The dynamical response of a quantum dot photonic integrated circuit formed with a combination of passive and active gain cells is investigated. When these cells are appropriately biased and positioned within the multi-section laser cavity, fundamental frequency and harmonic mode-locking at repetition rates from 7.2 GHz to 115 GHz are found. Carefully engineered multi-section configurations that include a passive waveguide section significantly lower the pulse width up to 34% as well as increase the peak pulsed power by 49% in comparison to conventional two-section configurations that are formed on the identical device under the same average power. In addition an ultra broad operation range with pulse widths below ten picoseconds is obtained with a 3rd-harmonic mode-locking configuration. The fundamental design principles for using QDs in mode-locked lasers are presented to explain the observed results and to describe why QDs are particularly well-suited for reconfigurable laser devices.