Performance Enhancement via XPM Suppression in a Linear all-PM Mode-locked Fiber Oscillator

We demonstrate strong performance enhancement of an all polarization-maintaining fiber oscillator mode-locked using a linear self-stabilized fiber interferometer via suppression of cross-phase modulation (XPM). Numerical simulations reveal that XPM significantly affects the saturable absorber dynamics resulting in strong distortions of the mode-locked steady-states and output pulse quality. For experimental verification, we construct an oscillator with XPM suppression, employing an intra-cavity YVO4 crystal to obtain a differential walk-off effect, and compare its characteristics with a reference oscillator in standard configuration. It is shown, that XPM suppression not only lowers the mode-locking threshold by more than 45%, but further results in improved pulse quality at the output ports and reduced nonlinear loss in the artificial saturable absorber.