Improvement of internal quantum efficiency in 1.55 μm laser diodes with InGaP electron stopper layer

This paper investigates the effect of the conduction band offset energy at the interface between the separate confinement layer (SCL) and the p-cladding on the temperature behavior of InGaAsP lasers emitting at 1.5 mu m. The performance of a laser structure incorporating an additional In0.81Ga0.19P barrier at that interface is compared to that of a regular laser structure. The results are analyzed using a comprehensive simulation software. It is shown that the current leakage at the SCL-p-cladding interface is not the dominant current loss mechanism at room temperature. However, at a higher temperature an additional InGaP electron stopper layer can efficiently reduce the electron leakage current. Finally our measurements show that above a critical temperature the absorption loss increases dramatically.