GaN-based technology for MQW modulating retro-reflectors operating in the visible and ultraviolet spectral ranges

Calculations based on the k·p perturbation approach have been used to study the properties of GaN-based electroabsorption modulators. The results indicate that optical transitions are dominated by the effect of piezoelectrically-induced electric fields. The measured extinction ratio of non-optimized devices is higher than 3 and 2.5 for modulators operating around 475 nm and 400 nm, respectively. In addition to applied voltage, carrier-induced screening seems an efficient method to drive the modulation.