Environmentally-stable wave-breaking-free mode-locked Yb-doped all-fiber laser

We report on experimental generation of wave-breaking-free pulses from an environmentally stable Yb-doped all-fiber laser. The compact linear cavity is constructed with saturable absorber mirror directly glued to the fibers end-facet as nonlinear mode-locking mechanism and chirped fiber Bragg grating (CFBG) for dispersion management, thus, without any free-space optics. Further, the laser was intrinsically environmentally stable, as only polarization maintaining (PM) fibers were used. In the wave-breaking-free regime, the fiber laser directly generates positively-chirped picosecond pulses at a repetition rate of 20.30 MHz. These pulses can be compressed to 218 fs in a HC-PBG providing a femtosecond all-fiber laser system. Adapting the intra cavity dispersion we have also generated chirped pulses with a parabolic spectral profile in the stretched pulse regime. We confirm numerically the wave-breaking-free pulse and stretched pulse evolution and discuss advantages and dis advantages of both regimes in terms of pulse quality.