Quantum Dot-based Mode-locked Lasers and Applications

This chapter deals with the quantum dot (QD)-based monolithic mode-locked lasers that have recently been the subject of intense investigations owing to the unique properties expected from three-dimensional confinement of carriers. Significant advances are readily achieved, opening the way to a large range of photonic applications. Both the InAs/GaAs and InAs/InP QD material systems are investigated with the demonstration of sub-picosecond pulse generation, multi-GHz repetition rates up to 134 GHz for fundamental mode locking, and more interestingly record timing jitter which is of prime importance for many applications. Specific configurations have also led to improved output powers. On the basis of these achievements, the first applications such as clock recovery at 40 Gbit/s in fiber optic communication systems, and very short pulse emitters for optical interconnects, are already reported. Further improvements are still expected in device characteristics such as temperature stability, output power, control of pulse characteristics, etc., to take full advantage of this new generation of compact, ultra-short pulse sources based on QD material.