Stability of welding techniques used in single-mode laser packages

Critical alignments of single-mode laser packages have been secured using laser welds and resistance welds. Two methods were used to ascertain submicron motions of the welded joints, which are caused primarily by stress relaxation: linear motion was measured by a Fraunhofer diffraction technique, and angular motion was measured by interferometry. Statistically significant groups of test joints were subjected to thermal stresses. Empirically derived design information is applied to ensure submicron mechanical stability of the device throughout its intended lifetime.<>