Résumé
Interband cascade lasers are semiconductor lasers emitting in the mid-infrared domain but relying on interband transitions, contrary to their intersubband counterparts, quantum cascade lasers. Our experimental study of the relative intensity noise in a multi-mode interband cascade laser at 4.1 μm shows that the room-temperature structure exhibits a relaxation frequency in the GHz range. We demonstrate that, far above the threshold current, the relaxation frequency increases with the bias current, and our simulations are in good agreement with our experimental efforts. Fitting of the relative intensity noise resonances gives access to several intrinsic parameters of the interband cascade laser under study such as differential gain, compression gain, and K-factor. This study is a clear step for understanding dynamics interplays in interband cascade laser structures, which means understanding the non-linear and modulation bandwidth limitations of such lasers.