Photoinduced transmittance at 1250 nm of InAs/InGaAs quantum dot based semiconductor optical amplifier measured via waveguiding configuration

New results on investigation of InAs/InGaAs quantum dot structure designed as a waveguide are presented. Photoinduced transmission and absorption recovery measurements using femtosecond pump-probe experiment in a waveguiding configuration, when exciting/probing from the edge of waveguide, were performed at a dedicated wavelength 1250 nm covering the ground state levels of a group of chirped quantum dots. The results of absorption saturation fit well electroluminescence results giving qualitative insight about density of states. From the absorption recovery kinetics picosecond lifetimes for the ground state were considered.