Abstract

Recently, time-stretch dispersive Fourier transform (TS-DFT) technique has been developed to measure the ultrafast transient phenomena in mode-locked lasers, especially for the build-up process of soliton which cannot be monitored with traditional techniques [1]-[6]. These works mainly focus on the starting dynamics of soliton [2] in the mode-locked fiber laser under anomalous dispersion. The spectral build-up process of dissipative soliton (DS) in the net-normal dispersion regime was reported in the recent work [4]. However, the starting dynamics of stretched pulse has not been studied experimentally no matter in temporal or spectral domain. Additionally, the evolution dynamics when the mode-locked fiber lasers are shut down also remains unclear. The starting and shutting processes are extremely important in some applications, such as laser rapid processing which need to turn on and off laser source repeatedly.

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