High frequency modulation of mid-infrared Quantum Cascade Lasers

I will present 26.5 GHz direct modulation of mid infrared buried heterostructure quantum cascade laser (QCL) emitting at 9 μm using an ultra-fast QWIP as a detector (65 GHz bandwidth). A significant increase of the modulation frequency bandwidth is observed by increasing the laser driving DC current. Finally, I will demonstrate that the laser cavity round trip frequency can be injection-locked by direct modulation of laser driving current, hinting to mode-locked operation