This project will focus on new multi-quantum-well lasers in MBE grown gallium antimonide based materials, with wavelengths around 2.33, 2.8, and 3.5 mikrometers, and with line widths and tunability as required for trace gas sensor applications and free sp ace optical communications. The project is headed by Prof. Bjørn-Ove Fimland at Department of Electronics and Telecommunications (DET), NTNU, in cooperation with Prof. Arne Rønnekleiv, also at DET, and Assoc. Prof. Turid Worren at Department of Physics, N TNU. Combined they will cover the main areas for the project; MBE-growth and characterization of laser materials, and laser design, processing and testing. The main collaborating research institutions are The Norwegian Defense Research Establishment, Kjel ler, Norway, and Center for High Technology Materials (CHTM), University of New Mexico, Albuquerque, USA. The project will run for 4 years and bring out 2 PhDs, We further plan to bring out at least 6 articles in refereed journals from the project.