Method to reduce the smile of high-power diode laser bar by balancing the thermal-induced stress

The smile effect of the laser bar increases the difficulty of laser beam coupling and limits its application. In this paper, the smile effect in the high-power laser on the microchannel cooler (MCC) and the method of reducing the smile effect by balancing the thermal-induced stress are studied. The model of diode laser packaging with MCC is established based on the finite-element method (FEM). The effect of the thickness of the N-foil on the smile effect and stress is analyzed. The bar is bent into a convex shape after the bar is bonded to the heat sink, according to the simulation. With the increase of the thickness of the N-foil, the bar deformation gradually decreases, and then the middle part of the bar reversely increases. The thermal-induced stress on the bar is balanced by optimizing the thickness of the N-foil. The minimum deformation was less than 0.2 μm.