Cavity Optimization of SESAM-Based PM Fiber Soliton Laser

We present a combined numerical and experimental investigation into the role of saturable absorber positioning in polarization-maintaining (PM) fiber soliton laser based on Semiconductor Saturable Absorber Mirror (SESAM). Simulations reveal a narrow optimal cavity region where precise SESAM placement enables stable single-pulse operation at significantly higher gain levels. This configuration suppresses background continuum buildup and delays the transition to multi-pulse operation. Experiments using an Er-doped PM fiber laser confirm these predictions, demonstrating increased pulse energy, broader spectra, and improved operational robustness when the SESAM is optimally positioned. These findings highlight a physically grounded and practically effective strategy for boosting the performance of soliton fiber lasers and are particularly relevant for advanced short-wavelength infrared (SWIR) systems based on Tm- or Ho-doped fibers.