Dissipative Solitons in Centimeter-Scale Fiber Lasers

Optical resonant cavities of the mode-locked fiber lasers have been intuitively assumed to be on the order of several or tens of meters because the nonlinear phase accumulation produced by long optical fibers is essential for pulse-shaping. However, for optical cavities smaller than 10 cm, ultrafast lasers can yield pulse trains with fundamental repetition rates reaching several gigahertz, affecting the pulse-shaping mechanism. For instance, Yb
³⁺
-doped fiber lasers with cavities <10 cm operate in the gain-guided soliton regime, which is unstable in the long-term operation and exhibits picosecond-duration pulses. Here, dissipative solitons (DSs) in centimeter-scale fiber lasers are demonstrated, and a general method for constructing DSs in small-length fiber lasers is presented. The long-term stability (assessed in terms of optical spectra) improved, owing to the dissipative system-mediated pulse stabilization with respect to perturbations. The intensity profile atop the spectrum was considerably flat, and measured maximal spectral width was 9.6 nm for a DS all-fiber laser with a 3.0 cm resonant cavity. In the temporal domain, the directly extracted pulse duration was 266 fs. In addition, the evolution of spectral broadening was consistent with the DS solution of a normal-dispersion dissipative system using a generalized nonlinear Schrödinger equation and rate equation.