Effects of self phase modulation of chirped pulses on compressed pulses

The pre-pulse duration and contrast are very important in the ultra-high power CPA laser system. The effects of the self phase modulation (SPM) were simulated on the peak intensity, pre-pulse duration and contrast of the compressed pulse, when the chirped pulse duration was 141 ps, the chirp coefficient was 1 000 and the B-integral value was 0, 1 or 2. The results show that when the B-integral value is 2, the SPM causes the peak intensity of the compressed pulse to decrease to 65%, and the pulse duration and pre-pulse duration to increase to 200 % and 300% respectively. When the B-integral ranges from 0.5 to 2, an approximate linear formulation can be used to describe the relationship between the pre-pulse duration and the B-integral value.