Numerical analysis on the cooling of a laser diode package with a thermoelectric cooler

An LD (laser diode), an essential unit of an LD package, has higher output power and faster working speed than an LED (light-emitting diode) but it is more expensive. The thermal characteristic of an LD should be estimated as the working performance as it is closely related to its temperature. The thermal expansion causes changes in its shape and position, which lead to a crucial problem regarding light transmission. An LD is located on the submount for insulation and cooling and all of them work in a closed package filled with an inert gas. A TEC (thermoelectric cooler) is used in order to control the temperature of the package, especially the LD. In this study, a heat transfer analysis, which includes conduction between the LD assembly and TEC, the natural convection of the filled gas, was performed for the three-dimensional model of the LD and TEC. The endothermic and exothermic characteristic of the LD and TEC was described and the thermal boundary condition of the TEC and the ambient air was established for the calculation. The analysis considered the change of LD current, TEC current, and the ambient temperature to explain the cooling characteristics of the LD package. © 2001 Scripta Technica, Heat Trans Asian Res, 30(5): 357-370, 2001.