We present experimental comparison of Type-I diode lasers emitting <3 μm wavelength in room temperature with increased strain in quantum wells (QWs). Due to diminishing hole confinement in the barrier, the performance of mid- IR Type-I diode laser is generally poor. Here we improve the hole confinement using quinary alloy in the barrier in conjunction with highly strained QWs. By using molecular beam epitaxial growth method, we achieve up to 2.3% strain in the QWs. At near room temperature, highly strained laser structure shows approximately 4 times improved laser performance than regular strained laser under the same testing condition. The study demonstrates significant improvement in laser efficiency using highly strained QWs in the GaSb-based type-I mid-infrared laser diodes.
In this paper, we briefly review optically pumped type-II "W" quantum-well semiconductor lasers that emit in the midinfrared
wavelengths. In addition, we demonstrate on-chip unstable resonator cavity devices that exhibit excellent lateral
We report on optically pumped mid-IR semiconductor lasers that are based on type-II wells. A systematic study of the effect of increasing the In-content in the InxGa1-xSb hole-well suggests that improved hole confinement results in improved power conversion efficiency at elevated temperatures that is also accompanied by a reduction in threshold power and a reduction in T0, the characteristics for threshold.
Stimulated emission in InAs/InGaSb/InAs/AlSb type-II quantum- well (QW) lasers was observed up to room temperature at 4.5 micrometer, optically pumped by a pulsed 2-micrometer Tm:YAG laser. The absorbed threshold peak pump intensity was only 1.1 kW/cm2 at 300 K, with a characteristic temperature T0 of 61.6 K for temperatures up to 300 K. We have also studied another type-II QW laser using 0.808-micrometer pumping sources with a much longer pulse length of 50 microseconds. The devices demonstrated a maximum output power of 1.6 W per facet at 83 K, with a corresponding differential external quantum efficiency of 24.8%.
We have developed and tested an integrated fiber-optic coupled diode laser array module for use as a reliable pumping source for solid-state lasers, and rugged enough to withstand the nine `gs' acceleration of a military airborne laser experiment. This compact laser module has produced 12 watts of peak power in cw and pulsed operation modes. The output beam comes from a flexible, yet hardened, fiber-optic bundle. The laser has a footprint smaller than a 3' X 5' card. It has a built-in thermo-electric cooler to provide wavelength control, and integrated cooling channels that assure continuous use. The fiber-optic output has proven itself in beam pointing and positioning applications, including end-pumping of solid-state lasers and as an airborne beacon. In the later application this compact laser was bright enough to allow continuous aircraft tracking from 200 kilometers with a beam divergence up to 10 degrees.