Optimal Condition for Suppressing Gain Dispersion Effects in Dissipative Soliton Generation

Gain dispersion impedes the generation of ultrashort dissipative solitons, especially in mode-locked lasers, by limiting the transform-limited pulse width and causing instability near zero dispersion. We have found a hyper-surface in the parameter space of a mode-locked laser for the best suppression of the gain dispersion effects. This is achieved by analyzing the proximity of a dissipative soliton to the stationary solution of the complex cubic-quintic Ginzburg–Landau equation in the absence of gain dispersion with the method of moments. Theoretical and experimental investigations show that the combinations of system parameters in a specific region near the hyper-surface allow for a dissipative soliton width that is very close to the minimum value, as well as a large stable mode-locking region at anomalous group delay dispersion. These findings provide new insights into ultrashort dissipative soliton generation and help to optimize mode-locked lasers with dispersion, nonlinearity, loss, and gain all taken into account simultaneously.