The power consumption of semiconductor diode laser bars has continually increased in recent years while the heat
transfer area for rejecting the associated thermal energy has decreased. As a result, the generated heat fluxes have
become more intense making the thermal management of the laser systems more complicated. A common solution to
this problem is to use the microchannel cooler, a small liquid enhanced heat sink capable of rejecting heat fluxes higher
than those of finned air sinks of comparable size. The objective of this study is to improve and enhance heat transfer
through an existing microchannel cooler using the computational fluid dynamics technique. A commercial software
package is used to simulate fluid flow and heat transfer through the existing microchannel cooler, as well as to improve
its designs. Three alternate microchannel designs are explored, all with hydraulic diameters on the order of 300 microns.
The resulting temperature profiles within the microchannel cooler are analyzed for the three designs, and both the heat
transfer and pressure drop performances are compared. The optimal microchannel cooler is found to have a thermal
resistance of about 0.07°C-cm<sup>2</sup>/W and a pressure drop of less than half of a bar.