Characteristic Analysis Of Time Lens Imaging System And Its Application In Stream Cipher

With the explosive growth of information,it is urgent to improve the speed of information transmission.The most direct solution is to improve the frequency of the signal.The time lens is put forward in this situation,which is designed to compress the signal in order to obtain a higher one in the beginning.However,with the development of high speed laser,time lens is more used in the detection of high speed optical signal.In this thesis,after the introduction of space-time duality a detailed introduction of time lens imaging principle,imaging and common applications.Then,based on the four-wave mixing time lens imaging system,the factors that affect the resolution of imaging system are studied,the effect of pulse width on the time lens imaging system is obtained and the numerical analysis using Matlab program is given by the theoretical derivation.Finally,according to the time reversal characteristics of time lens and the related theory of 4f system,the feasibility of applying the theory of time reversal to the stream cipher is verified by theoretical derivation and simulation.Main work in this thesis includes the following sections:1.In this thesis,the basic principle of time lens imaging system is derived,and the imaging conditions of time lens are obtained.Four methods of realizing time lens imaging are introduced.2.Several common applications of time lens imaging system are studied.It is found that the time lens imaging system can realize the signal compression,signal amplification,time frequency conversion and time reversal based on the difference of M value.Finally,according to different functions,the process is verified by simulation using Matlab program.3.According to the theory of imaging system,the factors that affect the resolution of imaging system are found.The width of the pump pulse has an important influence on the imaging system.According to the relationship between the chirped pump pulse and the dispersion pulse,the quantitative analysis is given by theoretical derivation and the quantitative analysis is given by theoretical derivation.Finally,the influence of the pump pulse width on the signal pulse width,the group velocity dispersion and the magnification of the optical fiber is verified by the Matlab program.4.According to the similarity between the time lens and stream cipher encryption and decryption,the feasibility of applying time reversal theory of time lens imaging system in stream cipher is studied.Then,the process of encryption and decryption is verified by theoretical derivation and simulation.This theory provides a method for real-time encryption and decryption of high speed optical signals.