基于激光混沌的全光物理随机数发生器

发布时间：2018-02-25 08:36

本文关键词： 随机数混沌保密通信全光信号处理　出处：《太原理工大学》2014年博士论文　论文类型：学位论文

【摘要】：随机数在蒙特卡洛(Monte Carlo)模拟、统计抽样、人工神经网络等科学计算方面有着广泛应用。尤其,在保密通信领域,产生安全、可靠的随机数(常称作“密钥”)关系着国防安全、金融稳定、商业机密、个人隐私等众多方面。随机数的产生方法分为两大类：伪随机数发生器和物理随机数发生器。伪随机数发生器基于一定的算法和种子,可以方便地产生速率达数十Gbps的随机数序列,具有成本低廉、易实现等优势,但它固有的周期性令其在安全通信中应用时存在重大隐患。物理随机数发生器则是以物理界随机现象作为熵源产生无法预测、非周期的真随机数,可保证科学计算的准确性及保密通信的安全性。然而,常规的物理随机数发生器受限于传统熵源(如热噪声、振荡器抖动等)的带宽,速率仅处于Mbps量级,无法满足现代高速保密通信的绝对安全需要。直到近年来,宽带光子熵源(如混沌激光、ASE噪声等)的出现极大推进了物理随机数发生器的高速发展。其中,混沌激光因其高带宽、大幅度等特性,获得了人们的极大关注,被广泛应用于高速物理随机数的产生。然而,现有方案均属于光电系统,是将快速变化的光信号转换为电信号,在电域中完成对随机信号的采样、量化及后续处理以产生高速随机数。据我们所知,截至目前已见报道的物理随机数发生器可达到的最高实时速率是4.5Gbps。若要进一步提高速率,则需选用超高速的电ADC、异或门等器件,势必面临“电子瓶颈”的限制,提升空间有限。尽管一些报道指出基于宽带光子熵源可产生码率达Gbps、甚至Tbps的随机数序列,但必须注意到,这些码率是将取样时钟的频率与多位ADC的位数相乘而得到的理论预期,并非实时在线输出。本论文致力于发展新型全光物理随机数产生方法,将宽带激光混沌源与全光信号处理技术相结合,在光域中完成随机数提取,可有效克服现有光电技术遭遇的“电子瓶颈”。而且全光方法产生的随机码可与现行光通信网络直接兼容——无需任何光-电或电-光转换。此外,随着下一代全光网络的发展和成熟,该技术将具有更大的潜在应用价值。本论文围绕“基于激光混沌的全光物理随机数发生器”这一研究课题,完成了如下工作： 1.介绍了随机数的应用及其重要性,归纳了随机数的产生办法及质量评价标准。尤其,针对基于激光混沌的物理随机数发生器进行了综合评述,详细探讨了当前国内外的研究现状,指出了发展全光随机数产生技术的意义。 2.提出了三种基于连续型激光混沌熵源的全光随机数产生方案,并数值论证了各方案的可行性。方案一利用光反馈扰动半导体激光器产生的宽带混沌信号为熵源,采用高非线性光纤中的四波混频效应对熵源信号采样,以高非线性光纤环形振荡器为全光比较器(仅有比较功能),结合“两路异或”技术,获得了5Gbps随机码。方案二采用光反馈和光注入联合扰动半导体激光器产生的带宽增强型混沌信号为熵源,以基于高非线性光纤的Sagnac干涉仪为采样器,利用四分之波长相移的DFB激光器为全光比较器(仅有比较功能),结合“延迟异或”技术,实现了10Gbps随机码的产生。方案三仍以带宽增强型混沌信号为熵源,但采用马赫增德尔电光调制器作为采样器,以四分之波长相移的DFB激光器为全光触发器(兼具比较和保持两项功能),结合“移位异或”技术,完成了Gbps随机码的产生。以上方案所产生的随机码均能成功通过随机数行业测试标准。 3.提出并数值证实了两种基于离散型激光混沌信号的全光随机数产生方法。这种类型的全光随机数发生器无需外部触发时钟、采样及后续逻辑处理过程,直接将熵源信号量化为随机数,大大降低了系统复杂度。具体地,我们详细分析和讨论了两类离散型激光混沌信号的产生方法及随机特性。它们分别是利用被动锁模光纤激光器产生的脉冲幅度混沌信号和利用光注入方式扰动双区半导体激光器获得的混沌自脉动信号。继而,分别利用两者作为物理熵源,结合全光触发技术,数值实现了可通过随机数行业测试标准的高速物理随机数。 4.对本论文工作进行了总结,并结合当前高速物理随机数的研究热点,指出了未来可能的研究方向。
[Abstract]:The random numbers are widely used in the fields of Monte Carlo simulation , statistical sampling , artificial neural network and so on . Especially in the field of classified communication , a secure and reliable random number ( often referred to as " key " ) is related to many aspects such as national defense security , financial stability , commercial secrets and personal privacy . The generation method of random number is divided into two categories : pseudo - random number generator and physical random number generator . The pseudo - random number generator is based on certain algorithm and seed . It can produce random number sequence of tens of Gbps conveniently . It has the advantages of low cost , easy realization and so on . However , the physical random number generator is limited by physical boundary random phenomenon as an entropy source . It can guarantee the accuracy of scientific calculation and the security of secret communication . However , the conventional physical random number generator is limited by the bandwidth of traditional entropy source ( such as thermal noise , oscillator jitter , etc . ) , and the rate is only on the order of Mbps , which can not meet the absolute security requirement of modern high - speed secure communication . In recent years , the emergence of broadband photon entropy source ( such as chaotic laser , ASE noise , etc . ) has greatly promoted the high - speed development of physical random number generator . In addition , with the development and maturity of the next generation of all - optical networks , the technology will have greater potential application value . This thesis focuses on the research project of " Laser chaos - based all - optical physical random number generator " , and completes the following work : 1 . The application of random number and its importance are introduced . The method of generating random number and quality evaluation standard are summarized . In particular , the present research situation at home and abroad is discussed in detail , and the significance of developing all - optical random number generation technology is pointed out . In this paper , we propose three schemes for generating all - optical random numbers based on continuous laser chaotic entropy sources , and demonstrate the feasibility of the schemes . The scheme 1 uses the broadband chaotic signal generated by the optical feedback disturbance semiconductor laser as the entropy source , and uses the four - wave mixing effect in the high nonlinear optical fiber as an entropy source , and combines the " two - way XOR " technology to obtain the 5Gbps random code . 3 . The method of generating all - optical random numbers based on discrete laser chaotic signals is presented and numerically confirmed . This kind of all - optical random number generator does not need external trigger clock , sampling and follow - up logic processing , directly reduces the entropy source signal to random number , greatly reduces system complexity . In addition , we analyze and discuss the generation method and random characteristics of two kinds of discrete laser chaotic signals . 4 . The work of this thesis is summarized , and the future research direction is pointed out combining with the research hot spot of the current high - speed physical random number .

【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：O415.5;TN918

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