Short‐period Ga0.51In0.49P/GaAsyP1−ystrained superlattices were grown, by organometallic vapor phase epitaxy, with periods around 70 A˚ and phosphorus compositions from 0.04 to 0.31. Ground state emission as high as 1.73 eV was observed. Model solid theory predictions fit this data well, particularly at lower P compositions. Type II structures were obtained for phosphorus compositions above 0.04. The introduction of phosphorus in the low bandgap regions of these superlattices was found to significantly improve their structural and optical quality. These superlattices provide, in many applications, a viable alternative to the quaternary alloy GaInAsP, which is required for obtaining these bandgaps in Al‐free systems lattice‐matched to GaAs. To our knowledge this is the first report on the growth and modeling of short‐period superlattices using this material system. ©1995 American Institute of Physics.