Self-stabilization of a mode-locked femtosecond fiber laser using a photonic bandgap fiber.

We demonstrate a self-stabilization mechanism of a semiconductor saturable absorber mode-locked linear-cavity Yb-doped fiber laser using an intracavity photonic bandgap fiber. This mechanism relies on the spectral shift of the laser pulses to a spectral range of higher anomalous dispersion and higher loss of the photonic bandgap fiber, as a reaction to the intracavity power buildup. This, in particular, results in a smaller cavity loss for the stably mode-locked laser, as opposed to the Q-switched mode-locking scenario. The laser provides stable 39-49 pJ pulses of around 230 fs duration at 29 MHz repetition rate.