Interband Cascade Lasers are now available as a  broad gain lasers suitable for use in an external cavity.

Interband Cascade Lasers are available as a  broad gain lasers suitable for use in an external cavity. You can find here a recent Optics Express article available in open access describing the performance of the external cavity system, or come to Photonics West 2022 to see a talk by the main author in the Novel In-Plane Semiconductor Lasers XXI session.

BG-3.2-3.6 Spectrum
BG-3.2-3.6 Spectrum

ICL chip BG-3.2-3.6 tuning range in External cavity