The purpose of this project is to advance the technology of interband cascade (IC) lasers and their facet coatings and to design, build, and deliver to NASA a tunable, narrow linewidth mid-infrared laser source operating in the 3.2 ¡V 3.6 micron wavelength band. Initial work will develop improved IC laser active regions as well as ultra-low-reflectivity anti-reflection facet coatings. We will also develop an effective epi-side-down die attach process for IC lasers using a Au/Sn solder. The objective of this initial work is to achieve laser chips emitting in the appropriate wavelength region and operating in continuous wave mode at heat sink temperatures > 25aC and with several 10s of mW of output power. The team will then use our extensive experience with external cavity laser sources to design, build, and deliver a versatile, tunable mid-infrared source to NASA using the developed IC laser gain chip. The delivered tunable laser source will be at a TRL level of 5 and will enable sensitive earth science trace gas measurements and enhance NASA¡¦s existing measurement capability by significantly improving the sensitivity and performance of trace gas sensing by virtue of a considerably improved source technology.