Amplification of external radiation in a semiconductor laser in the lasing state

Equations are derived to describe a semiconductor laser with injection of external radiation. The case of small signal amplification is analyzed in detail. It is shown that the transmission spectrum of a laser in the lasing state has side maxima separated from the natural resonance by several gigahertz. The results of an experimental study of this phenomenon are presented. A satisfactory agreement between the theoretical and experimental results is demonstrated.