The development of reliable joining techniques for ceramics and metals is crucial for energy applications, most especially for the sealing of miniaturized sensors to study multiphase flows. However, during one-step active laser brazing it is a serious problem that a high thermal stress concentration can occur at the joint interfaces or on the ceramic side of the joint due to mismatches between the CTEs (coefficients of thermal expansion) and/or elastic constants. The uncontrolled thermal residual stress can lead to cracks and defects in the brazement. In the present work, an elastic-plastic finite element method/numerical model was formulated to study the thermal residual stresses developed in the brazement between ceramics and austenitic stainless steel during cooling in active laser brazing. Laser interface patterning was employed to reduce the thermal residual stress. Taguchi method with orthogonal arrays was used for the interface optimisation to reduce the thermal residual stress. The magnitude of the simulated stress thresholds in non-patterned specimens was validated by a simplified quantitative estimate. This analysis shows that the thermal stress concentration can be well controlled by laser interface patterning. The cooling process in laser brazing could no longer be critical by using this technology, so that the reliability of the brazing joint can be decisively increased.