Ultrafast response of tunnel injected quantum dot based semiconductor optical amplifiers in the 1300 nm range

The ultrafast gain and refractive index dynamics of tunnel injected quantum dot based semiconductor optical amplifiers in the 1300 nm range are investigated using a heterodyne pump probe technique. In the gain regime, ground state wavelengths exhibit full gain recovery in less than 10 ps up to 3 times transparency, attributed to enhanced carrier refilling via the injector layer. The effect of the injector can also been seen in unusual phase dynamics at excited state wavelengths at this injection level.