Résumé
Interband cascade lasers (ICLs) are semiconductor lasers emitting in the mid-wave infrared (MWIR 3–6 μm) and can operate as frequency combs (FCs). These demonstrations are based on double section cavities that can reduce dispersion and/or are adapted for radio frequency operation. Here, we show that ICL FCs at long wavelengths, where the refractive index dispersion reduces, can be realized in a single long section cavity. We show FC generation for ICLs operating at λ ∼ 4.2 μm, demonstrating narrow electrical beatnotes over a large current range. We also reconstruct the ultrafast temporal response through a modified shifted wave interference Fourier transform spectroscopy setup with two fast MWIR detectors, which shows a frequency modulated response in free running operation. Further, we show that, through active mode-locking, the ICL can be forced to generate short pulses on the order of 3 ps. This temporal response is in agreement with Maxwell–Bloch simulations, highlighting that these devices possess long dynamics (∼100 ps) and potentially makes them appropriate for the generation of large peak powers in the MWIR.