This project will focus on characterize cryogenic microcoolers for optimum thermal performance and thermo-mechanical reliability when employed for high power LDs. High power laser diodes (LDs) are found in a wide range of industrial sectors including traditional tele- and data-com applications as well as heavy industries such as cutting, brazing, welding, etc. It is anticipated that their usage will continue to grow at a high rate as (1) material growth and laser epitaxial design are continuously improved and (2) higher efficiencies become possible by adopting advanced thermal management schemes. Successful completion of the proposed research will enable the industry to implement laser diodes whose power is much higher than the previously conceived maximum.