Semiconductor quantum dot lasers: Genesis, prospects, and challenges

Semiconductor nanostructures based on quantum dots present the most attractive solutions for achieving high-performance photonic devices. When one or more spatial dimensions of the nanocrystal approach the de Broglie wavelength, nanoscale-size effects create a spatial quantization of carriers along with various other quantum phenomena. Thanks to their compactness, great thermal stability, and large reflection immunity, quantum dot lasers are the most successful solution for low-energy consumption and optical-isolation-free photonic integrated circuits. When directly grown on silicon, they even show that the four-wave mixing efficiency is much superior compared to the conventional quantum well devices. This remarkable result paves the way for achieving high-efficiency frequency comb generation on integrated platforms. This chapter reviews the historical background of the field as well as the recent findings on and prospects of quantum dot lasers. Finally, it also highlights the importance of using nanotechnologies in industry for shaping the future information and communication society toward sustainability.