This PhD thesis focuses on the study of mode locked laser diodes based on novel optimized InAs Quantum Dash structures grown on InP substrates. It covers several important modelling aspects, the clean room processing of single and two section shallow ridge waveguide lasers, characterization of the fabricated devices and the evaluation of their performance in different application scenarios. Systematic characterization experiments and subsequent analyses have allowed to gain a much deeper comprehension of the physical mechanisms related to the mode locking regime in these devices, thus far not completely understood. This has allowed to better control most of the main physical phenomena limiting device performance, resulting in first demonstrations of record peak power, sub-picosecond pulse, low radio frequency linewidth and high repetition frequency mode locked lasers grown on InP substrates, opening the way to a vast number of potential applications in the 1.55 µm telecommunication window
