Optical properties of two-dimensional transmission-type spatial light modulators using InAs/GaAs short-period strained-layer superlattices (SPSLSs) in quantum wells, which operate near 960 nm, are investigated. The absorption characteristics of the individual pixels across a ∼200 pixellated wafer, i.e. the uniformity of the devices, are analyzed. The limits to performance of this spatial light modulator due to nonuniformity are also discussed.