Novel Design of Type I High Power Mid-IR Diode Lasers for Spectral Region 3 - 4.2 Microns.

摘要

Novel designs of the mid-infrared GaSb-based diode lasers were studied including those based on triple layer quantum well active regions, metamorphic virtual substrate and cascade pumping scheme. Cascade pumping of type-I quantum well gain section opened the whole new avenue of the mid-infrared diode laser development with the prospect of multifold improvement of the device characteristics. Cascade pumping was achieved utilizing efficient interband tunneling through "leaky" window in band alignment at GaSb/InAs heterointerface. The 100% efficient carrier recycling between stages was confirmed by twofold increase light-current characteristics slope of two-stage 2.4-3.3 m cascade lasers as compared to reference single-stage devices. The cascade pumping scheme reduced threshold current density of high power type-I quantum well GaSb-based ? ~3 micron diode lasers down to ~100 A/sq cm at room temperature. Devices with densely stacked two and three gain stages and 100-micron-wide aperture demonstrated peak power conversion efficiency of 16% and continuous wave output power of 960 mW. Corresponding narrow ridge lasers demonstrated above 100 mW of output power. Devices