Abstract

In this paper we describe a new design for mid-infrared quantum well (QW) diode lasers which has led to CW operation of 2.0 - 2.4 µm devices at temperatures as high as 100° C. Maximum output power levels of 1.9W and 0.5W and differential quantum efficiencies of 53% and 30% have been achieved at 2.0 and 2.3 µm, respectively. The InGaAsSb/AlGaAsSb devices were grown by MBE on n-GaSb substrates. The first report of lasing at wavelengths exceeding 2 µm was by H. Choi et al.[1] In their structure the multi-quantum well (MQW) active region is located near the AlGaAsSb cladding layers. This structure design significantly reduces carrier leakage from the QWs but. at the expense of increased optical losses since more than 90% of lasing mode propagates in layers with high free carrier concentration. Our recent studies of 2 µm InGaAsSb/AlGaAsSb lasers has revealed that Al_xGa_1-xAs_ySb_1-y waveguide layers with Al compositions as low as 30% can provide efficient carrier confinement in InGaAsSb QWs [2].

© 1998 IEEE