Explanation of low-frequency relative intensity noise in semiconductor lasers

Abstract

For the first time, the enhanced low-frequency relative intensity noise characteristics of semiconductor lasers is explained. It is shown, by multimode rate equation analysis, that the enhanced low-frequency noise is caused by coupling between longitudinal modes which can renormalize the resonance frequency of the individual modes to very low values. It is further shown that a single-mode laser will also exhibit enhanced low-frequency noise unless the side-mode suppression is high.