Numerical Investigation of Active Rogue Wave Generation Mechanisms and Techniques in Ultrafast Fiber Lasers With Artificial Saturable Absorber

This paper presents a numerical investigation of an all-normal dispersion mode-locked figure-8 fiber laser. A nonlinear loop mirror (NOLM) is employed as an artificial saturable absorber (SA) to achieve mode-locking. The precise control of the properties of light pulses by the NOLM is an essential element, enabling us to achieve mode-locking to generate ultrafast laser pulses. By reducing the bandwidth (BW) of the spectral filter in the laser cavity, we reveal the existence of rogue waves. We obtain stable dissipative solitons for a specific set of cavity parameters and a Gaussian spectral bandwidth filter. Instead of using the NOLM transfer function, we employ a fiber-coupler-based model, allowing us to manipulate various parameters of NOLM and obtain more precise outcomes. Wave heights surpassing four times the significant wave height (SWH) have been observed, providing evidence of rogue events. These findings contribute to understanding rogue wave generation in ultrafast fiber lasers and present new techniques for controlling and manipulating these extreme events.