We present an overview of our theoretical and experimental work on a novel type of semiconductor lasers – quantum well (QW) lasers with asymmetric barrier layers (ABLs). Our experimental work supports our theoretical derivations — ABL QW lasers demonstrate superior operating characteristics as compared to conventional QW lasers. In particular, the threshold current is lower and more temperature-stable, the light-current characteristic is more linear, and the wall-plug efficiency is higher in ABL lasers.