Period-one oscillations in optically injected semiconductor lasers

The characteristics of period-one oscillations in semiconductor lasers subject to optical injection is experimentally and quantitatively investigated. The changes in the frequency separation and in the magnitude difference between the principal oscillation and the sideband of the injected laser are studied as a function of experimentally accessible parameters, the detuning frequency and the injection strength of the injection signal. The frequency separation decreases as the injection strength and the detuning frequency decrease. The magnitude of the principal oscillation decreases with the decreasing injection strength and the increasing detuning frequency, while that of the sideband grows at the same time. At some operating conditions, these characteristics leads to a situation that the magnitude of the sideband becomes larger than that of the original principal oscillation, resulting in a frequency shift of the principal oscillation from the injection frequency to the sideband.