We report some improvements made in molecular beam epitaxial growth of AlxGa1-xAs/GaAs high-radiance LED's for optical communications. These improvements have been achieved by growing these wafers in a system which includes an air-lock wafer-exchange chamber. Interfacial recombination velocity as low as cm/s was obtained. The series resistance of the Burrus-type LED's was reduced by increasing the acceptor concentrations in the p-layers to a density as high as 1019cm-3using Be as the dopant. CW output of 5.8 mW, or a radiance of 92 W/sr. cm2, at a safe operating current of 150 mA has been obtained in these devices. The device performance is comparable to the best obtained in LPE-grown diodes of the same geometry.