Suppression of leakage current in InGaAsP/InP buried heterostructure lasers by InAlAs strained current-blocking layers

InGaAsP/InP buried heterostructure (BH) lasers with InAlAs strained current-blocking layers are proposed. For use as a current-blocking material with a bandgap energy larger than that of InP, InAlAs is superior to InGaP. This is because a wide bandgap can be obtained in the InAlAs without large bandgap shrinkage caused by tensile strain. A two-dimensional simulation shows that the leakage current in BH lasers with thin pnpn blocking layers is suppressed up to 85 degrees C by employing 100 AA In_1-xAl_xAs(x>or=0.54) layers.