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This paper presents a new experimental result about the influence of internally circulating modes(ICM) on the external quantum efficiency of InGaAs/GaAs/AlGaAs based single quantum well laser diodes with the wavelength of 980nm. The influence of ICM on laser performance is much stronger in the case of quantum well structures than in the case of the bulk active layer structures since the super thin active layer(thickness~6nm) allows substantially less absorption in the light travelling path in resonator. This latent ICM in optical resonator obviously deteriorates the external quantum efficiency of the laser emission from front and rear mirror facets.

InGaAlP/InGaP visible laser diodes emitting in the 600 nm range are considered to be promising optical sources for use in optical information systems such as high density optical disks, laser beam printers, and bar-code readers.1 One of the important problems to be solved for practical use is high threshold current of this system. Among many methods, high doping in the clad layer and compressive strain in the active layer2 are considered the most effective ones to reduce a threshold current. This study demonstrates that a very low threshold current can be obtained for simple one step epitaxial structure by applying these two effects.