Characteristic Analysis Of FWM Time Lens Imaging System And Its Application In Dispersion Compensation

The time lens imaging system is mainly composed of input dispersion,time lens and output dispersion.By controlling the parameters of these three parts,the system can realize two important functions which are temporal imaging and Fourier transform.As an essential part of the time lens imaging system,the time lens that possesses a simple structure and good modulation characteristics is widely used in optical communication and optical signal processing.This paper is focus on formula derivation.On the one hand,the effects of high-order dispersion,nonlinear effect and pumping pulse on the performance of the FWM time lens imaging system are analyzed and proved.On the other hand,the issue of dispersion compensation which can be solved by a 4f time lens system is studied.The main work of this paper is as follows:1.Establish the model of the time lens imaging system,deduce the condition of temporal imaging and Fourier transform,and verify the amplification and compression of ultra-short pulses,time inversion,Fourier transform and other related processes through Matlab simulation.2.Introduce four implementations of time lens,analyze the process of FWM in detail which is one of the methods above,establish the model of FWM time lens imaging system and derive the corresponding imaging conditions.3.Analyze the effects of high-order dispersion,nonlinear effect and pumping pulse on the performance of the FWM time lens imaging system by theoretical derivation and verify through Matlab simulation.4.Analyze the relationship between input dispersion,output dispersion and phase-shift coefficient of time lens when the 4f time lens system implements the Fourier transform;propose two schemes of dispersion compensation which are centralized compensation and stepwise compensation based on the 4f time lens system and verify the related theory through Matlab simulation;discuss the effects of signal length and signal interval on dispersion compensation using normalized variance which reflects the centralized compensation is better than the stepwise compensation under the same condition.