Ultrafast lasers with multi-GHz repetition rates can have applications in areas such as biophotonics, optical frequency metrology, optical sampling, optical communications and as astro-combs. Ultrafast waveguide lasers with monolithically integrated saturable absorber elements are very promising candidates for multi-GHz operation, benefiting from a low-threshold mode-locked operation and high efficiency due to the small guided-mode size and consequent strong saturation of both gain medium and saturable absorber. One of the most attractive features of such devices is their compactness and compatibility with integrated optics technology.