Passively mode locked all-fiber ytterbium oscillator with integrated hollowcore photonic bandgap fiber

The authors report a self-starting passively mode-locked fiber laser containing a HCF spliced into the cavity to provide anomalous GVD. The laser operates in the stretched-pulse regime, close to the zero cavity dispersion. To the best of our knowledge this is the first implementation of integrated HCF based intra-cavity dispersion control.