Strained-layer 1.5 μm wavelength InGaAs/InP multiple quantum well lasers grown by chemical beam epitaxy

A substantial reduction is reported in the threshold current densities for 1.5 μm wavelength InxGa1−xAs/ InxGa1−xAs1−xPy, strained-layer multiple quantum well (SLMQW) lasers over lattice-matched MQW lasers. Threshold current density was found to depend sensitively on the InAs content x and thickness d of the InxGa1−xAs quantum wells. Threshold current densities as low as 370 A/cm2 and internal quantum efficiency of 90% were obtained for separate confinement heterostructure SL-MQW lasers having four quantum wells and with x = 0.65 and d = 5 nm. Such a threshold current density is among the lowest values obtained thus far for 1.5 μm wavelength InGaAs/lnGaAsP MQW lasers. The present lasers were grown by chemical beam epitaxy.