it is found that the chaotic laser light source will expose the security defects,such as using the delay analysis technologies to obtain the SL external structure information,which will increase the possibility of the attackers using the delay information to try to reconstruct the laser chaos system,which will restrict the application of SL.The encryption of SL or the introduction of nonlinear factors can effectively ensure the security of the output chaos of the laser system.Based on the external cavity feedback semiconductor laser,the phase modulator is introduced into the feedback external cavity,and the digital random signal or analog signal is loaded in the phase modulator,which can not only be used as the phase encryption scheme to encrypt the operation,but also introduce the non-linear factor to optimize the chaotic output of the feedback.Based on the random phase modulation feedback laser,the structure of phase dual-feedback and the cascaded phase modulation structure are proposed,and the effect of phase modulation parameters on time delay signature(TDS)and phase modulation rate is studied emphatically.The results show that the random phase modulated dual-feedback laser can successfully conceal TDS at high speed phase modulation rate,but it cannot eliminate the phase modulation rate in the spectrum.When controlling high speed phase modulation rate of 15Gbit/s~28Gbit/s and low speed phase modulation rate lower than 8Gbit/s,the cascaded random phase modulated lasers not only can successfully conceal the TDS,but also can eliminate the information of low speed phase modulation rate on spectrum.Based on sinusoidal signal phase modulated feedback lasers,the effect of phase modulation rate on the enhancement of chaotic bandwidth is studied,and the maximum bandwidth is up to 30.9GHz.This paper studies the communication performance of the three structured phase modulated lasers,and analyzes the illegal attack methods: injection-locking method,direct linear filtering(DLF)method,key losses,delay information losses and the phase modulator parameter mismatch,to analysis of system security.At the appropriate rate of information transmission,it can not only guarantee the legal demodulation performance of the information,but also successfully resist several illegal attacks,so as to ensure the security of the system.The feedback mirror of phase conjugate feedback(PCF)laser adopts phase conjugate mirror(PCM),which introduces nonlinear factors to laser,which is more complex than conventional optical feedback(COF)lasers,and the synchronization of PCF lasers is very few.Based on PCF lasers,the synchronization conditions of closed-loop structures are presented: at the receiving end,appropriate phase shift are introduced into the feedback items or injected items,corresponding to 1.13π,0.44π(1.44π)respectively when the frequency detuning is zero.The synchronization performance of the two closed-loop structures has little difference,and it is easier to realize synchronization than COF lasers.Because PCF lasers have about 20% larger effective bandwidth than COF laser chaotic output,the communication performance of the two synchronous structures of PCF lasers is better than that of COF lasers communication system.更多还原