Abstract: A monolithic mode-locked diode laser with improved uniformity of light distribution along the cavity. The laser includes a multiple gain section with more than one gain subsection where the length of each subsection is less than the reciprocal gain coefficient in the gain subsection and a multiple saturable absorber section with more than one saturable absorber subsection where the length of each subsection is less than the reciprocal absorption coefficient in the saturable absorber subsection. The gain subsections alternate with the saturable absorber subsections and are optically coupled in a single waveguide. They are also allocated inside the monolithic cavity such that the total length of the gain subsections and the saturable absorber subsections is equal or close to the total cavity length. The cavity length preferably corresponds to a sufficiently low fundamental repetition frequency. Special measures are preferably provided to ensure mode-locking at the fundamental frequency.