Signal to noise ratio of ultrashort high-power pulse
Based on the nonlinear Schrdinger equation,a simulation was carried out to solve the problem of the signal-to-noise ratio being low.The research dealt with the influence of higher-order dispersion,spectral modulation and self-phase-modulation on the signal to noise ratio.Furthermore,a physical model was built to analyze the impact of the flatness of gratings.The results show that for a 100 fs input Gaussian pulse,in order to make the signal-to-noise ratio bigger than 10~8,the third-orderdispersion should be kept below 4.8×10~5 fs~3,the B-integral below 0.2, the amplitude of the modulation of spectrum below 10~(-4) and the flatness of gratings smaller than λ/100.