An Efficient Semi-Vectorial Model for All-Fiber Mode-Locked Femtosecond Lasers Based on Nonlinear Polarization Rotation

A novel closed form equation to model nonlinear polarization evolution based mode-locking in femtosecond fiber lasers is presented. A comparison with the full-vectorial model demonstrates the accuracy of the presented model. The new method takes less than 5% of the time needed by the full-vectorial method for the same computational platform. The comparison with the experimental results shows an excellent agreement with the new model's results.