Study on the chirped quantum dot superluminescent diodes

Quantum-dot (QD)-based optical devices are known to have a possibility to provide improved performances superior to those of MQW-based optical devices. Most efforts on the QD-based optical devices have focused on the broad area laser diodes and ridge waveguide laser diodes. One of the main issues for the QD-based LD is to grow QD uniformly in terms of size to obtain enough gain to lase. On the contrary, it should be noted that non-uniform growth of QDs can be of benefit to superluminescent diodes (SLD) requiring wider spectral bandwidth. Recently, two studies on the QD-based SLD have been reported. Heo et al. have been developed QD-based SLDs utilizing 3-stacked InGaAs QDs which are grown by atomic layer epitaxy (ALE) technique [I]. Zhang et a1 also have developed QD-based SLDs utilizing 5-stacked InAs QDs which are grown by Stranski-Krastanow mode [2]. It is noted that their QD-based SLD have been developed utilizing same kind of multi layers of QD.