Abstract

The use of bilayer InAs/GaAs quantum dot (QD) material as the active region of a semiconductor laser diode allows wavelengths in excess of 1500 mn to be accessed [1]. QDs localise carriers in three dimensions, leading to very different gain properties compared with quantum well and bulk material. Predicted improvements in the performance of QD laser devices include lower threshold current densities and reduced temperature sensitivity compared with conventional telecommunications InP-based quantum well (QW) long-wavelength lasers. Om devices consist of a three QD bilayer active region embedded in an otherwise conventional ridge waveguide structure semiconductor laser diode. This requires extremely good control of the growth parameters and is achieved using low InAs growth rates. The upper (emitting) dot layer exhibits a small inhomogeneous linewidth (usually <25 meV) allowing us to easily distinguish emission from ground and excited state transitions.

© 2007 IEEE