A Study of Forces and Motion Generated During Pulsed Laser Welding of Optical Packages

Abstract

This paper presents an analysis of forces and motions generated during interaction of pulsed laser energy with materials. The effects of this interaction on the subsequent dynamics of the material receiving this energy have important implications in the manufacture of laser diode packages. Small motions which occur during laser welding of the package assembly can cause serious losses in the amount of coupled power, thus degrading the performance of the package. This work is aimed at understanding how these movements occur. Various quantities such as force, acceleration and coupled power variations were measured during a laser welding operation. These measurements establish that significant thermal stress waves are generated during the welding process. However, the final relative motion between cylindrical specimens which are butt-welded by a laser beam occurs due to rapid cooling and shrinkage of the weld pool at the interface of the two specimens.