Ultrafast gain and refractive index dynamics in AlInAs/AlGaAs quantum dot based semiconductor optical amplifiers operating at 800 nm

The ultrafast gain and refractive index dynamics in AlInAs/AlGaAs quantum dot (QD) based semiconductor optical amplifiers is reported. Measurements in the forward bias regime indicate a complete gain recovery timescale of ∼ 5 ps while the phase dynamics occur over a much longer timescale. At increased pump powers, the impact of nonresonant carriers created by two-photon absorption is visible as an increased injection in both gain and phase dynamics. Reverse-biased measurements reveal a similar behavior to previous measurements on InAs QD devices.