Disclosed is a structure for an active region of a GaAs based VCSEL with strong optical output substantially within the range of 1.3 .mu.m and potentially for the 1.5 um range, making it well suited for the transmissivity of silica core fiberoptics. The active region of the VCSEL incorporates antimony in the quantum wells and portions of the barriers. The presence of Sb substantially smooths the surface of the barriers and quantum wells during the process of beam epitaxy, causing a higher critical thickness of each of the layers, thereby enabling fabrication with significantly reduced defects.