The Research And Application On Time Lens Imaging System Based On Fourier Transform

According to the correspondence of temporal and spatial,time lens can analogize the mature theory and application of the spatial lens completely,and it also has a simple and powerful feature as an optical element like the spatial lens.So the related technology research about time lens has a very important significance.At the same time,time lens system as a new type of optical signal processing system puts glorious in the field of optical fiber communication gradually.This paper is based on the derivation of the basic theory formula,on the one hand,it quantitatively analyzed the fiber parameters of the three modules of the time lens system,because the input and output fiber needs to provide effective dispersion transmission and time lens needs to provide effective secondary phase modulation.On the other hand,this paper summarizes the application of Fourier transform in time lens system from two aspects,firstly,make the frequency domain processing of the signal equivalent to the time domain using the Fourier transform of time lens;secondly,construct 4f time lens system to achieve the application of reducing White Gaussian noise using the nature that time jitter,dispersion and other linear factors in optical fiber transmission do not affect the envelope of signal spectrum.The main work of this paper includes the following parts:1.Deducing the space-time correspondence by solving the wave equation of the light and the response equation of the signal.2.Setting the transmission function of time lens,elaborating the time lens principle and deducing the establishment condition of the imaging system and the Fourier transform through the analog of the transmission function of space lens.3.Analyzing the advantages and disadvantages of two types of time lens,elaborating the basic principle of four wave mixing and the realization principle of four wave mixing,and deducing the corresponding imaging conditions,and then analyzing the parameters of three modules in four wave mixing time lens system quantitatively.4.Establishing the 2f-MZI time lens system by using the Mach-Zehnder interferometer,and deducing the phase shift coefficient of the Fourier transform and the phase shift coefficient of the interferometer.And analyzing the correspondence between the time and frequency of the Fourier transform of time lens system,and then building the 4f-MZI system according to the duality of Fourier transform,and proposing the Gaussian white noise reduction based on 4f-MZI time lens system.