Real‐Time Investigation of Ultrafast Dynamics through Time‐Stretched Dispersive Fourier Transform in Mode‐Locked Fiber Lasers

Abstract Real‐time investigation in mode‐locked fiber lasers (MLFLs) is important to understand the ultrafast dynamics before, during, and after the formation of stable laser pulses. However, the experimental measurement of these dynamics is restricted by the resolution of conventional oscilloscopes. The development of a time‐stretched dispersive Fourier transform (TS‐DFT) technique provides the shot‐to‐shot measurement of mapping the spectral information of an ultrashort optical pulse into time‐stretched waveform in the MLFL. Here, the recent progress and development of various fascinating dynamics in the MLFL, including the study of birth, evolution, and extinction process in MLFL, different types of MLFL, and complex motion dynamics in MLFL, have been reviewed. The issues and challenges encountered in this research area are discussed and several recommendations are suggested to overcome these problems. The integration of the TS‐DFT technique is expected to provide deeper insight into the real‐time investigation of various dynamics in the MLFL by displaying fascinating phenomenon and revealing unexplored trajectories.