Picosecond optical pulse response of mid-infrared intersubband semiconductor optical amplifiers

A mid-IR semiconductor optical amplifier (SOA) exhibits four salient features including, for example, a near zero linewidth enhancement factor; a short (picosecond) carrier relaxation time, a strong ultrafast nonlinear refraction (UNR) and strong gain dispersion. Gain dispersion is significant for mid-IR SOAs because they have small material gain bandwidths of magnitude several meV which is comparable to the bandwidths of picosecond optical pulses. In this case, all spectral components of the short optical pulses may not be amplified by the same amount.