We report on the design and elaboration of continuous wave (cw) distributed feedback quantum cascade lasers (QCLs) using a simple metal grating approach without epitaxial regrowth, neither for the grating nor for the thermal extraction. Room temperature cw single monomode QCLs with 30 dB side mode suppression ratio are demonstrated down to 4.5 μm with 20 mW output power and threshold of 1.5 kA cm−2. The beam quality factor (M2) does not exceed 1.22 for both axes. These results are discussed and the key issue of thermal management of the device is emphasized.

We have fabricated InP-based coherent quantum cascade laser micro-stripe arrays. Phase-locking is provided by evanescent coupling between adjacent stripes. Stripes are buried into semi-insulating iron doped InP. Lasing at room temperature is obtained at 8.4μm for stripe arrays comprising up to 16 emitters. Pure supermode emission is demonstrated via farfield measurements and simulations. The farfield pattern shows a dual-lobe emission, corroborating the predicted phase-locked antisymmetric supermode emission

We report on the design and experimental demonstration of a specific metal grating profile that enables a substrate emission of a quantum cascade laser. A low loss, index coupled, and horizontal cavity surface emitting laser (HCSEL) design is proposed, which is very robust against technological spreads. The detailed analysis of the metallic top grating is performed, enabling the laser still to operate as a distributed feedback laser while emitting from the substrate. Following this concept, HCSEL with InP cladding layers and InGaAs/AlInAs active regions have been fabricated. Room temperature HCSEL emitting at 5.65 μm with a low beam divergence is demonstrated.

We present a scheme for the realization of high performances, large tuning range, fully integrated and possibly low cost mid infrared laser source based on quantum cascade lasers and silicon based integrated optics. It is composed of a laser array and a laser combiner. We show that our metal grating approach gives many advantages for the fabrication yield of those laser arrays. We show the results of such a fabrication at 1350 cm-1 with 60 cm-1 tuning range. The silicon is a low cost option for the size consuming combiner. In the development of the SiGe platform, we present the loss measurement set up and we show losses below 1dB/cm at 4.5µm.The need for broadly tunable sources for Mid-Infrared spectroscopy has been identified for years. In order to detect a complex molecules or a set of simple molecules, one needs a source with a small line width and tunable over a few tens of wave numbers. External cavity sources are already available but with limited performances and cost reduction potential. Distributed Feedback (DFB) Quantum Cascade Lasers (QCL) is one of the favored sources for the Laser Spectroscopy ]. We propose here a monolithic tuneable source which is very appealing because of the compactness, the robustness and the usability. A single DFB QCL has a limited tuning range, the two main leverages being the temperature via external temperature control (slow tuning) and via the current (Fig. 1 right).