Laser Hammering Technique in Butterfly Laser Diode Module

The laser hammering technique on the coupling efficiency improvement in a lensed fiber butterfly laser diode module is studied in this work. The post weld shift (PWS) introduced from laser hammering technique is used to compensate the fiber alignment shift after laser welding in the packaging process. A wedge shaped lensed fiber was used in the coupling efficiency analysis of a 980 nm wavelength laser pumping signal. The 3D thermal-elastic-plastic finite element model was proposed to simulate the laser welding and solidification process by employing the MARC finite element package. The temperature dependent material properties were used in the FEM analysis. The commercial optical software, i.e. Zemax, was also employed in laser power coupling efficiency simulation. The effects of laser pulse sequence and power distribution on coupling efficiency improvement were discussed. The results showed that the proper laser hammering sequence combined with the proper pulse power distribution can improve the coupling efficiency significantly. The results also indicate that the proposed finite element model can simulate the fiber alignment shift induced by PWS in laser welding qualitatively and develop a design guideline for manufacturing laser module packages.