Amplified spontaneous emission spectroscopy on semiconductor optical amplifiers subject to active light injection

It is shown that measurements of the effect of optical injection with an external laser on the spectral response of a semiconductor optical amplifier can probe intrinsic properties of a working device. The data demonstrate that under saturated gain conditions the carrier energy distribution within the active layer of a AlGaAs/GaAs amplifier neither shows spectral hole burning nor carrier heating, but only a decreased density.