Short-Wavelength (760–920 nm) AlGaInAs Quantum Dot Lasers

Abstract

By adjusting the Al and In concentration of AlGaInAs quantum dots (QDs), their morphologic and spectral properties (i.e., size, height, density, and emission wavelength) can be engineered partly independently. In this paper, we report that this tunability can be used to improve QD laser properties and to realize QD lasers at wavelengths not achievable with the commonly used (Ga) InAs QDs. We show that using tailored AlGaInAs QDs grown on GaAs substrate, the device properties of QD lasers can be improved with respect to material gain, accessible wavelength range, and temperature stability of the wavelength. In particular, we report that the material gain in QD lasers can be notably increased (by a factor of 2.1). Furthermore, we demonstrate QD lasers with application key wavelengths in the range between 760 and 920 nm. The presented short-wavelength ( ~ 760 nm) QD lasers exhibit characteristics comparable to state-of-the-art quantum well (QW) lasers (light output > 20 mW, sidemode suppression ratios ~ 40 dB, Itr = 43 mA). We also demonstrate that AlGaInAs QDs can be used to fabricate QD lasers with extremely high temperature stabilities of the wavelength (0.072 nm/K).