ABSTRACT. To be determined.

ABSTRACT. We report on the development of fully phase-stabilized THz QCL optical frequency combs (FC) showing record dynamic range. By implementing an on-chip GTI, tightly coupled with the FC QCL cavity, we achieve wide dispersion compensation regions, where stable and narrow single intermode beatnotes extend over an operation range broader than that of the bare FC QCL. Independent and simultaneous control of the carrier offset frequency and repetition rate is demonstrated.

ABSTRACT. A model based on Maxwell-Bloch equations was developed in order to study phase locking dynamics of a free running mid-infrared QCL frequency comb. A thorough study of the impact of the dispersion and optical nonlinearities on the cavity mode dynamics was conducted. Recent experimental findings were reproduced for the first time, giving important insight into the governing mechanisms.

ABSTRACT. Quantum cascade laser frequency combs have substantial potential in sensing. We show that by blending them with microelectromechanical comb drives, one can directly manipulate the dynamics of the laser and fully control the comb state.

ABSTRACT. We demonstrate fundamental and harmonic frequency combs in monolithic ring quantum cascade lasers. We show by experiments and simulations that embedding defects in the waveguide is the key to control comb formation in these cavities.

ABSTRACT. In this paper, we present the recent progress in InAs-based QCLs epitaxially integrated on Si. We will also try to identify the origins of the obviously different behavior of the integrated QCLs made of different materials.

ABSTRACT. We experimentally demonstrate lasing and mode coupling of mid-infrared quantum cascade lasers monolithically integrated with passive InGaAs waveguides for integrated-photonics applications. A waveguide-coupled device produced up to nearly 300 mW peak power with Jth=3.5 kA/cm2 at room-temperature.

ABSTRACT. We present the first interband cascade lasers (ICLs) fabricated into ring-shaped cavities emitting in continuous wave (cw) operation. A second order distributed feedback (DFB) grating is used for single mode emission and light outcoupling through the GaSb substrate. The implementation of an epitaxial-side down mounting scheme facilitates improved heat transport from the active region.

ABSTRACT. A ~15-20 % gap is found between predicted and measured internal-efficiency values of state-of-the-art, high-power mid-IR QCLs. We show that this discrepancy is lifted by taking into account IFR-scattering-induced carrier leakage from the upper laser level and key injector states.

ABSTRACT. We present a large-area (1.5 mm × 1.5 mm) photonic crystal quantum cascade laser, with 1 W surface-emitting peak power at room temperature (289 K), and narrow beam shape.

ABSTRACT. Previous high power results utilizing geometrical power scaling for high continuous wave (CW) output are expanded upon by operating devices with high duty cycle pulses. This quasi-CW operation allows for a cooling cycle that gives an enhancement factor to average power. Max average powers are mapped based on duty cycle for multiple devices and interpreted via a time resolved projection model. Beam quality in this quasi-CW regime is examined.