In this study, the capacitance displacement system (CDS) is employed to measure the post-weld-shift (PWS) induced by laser welding in butterfly type laser module package. The advantage of CDS is able to simultaneously and immediately measure the direction and the magnitude of PWS. Furthermore, with the aid of notch clip, the PWS can efficiently and quantitatively be compensated by laser hammering technique to regain the coupling power. Reduction of the PWS is an important issue in developing low-cost and high-performance laser modules. The package yield of laser modules can be imp roved due to the real-time measurement and quantitative compensation. In comparison with the high-magnification camera with image capturing system (HMCICS) having 0.7£gm resolution, the capacitance sensor achieves 25.4nm and 0.1£gm in its resolution and accuracy, respectively. Besides, during the package procedure, the real-time displacement detection can be used to adjust the package parameters. As a result, the PWS is reduced that contributes to less coupling power loss. After welding, the result reveals that the PWS was measured as X=0.15£gm and Y=-4.58£gm, while the coupling power is 43.19%.

The post-weld-shift (PWS) introduced in the butterfly laser packaging is investigated in this study. The elastic-plastic-thermal coupled finite element model is employed in the stress and deformation analyses. The temperature dependent material properties are used to calculate the residual stresses and the post-weld shift distributions during the packaging process. The finite element package ¡¥MARC¡¦ is used in this study. And the commercial optical software, i.e. ¡¥Zemax¡¦ is also employed in laser power coupling efficiency simulation. The variations of laser welding sequence, Nd-YAG pulse laser power, and initial ferrule¡¦s alignment position on PWS for butterfly laser packaging are studied and discussed in this work. The results indicated adjust the sequence and pulse laser power properly can improve the PWS in butterfly packing significantly. Besides, the PWS correction technique, i.e. the ¡¥Laser Harmering¡¦, is also illustrated in this study. The simulate results showed that proper arrange the welding processes may improve the coupling efficiency over 75¢M.