Weld clip design for minimization of welding-induced-alignment-distortion in butterfly laser module packages

The welding-induced-alignment-distortion (WIAD) or post-weld-shift (PWS) is a serious issue in assembling of fiberoptic components using laser welding, which may significantly affect the packaging yield. Our previous investigations have revealed that an elimination or minimization of the WIAD in butterfly laser module packaging is possible if laser welding sequence and pulse shape of the welding lasers can be optimized. This work represents our further attempt in minimizing the WIAD by design of welding tools: the weld clip. By means of numerical simulations, the influence of seven different types of weld clip on the WIAD in the assembly of the butterfly laser module packages has been investigated. A realistic physics based laser-materials interaction model is employed and the model combines the spatal and temporal characteristics of the laser beam and the thermophysical properties of the material. The results show that the design of weld clip is important in packaging of the butterfly modules and the alignment distortion induced during the laser welding process can be controlled within the minimal range by proper design of weld clip and selection of process parameters such as the welding sequence.