A number of double heterostructure and quantum well lasers with wavelengths approximately 3.1, 3.2, 3.4, 3.85 - 4.1, and 4.5 micrometers have been realized in InAsSb/GaSb and HgCdTe/CdZnTe material systems. Peak powers at the few W level and average power at the few hundred mW-level were obtained from optically pumped broad-area lasers at >= 80 K. Threshold, efficiency, internal loss, and gain saturation studies are reported. A compact laser package was built, using a high-power diode array for pumping and a Stirling pump for cooling. Its performance with a 4-micrometers laser is described.