Data on threshold currents, the differential quantum efficiency, the emission spectrum, current tuning, and radiation power of mesastripe InGaAsSb(Gd)/InAsSbP double heterostructure lasers with lambda = 3.0-3.3 mu m and a cavity length of 70-150 mu m in a temperature range of 50-107 K are reported. In the experiments, the threshold currents I-th < 10 mA, a total output power of 0.5 mW/facet, and a single-mode power of 0.43 mW at 77 K in the cw regime were obtained. Lasers operated in the single-mode regime at currents I less than or equal to 6I(th), the spectral purity was as high as 650 : 1, the tuning rate was 210 cm(-1)/A, and the tuning range was 10 cm(-1) wide. An example of methane detection at 3028.75 cm(-1) is presented. (C) 2000 MAIK "Nauka / Interperiodica".