Research On The Chaotic Time Delay Concealment And High-speed True Random Number Generation Of VCSEL System With Fiber Grating Feedback

In recent years,with the rapid development of science and technology,we can embrace the world and live a wonderful life without leaving your home.For example,one can access to what's happening in the world,enjoy remote learning and office work at home,watch live broadcasts,shop and order food and groceries at home,and so on.The communication networks have continuously made breakthroughs in the direction of ultra-high speed,large bandwidth,and ultra-long distance.In addition,there are many ways to obtain information in today's society,and all kinds of information are displayed to us.While the advantages mentioned above have made our work and life rich and convenient,the information security of the country,enterprises,and individuals is also seriously threatened.Information security is the primary problem that must be solved in the information age.Only information security is guaranteed,will the development of the information age become more and more high-quality.Optical chaotic communication has received widespread attention due to its good confidentiality,large capacity and low power consumption.Because it can not only realize the construction of ultra-high-speed,large-bandwidth communication network,but also solve the problem of information security,it has become an emerging secure high-speed optical communication technology.As one of the commonly used light sources in laser chaotic systems,semiconductor lasers are highly valued by scholars.Among them,the vertical cavity surface emitting laser(VCSEL)has some obvious advantages compared with other conventional semiconductor lasers,such as low power consumption,low threshold current,easy integration into a large-area array,single-longitudinal mode output,low cost,and rich polarization characteristics.Thus,VCSELs have attracted lots of attention.This thesis is based on the key pain points in the field of secure optical communication and the frontier research hotspots at home and abroad.The mutually-coupled VCSELs system with the introduction of Fiber Bragg Gratings(FBG)is focused on,and concealment feature of time delay signature(TDS)in the multi-channel chaotic output signals is studied.The sub-peak value in the autocorrelation function(ACF)curve is defined as ? in the thesis,which is used to quantify the TDS concealment effect.In addition,the generated multiple chaotic signals with low TDS is applied to generate high-speed physical random numbers.This system has simple structure and low power consumption,which has potential application in secure optical communication systems,and will help the generation of high-speed physical random numbers.The main work is as follows:1.The characteristics of TDS in mutually-coupled VCSELs subjected to FBG feedback systems(FMC-VCSELs)is numerically studied,and is compared with traditional mutual-coupled VCSEL systems(MC-VCSELs).The influence of the coupling coefficient of FBG,the frequency detuning between the two VCSELs,the bias current,and the injection intensity on the concealment of TDS in the chaotic signals output by the two systems are discussed in detail.The results show that under the same conditions,the FMC-VCSELs system has a better TDS concealment effect than the MC-VCSELs system.2.The characteristics of TDS in the mutually-coupled VCSELs with public FBG feedback(FMCEC-VCSELs)are experimentally studied.First,the curve of ? value of the two VCSELs in the traditional mutually-coupled VCSEL system(MCEC-VCSELs)with two frequency detuned VCSELs is measured,It is found that the TDS cannot be successfully concealed only by changing the frequency detuning between two VCSELs in the MCEC-VCSELs system.Next,the curve of the ? value as a function of the injection intensity in two systems are measured,the results showed that under the same injection power,the effect of TDS concealment of the FMCEC-VCSELs system is significantly better than that of the MCEC-VCSELs system.In addition,the curves of ? value as a function of the frequency detuning between FBG and VCSEL in FMCEC-VCSELs system are further measured.The results show that the TDS can be suppressed best when the main polarization mode of VCSEL locates at the edge of the main lobe of FBG.3.Since both FMC-VCSELs and FMCEC-VCSELs systems can generate low TDS chaotic signals,these two systems are further applied to generate physical random numbers.In the FMC-VCSELs system,a novel post-processing method is proposed.That is,the XOR operation is performed between the digitized delay differences of the two polarization components of the VCSEL,and finally the dual-channel physical random number at a rate of 333.2Gbit/s is generated.In the FMCEC-VCSELs system,a proven dual-channel physical random number is realized at a rate of 800Gbit/s(2×5LSBs×80GHz)through a simple post-processing method of selecting 5 least significant bits.