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 108, the third-order-dispersion should be kept below 4.8×105 fs3, 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 .