We report the solid source molecular beam epitaxial growth of InAs/InP quantum dot (QD) superlattices and the effect of As/P exchange on the interface between InAs and InP. The InAs QDs were found to have an average lateral diameter of similar to 40nm and a density of 3-4 x 10(9)cm(-2). The QDs superlattice has photoluminescence (PL) emission centred at 0.77eV with a linewidth of 64meV at low temperature (4K). X-ray diffraction (XRD) spectra showed evidence of significant As/P exchange on the interface between InAs and InP during in situ annealing under Pt pressure before growing the spacer layer of InP. An average P composition of similar to 30% in the resulting InAsP QDs in samples: annealed for 50s was deduced from dynamical simulations of the experimental XRD spectra. The QDs superlattice PL emission exhibits a blueshift following an increase in annealing time, and emission at 1.55 mum and at 300K was achieved. This observation holds promise for possible telecommunication device applications at long wavelengths.