A Research Of Secure Optical Communication System Based On Optical Fractional Fourier Transform

Optical communication technology has become an extremely important part of modern communications technology with its high bandwidth,low loss,high speed etc.The Internet age has brought tremendous changes to our lives.At the same time,our daily life is threatened by spam messages,loss of account password,the disclosure of private information.A new encryption method is need for optical communication system to protect personal data and build a harmonious society urgently.Optical fractional Fourier transform is a time-frequency transformation of the order p.it can hide the information both in the time domain and frequency domain,which means it can be used for secure optical Communication technology.In this paper,the two equivalent models of the time lens are derived from the Maxwell equations and space-time duality theory.The feasibility analysis of optical fractional Fourier transform which is realized by time lens is done.On this basis,the mathematical model of optical fractional Fourier transform is established,and the key controllable parameters are determined.When p=1,the time-frequency transformation characteristic is proved by MATLAB,and the spectral characteristic is found.Moreover,with basic transformation module is built,the influence of order p is studied and the range of order p is defined.The requirements of controllable parameters are obtained by comparing with each other by using VPI software.Three schemes are proposed: a simple control scheme,a delay-based control scheme,and a clock-based control scheme to solve the problem of synchronous control.Based on the joint simulation of VPI and MATLAB,10 Gbps system corresponding to three schemes is built respectively.Through the analysis of the results,the three schemes all meet the basic requirements of communication.By comparing the confidentiality performance and advantages of the three schemes,the best method is clarified.Finally,a 4 × 10 Gbps optical communication system based on the clock control scheme is established,each channel satisfies the basic requirements of communication.