The optical transitions of uncapped and capped InAs/InP self-assembled quantum dot structures in the energy range of the bulk InAs E1 transition are studied using modulation spectroscopy and Raman scattering. Islands and wetting layer exhibit one and two features, respectively. The deformation potential theory and the single band effective mass approximation account for the island-related feature successfully in a wide island-height range (3–7 nm). These models also explain the existence of the highest energy wetting layer related feature, but not of the lowest energy one.