The present status of quantum dot lasers

We review the present status of the rapidly developing field of semiconductor laser diodes based on self-organized quantum dots (QDs). Several milestones have been achieved since the first realization of such a device in 1994: above room-temperature cw operation, the lowest threshold current density of any semiconductor laser diode, high temperature stability, an extended wavelength range on GaAs substrate and high power operation. After a brief introduction we discuss the tremendous advances in epitaxial growth, device performance, and theoretical understanding of QD lasers. Three applications of large commercial interest are discussed in detail: 1300nm QD lasers on GaAs substrate, QD surface emitting lasers, and high power QD lasers. Finally, we give an outlook on future developments. (C) 2000 Elsevier Science B.V. All rights reserved.