Autosetting Mode-Locked Laser Using an Evolutionary Algorithm and Time-Stretch Spectral Characterization

There is an increased research effort on the development of smart ultrafast laser systems with the intended goal of converting the high parameter sensitivity of the complex laser dynamics from a practical challenge to an opportunity. Evolutionary algorithms have the potential to find suitable mode-locking parameters and optimize the laser output according to the user specifications. In this article, we present the auto setting of optimized self-starting ultrafast pulse regimes at the optical telecom wavelength. We implement an evolutionary algorithm on a normal-dispersion fiber laser cavity mode-locked through a 4-parameter nonlinear polarization evolution. By using a consistent scheme of intracavity liquid-crystal retarders for polarization control, and the time-stretch dispersive Fourier-transform technique for real-time spectral output analysis, we show that we can achieve an efficient and fast optimization of the mode-locked state, with the ability to tune its spectral width.